Tuesday, March 15, 2011

Nuclear vs Solar

The tragedy of the earthquake and subsequent tsunami in Japan have now raised the threat of nuclear radiation escaping from nuclear reactors melting down and releasing atomic radiation into the air. This danger, along with the difficulties of storing used and highly radioactive fuel and materials have long stymied the expansion of nuclear power. The Three Mile Island accident in the U.S. during the 1970's and the Chernobyl nuclear disaster in 1980's pointed to the danger that nuclear energy poses. How ever, the threat from chemical & fossil fuel energies have become apparent in the last 20 years. This danger, both to human health and the global climate have suggested that the only way to power our advanced technological civilization necessarily involves more nuclear power.

The argument arises from the assertion that wind and solar power are insufficient to provide the necessary energy. Given that wind arises from solar energy– the heating and cooling of air masses by the sun's heat– how much energy actually reaches earth?  And how much energy do humans use?

It is estimated that the earth receives 1.8 x 1017 Joules/s (1) or about 1.6 x 1022Joules everyday from the sun. In contrast, humans consume about 4.7 x 1020Joules(I derived this figure by converting the Tonnes of Oil equivalent provide by BP into joules). Elsewhere I have seen figures of total energy consumption a magnitude smaller. So total human energy consumption seems to range between a 1/10 of a percent and 1 percent of solar energy. So why can't we gather that energy? It would require turning over 1 percent of the earth's surface to energy production with up to 3 percent to accomodate population growth and increased demand. On the other hand, we wouldn't be injecting an extra 1 to 3 percent of the energy the planet's ecology has evolved to cope with, with the attendant pollution.

So if we want to maintain the lives we enjoy, we either have to accept the dangers of nuclear radiation or that massive changes as we incorporate solar, wind and wave power.  

(1) http://helios.gsfc.nasa.gov/qa_sun.html#sunenergymass


"If I had to choose between betraying my country and betraying my friend, I hope I should have the guts to betray my country."
-E.M. Forster