Now that summer is coming to a close I think it’s time to get the project moving. I can’t really afford it but with some modest expenditure I think I can get the vacuum chamber up and running.
It occurs to me that the project needs some sort of aim. Although ultimately I’m just playing at this, there should be some point to the experiments.
The big fusion experiments – NIF and ITER – are likely to succeed in generating net power at some point in the near-ish future. Then what? You can be sure that domestic electricity bills won’t go down. The power companies will simply claim that new fusion power stations require huge capital expenditure to justify keeping bills high (or even increasing them). One way or another the status quo will remain the same.
More importantly, these giant power stations will not help developing nations which cannot afford to build huge national delivery grids (which in any case suffer from transmission losses). In some, particularly mountainous, places it is simply impractical to build pylons and power lines.
Fuel cell technology may yet develop to the point where it becomes a realistic method of powering vehicles. The problem is that fuel cells run on hydrogen and hydrogen is currently produced in volume by cracking methane using steam. This requires large amounts of power and generates CO2; not good for the planet.
Thomas Edison’s vision for power delivery was to have neighbourhood power stations. He was wildly wrong in one respect – he wanted to use DC voltage. Thank god for Nikola Tesla who realised that high voltage AC was the more efficient method of delivery. Still, local production of high voltage AC power offers an intriguing prospect.
If fusion is really going to deliver on its promise then it needs to be delivered in a more democratic way. While ITER and NIF can press ahead with multi-megawatt reactor designs I want the aim of this project to deliver a small, portable reactor. I know that realistically I don’t have a chance but I want this to guide the experiments I do.
Imagine if you could build a small scale fusion reactor about the size of a modern car engine, delivering say 50KW. Every home would have one the wall next to the boiler. There would be no transmission losses and power generation would be taken out of the hands of a few big corporates. It would be simple to roll such devices out to every village in the developing world bringing power to everybody equally. If it were light enough you could put it in a car and solve the problems of fossil fuels overnight. It’s a bold vision but a democratising and highly disruptive one.
So this is the goal of the project – to build a small 50KW reactor (luckily one that fits inside the vacuum chamber I have). It may not be possible at all but it’s worth pursuing and you can be sure that no big corporation or research project is looking at it.
There are some big challenges with a small scale reactor. The first of these is heat. Much of the energy of a fusion reaction is releases in the kinetic energy of the reaction products. This means heat. Trying to recover the heat output of 20 kettles quietly, in a small space is a problem. Not an insurmountable though.
Another problem is the reaction products themselves. The cheapest and most plentiful fuel is deuterium but D-D reactions produce high energy neutrons. These cause problems with energy recovery, shielding and their effect on the reactor components. Nobody wants a highly radioactive box on their kitchen wall. The answer, then, lies in advanced aneutronic reactions such as proton-Boron11 but then these require much higher temperatures.