Friday, November 23, 2007

e2: energy: Coal and Nuclear

In the final episode of the e2: energy PBS series, the episode covers what are probably the two most controversial sources of electricity. Coal, due to its pollution, and Nuclear due to its economic costs and wastes. But, as is pointed out at the beginning of the episode: "Energy and economic well being are infinitely linked."

The first half of the episode focuses on the problems and possible futures coal fired electric plants. While in the 20th century, new fuels were introduced, and coal was considered the fuel of the 19th century, coal is increasing the fuel of the 21st century due to growing economies and growing energy needs. The downside of our continued reliance on coal is pollution, not only in Green House Gasses, but other toxics, such as mercury. Add onto this, that any plants built now will be with us for 50 years, no one is going to shut down a power plant while it is still functional.

One possible future of coal is Carbon Capture and Sequestration. This technology hasn't been tested yet point out opponents and doubters of whether coal can ever be clean. One project, is the FutureGen coal plant sponsored by the Department of Energy. The proposed solution is to gasify the coal, remove CO2 and other polutants from the gas, and inject the CO2 into the ground. Currently undergoing site selection, between 12 sites in 7 states.
For the carbon sequestration, the carbon dioxide would be liquefied and pumped underground, not into a giant gas bag or cavern, but rather fill porous rock structures where a massive release becomes very unlikely, even with a geological event. The open questions include will this work in other than pristine pilot tests and what is the impact of this extra carbon on water supplies.

The reality is that coal isn't likely to go away, there is enough coal to supply the entire energy needs of the planet for the next 600 years according to the database. Couple that with the existing base of coal fired plants in the world, many of them newly constructed in China.

Nuclear is the focus of the second half of the episode, but nuclear is not without its detractors. It has the potential to generate vast amounts of power, it could take 10,000 windmills to replace 1 nuclear power station, for instance. But, as is pointed out the biggest hold up with nuclear is perception of risk regardless of the lack of CO2 emitted during generation of power. However, some other real problems with nuclear are storage of spent fuel, proliferation, security risks. Not mentioned in the episode is the high demand for water made by nuclear plants.

Some newer technologies are discussed that attempt to address the spent fuel and huge up front costs of building mutli-gigawatt nuclear plants. Pebble Bed technologies, safer up front, storage problem reduced due to the use of graphite encapsulation of the fuel through its entire lifecycle. Under design and review is the idea of miniature modular power plants that can be shipped and assembled onsite rather than the monolithic plants currently in use. The chief improvement of the modular plant is to achieve economies of scale at a manufacturing facility and allow easy build out of capacity at a fraction of the cost of building a large nuclear plant, using a Lego brick inspired design principle.

"Can we design our ways away from the abyss? Do we have the will, the smarts, or more importantly, the leadership?" asks the narrator.

"We should be betting on all of
these options, there is no silver bullet," says Vijay Vaitheeswaran, correspondent for The Economist.

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