Monday, May 18, 2009

Is Nuclear Fusion the Answer

I was asked on another site why I advocate renewable energy forms such as wind, and solar, rather than research into nuclear fusion.  The point was made that diffuse energy sources (wind and solar) require vast transmission lines that are ugly and ruin the landscape.  I replied that I am a rational environmentalist, and completely enjoy the outdoors. Few things are as refreshing as hiking and camping through the High Sierras or sailing the high seas.

But as an engineer, I am also aware that the benefits of abundant energy are worth the costs of having it. Economies of scale dictate that power lines will be built to bring the power from the large generating plant to the consumer. Distributed generation, as that term is now used, reduces the need for power lines because the power is generated either on-site, or much closer to the consumer. Cogeneration in industrial facilities also reduces the need for transmission lines. The realities of solar and wind power require some transmission lines to collect and send the power to the consumers.

One could also argue that telephone poles across the land are a blight, yet for decades that was (and still is) the case, just so consumers could use telephones rather than wait for snail mail for communication. Roads, highways, bridges, railroads, ports, cities, all are useful yet change the natural landscape.

As for nuclear fusion, it has been a long while since I looked into the state of that art (early 1980’s). There seem to be insurmountable difficulties in finding materials of construction that will not melt or evaporate at the very high temperatures obtained in a fusion reaction. Magnetic pinch bottles were used, and perhaps still are, to squeeze plasma until it begins the fusion process. Even if that fusion process is someday sustainable (they were thrilled at achieving fusion temperature for a fraction of a second), melt-down is a very real problem.

There were two fundamental problems to overcome, the first being how to sustain the fusion reaction, the second how to keep the thing from melting. Sustaining the fusion reaction required a magnetic bottle with an inlet for fresh fuel, and an outlet for the reaction products. The nature of a magnetic bottle does not allow for inlets or outlets, at least at that time. There may have been advances since then, I do not know.

Then, finding a way to do something useful with the heat without melting the reactor is a bit of a problem. The materials science professors and researchers were having quite a bit of difficulty with that one. It had something to do with the energy of inter-atomic bonding, under which everything they tried disintegrated at those temperatures.

It is a very good thing that the sun is so very far away from Earth.

Therefore, unless some amazing breakthroughs in magnetic bottles and heat-resistant materials have occurred, or will occur, fusion is off the list of energy providers.

We (the engineers) are much closer to having renewable energy storage systems that work reliably and economically. At that point, wind, solar, wave, and ocean current energy will provide everlasting, cheap, reliable power. And that is a very good thing.

Roger E. Sowell, Esq. 

1 comment:

Anonymous said...

It's been said that nuclear fusion is the power of the future - and always will be.

Andrew W