Tuesday, March 27, 2012

The Beginning of the End for Coal?

I saw in Tuesday's Washington Post that the EPA was ready to issue its proposed rules for CO2 emissions from new power plants. When finalized, these rules would apply to facilities larger than 25 MW that begin construction more than a year hence. As the Post notes, the chosen CO2 emissions limit of 1,000 lb. per gross Megawatt-hour (MWh) generated would make it virtually impossible for a new conventional coal-fired generating plant to comply with this requirement. That looks like another positive for natural gas, which is coal's nearest competitor today. It might also help baseload renewables such as geothermal, since wind and solar power don't ordinarily compete directly with coal. However, anyone reading this as the epitaph for coal in the US shouldn't be too hasty, because the EPA has left room for technology and other strategies to keep coal in the future mix.

I'm completely swamped with work and other commitments at the moment, so this posting will be more like an extended Tweet. However, I thought this news was too important not to comment on it, however briefly. Lacking the time to research these data myself, I'll rely on Ms. Eilperin's thoroughness and use her figures of 1,768 lb. CO2/MWh for the average US coal plant and 800-850 lb./MWh for gas. The latter is certainly a long way from state of the art, and I'm sure that a modern ultra supercritical coal plant would come in considerably below the 1,768 lb. mark, as well, yet still above the magic half ton. What intrigues me about the EPA's chosen performance standard is that meeting it would require much less than 100% capture and sequestration of a facility's CO2 emissions. Perhaps as little as 25-30% would be sufficient, particularly, if the plant were also designed to be co-fired with biomass, as some existing coal plants are. That combination, or some other similar strategy, could significantly reduce the cost of compliance and keep coal in the game.

I know that outcome wouldn't please those who see coal as not only the logical place to seek large-scale greenhouse emissions reductions, but also a major contributor to various local environmental impacts. Yet it's also an enormous domestic energy source, the global demand for which continues to grow. Moreover, as coal is increasingly displaced from power generation by cheap natural gas, its price is likely to drop, making it more competitive for export. So perhaps this isn't the beginning of the end for coal in the US, but just the start of a new phase.

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