Monday, July 2, 2012

Carbon Capture- Will It Save Us?

Last week a three-judge panel of the U.S. Court of Appeals in Washington ruled that the U.S. Environmental Protection Agency, EPA, had “substantial record evidence” that greenhouse gases probably caused the climate to warm over the past several decades, the EPA had concluded that greenhouse gases are pollutants that endanger human health in 2009.  Opponents to that determination had essentially asked the Court to re-weigh the scientific evidence before EPA and reach their own conclusion. However, the three judge panel wrote in the opinion for the case that. “(t)his is not our role.”

 Back in  December 2009,  the EPA officially found that greenhouse gases in the atmosphere threaten the public health and welfare of current and future generations the agency,  and started on the path to regulate carbon dioxide, CO2, after the  "American Clean Energy and Security Act”, also known as the Waxman-Markley energy bill was defeated in the Senate. After collecting CO2 emission data from industry the EPA “found” in 2012 that the largest carbon dioxide generators are the largest stationary combustion sources. It was no surprise that the largest (coal) electrical generation and industrial plants in the nation- big furnaces generate more CO2. For the past decade electrical generation has accounted for approximately 40% of the carbon dioxide emissions in the United States and worldwide. At the end of March 2012, the EPA proposed the first Clean Air Act standard for CO2 rule targeted at power plants.  The agency plans to phase in industrial facilities covered by the carbon rules through 2016. Under the new rule, new power plants will have to emit no more than 1,000 tons of CO2 per megawatt-hour of energy produced. That standard effectively changes the fuel of choice for all future power capacity additions to natural gas, nuclear, or the renewable category (with government subsidies). All existing plants and currently permitted and built in the next 12 months will be grandfathered and exempt from this new rule for now.

Coal electrical generation plants currently produce about 1,800 pounds of carbon dioxide per megawatt-hour of electricity. EPA says the CO2 rule that requires new plants to produce no more than 1,000 pounds of CO2 per megawatt-hour as creating “a path forward for new technologies to be deployed at future facilities that will allow companies to burn coal, while emitting less carbon pollution.” The EPA in their new regulations and Department of Energy, DOE, in their research grants are pushing forward on the development of Carbon Capture. In June the International Energy Agency, IEA, released its preliminary 2011 estimates of world CO2 emissions from fossil fuel combustion. World CO2 emissions rose by 1 billion metric tons, a 3.2 % increase over last year to reach 31.6 billion metric tons. The worldwide level of CO2 is now higher than the worst-case scenario outlined by climate experts just five years ago and within 1 billion metric tons of the IEA point of no return. (That is the point where mankind cannot hold global warming at 2 degrees Celsius.)
 In 2011 the top four world generators of CO2 emission from fossil fuels were (from highest to lowest) China, the United States, the European Union and India who edged out Russia to take the number four slot. China increased emissions contributed almost three quarters of the global increase, with its emissions rising by 720 million metric tons, or 9.3% to 8.46 billion metric tons of CO2, primarily due to higher coal consumption. India’s emissions rose by 140 million metric tons or 8.7% to 1.75 billion metric tons. Since 2000, China has more than tripled its installed capacity of coal power plants, while India’s capacity has increased by 50%. Neither country has used the most efficient designs and technologies available for those plants and those plants will continue to operate 24/7 for decades to come.

CO2 emissions in the United States, in contrast, fell by 92 million metric tons in 2011, or 1.7% to an estimated 5.32 billion metric tons. The European Union increased their CO2 emissions from fossil fuel by 69 million metric tons to approximately 3.56 billion metric tons. Japan’s CO2 emissions increased by 28 million metric tons, or 2.4% to approximately 1.19 billion metric tons, as a result of a substantial increase in the use of fossil fuels in power generation post-Fukushima tsunami. Russia and Canada reportedly remained fairly stable from the previous year. Nonetheless, the IEA still believes that it is still possible to prevent the earth’s temperature from rising more than 2 degrees Celsius if “timely and significant government policy action is taken, and a range of clean energy technologies are developed and deployed globally.” One of the key technologies according to the IEA is carbon capture.

In 2009 DOE supported eleven projects to conduct site characterization of geological formations for CO2 storage. Carbon capture is really three activities: Gathering or capturing of CO2 from point sources (power plants, industrial plants, and refineries), transporting the captured CO2 to a geological storage site, and injecting the CO2 into the ground for permanent storage and monitoring the site for eternity. Capturing and transporting CO2 from industrial plants is technologically possible but is currently prohibitively expensive, though DOE’s National Energy Technology Laboratory and several universities are exploring ways to bring down the costs or raise the costs of other energy sources.  A significant portion of the CO2 generated in the United States and the world is not generated from large stationary point sources, but from cars, homes, and smaller sites. Only about a quarter of the CO2 generated from fossil fuel combustion annually is generated at large point sources the only possible capture points. Storing even a portion of this amount of CO2 would require capturing the gas at many locations around the country and transporting it to facilities that could inject the CO2 into appropriate subsurface rock formations. According to the researchers efficient underground storage of CO2 requires that it be in the supercritical (liquid) phase to minimize required storage volume.

In order for CO2 to remain in a supercritical phase, the pressure in the storage reservoir must be greater than about 68 atmospheres and at temperatures above 31.1°C. (Sminchak et al., 2001). These conditions require that the CO2 be injected at high pressures, which can only be achieved at depths greater than about 2,600 feet below the earth’s surface. The supercritical CO2 will be injected into the geologic formations that are overlain by appropriate sealing formations and geologic traps that will prevent the CO2 from escaping as the CO2 injection well remains in continuous operation for years or decades. The volumes of supercritical CO2 envisioned for carbon capture are huge. A recent U.S. National Research Council report suggests that carbon capture and deep earth sequestering could potentially induce earthquakes because significant volumes of fluids are injected underground over long periods of time. However, insufficient data exists at this time to evaluate this risk. An IPCC Special Report on CO2 capture and storage suggests that between 73 and 183 million metric tons of CO2 could be captured and stored worldwide from both coal and natural gas energy plants each year (Metz, 2005).  The IPCC envision that carbon capture and well injection would take place at a number of locations, ideally places near to power plants that produce CO2 to avoid long transportation distances under pressure.

American Electric Power, AEP, participated in three DOE funded projects to advance CCS technologies. All were conducted at the Mountaineer Plant in New Haven, West Virginia (from which some of my power is supplied within the PMJ Interconnection). AEP planned to replace its pilot demonstration CO2 capture plant with a larger $668 million Carbon Capture and Storage facility, which would have buried more than 1 million metric tons of CO₂ a year, splitting construction costs evenly with the DOE, but failed to obtain the consumer rate increases necessary to fund the experiment. The project has been discontinued. In 2010 there were almost 1,400 coal fired electrical generating units in the United States if each were to be converted to carbon capture operation the total cost would be almost a trillion dollars in construction costs (assuming no cost over runs) and capture 1.4 billion metric tons of CO2 per year. This would represent 26% of the net annual CO2 emissions of the United States and increase average electrical rates 25% nationally for just building the units. Electrical rates would have to increase more if there were any annual operating costs of the Carbon Capture unit. Actual rate increases would be regional.  

The AEP projects were demonstrations of Alstom’s Chilled Ammonia Process for Post-Combustion CO2 Capture. The process uses ammonium carbonate to absorb CO2 and create ammonium bicarbonate. This resulting ammonium bicarbonate is converted back to ammonium carbonate in a regenerator and is reused to repeat the process. The flue gas, cleaned of CO2, but with the tell-tale smell of the ammonia reaction, flows back to the stack and the captured CO2 is sent for storage. Once captured, the CO2 is compressed into a liquid state and is injected 1.5 miles beneath the earth’s surface. Several major pilot projects, in Europe have also been cancelled in the last few years because of doubts over their financial and technical viability. Some are still under consideration for EU and government funding, but the need to rescue the Euro and European Banks has taken the financial resources of the European Union. Ayrshire Power in Scotland, blamed their cancelled plans for a new carbon-capture power station at Hunterston on the recession and anxieties about winning funding from the government and the same reasons were given for the cancellation of the Longannet power station in Fife.

 Globally, only a few, small-scale commercial carbon capture projects are in operation. The oil and gas fields in the North Sea are the site of the world’s first offshore commercial CO2 capture and storage project. Carbon dioxide is captured at a plant located on the offshore natural gas platforms and is stored underground in a sandstone well approximately 2,600 feet below the sea bed. The CO2 tax levied on offshore oil and gas operations by the Norwegian government made the project worthwhile and the drilling rig and available aquifer made it possible. CO2 is removed from the natural gas produced at the Sleipner field in the North Sea and re-injected it into a very porous, permeable sandstone and saline aquifer above the oil and gas reserves. Approximately 1 million metric tons of CO2 have been stored each year since 2000 when the system went into operation. This is just a small fraction of the 31.5 billion metric tons of CO2 released into the atmosphere each year.  It appears as if the United States has passed the point of peak CO2, but the atmosphere of the earth is interconnected and China and India appear to be increasing their CO2 emissions by 860 million metric tons a year. It matters what kind and how efficient a power plant is installed in China or India since they will be sending particulates and CO2 into the atmosphere for decades. Nonetheless, we have no control over the growth in India and China’s coal fired power supply, nor in the abandonment of nuclear power by Germany, Belgium, Switzerland and Japan in the next decade in response to the damage to the nuclear reactors that occurred in the Japanese Fukushima tsunami. 

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