Remember the time a decade or two ago when two professors announced that they had carried out a fusion reaction? Well, that didn’t work out so well and was soon forgotten. More recently it became known that a multi-national consortium including Russia, China and India as well as the European Union are building an International Thermonuclear Experimental Reactor (ITER) in the South of France (cost: $20 billion eventually) to develop fusion energy. And now it turns out that several other startups are working in this area. So, here are some highlights on what is going on, as described in the Nov. 2nd issue of Time magazine.
First, some basics. To create fusion, you have to heat atoms so high that they want to “fuse”.(This is what goes on in the sun!) On earth this means heating atoms up to 100 million degrees Celsius. At these temperatures, they becomes a plasma, which is neither a liquid or a gas. And you have to confine it without touching a surface, which it would immediately vaporize. The plasma therefore has to be controlled some other way and that is magnetically.It is a real “break” that electromagnetic fields can be used to contain and compress plasmas without actually touching them. This is usually accomplished by a device known as a tokamak(from Russian), a large hollow metal doughnut wrapped in huge electromagnetic coils.
The challenge for the plasma being created is to achieve a hot enough temperature long enough for fusion to take place. Tri Alpha is concentrating on the “long enough” part, which they deems more difficult than the “hot enough” part. The company now claims success with the former at 12 milliseconds.
As to the material subjected to these extreme conditions, this can be hydrogen, lithium, deuterium or other atoms. And the amount required is very small because of the amount of energy released. If this can be successfully done, “it will transform the world as completely as any technology in the past. Scientists think that this will happen “sooner than you think “.
Courtesy: Time Magazine
There are a number of small high-tech companies in several countries working on creating a fusion reaction, using different approaches. The apparatus being constructed by one of these, Tri Alpha Energy, is depicted above. Other companies include General Fusion near Vancouver and Helion Energy in Redmond, Washington. Investors in firms like these include Jeff Bezos, Microsoft co-founder Paul Allen and Goldman Sachs. Tri Alpha has raised “hundreds of millions” so far. The Lawrence Livermore National Laboratory has built one of the most powerful laser systems in the world which can deliver 500 trillion watts, about 1000 times as the power the U.S. is using at any given time.
The obvious goal for these machines is to get a reactor to put out more energy than is put in. According to the article, the developers are quite optimistic about this. For some time, people in the field used to say that fusion reaction is always 30 years away. Tri Alpha now believes that in three to four years, the risk changes from a science risk to an engineering risk and that within a decade there could be first commercial steps. Helion says that they will have a small (truck-sized) reactor commercial within six years.(!).
Since fusion energy plants by utilities will be very expensive, the “gain” (i.e. energy output divided by energy input) will have to be in the 15-20 range. ITER’s goal for “gain” is 10. To date, no fusion reactor has reached a ratio of 1.