by nanne
Thu Aug 20th, 2009 at 05:33:14 AM EST
In reply to an article finding that the cost of carbon capture and storage might be prohibitive, Magnifico writes:
Or... we could stop using coal, since Coal Is Carbon CapturedTM. Why take it out the ground, capture the carbon, and then stick it back in the ground. Wouldn't it be simpler, cleaner, and less destructive to simply just not take coal out of the ground in the first place?
Simpler, cleaner, less destructive: surely. The issue is, can we manage to leave all the cheap coal in the ground?
Cost estimates for CCS vary a lot. In the Stern Review, which favours CCS, it is assumed that there is a central range of costs that varies between $19 and $49 per ton of carbon dioxide. A NYT article quotes a researcher who assumes a cost of $60 to $65. The article cited by Magnifico uses figures ranging between $120 and $180, or (presumably) half of that 'as the technology matures'.
Diary rescue by Migeru
Carbon capture and storage may make sense if we only look at climate change. The domestic political economy on climate change legislation will be a lot easier in many countries if we can co-opt the coal lobby. International coordination will also be easier, provided that we can convince India and China to go along when the technology has 'matured' - we will not have to worry as much about a disadvantages to our energy-intensive industries.
In terms of climate change, the upside of CCS is that the technology can remove up to 80-90 percent of carbon dioxide emissions at what could be a lower cost than replacing fossil fuel plants with renewables, with the main downside being uncertainty related to sequestration. However, coal has a variety of negative effects aside of causing climate change, like emissions of heavy metals and the destruction of nature and landscape that accompanies its extraction.
What really makes CCS a misdirected research strategy, though, is that it will cause efficiency losses of at least 10% for capture, and a few more for transport and sequestration. The European Commission estimates a 35% net efficiency for a demonstration project to be launched in 2015, as opposed to a 45-47% current net efficiency for new coal plants without CCS. So, we will need a lot more coal to feed CCS plants. While coal is not yet on the brink of running out, there is less cheap coal available for extraction than has been assumed, as the Wall Street Journal pointed out this June:
Last year, the U.S. Geological Survey completed an extensive analysis of Wyoming's Gillette coal field, the nation's largest and most productive, and determined that less than 6% of the coal in its biggest beds could be mined profitably, even at prices higher than today's.
"We really can't say we're the Saudi Arabia of coal anymore," says Brenda Pierce, head of the USGS team that conducted the study.
No one says the U.S. is facing a coal shortage. But the emerging ranks of "peak coal" theorists argue that current production levels may be unsustainable and, if anything, create a false sense of security. David Rutledge, an electrical-engineering professor at the California Institute of Technology who has studied global coal production, figures the U.S. has about half as much recoverable reserves as the government says, which would work out to about 120 years' worth
Given that we will need to replace parts of the existing stock of power plants, that centralised coal power plants are built for a period of around 50 years, that we need to be able to phase out fossil fuels, and that there is a need to reduce greenhouse gas emissions in the current time, there is an obvious solution. Power plants need to be a lot more efficient, and power plants need to be able to run on more than one fuel. We have long had the technology for multi-fuel
combined heat (cooling) and power plants. A plant of this kind run with coal will achieve efficiencies of 70% and above. The technology is highly scaleable. As the plants are generally built for a shorter period of time, there will be no sunk costs when renewables become cheaper, and local CHP using biomass or waste gas as fuel can be a good complement to solar and wind energy.
