Via Washington Post : "American Electric Power, a major electric utility, is planning the largest demonstration yet of capturing carbon dioxide from a coal-fired power plant and pumping it deep underground". The technology involves " a new process — so far tested only at laboratory scale — that uses chilled ammonia to absorb the gas for collection. The process was developed by Alstom , a major manufacturer of generating equipment, and aims to reduce the amount of energy required to capture the carbon dioxide". By putting the long pipe dream of sequestration (pun intended) to test, AEP is going a long way to satisfy the critiques offered in a recent MIT study. We note from the Alstrom site that:- "The technology has the great advantage versus other technologies of being fully applicable not only for new power plants, but also for the retrofit of existing coal-fired power plants The captured CO2 will be designated for geological storage in deep saline aquifers at the site."Even if the prototype containment project is cost effective and reliable, there is more to think about. Coal plant stack scrubbing to remove sulfur oxides (SOX) alone can "parasitize" up to 25% of the power output. Mercury scrubbing and/or particulate removal as separate projects would take more energy still. The WaPo article adds that:- "Some experts have estimated that nearly a third of a power plant's energy output might be needed to pull carbon dioxide from the waste stream. Alstom hopes to hold it to 15 percent".
So, lets put the old micrometer on the fog bank and sum the total pollution control power losses. If the pollution control trains are bolted on separately, the power losses might average 20% for SOX + 15% for C02 + another 10% for particulates and mercury removal. Power output nearly half gone, plus or minus 10%.
That cumulative power loss explains the importance of an integrated pollution control system cost-effectively handling all the major pollutants with a single investment. And, it explains why there's been so much push back against EPA implementing New Source Review and regulating C02 as a major pollutant.
For modest details on the Alstom ammonia based pollution control technology look here .
If this test application is a success from a sequestration standpoint, and the scale-up to commercial determined to be cost effective, where might the technology be deployed? Deep saline aquifers, like those shown in the post graphic, where saline groundwater precludes withdrawal for potable water supply, are optimal. Image credit: US Department of Energy .