Wednesday, June 28, 2006
Kicking the Carbon Habit
Dear Mr. Sweet,
I just finished your book, Kicking the Carbon Habit: Global Warming and the Case for Renewable and Nuclear Energy, and I wanted to write to commend you for it.
However, I must add that the discussion of nuclear power needs significant expansion to address a key issue, one that you clearly recognize as critical when discussing other forms of energy. We can call this the EROEI (energy return on energy invested).
There is a growing realization that nuclear plants require so much embedded energy that they are net energy sinks for a non-trivial period, and that nearly all of this energy causes the release of CO2.
That is, the enormous amounts of energy that go into making the plants (particularly in concrete but also in various steels) and the fuel rods (mining, milling, enriching, fabricating) is not at all insubstantial.
Thus, it is incorrect to ignore this or to say that nuclear plants are essentially zero carbon plants. Sure, they don't emit carbon (or anything else) while burning fuel, but that's like saying that hydrogen is a zero carbon fuel by ignoring all the carbon released in making hydrogen.
Naval nuclear plants, for example, use such high-enrichment fuel (to avoid refueling requirements) that they never produce net energy. And while civilian light water reactors do not require that kind of enrichment, new nuclear plants still start out with a huge carbon and energy debt to work off, which means it is years before they produce more energy than they consumed along the way (I have heard estimates exceeding 15 years when all the construction and fuel cycle energy use is accounted for).
Given that a plant ordered tomorrow would probably not carry base load for ten years, and would probably not reach an energy profit for at least another decade, it's very unclear whether the commitment of $100 billion for nuclear plants is a very wise investment for the United States. On a CO2 reduction per dollar basis, I suggest that the same money would be far more effectively spent on national and local rail projects (to elminate truck transport and to slash airline travel), combined heat and power plants (such as Tom Casten proposes, which you seemed to dismiss far too lightly), conservation, and small, distributed generation projects.
Again, I want to commend you for the book, especially for the sections discussing the climate modelers, which was fascinating. And I do hope you will revise and expand the third section so that it offers lay readers a more rigorous look at the energy alternatives and the net energy return they offer.