Tuesday, July 17, 2007

Rethinking Nuclear

Periodically, I've noted the growing interest in nuclear power as a source of low-greenhouse-gas energy, and the way this issue is splitting environmentalists. Designs for generating electricity safely and reliably using nuclear fission have improved steadily since the last big wave of nuclear construction peaked, at least in the US--Japan and France built dozens of plants after we stopped. But while the technology has advanced, I wonder whether our mindset about it remains stuck in the model that prevailed in the 1980s, when large, centralized power plants were the norm everywhere. Is it time to rethink the application of nuclear energy to maximize its leverage on reducing greenhouse gas emissions?

What if nuclear power hadn't been discovered before World War II, and instead had emerged from the laboratory only a few years ago? How might we consider exploiting an energy source with its properties today, without the baggage of the last sixty-plus years? Is it pre-determined that the only way to tap the energy of the atom is in 1,000 MW increments? The record of the US nuclear naval propulsion program suggests otherwise. Consider the difference between coal-fired power plants and those burning natural gas. There are important economies of scale in the transportation and handling of coal, and in the sizing of boilers, that create a strong bias towards large plants. In contrast, gas-fired power comes in a wide variety of sizes, from under 100 kW to hundreds of MW, at least in part because the fuel infrastructure is so simple. So is nuclear power more like coal or gas in this regard? It's probably somewhere in between, after you factor in the need to contain the radioactive fuel.

I can think of lots of ways to use a medium-sized source of intense heat that doesn't need to be re-fueled continuously, and making power is only a sub-set of those applications. Combined-heat-and-power (CHP) at facilities that need large quantities of process heat and currently burn huge amounts of fossil fuels might be a better, more efficient candidate. Oil sands production shares those characteristics, and there was a brief flirtation with this idea several years ago. And I recently ran across the website of a company that wants to use nuclear energy in an even more novel way, for coal-to-liquids. CTL requires both process heat and large quantities of hydrogen to upgrade solid coal to liquid hydrocarbons, and using nuclear power, rather than coal or natural gas for these purposes would shrink the net emissions of CTL fuels down to roughly the same range as petroleum products.

Realistically, we can't ignore the legacy of the Cold War or nuclear accidents, nor the prospect of further weapons proliferation or WMD terrorism. But that doesn't mean we shouldn't examine where a "clean sheet" approach to nuclear energy might take us, particularly if it involved smaller scales, quicker implementation, and fuel cycles that are less vulnerable to accidents or proliferation. That might not be sufficient to convince critics to turn in their "No Nukes" signs, but it would go a long way towards convincing the public that nuclear energy is a viable element of our low-carbon energy future.

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