Jacques Mattheij

Technology, Coding and Business

CNC Lasers (cutters, engravers)

CNC Lasers for cutting and engraving

Laser cutters can injure or blind you permanently if you do not follow safety procedures! This post is an attempt to collect all of the information that I’ve gathered over the last year or so regarding budget laser cutters. There are no affiliate links on this page, I have no ties to any of the companies mentioned here other than that I’m a reasonably satisfied customer of some of them. If you have corrections or suggestions for expanding this article or if you want to contribute information for the materials section please contact me via jacques@modularcompany.com . The intention is to make this a ‘living’ document and to expand it and update it over time.

LASER CUTTER / ENGRAVER SAFETY

DO NOT STARE INTO LASER WITH REMAINING EYE

Sounds funny, doesn't it? Well, it isn't. Before you read the rest of this document I would love it if you read through this safety section in its entirety. If I could I'd add an exam that you have to pass before you can read the remainder but that would be annoying. So I will trust you to do exactly that: read this text as if your eyesight and general health depend on it because they do.

Lasers are dangerous. They are both dangerous because of the concentrated light that they emit and they are dangerous because of the fumes given off during the operation of the machine. This is why you can use them to cut and mark materials with in the first place. They can start fires and they will do so exactly when you're not monitoring the machine. There is no such thing as a safe laser that can cut or engrave material in any useful capacity. Do not let yourself be taken in by manufacturer marketing materials that show open frame lasers or enclosed lasers that do not vent to the outside.

Laser safety is a major subject in its own right and using one responsibly is more work than throwing caution to the wind. But your eyes, your family, your pets and your insurance company, and ultimately yourself are going to be much happier if you take these warnings into account. If you don't understand something in the safety section play it safe: don't do it. If you think something in this safety section is wrong, needs improvement or better wording by all means, contact me: jacques@modularcompany.com and I'll work with you until both you and I think it is the best possible because this is the most important part of this document. I'm most grateful to everybody that contributed safety related advice from the HN comments on this article, specfically and in no particular order: 0xEF, 542458, msds, avar, cstross, sen, cyberax, nullc, rocqua, mittrhowaway, jfim, elihu, kragen, FuriouslyAdrift, iancmceachern, xyzzy123 and CarRamrod.

  • NEVER use an open frame laser ‘as is’ a laser needs an enclosure
    • even if the manufacturer shows a video or a photograph depicting the machine in a dwelling
  • Lasers should not be used in living spaces
  • Children and pets should be kept away from an operating laser
  • Lasers should never be operated unattended
  • enclosures should be ventilated
    • the exhaust system should be capable of removing a multiple of the volume of the enclosure every minute as well as the total volume of air injected by the air assist if your machine has this feature, you want ample capacity here.
    • the exhaust system should be leak free and vent (filtered!) into the environment away from any occupied structure
    • any windows in the enclosure should filter out the wavelength of the laser you are using (but better to use a camera!)
    • enclosures should be ventilated even if the manufacturer claims otherwise.
  • enclosures should have an interlock
    • as soon as the enclosure is opened that should count as an e-stop, the machine should be disabled completely
  • enclosures should have an e-stop switch on the outside that cuts all power to the system
  • if possible an optical fence can create a perimeter around the machine that can’t be entered when it is running
  • enclosures should be fire proof
  • the bottom of the enclosure should be able to withstand a sustained direct hit from the laser head at its lowest possible position at maximum power while not in motion.
  • there should be a fire extinguisher of sufficient capacity near the enclosure
  • there should be a fire detection system.
  • some materials should never be cut or engraved
    • do not cut or engrave PVC under any circumstance, using PVC will create hydrogen chloride1 which is super dangerous
    • do not cut or engrave Polycarbonate unless you can work under an inert atmosphere such as nitrogen
    • do not attempt to cut or engrave leather, the smell is awful and it can be very dangerous
    • if you do decide to cut or engrave leather make sure it hasn’t been tanned with Chrome
  • depending on the wavelength the laser light itself may be more or less dangerous, the safe power limit depends on the wavelength
    • Damage from laser light may not be readily apparent at first because your brain is very good at working around such damage.
    • You wil need to get the best quality safety glasses for the wavelength of your machine that you can afford, and you need to procure them from a reliable source. Do not skimp on this, even if your last name is Scrooge. Green is almost certainly the wrong color for your glasses, orange/brown is what you are looking for and glasses that absorb the beam will be damaged (smoke, burning) by a direct hit. Think of it this way: if the glass doesn’t aborb the beam effectively that means the light gets passed on to your eye!
    • you will always need to wear these when near the laser is powered up.
    • that still does not obviate the need for an enclosure
    • the best way to observe a laser cutter is indirectly, through a camera, get a camera!
    • It’s not just direct hits of the beam emerging from the laser aperture that are dangerous, a reflection can do serious damage at these power levels
    • Visible light lasers, which includes most cheap diode lasers, anything between 380 and 750 nm can give a false sense of safety.
    • You can see the beam.
      • But if you can see it it may be too late already, anything over 1 mW is dangerous
      • This makes the light hard to block
      • They may ‘leak’ at other frequencies as well making the light even harder to block.
    • Fiber lasers using IR at 1064 nm are probably the most dangerous in the sense that your eye will focus the light just fine but there is no blink or avert reflex2
    • On deep infrared (CO2) machines the beam will be invisible
    • your eye(s) will be damaged before you are even aware of it
    • but the wavelength itself is a bit safer, damage will not be immediately catastrophic
    • if your machine has a ‘pilot laser’ you’ll have an idea of where the invisible (and much more powerful) IR beam is
    • So any laser of sufficient power to cut or engrave materials should be enclosed and shut off automatically if the enclosure is opened.


If any of the above items make you reconsider using a laser cutter/engraver that is perfectly fine, you may be better off joining a local makerspace where they have a machine set up with all of the safety requirements covered (hopefully!). It’s a valid alternative to having one set up in your own workspace.

Introduction

CNC gear has been getting cheaper and cheaper over time, since the 1980’s when I first3 encountered it. But laser cutters for the longest time refused to join the trend, they were very expensive, fragile, large, heavy and consumed a ton of power. That all changed to the point that today you can buy functional CNC laser cutters and engravers for less than $1000. Obviously these aren’t going to punch through thick steel like their industrial cousins do, but for cutting wood and various other materials as well as to engrave text or images on suitable backgrounds they perform remarkably well.

This article attempts to give a lot of background material to help you get started if you already have one of these or if you are considering buying one. If you haven’t bought a machine yet I’d recommend you read the article in its entirety before pulling the trigger on a particular machine. This is especially important in light of the pretty high pressure sales tactics that some of the manufacturers of this gear employ, keep in mind that you are buying a tool that in industry would require you to go through a required safety course and which would not operate without a large amount of safety measures including interlocks, optical fences and other tricks of the trade to keep the operators safe. Educating yourself a bit before bringing this kind of kit into your home is going to save you from possible injury, a ton of hassle and reading is free.

Laser cutters are of the class ‘subtractive manufacturing’, which means in technical terms that they shape the work piece by removing those bits that you do not want. In this sense they are much like other cutting devices such as rotating knife cutters, tool-and-die cutters, water jet cutters and plasma cutters. The main differences are that compared to rotating knife cutters they cut deeper, compared to tool-and-die cutters that there are no setup costs, compared to water jet cutters that they are relatively cheap and tend to char the edges of the piece to be cut slightly if it is combustible and that compared to plasma cutters you can also cut material that is non-conductive. This makes lasers the cutting tool of choice for a wide variety of materials, and it is precisely this versatility that makes them an excellent tool for hobbyists and the ‘maker’ crowd. And just like those other tools they are also excellent in producing large amounts of scrap, this isn’t a 3D printer where 97% of your input material becomes your work product, it’s not rare to have 20 to 30% scrap which you will need to dispose of.

History

Laser cutters have been around since 1965, coincidentally the year that I was born. But even in the mid-80’s to find a laser cutter in the wild was a rare occasion, especially because they were horrendously expensive. The reason for that expense is that a laser cutter is on two extremes of the technology curve at once: on the one hand it is a machine that carves up various materials and does so by using energy densities that you normally do not encounter on earth, on the other hand it uses absolutely incredibly precise optics for doing so. And on those first lasers the optics were impressive indeed: water cooled glass jacketed quartz tubes that output the laser beam across free space to a mirror mounted on a carriage for the X-axis, then to another mirror mounted on the Y-axis and finally down a focusing lens onto the material.

Much later these found some competition from so called fiber lasers, a variation that uses a solid state laser and a fiber amplification stage to create very small spot sizes for a much more efficient process able to cut more and sometimes thicker materials for a given power budget.

The semiconductor industry, which gave us diode lasers without any optics other than small mirrors mounted in the head to collate the beams and a focusing lens are the main driver behind the orders of magnitude in cost reduction, and these as well as smaller and lighter versions of the industrial machines mentioned above are the ones that you are most likely to encounter as a hobbyist or small business that wants to get into CNC laser work.

What you can buy

There are a ton of different companies offering laser gear, typically made in Asia, with or without an enclosure and of varying quality and power. At the time of this writing a typical diode based laser can be had for well under a thousand dollars. From a practical point of view these are functional tools, but from a safety perspective they are not usable at all, they’re excellent fire starters and are able to do you (and your eyes) great damage. If you want to work with these machines in a responsible manner you’ll need to do some work. It is probably more productive to think of most of these products as kits and starting points rather than as the finished article, even if they do work out of the box (usually after assembling them).

The most important parameters to look for when selecting a laser cutter are: optical output power and head construction, wavelength, cutting bed area, air assist, accuracy, cutting speed, enclosure and type of laser.

Optical Output Power & Head construction

The optical output of a laser cutter is measured in Watts. There are some manufacturers that advertise with the electrical input power of the device, but since lasers are quite inefficient this wrong foots the buyer into thinking they have bought a machine that is much more powerful than it actually is. Most manufacturers of cheap diode lasers tend to exaggerate a bit even if they do specify optical output power. A typical industrial tube laser or fiber laser of several thousand Watt will cut about 10 mm worth of mild steel. So it should be clear that an entry level diode laser of 40 W or so tops isn’t going to be doing much cutting in metal (even if the wavelength was optimal, which it really isn’t). And it also should be clear that a 5W laser isn’t going to cut much of anything and if it does that it will do so quite slow. A typical diode laser head contains one or more laser diodes, a set of mirrors and lenses to combine the output of all of the diodes and a focusing lens that aims the laser diode output at (hopefully) a single small spot on the work piece. The typical arrangement of all of the diodes within the head is a critical part in both the spot size as well as the depth to which the machine will be able to cut: as you get further away from the focal point the chance of the individual beams diverging increases and that will reduce the available power and increase the spot size. It may also cause the spot to be asymmetrical, for instance a spot can be wider than it is long which will make the machine penetrate material in one direction and barely scorch it in another! For any given power output fewer diodes is better because you’ll have a smaller spot size where that power is concentrated, but likely your diodes will run hotter and have a shorter operational life.

So the amount of raw optical power available and the geometry of the head is critical in deciding which machine you will buy. A typical high efficiency laser diode for cutting applications is 5 to 6W. For a 30W machine you can assume five or six diodes, depending on the make (and whether or not the numbers are accurate…). A powerful cutter head will usually have a small fan attached to forcibly cool the diodes to keep them below the temperature at which they self destruct. This is a very important feature and if the fan ever gets blocked or fails the laser head will die in short order. Bluntly: more power is better. You’ll cut either deeper or faster and there will be materials that you suddenly can cut instead of not at all. 5 or 6W machines will have a single diode and a very nice and tight spot. Above that you’ll have two or more diodes and an ever decreasing return on that extra theoretically available power. I’m not sure what the practical upper limit is but I already find that the spot size of a 6 diode factory aligned array laser is sub-optimal. It doesn’t perform six times better than a 5W single diode, more like three to four times better, and there is more spillover near the edge of the cut, especially in the plane the diodes are mounted in.

The output spot size is a very important factor to consider, a larger (less tightly focused) spot size means more overspill and a wider cut. You need to compensate for that in your design if you want to construct things that are solid, typically on the order of 0.1 mm press fits will have enough friction in them that you won’t even need glue. Most diode based lasers cut with the spot size that is so closely focused that near the surface of the work piece the so called ‘kerf’ is only about 0.4 mm wide. Deeper in the cut this can get a bit wider, this effect will be more pronounced when you cut thicker material because the beams that converge on the focal point will diverge beyond it. Even so, my ‘30W’ (take that with a grain of salt) laser head will happily cut 18 mm thick softwood and softwood based plywood, which I find nothing short of incredible. It’s not super fast at those thicknesses, 250 mm/minute (about 10”) on a good day, but it goes and if you’re patient you end up with very usable work pieces. And 18 mm is thick enough for actual construction pieces.

A valid alternative to buying a new machine, especially if you are looking at this to start a business is to buy a second hand industrial machine, either fiber or CO2 depending on your needs. These are not for hobby use, heavy, require a lot of power and they’re large. But from a throughput perspective they will leave the hobby machinery in the dust. Evaluating such a machine will require some expertise, you may want to find a buddy with relevant experience to help guide you and protect you from buying a very large doorstop. Parts and service will be quite expensive. You could still buy a cheap diode laser to start with to gain experience and to try your designs (assuming that the cutting capacity is sufficient), but in the long run the industrial machine is probably a better investment. rstop

Wavelength

The wavelength of a laser is the characteristic that defines the color of the laser. Typical diode lasers range from 400 to 800 nano meters, but more typically between 400 and 470 nm, corresponding to violet to blue4 in the visible spectrum. For some materials this works well, for others less so because they are able to reflect these wavelengths resulting in most of the power not being absorbed by the work piece. Longer wavelengths tend to do better for more difficult materials (such as metals) but there really is no diode laser that can cut metal reliably or at any usable thickness. You may be able to cut very thin steel foil with them. Fiber lasers typically have a wavelength of 780 to 2200 nm, which is infrared to deep infra red, very suitable for cutting metals. They are super dangerous if not properly enclosed because you still focus but won’t blink or look away. CO2 lasers range from 9.3 um to 10.6 um, much longer wavelength than either fiber or diode lasers. On the plus side that makes diode lasers moderately safer for use by people that haven’t been specifically trained: you can see the beam and if you can then you at least have a chance to block it.5 Diode based optical lasers are in some ways more dangerous than their industrial IR counterparts. For one they usually ship without an enclosure, so there are no interlocks that will disable the laser if the user gains access to the guts of the machine. For another the visible nature of the laser beam makes it harder to block and there may be leakage into other parts of the spectrum making them even harder to block. On industrial infrared and deep infrared lasers the beam is invisible and the damage will be done before you are even aware of it but the machines are properly enclosed and have safety interlocks. If you ever get an infrared head for your laser get one that has a visible light pilot laser to make sure that you know where the beam is. Laser light can reflect in the most crazy ways and any kind of concentrated escaped light can be quite dangerous. I know this all sounds alarmist but this is a very real issue that you should never underestimate, a laser cutter of any power (even a 5W one) should be operated in an enclosure and with sufficient safety that the operator will never be exposed to the direct beam or a reflection of the beam.

Cutting bed area

A larger cutting bed will allow you to make larger work pieces, but it will also require more space for the machine. I have a 61x61 cutting bed, the machine itself is 70x80 cm and the enclosure is 1 meter x 84 cm and over a meter high. That’s quite a bit of space. But the upside from that larger cutting bed is that I have less waste (because more nesting can be done) and I can run much longer jobs in one go. All of this makes it worth it for me. But if all you do is small work then there is no point in getting a machine with a large bed. Keep in mind that you won’t be using exactly 100% of the cutting area due to hold-down, end stops, the need to ‘frame’ the work piece (to ensure that you are cutting material rather than air near the edges) and so on. Usually one axis can be completely used and one you will lose a little bit on the sides.

Air assist

For a proper cutter rather than just an engraver air assist is a must. Typically 10 to 15 liters per minute for a 20 to 40W machine. The function of the air assist is the get rid of the bits of material that the laser has already hit so that you can go deeper. The laser beam is otherwise blocked by the debris in the cut. This is a very effective mechanism and it increases the apparent power of the laser considerably. But don’t overdo it: too much air and you’ll be cooling your work piece faster than the laser can heat it up!

Accuracy

A typical laser cutter will have an accuracy of about 0.1 mm, which is for this price level ridiculously accurate. Given that you are not machining metal on a lathe or a mill and that the machines are less rigid by design more accuracy will come at a steep increase in price and you likely won’t need it anyway for the work pieces that you will want to make. The main factors in the (repeat) accuracy of the device are the way the motors drive the gantry and the head. Typically these slide freely on some kind of bearing and the movement itself is effected by a belt and a gear on the motor. Motors tend to be stepper motors, not servos so any kind of step loss will cause an immediate failure of the work piece (with servos the controller would correct for any positioning error). But because there is no back pressure from the tool this less of a problem than it would be with a milling machine. Another factor in accuracy is how square the machine is, and how level it has been set up. It pays off handily to spend some time on this and to ensure that the machine is as square as you can make it (the open frame based machines can flex quite a bit) and as level as you can make it. This will result in more accurate work and more consistent depth of cut and penetration depth across the whole of the work surface.

Cutting speed and movement speed

Cutting speed is usually limited by the laser head power, for a given job the cutting speed will simply be the highest speed at which you can still reliably penetrate the material. Movement speed is usually limited by the weight of the gantry in the Y direction and the weight of the head in the X direction. The size of the stepper motor and the stability of the power supply may come into play as well. The quality of the ways across which the gantry and the head assembly move and how much friction there is in the system will further affect the speeds.

Enclosure

A laser cutter really needs to be enclosed, do not be fooled by manufacturers that show their machines in living areas or office like environments, it will simply not work. You will need a proper enclosure with fumes extraction and a path out of your building to use these responsibly. Here is an example, the enclosure that I built (if you look carefully you’ll see it is an old folding bed that was repurposed because I just love recycling stuff):

Type of laser

You can choose either a diode, fiber or CO2 laser depending on your needs, budget and space. CO2 lasers are the most versatile but finicky and require a lot of maintenance. Fiber lasers are ideal for cutting metal. Both of these are quite pricey and if they break the parts will be pricey as well. You can get them in very large formats and if you have the space (and the money) they may well be a good choice. Diode lasers are for the most part hobbyist and maker territory so the bulk of this document is geared towards those kinds of machines and applications.

Engraving vs cutting

Typically cutting requires more power than engraving when using the same material. Some materials can be engraved well, others not so much. As a rule, if you can cut it you probably can engrave it as well, but the reverse definitely isn’t true. Engraving is a surface treatment, so the thickness of the underlying material isn’t all that important whereas for cutting it is probably the next most important parameter besides the material itself.

How to install a laser cutter

A laser cutter must have an enclosure. Even if these are sold without using them naked is going to cause you a bunch of problems. For starters, laser cutting isn’t a very clean process. Your laser cutter will produce smoke, sometimes large quantities of it and this smoke can be extremely unhealthy to breathe in. To use a laser cutter properly your enclosure should be ventilated. A laser cutter with an ‘air assist’ (a small air pump that pushes air out parallel to the laser beam to enable it to make deeper cuts) is going to require a clean air intake to ensure it doesn’t foul up the optics. Your enclosure will need a window so you can keep an eye on what’s going on in the enclosure. And speaking of eyes, that window should block a large fraction of the laser light to make sure you keep the use of your eyes rather than that you end up finally getting that joke seen in physics labs (‘Do not stare into laser with remaining eye’).

You probably also want to invest in a pair of laser safety goggles with glass colored to match the wavelength of your laser. If you already wear glasses make sure these are sized such that they will fit over your existing glasses. A laser cutter should be set carefully level and any kind of support needs to be square and warp free. Inside the perimeter of the laser cutter you will need a sacrificial bed or a bed that the cutter can’t cut to support the material that you intend to cut. This so that the air has a place to go to and so that you don’t end up cutting whatever supports your material. Because laser cutters can generate a lot of localized heat (that’s what they’re made for!) there is some non-zero chance of setting your work piece on fire. So a laser cutter should never be operated unattended, and you should have some means of putting an actual fire on the bed of your machine out. The surface below the laser work area should be fire proof.

You will need an easy to access e-stop in case there is a fire or other mishap (it will cost you a work piece but that’s a small price compared to burning down your house or garage). You can use one of those big red mushroom switches that stay in position after you’ve pressed them to de-energize the system or you could use a multi-outlet bar with a switch. Never ever cut PVC, the fumes that it produces are extremely toxic and it will corrode your machine and/or injure or kill you. Chlorine gas is super dangerous and cutting PVC with a laser will produce it in quantities large enough to be a real problem.

Driving the laser

Most lasers talk to their host computers (you’ll need one of those too) using a serial-over-USB protocol, and the language they speak is called G-Code6, which is a venerable but highly effective way to control various machinery by computer. G-Code is universal and used to control anything from lathes and mills to laser cutters, coordinate drills and pretty much anything else used in manufacturing these days. But programming G-Code directly is somewhat tedious, especially if you change your design frequently so the usual pathway is that you have some piece of software to create the design and then a piece of software to take that design (in some intermediary format) and to convert it to G-code. Consumer targeted software packages that are relatively easy to use and feature rich are:

  • LightBurn, https://lightburnsoftware.com/ , LightBurn is a great piece of software, kudos to the makers for supporting Linux even though that is only a fraction of their market. It works quite well as long as you stick to the supported Linux versions, just dedicate an old laptop to your Lasercutter and you’ll be fine. LightBurn supports a camera that you can position over the bed of the cutter to keep you informed about what’s happening inside the enclosure. If you run into trouble with support for your camera you may use ffmpeg to convert the camera’s format to one that LightBurn can handle like so: ‘ffmpeg -i /dev/video4 -map 0:v -vf format=yuv420p -f v4l2 /dev/video6’ where /dev/video4 should be your real camera and /dev/video6 v4l loopback device (created using ‘sudo modprobe v4l2loopback’). I really should do a separate article on working with LightBurn. It is one of very few pieces of closed source software that I use and was very happy to pay for.
  • LaserGRBL, https://lasergrbl.com/
  • OpenBuilds, https://software.openbuilds.com/
  • LaserWeb, https://laserweb.yurl.ch/
  • lots of others, if I’ve missed your software please send me a name and a link to include

Some of these are free, some are commercial software, in the end all of them will work but the convenience level may vary and some may work better (or worse) for your particular setup and material. Try before you buy, make good use of the trial period and cut as many different materials and thicknesses as you can to get a good feel for the software before you decide. Pay special attention to how the software fits into your workflow, whether the file formats that you intend to use are supported without conversion steps and that the import of those files is error free.

The laser driver software that I’ve seen all still misses tricks of the trade and more than once I’ve seen (subtle) bugs. For instance, radius compensation (to offset the path half the beam width so you get more accurate work) needs to be done to the outside for outer curves and for the inside for inner curves but the software tends to get confused by what is outer and what is inner especially if the tool path changes direction. This is the result of a naive implementation of the correction, the right way to do it is to first figure out if a curve is inner or outer and then to offset in the direction of the scrap. But that implies that you know what the scrap is and that information isn’t necessarily present in the input file to the laser so the software has to make an educated guess. And this doesn’t always work. Other bugs I’ve seen relate to penetrating thick material. In order to do that you normally start well in the scrap and then spiral into the edge of the work piece so the laser is always in motion when it hits the work piece itself. Constant beam power (so that you always cut with the same amount of power) is another fact that you really would need to offset for, especially if the spot size is asymmetrical, so you need to cut slower in the direction where the beam is less focused for consistent results. All of this is tricky to get right and some of the software out there is better at these things than others, but nothing on the market today gets all of these factors right.

In this extreme close-up of the back of a piece of birch plywood you can see the effect of an asymmetrical spot, the machine clearly favors cutting in the ‘X’ direction because that’s the orientation of the lasers in the head which results in a beam that is slightly wider than tall. In the ‘Y’ direction that causes some of the beam to spill over onto the side of the cut. So you will need to go slower in one direction than the other, but because most software can’t do that what you end up doing is to slow down to the lowest speed that will still penetrate the work piece in all directions of travel. This will result in a slower cutting speed and some loss of accuracy in one dimension. Knowing your cutter intimately will help to identify and correct such issues:

Making the design

To cut any kind of material at all you first need a design. You can make your own designs, you can buy designs made by others and you can adapt designs and artwork that wasn’t necessarily intended for laser cutting or engraving using software. There are also free laser cutter design generators that will generate a bespoke pattern for you on the fly. Software used for the design phase is quite varied, on the one hand there are parametric tools that are closer to programming environments than design software, on the other hand there are fully interactive drawing programs, CAD software, photo manipulation software etc. Depending on your skill level and goals you will select the package most appropriate for your needs. If you are more of an artist than a technology person you will likely gravitate to drawing programs and if you are an engineer you will probably feel most at home with a CAD program. If you’re a programmer then parametric design software may be the thing for you. In each of these categories there are multiple contenders.

The list of subjects of things that you can make is pretty much endless, but things that I keep coming across are all manner of boxes, jigs for other tools, decorative pieces and functional machinery. The longer I work with the laser the more ways I find myself using it.

For each of these there will be ways to arrive at the two-dimensional intermediary file that will be used by the laser driver software to be converted into G-Code. Common file formats in use for cutting are SVG, DXF and JPG. Usually the software will support quite a few more of these, it is crucial that whatever format the design software exports can be imported into the the laser driver software.

More resources for designs:

Materials

You can cut/engrave a wide variety of materials with results ranging from ‘excellent’ to ‘unusable’ depending on the power of your machine, the speed of the movement of the laser, the state of the optics (clean, undamaged) and the state of the material. I intended to create a catalogue of machines, materials, cutting speeds and power levels here to save everybody the trouble of having to re-run these for normal conditions. In case of troubleshooting or exceptional conditions you may still want to create a materials test. I use ‘LightBurn’, so those are the materials test coupons shown here but most laser driver software will support a similar feature.

I will add photographs of front and back of all materials tests to save you some work.

Note that not all materials are safe to cut with a laser (I’ve added details for those materials that I’m aware of) and not all materials can be cut with a laser. Some materials will give off toxic fumes. These can cause respiratory issues, eye issues, major injury or in an extreme case death. Do not cut materials that you are not 100% sure are safe to cut and don’t try anything new without first consulting the material safety data sheet and at a minimum your friendly local search engine to determine whether or not it is worth trying at all.

If you want me to try a particular material either send me a sample or send me a photograph of front and back of your own materials test (see below for what those look like).

Wood

Wood is an excellent choice for material to be cut. A moderately powered laser cutter will be able to cut through several millimeters of material with relative ease, usually the limiting factor is the cutting speed, a less powerful laser will go slower (and has a higher chance of scorching the material). Diode lasers will happily cut softwoods even at impressive thickness but struggle with hardwoods. Hardwoods are more dense than softwoods so the laser needs more power to do the same job and that power isn’t always available. Also, because more power (or lower speeds) are needed charring can get excessive (or even outright burning). Careful balance in power and speed and sometimes increased numbers of passes can get the job done and there are some tricks of the trade to do the seemingly impossible. Engineered wood is hit-and-miss, you’ll also have to deal with the fumes in a more responsible way because besides carbon from vaporizing wood you’ll also be vaporizing some glue and this can produce some pretty nasty stuff.

If you don’t like the dark edge that laser cutting gives the wood consider oversizing the sides of the work piece by 0.1 mm or so and sanding off the excess. It’s an extra step but the difference in looks may well be worth it. Cut wood can smell burnt for a long time. You can reduce this smell by sanding off the edge, by lacquering or painting the piece or by sandblasting it (lightly, wood abrades very quickly). Lacquer and paint don’t adhere very well to the burned edge because some of it is loose material, that’s also why these particles make it into the air. It is essentially the same as a very thin smoke because of the air movements liberating particles from the workpiece. That’s also why eventually the smell fades (but this can take a long time, up to months).

If you’re going to cut plywood, be aware that not all plywood is created equal and that some is put together with glues that give off bad vapors, if there is a thin black line between the plys that means you probably have plywood with ‘phenolic resin’. It may also result in being harder to cut.7

Based on quite a large number of material tests here are the results (nominally 30W cutter, clean optics, air assist on):

  • Birch plywood
    • 2.6 mm, 60% power, 700 mm/minute, single pass (for more speed: 100% power, 1000 mm/minute, less laser life though)
    • 4.1 mm/5.5 mm, 60% power, 450 mm/minute, single pass (for more speed: 100% power, 800 mm/minute)
    • 7.8 mm, 60% power, 200 mm/minute, single pass (for more speed: 100% power, 400 mm/minute)
    • 11.8 mm, 60% power, 150 mm/minute, single pass (for more speed: 100% power, 250 mm/minute)
    • 18 mm, 80% power, 300 mm/minute, three passes
  • MDF
    • 3.2 mm coated, 80% power, 500 mm/minute, single pass (more power doesn’t seem to help)
    • 9 mm, 80% power, 200 mm/minute, single pass (more power doesn’t seem to help)
  • Hardwood ply
    • 3.7 mm, 70% power, 200 mm/minute, single pass (not a very clean cut)
    • 3.7 mm, 50% power, 600 mm/minute, 4 passes (cleaner cut, but a bit more charring at the top, should use masking tape)
    • Thicker hardwood ply: terrible results, unusable.
  • hardboard
    • 3.4 mm, 60% power, 450 mm/minute, single pass (for more speed: 100% power, 750 mm/minute)
  • hardwood veneer
  • solid hardwood
    • Solid harder woods more than a few millimeters thick are difficult to cut using a laser. I’ve tried a few test pieces but nothing usable came out so far. It’s entirely possible that I need to change my approach to this and that the problem lies with me but I suspect that the density of the material is such that the laser simply doesn’t have enough power once you go out of the immediate focus of the beam and so you end up with very little depth of penetration. I intend to set up some tests to determine what exactly the limits are and whether or not something can be done about it.

The following are materials test coupons made using a nominally 30W ‘Sculpfun’ S30 Ultra, it’s sold as an open frame machine with just about zero safety features for $1000 or less. Technically it probably shouldn’t be on the market at all, it is that unsafe but I’m happy that it is and with some work you can make it both safe to use and more effective than what you get out of the box. If you want to inspect a particular coupon more closely just click on the image to open it in a new tab.

MaterialFrontBack
2.6 mm birch
4.1 mm birch
Oops...
If you look closely you'll see that I forgot to reduce the power for the engraving so the letters have been burned clear through the material!
5.5 mm birch
7.8 mm birch
12 mm birch
18 mm birch
Some charring at the back, but usable
3.2 mm coated MDF
9 mm MDF
3.7 mm hardwood ply
3.7 mm hardwood ply, 4 passes
3.4 mm hardboard

Bamboo

I haven’t been able to get my hands on a suitable piece of laminated bamboo yet but it’s an interesting material and I expect it to work reasonably well, though the strong directional nature of the material may require some trickery to get it to work properly.

Paper/Cardboard

Paper and cardboard are fine to cut, you can use pretty high cutting speeds but air should be off to avoid blowing the material away. If you move too slow you’ll end up with too much charring on the edges. It may be possible to stack several layers on top of each other and cut them all at once. Be careful when using air in combination with paper or cardboard, it can hinder more than it can help and it can cause work pieces to be blown away. You can add some tabs to keep things in place but then you’ll have to cut these later to separate the work piece from the scrap.

  • Corrugated cardboard
    • 5.7 mm 3 ply packaging cardbord, 60% power, 1000 mm/minute, single pass. (for more speed: 70% power, 1400 mm / minute)
MaterialFrontBack
5.7 mm corrugated 3 ply cardboard

Textile

Organic textile tends to work very well, synthetic fabrics much less so, they tend to melt rather than cut cleanly and the results can be very messy (and hard to separate from the cutting bed).

Leather

I would highly recommend against cutting or engraving leather. It can be done but the results aren’t all that nice to look at and the smell is just horrible. If you want to make a lot of enemies in a short time however, cutting leather with a laser may just be the thing. Leather tanned with Chrome will release highly toxic vapors so unless you have material that is certified safe to be cut with a laser stay away from leather altogether.

Metal

Unless the metal is super thin it likely will not work well to be cut using a diode laser. I have yet to try some more exotic materials (such as Titanium) but all of my metal cutting experiments have ended in utter failure. Not a single successful cut, the best I achieved was some minor discoloration on stainless steel at maximum power. It is clear that the short wavelength of the laserhead that I’m using (455 nm) is too short for any serious metal work. A several KW fiber laser is ideal for this kind of work, it will cost a pretty penny and will probably arrive on a flatbed truck. You’ll need tri-phase power and you may need a permit to run one in a residential area because of the metal vapor. I would not recommend this unless you are sited in an industrial area (or in the middle of nowhere).

Anodyzed Aluminum

Some metal, notably anodyzed aluminum can be engraved quite well. You are essentially evaporating the layer on the aluminum exposing the bare metal underneath, which gives a nice effect. You could do the reverse, evaporate all of the cover except for where you want the pattern to appear but this will likely take a long time.

You could also use a marking spray, fluid or paste, these tend to be very expensive though and it may be worth researching alternatives.

Stainless Steel

Cutting stainless steel is probably out of reach for diode based systems, but you may be able to engrave them effectively.

Dykem Red engineering marking fluid makes for an excellent laser engraving on stainless steel, when using these low-power blue diode lasers. You just spray it on, engrave, and wipe off the excess with isopropanol(‘IPA’). The IPA can be a little difficult to remove, so warming it up helps, but it won’t wipe off where the laser has engraved it. It works well in a pinch and creates a nice, reddish permanent mark (that doesn’t come off in IPA).

Acrylic

Haven’t tried this yet but it will happen soon.

Polycarbonate

Hard no, you can not safely cut this with a low cost diode laser/air based system.

Most plastics & PVC

Plastics and PVC should not normally be cut with a laser, they will give off highly toxic vapors and the results will be sub-optimal. There is a fair chance that your work piece will end up welded to the bed (with the risk of damage to the bed) and that it will catch fire, you may not care about this while you are recovering in the ER (or when you’re not recovering in the morgue…). Seriously: stay away from most plastics and all PVC.

Stone & Ceramics

To be tested shortly

Delrin / Acetal

Expensive! To be tested (I first need to find some)

Other online resources

Tricks and tips

This section is dedicated to various little bits of knowledge that may help to extend the life of your machine, extend its capabilities or to make your life easier.

Thicker material

Cutting thicker material in one go isn’t always feasible. The temptation usually is to run the laser for multiple passes but beyond two or three of these it is pointless: the beam will diverge in the cut to the point that you’re only getting a minimal amount of power deeper in the cut (and you’ll be hitting the sides more than the bottom of the cut where you want to be). One way to get past this seemingly insurmountable limitation is to flip the material over and to cut a mirrored pattern from the other side. This ‘one weird trick’ instantly doubles the depth to which you can cut! Registration can be aided by pilot holes and a fixture mounted on the cutting bed. An easy way to achieve this is by sticking two pins (at least two!) through the material to be cut in such a way that when you reverse the material the pins will swap position. That way you have perfect registration provided you don’t move the pins (or the head!!) during the swap. Do remember to mirror the pattern on the second pass.

Laminate!

Another way to change the thickness of the resulting work pieces is by lamination. You cut identical patterns out of thinner wood which you then glue on top of each other under pressure to create a work piece that is much thicker than what your machine can normally produce. This for instance allows you to create hardwood gears from thin slices. Lamination is a very useful technique and if you get good at it you can produce work pieces that would require machines orders of magnitude more expensive than the ones you’ve got or that might be entirely impossible to make. You can also achieve interesting effects by purposefully offsetting the laminations (translation, rotation) or by ‘slicing’ a design in one dimension and then to glue the layers together to achieve a three dimensional effect. If you want to go fancy you could even sand down the steps of the slices to the point where you have a continuous surface.

You can add strength and precision to the laminations by adding registration holes that you hammer hardwood dowels into. This gives you almost perfect overlap between the layers (to within the precision of your machine) and the dowels have their grain oriented in a different axis to give your work piece more strength. Keep the dowels just a bit shorter than the total workpiece thickness so that you can still apply sufficient pressure during the glueing, and put some glue on the dowels as well while you’re at it.

More air

Air assist greatly improves cutting depth but the typical air pump that comes with a laser cutter is anemic and barely has enough airflow for the job. An entry level shop air compressor will do much better, but you’ll need to dry the air and make sure it is oil free. Take care not to overdo it, the hose needs to stay attached to the cutter head and you don’t want to end up cracking your optics. A typical laser head will use anywhere from 10 to 30 liters per minute, which the manufacturer supplied pump may not be able to provide. Some experiementation can help determine the optimum for your laser at a given power level. Higher power levels will tolerate more air, above a certain limit more air actually works against you because the material is cooled too much and below a certain limit you won’t be removing material fast enough to get the full benefit of the air. So there definitely is an optimal amount of air for any particular cutter/material/powerlevel combination.

Longer materials

If your enclosure permits it you may be able to use the registration trick on the same side of the material as well to create work pieces that are longer than the machine can comfortably cut in one go. You’ll need to move the entire support under the cutting head to make sure that you don’t lose the registration for the individual pieces (because presumably the laser has penetrated the material fully, so some of the work piece is now already cut).

Clean your optics!

It happens very gradually so you may not notice but typically it won’t take more than a few hours worth of cutting to have a measurable degradation in cutting power due to contamination on the focusing lens. You’ll eventually notice that you won’t be able to cut materials that you could cut before or that you will need to slow down too much. That’s a sure sign that your optics are not clean. I clean the optics on my machine prior to any major job, it usually takes less than five minutes and the results are so much better. Always be very careful when you put it all back together that you don’t end up cross threading the nozzle onto the head, this is very easy to do (fine thread, large diameter). The best way is to spin the nozzle counter clockwise until it ‘clicks’, this is a sign that the start of the thread has ligned up on both pieces and then to gently rotate the nozzle clockwise to screw it back on.

If you do not periodically clean your lens the fumes deposit will build up on it which will then fuse to the glass of the lens. This makes the damage permanent so better get in there before that happens. In an extreme case a lens could crack because of uneven heating/cooling due to deposit build-up. Clean your lens with a lens cleaning cloth (used for camera lenses, your laser cutter manufacturer may have supplied a small piece of this). If you have a more serious contamination (for instance because your extraction failed or you had a fire in the enclosure) then you may need to use some alcohol, in case the problem is very bad and as a means of last resort you can use some acetone. But make sure the lens is completely clear and dry before closing it all up and using it.

Tie down your material

If the material is light and you’re using air assist or bump the cutter enclosure there is a fair chance that the material will shift a bit as the cut interacts with the air stream coming out of the nozzle. This can shift the material around. It doesn’t have to be much for the effect to be noticeable and in an extreme case could easily ruin your work piece. I use simple 3D printed tie-down pins to hold light materials to the cutting bed. This also helps to flatten the material which ensures that the focus is consistent across the whole material.

Ensure the air flow is unobstructed

It probably seems obvious but more than one tricky problem ended up being related to the air hose being kinked, sometimes in places where it was hard to see that this was the case (at the pump exit). You can also have fouling on the nozzle (usually carbon deposits, more likely to happen after periods of cutting without air assist) and obstructions (dust, other stuff) on the air intake of the pump. All of these will reduce or even completely stop the flow of air to the nozzle. A missing O-ring on the nozzle could cause air to leak out of the top of the nozzle rather than that it is all directed out of the bottom.

Painters tape against scorching or as a stencil

If the surface finish of the work piece is critical and you don’t want to sand it a layer of painters tape can help protect the surface, any scorch marks will be on the tape (which burns through easily). This is more of an issue with diode array based heads because they tend to ‘spill’ a bit more off to the side of the cut. So called ‘Transfer Tape’ sells in rolls up to 30 cm wide and is cheap. If the material underneath is something you can’t engrave on directly consider spraying through the removed transfer tape effectively using it as a stencil.

Coating the surface may help

Both for engraving and for cutting if the surface is reflective it may help to have a matte coating on the surface you intend to cut or engrave, this can aid absorption of the energy the laser delivers resulting in more work being done.

Periodically re-tighten belts, keep an eye on set-screws

The belts that come with diode laser cutters tend to stretch a bit and slip over time so it will pay off to re-tighten them periodically, especially the ones connected to the main gantry because these are hauling quite a bit of weight endlessly back-and-forth across the table. In a very bad case you’ll see overshoot and undershoot when moving in the y-direction (usually visible as a little vertical squiggle at the beginning of a new horizontal line). In my machine there are in total 6 set screws that all have the potential to come loose over time, this can cause excessive wear and slop in the affected axis. Check that your set-screws are still tight (but don’t overtorque them!) every couple of months or so or if you suspect there may be an issue.

Changelog

  • 2024/Jan/26 first version of this document

References:

48x32, A 1536 LED Game Computer

My children are hopelessly addicted to their gaming devices. This is a problem, but not one that I can directly solve because the school mandates that they have both an Android smartphone and a Windows laptop. Rather than to meet the problem head on I figured the better way to address it is to replace consumption with creation. But creating anything at all on a smartphone or a laptop, where the competition is insane, and the toolchains super complex is going to be an uphill battle. After all, a typical game title these days has a studio full of people dedicated to it, large teams of developers and so on. There isn’t really anything you can do that will come close to being able to compete with the eye candy and 3D stuff your average game contains.

But where you could compete is on the fun factor. And in that sense some of those old games are right up there with the new ones, if not downright more fun. It’s also a much better match for my skillset, and far easier for a novice to get into if we piggyback on the Arduino eco-system, which has some fairly powerful options in their offering. More or less by chance I ran into a place that sells interesting hardware bits, in this case a 32x8 display of addressable LEDs.


Not a cheap component at 20 euros each or so, but actually cheaper than the individual LEDs. Still, 32x8 is a bit anemic for any kind of game so I ganged up 6 of them in a rectangle for a 48x32 display, which gives this project its name. On a typical high res display that’s about 2 characters worth of space but because the LEDs used are huge compared to your typical pixel on a normal screen the display ends up quite large. 48x32 cm works out to about 19x12”.


An enclosure of sorts is a must, so I lasercut a box with a relatively cheap Chinese made lasercutter that cuts plywood like it’s cardboard and with insane precision. I could never make something with this level of fit by hand. Getting it all to work was a bit fiddly but in the end I got a set of parts that were good to be used for the real thing.



Joysticks were another challenge, but a smaller one, Thingiverse to the rescue, a really simple thing to print and it fit on the first try, here is the finished result and what’s inside it:



Putting it all together, an Arduino R4 as the computer component and some standard wiring and some connectors to hook it all together will get you this:


And after some more work here is the Nokia ‘Snake’ game in its natural environment:


Note how the graphics are all composed of single LEDs, the features are obstacles (purple) food (yellow), the snake itself (green) and the snake head (blue). This is a single player game but I’ve also built a number of simple two player games with it.

In the next installment I will walk you through the software and show you how to make simple games, if you already know how to program or want to build one of these yourself the cad files and the include file are here.

Drastically Reducing Our Powerbill

Since the outbreak of the war in Ukraine the price of gas and electric power in the European Union has gone up enormously. Russia, a major supplier of gas to the EU has been sanctioned heavily, buying natural gas from Russia effectively pays for them to wage war on Ukraine and the price of electricity is tied to the price of natural gas, which has been going up and down like a jo-jo, but far more up than down. Not all countries are equally affected by this, countries that have a large proportion of hydro power and countries that have their own - and still usable - supplies of natural gas have an easier time to deal with this than countries that do not. The EU energy market - not the most transparent affair for mere mortals - which allows foreign suppliers access to the domestic markets can cushion some of these aspects but the difference in average price as well as the various means offered by governments to take the edge of for their citizens vary greatly, as do the individual contracts and the options offered by the various suppliers.

Ever since the beginnings of the COVID crisis we have worked from home, which means that all of the gear that used to sit in our offices is now here in the house and obviously that uses quite a bit of power. The house has four occupants, two adults, two teenagers and is about 200 square meters divided across three levels. The house has 25A x 3 phase 240V service and a natural gas line, which is used for both domestic hot water, some of the cooking (a hybrid gas/electrical stove) and the water based central heating system.

A typical setup in the Netherlands, where I live is that you have a network that serves your region and a choice of various suppliers. Once the price of energy started to go up faster than anticipated several of the suppliers here went bankrupt overnight, forcing their customers to re-negotiate with a different supplier at an entirely different rate. The practice effect is that for many households here since Jan. 1st 2022 the price of energy delivery has gone up tremendously, factors of five are not exceptional though in many cases - fortunately - it is still less than that and people that had the foresight to lock in their contracts prior to the outbreak of the war are sitting pretty, for a while at least.

Our household was not one of those, so when in August, after the annual adjustment we received the new tarifs it was bad. Our energy bill basically tripled overnight and roughly 1/3rd of my take-home salary would have gone towards the energy bill without some countermeasures. The plan we came up with was to create a mixture of savings measures and to install some generating capacity of our own, and to offset some of our heating requirements with an air-air heatpump that we already had but only used in airconditioning mode.

This house was built in the early 1970’s, it is not insulated all that well between the inner and the outer wall, and fixing that is a very expensive affair, both because of how the house was built as well as because there is already (bad) insulation in there. Removing the old insulation and replacing it with something better would be nice but from a cost-benefit perspective it is not the best investment right now (though we may still opt to do this in the future). What we could do fairly easily is to drop the temperature that the gas fired central heating system operates at. The default the heater was programmed to was 65 degrees Celsius, we dropped that to 45 degrees which had an immediate effect on the gas consumption. We also dropped the thermostat from a toasty 20 degrees to 18 degrees, which may not seem like much but the difference was very noticeable. Lower than that is not an option, for one humidity would become a problem, for another the house is very unevenly heated and 18 where the thermostat is can mean anywhere from 16 to 20 depending on where (how high up) you are in the house. But the every room has thermostatic valves on the radiators and those we adjusted to try to get the rooms as close to each other as possible temperature wise. Another thing we did was to change from using the front door of the house to using the backdoor, which does not sit next to the stairwell. This reduced the amount of air exchange every time someone came into or left the house. For myself, I have tried to take shorter showers, though I definitely miss them (joint issues). Together these simple measures shaved off more than half of our gas consumption.

On the electrical side there was a lot that could be done as well. First we made inventory of all of the consumers that we had, and decided whether or not we really needed them, if they could be replaced by something less power hungry if we did and if not if we could reduce our usage. We replaced all of the remaining halogen bulbs (we still had quite a few) with LEDs, in some cases this required some minor rewiring because not all of the power supplies for the halogen bulbs liked the LEDs but because they draw so much less power it was easy to move some of these to supplies that worked well. For some bulbs finding an LED replacement was quite tricky but in the end we found a way to get rid of all of them. Identifying consumers can be quite hard, we installed a ‘Smile P1’ interface to our distribution point to determine momentary power draw and flipped circuit breakers one-by-one until we had a reasonable insight into how much power each circuit was using. The worst consumers: my main computer (a beefy I7 with a very large amount of RAM and a 1080ti graphics card that I used for the machine learning portion of the Lego sorting machine), our NAS (a 12 bay Synology) and a domestic water heater in the kitchen (which took forever to find). The second fridge/freezer was switched off as well, and a whole slew of ghost loads was killed off by simply pulling the wall warts when the devices are not in use. My computer was replaced by an old laptop that I still had but did not use, it has a provision for dual monitors (besides the built in LCD) so I still have more or less the same setup as before, with just half the RAM. I did replace the rotating rust drive with an SSD, which was surprisingly affordable given the capacity.

All of these changes together cut our monthly consumption from about 800 KWh on average (which is insane) to a much more reasonable 270 KWh. And the solar panels completely offset that during the month of October. Another batch of 10 panels will arrive next week, which will allow us to heat part of the second floor using an air-conditioner run in reverse (a split air conditioning unit is essentially just a heatpump and you can run those in reverse). This should further reduce the gas bill.

When we bought this house it had 16 solar panels installed, but we had to take those down to modify the attic space. The plan always was to put them back up once that work was done but we had simply not gotten around to it yet, just prior to removing them the inverter broke and since the start of the war in Ukraine the availability of solar panels and inverters is quite bad, lead times are several months. After searching on the local equivalent of Ebay I found one party that still had a slightly older model inverter sitting around, a 3 Phase 4KW unit that they somehow never sold. I don’t particularly care for the latest and greatest in inverters so I was happy to take it off their hands at a bit of a discount. When it arrived it turned out the inverter had been dropped, and quite badly, the casing was cracked, the DC disconnect had been bent out of shape and a bolt had broken out of the cast aluminum housing. It must have taken quite a fall given the amount of foam that the inverter came packed in, weirdly enough the cardboard box was fine though it did look as if the inverter had been re-packed at least once before (judging by the amount of packing tape on the box). I contacted the company and they were super reasonable about it, they offered me to either take it back for a full refund or a 50% discount if I wanted to keep it. I’m not afraid of power electronics, wired up a test installation and inspected the inverter mechanically, it worked in spite of the damage and did not get overly hot or let out any magic smoke, so I took the discount. This allowed me to re-install the 16 panels that I had before on the roof of our garage.

I then ordered another batch of panels, much more modern (the other ones are about a decade old, 265 Watts each), 400 W AEG units that I found a reliable supplier for and went to pick them up, then installed those on a covered area outside in the garden. 10 of those comes to 4000 Watts installed power, plus the 16 265 Watt ones, another 4250 Watts (but given their age I would derate those to probably closer to 200 Watts today, so say 3200 Watt). Adding all of that up gives you a bit over 7000 Watts in installed power, much more than the inverter could handle. Another trip through the second hand listings and I found a single phase unit that will do 3000 Watt. The panels are mounted flat on the garage and lean-to roofs, so that’s a double penalty, first there is the problem of the angle at which the sun shines on those panels, and second the houses here will shade the panels during part of the day. But it makes a nice bit of power,

From an initial 1500 euros / month we are now down to about 350 euros ex government rebates, and that is in the bad part of the year. Obviously, December, the worst month for solar is still to come and I definitely don’t expect miracles, but as long as we still have net-metering here (until Dec 2024 at a minimum) we can compensate for that during the summer. The total cost of the installation was about 10K, which I expect - assuming prices remain steady - to pay for itself in less than four years. Clearly, the energy savings are a major factor in the whole picture, without that the effect of the solar installation would be far less. But the two combined meant that for October our electricity usage relative to the grid was negative, resulting in a portion of our gas usage being offset by electricty over production.

There are some things that helped which may make this hard to replicate: the first, and most obvious one is that we had enough savings to make all of this happen on short notice. we also had a lot of surface area to play with, 60 square meters of flat roof which is now completely covered with panels, and another 30 square meters higher up on the roof of the house which will soon be covered as well. Not every location has such a large amount of usable roof area. The second factor is that even though there is some shading we don’t have any really high buildings nearby that shades the whole installation. Mounting panels flat is not ideal, for one they make less power than when they are properly ‘aimed’, for another they can easily foul up (leaves, bird droppings and so on). But even if the panels are positioned less than ideal, are partially shaded and need periodic cleaning (or are simply not perfectly clean) the sheer quantity of them means that even of the whole setup is operating at 10% efficiency it still handily outstrips our usage during the day with the sun this low in the sky. Once we’re past the solstice it will get better day-by-day and during February and March (when we consumed the most gas in other years) I expect to be able to use the air-air heatpump for heating purposes a lot. Finally, not everybody is able to adjust the temperature just like that, if you have health issues or if your house is even more humid than this one you may have to keep up the heat just to avoid ending up with fungi or damage. But even then a critical look at your power consumption may help identify some areas where you can save.

I hope this article will help someone looking to do something similar, if you have questions or feedback feel free to reach out to jacques@modularcompany.com.

The Golden Egg Circus

In 1989 I got a call from a friend to come along to visit a studio in Landsmeer, near Amsterdam, where something quite amazing was being constructed, a circus with nothing but eggs, both as the performers and as the audience. I was - and still am - a huge Jim Henson fan and immediately felt an interest to see what was going on.

We were received by Jacques Meijer and his wife in their house in Landsmeer, attached to which was a large workshop. After the obligatory tea and smalltalk we entered the workshop/studio and the lights came on. This is one of those ‘you had to have been there’ things, it is hard to describe how incredible the sight was. More than life-size, the Golden Egg Circus model towered over us, high up a trapeze, on the ground a circus ring where the strongest egg was breaking bricks and brave eggs tamed tomatoes jumping through flaming hoops. Eggs, eggs, eggs and more eggs wherever you looked. The attention to detail was nothing short of unbelievable, everything built to exacting scale. It was clear immediately that many years of work had gone into this project, as well as a small fortune.

The whole thing was constructed as the location for an animated feature film to be shot in 35 mm, with special gantries to move the cameras around. The problem: the circus orchestra had to be animated in time with the music. The eggs didn’t actually have any instruments but they were supposed to rotate and bob up and down to match the music in realtime and the owner had no idea on how to go about this, his specialty was photography and film, not the actual animation. After a long evening talking it all over I decided to let the offer go, for one I didn’t really feel comfortable taking this man’s money because it was clear that he was already way over budget and had no idea what it would take to make his vision become a reality in terms of computers, servos and mechanics to make a fair sized orchestra come to life (as I wrote above, I was/am a huge Jim Henson fan and had seen some of what it took to animate the muppets), and another reason is that I felt that in spite of all the work and effort that went into it that it wasn’t really going anywhere. It was beautiful, absolutely gorgeous but I just could not find much enthusiasm for the whole concept of an egg circus. Great idea, though!

So, we left and for many years I didn’t even think about it, until last night when I suddenly remembered about it and decided to search online to see if anything ever came of it. I found a website with some photographs, a (paywalled) newspaper article that referred to the circus from 1995, when apparently the funding was still missing. I don’t think it ever happened, and according to his CV Jacques Meijer was still active in 2021.

In an alternative universe, Jim Henson has a barn behind his house where a model of a 1930’s variety theater has been built, with a weird little frog as the master of ceremonies and a pig with an attitude as his love interest. Monsters lie discarded in heaps and a detuned piano with a couple of broken strings sits in a dark corner. In that universe Jacques Meijer’s egg circus is a hit, children have egg dolls, everybody has their favorite egg and artists line up to be allowed on the next episode, still going strong after more than 30 years of week-by-week productions, as well as a couple of feature films. The Golden Egg Circus coming to your hometown is the event and people will talk about it for years.

In this universe, I feel privileged to have spent an evening with its creator, who relentlessly kept on pushing his idea, year after year, and even if hardly anybody has seen the egg circus in all its glory I hope that one day it will see the spotlight.

Kernenergie vs Zon en Wind

Dit is een antwoord op de Tweet thread van @Inge_v, die een hele berg redenen aangaf waarom ze vond dat Kernenergie de enige optie is in plaats van zon, wind en andere renewables.

Het begon met:

Ik ben tegen wind en zonne energie, en voor kernenergie. Dat is duurzamer en ik heb er vertrouwen in dat we een manier vinden om het afval goed te verwerken.

De hoofdmotivatie was dat het duurzamer is en dat ze vertrouwen heeft in dat we een manier vinden om het afval goed te verwerken.

Om maar even met die laatste te beginnen: vertrouwen hebben is niet hetzelfde als zeker weten, het is een vorm van hoop en hoop is het begin van teleurstelling. Sinds 1956, de opening van Calder Hall, de eerste commerciele nucleaire centrale is er eigenlijk maar heel weinig voortgang te bespeuren.

In het kort komt het neer op de aanname dat volgende generaties het probleem wel zullen oplossen. Maar ja, als dat in 65 jaar nog steeds niet gebeurd is dan denk ik dat enige aannames daarover op zij gezet kunnen worden. Als er een echte oplossing was dan hadden we die nu wel gevonden. Begraven, de ruimte in schieten, opwerken voor hergebruik: het is allemaal of besproken of ook werkelijk geprobeerd. Of we zijn het zelfs aan het doen (in het geval van begraven). Maar voorlopig ligt dat spul er maar te liggen en wordt het de aankomende generatie er niet makkelijke op gemaakt: die hebben al te maken met klimaatverandering en gigantische vervuiling en krijgen er dan dit probleem ook nog bij. Oh, en of ze onze oude dag ook nog even willen verzorgen. Wat mij betreft zouden we de wereld voor de volgende generatie beter moeten achterlaten en niet slechter, al helemaal niet opzadelen met problemen waar we zelf geen oplossing voor hebben.

Vanuit de nucleaire lobby is er een veelheid van informatie over dit onderwerp. Het komt altijd op hetzelfde neer: er is geen oplossing die echt werkt. Maar dan met 10,000 worden en een hoop hand gewuif. Hier een voorbeeld.

Je zou er bijna blij van worden. Maar als je het allemaal goed doorleest staat er toch echt dat er geen oplossing is.

Wel dat het allemaal wel meevalt, maar om de een of andere reden willen de lobbyisten zelf liever niet dat dit afval in hun achtertuin terecht komt. Het liefst ver weg. Zo ver weg dat als het onverhoopt in het grondwater terecht komt ze er zelf geen last van hebben.

Dan, het woordje ‘duurzaam’. Duurzaam heeft een hele specifieke betekenis in deze context: “het milieu weinig belastend”.

Dat is kort en krachtig. Het milieu is de planeet en alles wat leeft en zich in de biosfeer bevindt. Als kernenergie werkelijk duurzaam zou zijn dan zou je er niet drie hekken en een enorm veiligheids apparaat omheen hoeven zetten. De winning van Uranium (de grondstof voor kernsplijting), de opwerking daarvan, het gebruik, de afvalverwerking en - onverhoopt - bij een calamiteit de vervuiling van de omgeving alsmede de bouw van alle infrastructuur om dit te kunnen doen hebben enorme impact, en sommige van deze processen zijn zo gevaarlijk dat we vinden dat maar een select aantal landen ze mag gebruiken. Kernenergie duurzaam noemen is vergelijkbaar met overbevissing duurzaam noemen: de problemen stapelen zich op maar je ziet het niet dus kun je net doen of het niet bestaat.

Zolang er maar stroom uit het stopcontact komt en alle narigheid zich over de horizon bevindt (liefst op een ander continent) maakt het immers allemaal niet uit. Maar het milieu is allesomvattend.

Het gaat niet alleen om ons milieu. Het gaat ook om het milieu elders, en het gaat ook om het milieu in de toekomst. En daar zit de schade. Dat je die niet ziet als je je lampje aandoet doet daar verder niets aan af, al die ellende blijft.

Zonne-energie is niet milieuvriendelijk vanwege de accu's die ervoor nodig zijn als je de energie wil kunnen opslaan voor bv in de nacht. Het maken van die accu's levert ontzettend veel milieuschade op. De accu's gaan op dit moment maar 10 tot 15 jaar mee.

Dit staat bol van de aannames, en mist een aantal zaken. Allereerst: zonne energie is om diverse redenen belastend voor het milieu, maar accus hebben daar absoluut niets mee te maken. Zonne energie heb je iedere dag, helemaal gratis en voor niets zonder dat daar ook maar een accu aan te pas komt. De milieu belasting van zonne energie zit hem - in geval van zonnepanelen, die ik voor het gemak maar even als voorbeeld gebruik - in de fabricage fase (grote halfgeleiders, die veel chemicalien gebruiken tijdens de fabricage). Het gebruik van zonnepanelen als ze eenmaal geinstalleerd zijn vergt verder geen accus. Immers: je kunt de energie direct gebruiken door een inverter (een soort van transformator, maar dan veel complexer) te gebruiken om van de stroom van de zonnepanelen direct netspanning te maken. Die kun je zelf benutten, of je kunt het overschot het net in pompen en daar wat mee terug verdienen. Iemand anders, die meer stroom nodig heeft dan ze op kunnen wekken (bijvoorbeeld: iemand in een flat) kan die stroom dan meteen gebruiken. Blijft er nadat alle balans is opgemaakt nog steeds stroom over dan kan de generatie capaciteit omlaag. En zolang er nog niet voldoende geinstalleerde capaciteit is om aan alle behoeftes te voldoen heb je dus in principe geen opslag nodig.

Opslag komt pas om de hoek kijken als je als het donker is energie wilt gebruiken die overdag gewonnen is. Daar kun je batterijen voor gebruiken. Maar wat je ook kunt doen is gewoon helemaal niets. Je gebruikt dan andere energiebronnen.

Dus het hele accu verhaal doet niet ter zake in een net gekoppeld systeem. Het is wel belangrijk als je helemaal op jezelf staat. In Canada, in de rimboe bijvoorbeeld (ik heb er gewoond, en daar had ik dus wel een accu nodig). Maar hier in Nederland, of eigenlijk overal waar het electriciteits net ligt hoeft het niet.

Daarna wordt de accu afval, die ook weer ontzettend veel milieuschade oplevert.

Ja, maar die heb je dus niet nodig.

Bovendien is de huidige stand van zaken dat er met zonnepanelen nog een vrij groot risico is op brand. Ik ga er wel van uit dat de techniek op dat punt zal verbeteren.

Ik heb echt geen idee wat de bron is van deze zin, maar dit is wat een zorgvuldig onderzoek (dat je hier kunt lezen er van zegt: op 800.000 installaties zijn er 23 brandincidenten geweest. Dat is 0,0029%. En ja, het kan altijd beter. Van iedere brand wordt de oorzaak vastgesteld en als er een oplosbaar probleem wordt vastgesteld dan zal men het bouwbesluit en de regelgeving rond zonnepanelen er op aanpassen. Van belang, zoals bij iedere electrische installatie, is dat de installatie gedegen is aangelegd, iedere paar jaar geinspecteerd wordt en bij een defect gereparareerd wordt. Blikseminslag kan voorkomen dus moet de installatie geaard zijn. Ik heb geen lijstje van oorzaken van die 23 branden, maar ik heb alles bij elkaar in heel wat eletrische installaties gezien in gebouwen waar ik gerenoveerd heb en ik maak me meer zorgen over wat er in m’n huis aan electrische narigheid zit dan de panelen op het dak. En dat geldt voor alle huizen met een installatie ouder dan een jaar of 20, zeg maar nadat de heren hobbyisten er aan hebben gesleuteld. Dus, dat brandgevaar dat valt wel mee. Even ter calibratie, in NL hebben we per jaar 66.000 woningbranden (bron.

Gaat het om grote velden met zonnepanelen, dan houden die panelen de zon weg op de plaats waar die panelen staan. Dat heeft ook invloed op de flora en fauna onder het veld, en op de temperatuur. Het wordt daar kouder en het is onbekend wat voor invloed dat zal hebben op de omgeving eromheen.

Dit is een beetje een drogreden: dat geldt voor alles wat je met een stuk land doet. Als je er een gebouw op neerzet dan heeft dat invloed op de flora en de fauna onder het gebouw: die verdwijnen. Teel je er gras dan staat er geen bloemkool of bos en zet je er een kas op dan heb je nog maar heel weinig dieren over (merendeel insecten en knaagdieren). Uiteraard, alles wat je grootschalig doet heeft invloed op de natuur. Maar kijk eens hoe een uranium mijn er uit ziet (oh ja, die ligt over de horizon), hoe groot de exclusion zone rond Chernobyl is (maar: wel mooie natuur!) en wat er allemaal komt kijken bij het neerzetten van een kerncentrale. De impact daarvan is enorm. Nog even los van het feit dat we grote gebieden hebben die toch al gecultiveerd worden, en of je er nou aardappelen verbouwt of zonnenergie dat maakt mij persoonlijk niet zo heel veel uit.

Verder is zonne-energie qua levering niet betrouwbaar, omdat er geen energie komt als het donker is en te weinig als het zwaarbewolkt is. Daarvoor moet er een achtervang zijn.

Ja, dat klopt. Zon alleen is niet genoeg, tenzij je bereid bent om als maatschappij in de nacht je consumptie terug te schroeven. En dat doen we al. Jarenlang hebben we op allerlei manieren juist die nachtconsumptie gestimuleerd: de dag/nacht telwerken zitten nog in heel veel huizen. Dan kon je op de goedkope nachtstroom je was doen. Ook zo leuk voor de buren. Maar goed, het was een duidelijke stimulans om de ‘baseline’ die in de nacht een stuk lager ligt wat op te vijzelen zodat de centrales efficient konden blijven draaien.

Helaas, dat kan niet meer. Maar waarom zouden we dat niet omdraaien: dagstroom. Zolang de zon schijnt betaal je minder voor je stroom. En als de zon onder is of er lokaal te weinig zonlicht is dan betaal je meer. En dat is dan best wel simplistisch want zonne energie is natuurlijk niet de enige vorm van duurzame energie. Windenergie, stromend water en nog wat niche bronnen kunnen prima gebruikt worden om de dip deels op te vangen. En de combinatie van het sturen van het verbruik (dit zou ook nog kunnen door apparaten op afstand aan te sturen), wind, zon en eventueel waterkracht samen is een hoop minder kwetsbaar dan alleen de zon. Er is geen energieleverancier die zich op een enkele bron zou toeverlaten. Dus ja, voor zon is er achtervang nodig. Maar niet zoveel als je zou denken en met wat efficienter gebruik nog veel minder.

Die achtervang wordt meestal geleverd door hetzij een kolencentrale, hetzij een biomassa centrale. Die centrale moet continu aanstaan omdat zowel een kolencentrale als een biomassa centrale niet stante pede kan worden aan- en uit gezet.

Dat is een mooi voorbeeld van iets dat echt niet klopt: zonne energie en windenergie vullen elkaar best aardig aan, het is niet perfect dus met overcapaciteit zul je een deel van het gat moeten wegwerken maar je komt er veel verder mee dan met een van de twee en ze zijn in eerste instantie elkaars achtervang. Pas als er en geen wind is en geen zon is heb je nog wat meer nodig. Maar: de wereld is inmiddels aardig verbonden, en de kans dat het over een groot deel van de aarde windstil is en er geen zon schijnt is best klein. En met High Voltage Direct Current (zeg maar: een lange afstandsverbinding voor zeer grote hoeveelheden electriciteit) is het mogelijk om die afstanden te overbruggen. Het fijne van electriciteit is dat als je de infrastructuur eenmaal hebt de marginale kosten voor het vervoeren van de electriciteit zich beperken tot in eerste orde de verliezen. En die verliezen gaan omlaag als de spanning omhoog gaat. het is dus prima mogelijk om stroom als het moet over vele duizenden kilometers te verplaatsen. En dan heb je dus pas als er over dat hele gebied en geen zon en geen wind is je achtervang nodig, en die kans is al een heel stuk kleiner dan als je dit alleen lokaal bekijkt. HVDC links schieten als paddestoelen uit de grond. Het wachten is eigenlijk op een intercontinentale variant, maar omdat ik me eigenlijk alleen wil bezighouden met de bestaande techniek, en niet met hoop (zie aanvang van dit artikel) laten we dat buiten beschouwing.

Overigens: op gridscale is de beste batterij voor dit soort doeleinden op dit moment waterstof, al is de opslag en de verwerking daarvan ook niet zonder problemen en risicos. En we gaan dit niet in een keer oplossen, maar wel geleidelijk en dat is nog zo’n mooi voordeel van zonne energie en wind energie: je kunt ze stapsgewijze bijplaatsen, conintue, iedere dag weer tot je voldoende hebt. Kernenergie centrales worden niet in een paar jaar gebouwd. Dat duurt 15 jaar of langer. Er van uitgaande dat ze afkomen (zie dit voorbeeld van eentje die het niet gehaald heeft.

Dus staat die centrale de hele tijd aan op een submaximaal niveau (dat vervuilender is dan op maximaal niveau) en wordt opgeschroefd als er onvoldoende zon is.

Het slechte ontwerp van een backup centrale kun je niet aan zonne of windenergie wijten, je zou er natuurlijk ook een kunnen gebruiken die wel afgeschaald kan worden zonder vervuilender te worden, en dat kan gewoon.

Ik neem aan dat ik niet in hoef te gaan op de duurzaamheid en milieuvriendelijkheid van een kolencentrale.

Nee, al helemaal niet omdat een kolencentrale meer radioactiviteit de lucht in gooit dan een kerncentrale (bron).

Op de biomassa kom ik nog terug omdat dat ook speelt bij windenergie.

Dat mag, maar dat is natuurlijk net zulke onzin als bij zonne energie. Zonne energie en windenergie vereisen geen biomassa of kolencentrales. Dat is echt nonsens.

De achtervang kan ook worden geleverd door een kerncentrale, maar dan heb je de zonnepanelen niet meer nodig.

Kerncentrales zijn niet iets magisch waardoor je in een klap alle capaciteit van een gebied kunt leveren. Als dat zo was dan hadden we met Borselle genoeg om deze hele uitwisseling niet te hebben. Kerncentrales hebben net als iedere andere centrale een bepaalde geinstalleerde capaciteit. Ga je op die capaciteit zitten dan ga je sneller door je brandstof heen dan als je minder gebruikt. Zonne energie en windenergie in combinatie met welke andere soort centrale dan ook zullen altijd zorgen voor een gereduceerd verbruik in die andere centrale.

Windenergie is ook niet milieuvriendelijk. De windmolens gaan maar 10 tot 15 jaar mee, en zijn niet recyclebaar. Na die 10 tot 15 jaar heb je een stuk afval wat je niks mee kan. Voornamelijk kunststof/ plastic, wat niet afbreekbaar is. En uiteindelijk in de vorm van micro-plastics in de zee en het grondwater terecht komt.

Hier worden een aantal zaken door elkaar gehaald. Allereerst: de reden dat we de afgelopen jaren in hoog tempo oudere generatie windmolens vervangen door nieuwere is tweerlei: ten eerste proberen we het aantal windmolens te beperken en de nieuwe zijn veel krachtiger dan die van een paar jaar terug. We doen nu vele malen meer per windmolen dan 15 jaar geleden (bron). Dus oude windparken zijn versneld afgeschreven. Er is kans dat dit nog een keer gaat gebeuren. Ten tweede: windmolens zijn voor een heel groot deel (de nacelle, de toren) te recylcen. De fundering niet (maar dat is een stuk inert beton) en de bladen meestal ook niet (voornamelijk: glasvezel, hout, carbon vezel, kunsthars, ook allemaal inert). Dit resulteert niet in ‘micro-plastics’, dat is een heel ander verhaal en is qua vervuilingsgraad niet te vergelijken met wat een kernenergie centrale of een kolen centrale aan afval produceren. Het enige wat er schoner is is een gas turbine gebaseerde centrale en ook die produceert (veel) CO2.

Windmolens vermoorden duizenden insecten en tientallen vogels per stuk per dag. Daar is geen oplossing voor nog, en t.a.v. de insecten is ook geen oplossing mogelijk. Die insecten maken een onvervangbaar onderdeel uit van het ecosysteem. Denk bijvoorbeeld aan de waarschuwingen vorig jaar dat er te weinig bijen zijn. De windmolens in de Noordzee maken dat gebied voor de vissen en onderwaterdieren onleefbaar.

Ook hier weer een berg onzin. Insecten worden voornamelijk door vogels vermoord, niet door windmolens (en we spreken dan over opeten, vermoorden is zo’n emotioneel beladen term), en tientallen vogels per stuk per dag is gewoon uit de lucht gegrepen. Ja, er vliegt wel eens een vogel tegen een windmolen aan. En als er een hele zwerm vogels door het rotor vlak vliegt dan ziet dat er vast minder prettig uit. Maar dat komt zelden voor. Wat wel vaak voorkomt: huiskatten die vogels opeten en vogels die tegen ramen vliegen bron. De term ‘birdbrain’ komt wel ergens vandaan. Datscheelt dus voor de katten alleen dus een factor 10,000. Dat is geen kattepis.

Insecten zijn zeer vervangbaar. De hoeveelheid insecten is als massa vele malen meer dan de mensheid, het enige wat ze nog verslaat zijn de bacterien. Overigens: op de hoogte van de gemiddelde windmolen zijn er bijna geen insecten meer, die bevinden zich voor het overgrote deel in de eerste meters boven de grond of boven een bos.

Wat de situatie op zee betreft: de oceaan is absoluut enorm. Windmolens staan over het algemeen in zeer kleine gebieden (ook al lijkt dat misschien niet zo als je er van het strand naar kijkt), omdat een park op die manier rendabeler op het net aan te sluiten is, onderwaterkabels kosten een smak geld. Dus daar zitten al best wel limieten op. Verder zijn er heel veel studies over windparken op zee en hun invloed, en er is er niet een waar uit zou blijken dat het leven in de zee voor ‘vissen en andere waterdieren onleefbaar’ zou worden. Vissen hebben veel uitwijkmogelijkheden. Als er nou een onvervangbaar koraalrif zou liggen precies waar je je windpark neer wil zetten is dat een andere kwestie.

Nu eens een leuke breinbreker: als jij een vis was en bleek dat die rottige vissers met hun bootjes niet te dicht bij zo’n windmolen willen komen omdat hun netten dan verstrikt raken, waar zou jij je kamp dan optrekken? Juist ja.

Denk maar eens aan de relatieve warmte die je ervaart als je door een fikse winterstorm loopt en in de luwte van een gebouw komt. Achter de windmolen ontstaan kleine wervelwinden en achter een groot veld is er minder wind dan er zonder dat veld zou zijn.

Errm. Nee dus. Een windmolen heeft een zogenaamd ‘zog’, en dat zog is na 3x de wiekdiameter alweer geheel verdwenen. Vandaar dat windmolens op die steek afstand in windparken ziet staan. (bron) Over grotere afstanden is het effect sterk verminderd, maar als je echt heel erg je best doet dan kun je bewijzen dat er een windmolen stroomopwaarts staat op grotere afstand. Toch maakt dat niets uit: immers, de wind is van zichzelf al zeer grillig, en je hebt geen ‘recht op wind’, ook niet op een bepaalde afstand van een windmolen. Het is immers geen zeilwedstrijd of zo, maar zich verplaatsende lucht. En of die lucht nou stilstaat of niet is een relatief klein verschil. En dan nog zo wat: volgens ‘Betz’ kun je lucht maar zoveel afremmen voordat je windmolen niet meer werkt. En dan is er nog het feit dat een windmolen alleen de lucht afremt die er doorstroomt, een kleine fractie van wat er omheen stroomt. Al met al een enorm overtrokken argument waarvan de impact eigenlijk helemaal niet negatief hoeft te zijn.

Het wordt achter dat veld dus een heel klein beetje warmer. 

Nee, het waait er wat minder. Maar dat had de wind dus ook al uit zichzelf kunnen doen.

En ook voor windenergie geldt dat die niet betrouwbaar is. Als het windstil is heb je geen energie. Dat wordt totnogtoe ook opgevangen door kolencentrales en biomassa centrales die de hele tijd aan moeten staan.

Als het windstil is heb je lokaal geen wind energie, niet geen energie. En daar komen de kolen en biomassa centrales weer die net als bij de zonne energie gewoon niets met windenergie te maken hebben.

Dit continu heen en weer schakelen tussen niet gerelateerde argumenten is een veelgebruikte taktiek om in dit soort discussies de overhand te krijgen. Ik heb er zelf een hekel aan, formuleer m’n argumenten liever wat zelfstandiger om daarna tot een totaal plaatje te komen. Anders wordt het zo’n zootje en lijkt het net of een enkel argument hout snijdt terwijl dat in het grotere plaatje helemaal niet het geval hoeft te zijn.

Dan de biomassa centrales. Die zijn ook niet milieu- of klimaatvriendelijk. 

Dat klopt, maar die zijn ‘out of scope’, we hadden het over zon, wind en kerncentrales. Dus deze gaan we er niet bij betrekken.

In theorie gebruikt men bio-afval, dus bv snoeiafval, het afval wat overblijft bij het oogsten van maïs etcetera. Dan zou het nog enigzins meevallen. Maar in de praktijk worden overal ter wereld bomen gekapt om de biomassa centrales mee te vullen. Terwijl bomen juist onderdeel zijn van de oplossing vh klimaatprobleem. Bomen zetten CO2 om in zuurstof namelijk.

Ik ga hier verder niet op in (ook hier weer een aantal aannames, maar het basis punt is valide: biomassa vervuilt en wat je aan hout verstookt heb je niet zo 1-2-3 weer in koolstof omgezet).

Bovendien levert het verbranden van hout meer CO2 uitstoot op dan het verbranden van kolen. En biomassa is hout.
Is kernenergie dan zo duurzaam? Zul je denken, waarbij je vooral denkt aan de kernafval die het produceten van kernenergie oplevert.

Nee, dat denk ik niet. Ik kijk naar het gehele plaatje: delfstoffen winning, transport, bouw, exploitatie, afvalverwerking, decomissie.

Daar geef ik een drieledig antwoord op.

Ten 1e betekent duurzaam eigenlijk dat het moet gaan om energie die niet op gaat. Dat geldt zowel voor zon-, wind- en kernenergie. Er zal altijd zon, wind en nucleaire grondstoffen zijn. Dat raakt niet op, in tegenstelling tot kolen, gas en biomassa. Klimaatvriendelijk: bij het produceren van kernenergie komen 3 dingen vrij, waterdamp, energie en kernafval. Alle drie hebben die geen positief of negatief effect op het klimaat. De waterdamp vervliegt, de energie wordt gebruikt en kernafval is ontieglijk lastig spul maar het geeft geen CO2 uitstoot of andere uitstoot.

Dat is niet wat duurzaam betekent. Duurzaam betekent: weinig impact op het milieu (zie boven). Voor kernenergie geldt dit bij uitstek niet.

En nucleaire grondstoffen zijn ook een eindige vorm van brandstof, er is genoeg voor een jaar of 80, bij huidig gebruik. Gaan we veel meer gebruiken dan is dat er dus niet (bron). Wat ik me altijd afvraag als ik dit soort argumenten lees is waar mensen hun informatie vandaan halen. Want een goed argument begint bij goede feiten.

Nucleair heeft onmiddelijk, tijdens de constructie en het maken van de brandstof al een enorme impact op het klimaat. Maar dat is helemaal niet het belangrijkste argument tegen kernenergie, dat is veel simpeler. Het is gewoon te duur. Kernenergie wordt op dit moment nergens ter wereld winstgevend geproduceerd. Zon en wind daarintegen hebben er al een paar keer voor gezorgd dat de momentele energieprijs negatief was.

Verder, als ik mag kiezen tussen sterk verminderde CO2 uitstoot, matiging van gebruik en eventueel indien echt nodig omdat we nog geen HVDC links voldoende hebben hier en daar wat gas centrales dan denk ik dat dat een werkbaar plan is. En als je dan de prijs van die door de gascentrales geleverde KWH flink hoog inschaalt dan is er een enorme stimulans om er vooral geen gebruik van te maken.

Milieuvriendelijk: doordat er geen schadelijke uitstoot is, heeft kernenergie ook geen negatieve effecten op het milieu.

Dat is dat typische over-de-horizon ding weer: zolang het maar niet in het zicht of in het heden is maken de negatieve effecten op het milieu niets uit. Alleen, zo werkt het dus niet. Die effecten zijn er gewoon of je ze nu wilt zien of niet.

Zoals het nu wordt opgeslagen levert het geen milieuschade of schade aan mensen en dieren op. En zoals ik al zei, ben ik ervan overtuigd dat we een goede manier gaan vinden om kernafval te verwerken. De mens is slim en creatief. Mijns inziens is kernenergie voor nu de beste oplossing. Er zijn veel initiatieven om nieuwe vormen van energie te vinden. Zoals zwaarwatercentrales en het halen van energie uit algen. Dat heeft nog geen werkbare oplossingen opgeleverd, maar mogelijk levert dat in de toekomst betere oplossingen. Voor nu denk ik echter dat kernenergie het schoonst is, omdat er geen schadelijke stoffen in het milieu komen en we voor nu goed werkende opslagmogelijkheden hebben voor het afval. En omdat ik ervan uitga dat we een oplossing vinden om het kernafval uiteindelijk goed te verwerken.

Dit is voornamelijk wensdenken en reeds op vele fronten door de praktijk ingehaald. Er zijn diverse plaatsen waar kernafval en of de nasleep van ongelukken heeft gezorgd voor milieuschade. En wat er in de toekomst nog uitgevonden gaat worden weten we niet, maar het geeft ons geen vrijbrief om daar een voorschot op te nemen en onze (klein)kinderen met onze ellende op te zadelen. Dat is niet fair.

Zo, dat was een heel verhaal. Ik hoop dat ik niks vergeten ben. Einde draadje.

Ik mag hopen van niet. Wat ik op vind vallen is dat dit een veelheid van informatie is die voor een niet geinformeerde leek lastig te weerleggen is. Het staat bol van de propaganda en de aannames, nog even los van de hoop. Het zou fijn zijn als iedereen die een mening over deze onderwerpen heeft zo duideijk zijn gebrek aan logisch redeneren en z’n kennis over de stand van de techniek op tafel zou leggen, dan komt er misschien nog iets van een discussie op gang.

Wat mij betreft is het simpel: het afvalprobleem en de economische factoren, gekoppeld aan het tijdsbestek waar we in zullen moeten schakelen betekenen voor mij dat kernenergie geen oplossing is, en zelfs geen deel van de oplossing is. De winnende combinatie is wat mij betreft vol inzetten op wind, HVDC en zonne energie daar waar dat kan, en verder zo veel mogelijk met economische stimulansen werken om gebruik te koppelen aan beschikbaarheid. Alleen dan gaan we er komen. Doen we dat niet dan zul je vanaf 2030 of zo je energie consumptie broeksriem strak mogen aanhalen.