Is Nuclear Fusion the Answer to Our Energy Problems?

The release of nuclear binding energy into heat and electricity could be the ultimate solution to the current energy crisis. In order for this to happen, nuclear fusion must be technically and economically feasible, socially acceptable, and we must be certain that there are enough fusion fuels to make nuclear fusion a sustainable process, more than 1,000 years. The estimated global energy usage is about 50kWh/day/person assuming a population of 6 billion, and usage is estimated to rise to 72 kWh/d/p assuming a population of 10 billion in the next 50 years. So lets see how fusion can meet these demands.

The two most promising types of nuclear fusion are the DT reaction (deuterium to tritium) and the DD reaction (deuterium to deuterium). Deuterium is a naturally occurring isotope of hydrogen, but tritium is a heavier isotope of hydrogen that is not commonly found on its own but can be made from lithium. Therefore, DT nuclear fusion is dependent on the amount of lithium available. The current lithium reserves on land, about 9.5 million tons, is enough to provide 10 kWh/d/p (20% of current daily usage) for about 1,000 years. If we are able to use the vast resources of lithium in the ocean, we could produce 105 kWh/d/p (2 times current usage) for over 1 million years.

DD nuclear fusion has even more potential but is even more speculative than DT fusion. With 33g of deuterium naturally occurring in every ton of water, and an energy release of 100,000 kWh by fusing just one gram of deuterium, it is estimated that DD nuclear fusion could provide 30,000 kWh/d/p (600 times current usage) for 6 billion people for 10 million years!

Since 1991, several megawatts of DT reaction fusion have been released in a very controlled environment. While the technological advances in nuclear fusion will take generations to work out, other aspects such as safety, the economics, and environmental impacts have more certainty.

Unlike nuclear fission where several years worth of materials are stored in the reactor core, at each fusion instant only a small amount of fuel is present, making nuclear explosions such as the one in Chernobyl highly unlikely. Also, Tritium is the only radioactive material needed for fusion (until DD reaction becomes viable.) Deuterium and Lithium are not radioactive, and the direct product Helium, has no greenhouse effects, is not radioactive, and is an inert gas that can be used other ways in industry.

Presently, a fusion power plant is estimated to cost a little bit more than what a nuclear plant today costs and will have to have an output of greater than 1GW to be cost effective; however, the fuel will be cheap and abundant. The fact that the fuel sources are inexhaustible and the increasing cost of electricity created by exhaustible resources must also be taken into account when considering the overall economic viability of nuclear fusion.

There is no mistaking the technical difficulty of bringing even the DT nuclear reaction to a commercially viable point, but there has been no indication that it will not be successful someday. With its potentially massive benefits over current electricity production, I think fusion investments and development efforts should continue.

Sources:

1) Eckhartt, D. (1995). Nuclear fuels for low-betafusionreactors:

Lithiumresources revisited. Journal of FusionEnergy, 14(4):329–

341. ISSN0164-0313(Print) 1572-9591(Online). doi: 10.1007/

BF02214511. http://www.springerlink.com/content/35470543rj8t2gk1/.

2) Ongena, J. andVanOost, G. (2006). Energyforfuturecenturies.

Will fusionbeaninexhaustible, safeandcleanenergysource?

http://www.fusie-energie.nl/artikelen/ongena.pdf.

3) Mackay, David. (2009). “Sustainable Energy – Without the Hot Air.”

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