Retrofitting Coal Power

I got lucky last fall. Together with a friend I toured what many consider America’s most important power plant to see the future of coal. But it turns out: There is nothing to see, really. Long pipes connect the colossal Mountaineer Power Plant on the Ohio River to a structure four stories tall made of metal beams and aluminum tubes. Three hundred feet further down the road a pump station sits listlessly under the winter sky, two pipes disappear in the ground. That’s it. Nothing is moving. But energy companies and politicians along with environmentalists the world over are watching closely what’s happening in New Haven, West Virginia.

Here the United States government and American Electric Power, America’s biggest provider of electricity, are developing a technology that attaches to a coal plant, filters carbon dioxide out of the power plant’s emissions and stores the gas directly underground. Their goal: Pioneering a process that reduces CO2 emissions, which significantly contribute to manmade global warming, and thus creating a future for the most abundant energy resource in the US. The pilot project is the first of it’s kind in the world. It got under way in September and the Department of Energy just announced that it would fund its expansion with $334 million dollars.

The importance of the project becomes clear when we consider the role coal plays in the US economy – and in climate change science. America generates nearly 50 percent of it’s electricity with coal and is home to the lion share of the world’s known coal reserves, some 27 percent. At the same time, the fuel is responsible for 80 percent of all CO2 emissions in the power sector and a big reason why the United States, a country with less than 5 percent of the world’s population, produces more than 20 percent of global carbon dioxide emissions.

Enter carbon capture and sequestration, as the technology at the 30-year-old Moutaineer plant is called. Or CCS for short. Essentially it consists of a chemical factory and two deep wells, AEP engineer Gary Spitznogle told me. “In the factory smoke that has been diverted from the plant’s chimney is mixed with a chilled ammonia-based chemical. Once the mixture is heated, the carbon dioxide separates itself and is pumped nearly two miles into the earth under a protective layer of sandstone,” explains Spitznogle. There the liquid CO2 displaces saltwater from fine pores in a layer of dolomite and stays put, theoretically of tens of thousands of years.

At the moment AEP is operating a small-scale validation of the technology together with the French company Alstom, which captures less than 2 percent of the CO2 emitted by the power plant. But with the financial assistance of the federal government, equivalent to half the cost of the projects next phase, AEP plans to scale-up the project until 2015. At that point the CCS project is supposed to capture 90 percent of the carbon dioxide from 235 megawatt of the plant’s 1,300 megawatt capacity. With the help of of CCS technology AEP, America’s biggest emitter of CO2, could eliminate all CO2 emissions by retrofitting their fleet of existing coal plants by 2025, says the company’s CEO Mike Morris.

But whether or not those long-term goals are achievable, remains to be seen. From the power generator’s perspective lowering the operating cost is the first priority. CCS is only cost-effective for AEP if the technology consumes 20 percent of the electricity generated in the plant or less – currently the test unit is using 35 percent. At this price coal power could easily cost as much as or more than nuclear or solar power. Project risk analyses also list geological shifts, earthquakes and contamination of water supplies as potential complications, according to the New York Times, all of which worry residents. Most importantly though, in order to move the CO2 emitted by all 600 US coal-plant to places where the gas could be stored underground, a giant national pipeline network would have to be constructed. Many regions of US have little to no storage capacity.

That’s why advocates of renewable energy think CCS the wrong investment. David Holtz, executive Director of Progress Michigan, an environmental group, told the New York Times CCS resembled a methadone cure for addiction. He argues the industry would do better to go cold turkey. “There is no evidence that burying carbon dioxide in the earth is a better strategy than aggressively pursuing alternatives that clearly are better for the environment and will in the long-run be less costly.”

Power generators like AEP disagree and are eager to see the New Haven CCS project supply evidence of coal’s cleaner future. The rest of the world will be watching too.

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3 Comments

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3 responses to “Retrofitting Coal Power

  1. Alex

    Carbon capture and storage (CCS) technology is an essential medium term solution to mitigating greenhouse gas emissions in the United States.

    The United States alone employs over 300GW of coal power, which accounts for ~50% of total electricity production and 30% of CO2 emissions. China uses coal to produce 80% of its power, amounting to an additional 223GW–with more being added every year [1]. Replacing this coal power with solar power would require 6,642 square miles of panels at the equator (assuming 30%CF, 10%eff., 1kW/m^2 solar intensity). Clearly any attempt to mitigate climate change must reduce these emissions without shutting down these plants.

    As a recent perspective in “Science” [2] points out, the challenges faced with carbon capture mirror those encountered when limestone slurry scrubbing was first proposed as a means of mitigating SOx emissions. “Limestone slurry scrubbing for flue gas desulfurization was first applied at two British plants in 1936, and was identified as an effective technology as early as 1965. However, it was deemed to have unacceptable capital cost, poor reliability, and poor environmental performance, as well as being too commercial, and therefore was considered an unworthy candidate for government-funded research and development. Work on limestone slurry scrubbing continued, nevertheless, gaining increasing attention through the 1970s and beyond, and now it is the dominant technology for flue gas desulfurization.”

    The IPCC even issued a special report [3] evaluating this technology. The conclusion was that “In most scenarios for stabilization of atmospheric greenhouse gas concentrations between 450 and 750 ppmv CO2 and in a least-cost portfolio of mitigation options, the economic potential of CCS would amount to 220–2,200 GtCO2 cumulatively, which would mean that CCS contributes 15–55% to the cumulative mitigation effort worldwide until 2100, averaged over a range of baseline scenarios.” The report also concluded that the combined cost of capture, transportation, and geological sequestration of CO2 is $17-91/tCO2.

    Assuming 2.1lb CO2/ kwh electricity produced, this amounts to an additional 1.6-8.7c/kwh (on top of the ~5c/kwh wholesale price)–not a small amount, but much cheaper than pricey solar power.

    CCS is a viable technology that we have a lot of experience with. Over 2500km of pipelines are currently used to transport CO2 for enhanced oil recovery in the western United States [3]. In addition, “hundreds of plants currently remove CO2 from natural gas, hydrogen, and other gases with low oxygen.” CCS has applicability beyond coal–it can be employed to scrub CO2 from coal or natural gas flue gas (which has about half the carbon emissions as coal). Numerous plants and demonstration projects around the world have proved that CCS works at a small scale (up to 40MW), and a reasonable timeline for scale-up would allow an 800MW CCS plant to come online as early as 2013 [2].

    CCS is not only a viable and practical technology, but an essential one. All of the IPCC’s mitigation scenarios include a substantial wedge for CCS emissions reductions. The world cannot afford to wait any longer to encourge the swift and large-scale deployment of this technology.

    References:

    [1] http://www.world-nuclear.org/info/inf63.html

    [2] G. Rochelle, Amine Scrubbing for CO2 Capture, Science, V325, P1653, 25 Sep 09

    [3] http://www.ipcc.ch/pdf/special-reports/srccs/srccs_wholereport.pdf

  2. theakvoice

    Carbon capture and storage (CCS) technology is an essential medium term solution to mitigating greenhouse gas emissions in the United States.

    The United States alone employs over 300GW of coal power, which accounts for ~50% of total electricity production and 30% of CO2 emissions. China uses coal to produce 80% of its power, amounting to an additional 223GW–with more being added every year [1]. Replacing this coal power with solar power would require 6,642 square miles of panels at the equator (assuming 30%CF, 10%eff., 1kW/m^2 solar intensity). Clearly any attempt to mitigate climate change must reduce these emissions without shutting down these plants.

    As a recent perspective in “Science” [2] points out, the challenges faced with carbon capture mirror those encountered when limestone slurry scrubbing was first proposed as a means of mitigating SOx emissions. “Limestone slurry scrubbing for flue gas desulfurization was first applied at two British plants in 1936, and was identified as an effective technology as early as 1965. However, it was deemed to have unacceptable capital cost, poor reliability, and poor environmental performance, as well as being too commercial, and therefore was considered an unworthy candidate for government-funded research and development. Work on limestone slurry scrubbing continued, nevertheless, gaining increasing attention through the 1970s and beyond, and now it is the dominant technology for flue gas desulfurization.”

    The IPCC even issued a special report [3] evaluating this technology. The conclusion was that “In most scenarios for stabilization of atmospheric greenhouse gas concentrations between 450 and 750 ppmv CO2 and in a least-cost portfolio of mitigation options, the economic potential of CCS would amount to 220–2,200 GtCO2 cumulatively, which would mean that CCS contributes 15–55% to the cumulative mitigation effort worldwide until 2100, averaged over a range of baseline scenarios.” The report also concluded that the combined cost of capture, transportation, and geological sequestration of CO2 is $17-91/tCO2.

    Assuming 2.1lb CO2/ kwh electricity produced, this amounts to an additional 1.6-8.7c/kwh (on top of the ~5c/kwh wholesale price)–not a small amount, but much cheaper than pricey solar power.

    CCS is a viable technology that we have a lot of experience with. Over 2500km of pipelines are currently used to transport CO2 for enhanced oil recovery in the western United States [3]. In addition, “hundreds of plants currently remove CO2 from natural gas, hydrogen, and other gases with low oxygen.” CCS has applicability beyond coal–it can be employed to scrub CO2 from coal or natural gas flue gas (which has about half the carbon emissions as coal). Numerous plants and demonstration projects around the world have proved that CCS works at a small scale (up to 40MW), and a reasonable timeline for scale-up would allow an 800MW CCS plant to come online as early as 2013 [2].

    CCS is not only a viable and practical technology, but an essential one. All of the IPCC’s mitigation scenarios include a substantial wedge for CCS emissions reductions. The world cannot afford to wait any longer to encourge the swift and large-scale deployment of this technology.

    References:

    [1] G. Rochelle, Amine Scrubbing for CO2 Capture, Science, V325, P1653, 25 Sep 09

    [2] http://www.world-nuclear.org/info/inf63.html

    [3] http://www.ipcc.ch/pdf/special-reports/srccs/srccs_wholereport.pdf

  3. shpant

    Notwithstanding our trying to transition to carbon-free electric power, coal plants will still continue to operate for decades. Once they are built, they are the cheapest source of base load power generation in most cases and they will not be phased out unless there is an appreciable economic incentive, viz. a high price on carbon. Unfortunately, there is no guarantee that the entire world will shake hands on such a carbon price. Given this understanding, and the awareness that we have to achieve significant reductions soon, retrofitting coal power plants with CCS is an effective strategy for reducing CO2 emissions; despite what renewable energy proponents may feel.

    However, one size does not fit all! Due to the high costs of CCS, it does not make sense to retrofit all 600 U.S. coal-plants nor build “giant national pipeline networks.” Retrofitting coal plants should be a decision made on a case-by-case basis with not only a cost-benefit analysis, but also a complete evaluation of site specific factors. For example, retrofitting is not an attractive option for old, low efficiency, small plants since the cost of retrofitting varies with age (increases for older units) and condition of the plants. Why squander money in retrofitting old plants when we could use it to chart future roadmaps for alternate energies like nuclear or solar?

    According to a recent MIT report, high efficiency, relatively large plants of capacity 300MWe or more are ideal for CCS retrofitting. These plants constitute slightly less than half of the standing units. The report estimates that 90% carbon capture, from 59% of existing coal power capacity in the United States, decreases 50% of the power sector CO2 emissions. Other factors for evaluating retrofitting decisions include closeness to CO2 pipelines; availability of capture space, water; and SO2 & NOx reduction capabilities of the power plant.

    Additionally, since there is no one panacea for reducing carbon emissions, there has to be considerable flexibility in our approaches to the problem. CCS is one way of retrofitting coal power; but other relatively simpler ways such as efficiency retrofits and biomass co-firing should be a part of the mix too. The report indicates that efficiency retrofits for older, lower efficiency plants provides a 4% – 5% reduction in carbon emissions with a “high benefit/cost ratio” for carbon reduction.

    Finally, to be able to formulate policy decisions for implementing CCS, an inventory of power plants and their relevant attributes needs to be created. This will help in assessing the true potential of CCS in CO2 mitigation.

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