Public Power - September 2008 - (Page 28)

Capturing Coal’s Carbon mental considerations and financial strength and support. “We also looked at such issues as cost and the adaptability to specific power plants,” said Hill. The G&T chose Powerspan’s ECO2 technology. Selecting a coal-fired plant for the demonstration was a no-brainer. Basin Electric has three coal-fired plants, one of which is the 900-MW, two-unit Antelope Valley facility in North Dakota. Antelope Valley burns lignite, a low-rank coal mined in the state. Because lignite has a lower heating value than other coals, it is used in greater quantity to produce the required amount of steam. The ECO 2 technology requires a low-sulfur environment, so the Antelope Valley plant will employ Powerspan’s ECO multi-pollutant system upstream of the carbon capture technology to reduce sulfur dioxide to an extremely low level. But the Antelope Valley plant was the ideal choice for another reason—its proximity to the Great Plains Synfuels Plant, the nation’s only commercial-scale coal gasifica- tion facility. The plant is operated by the Dakota Gasification Co., a wholly owned subsidiary of Basin Electric. The CO2 captured at the plant is piped to Canada’s Saskatchewan province, where it is used for enhanced oil recovery. Because the infrastructure for delivering CO2 to Canada already existed next door, Antelope Valley has ready access to an end-use for the captured carbon. When CO2 is injected into oil pockets, it acts as a solvent, reducing the viscosity of the oil. Enhanced oil recovery could extend the life of the Saskatchewan oil fields by an estimated 15 to 20 years. Construction of a 120-MW carbon capture system is expected to start in 2009, subject to engineering studies and permits. The demonstration is scheduled to begin in 2012, and will run for a couple of years, said Hill. The Powerspan system will capture approximately 1 million tons of CO2 annually, nearly one-eighth of the plant’s total carbon emissions. In 2007, Antelope Valley emitted 7.8 million tons of CO2. “We’re focusing on the Powerspan technology now,” said Hill. “But we’re keeping an eye on what else is out there.” While the CO2 captured at Antelope Valley could be piped to Canada for enhanced oil recovery, it is more likely to be used in North Dakota’s own oil fields. Basin Electric is a member of the Plains Carbon Dioxide Reduction Partnership, which is planning a demonstration project in the Williston Basin region of North Dakota that entails the use of CO2 for enhanced oil recovery. “The carbon dioxide captured from the Antelope Valley demonstration will be used for this project,” said John Harjun, associate director for research at the partnership. Parish plant demonstration. Another utility, NRG Energy, plans to test Powerspan’s ECO2 technology. “We believe we have a responsibility to combat climate change,” said Will Stokes, NRG Energy’s vice president of asset management for the Texas region. “We want to make the right environmental and business decisions. Our focus is to support efforts to reduce carbon emissions and make the economics of the project work.” Like Basin Electric, NRG Energy looked at a number of different technologies be- fore deciding that Powerspan’s process was viable and the energy demands would work. “It’s a big step from a pilot project to a commercial-scale demonstration project,” said Stokes. “This technology has the potential to make that step, and we wanted to help advance it. But we’re not an R&D company. We want to find technologies that show great promise, and help to develop them,” said Stokes. To make a process like this—carbon capture and storage—work, there must be carbon cap and trade regulations in the foreseeable future, said Stokes. And, he added, government funding programs will be needed. “This is a very clear opportunity for post-combustion carbon capture technologies, and will hopefully be part of the overall solution to greenhouse gas emissions.” The cap-and-trade program for sulfur dioxide and nitrogen oxides gave utilities an incentive to reduce emissions and helped spread emission control technology, said Stokes. A carbon reduction program could do the same. For the Powerspan technology demonstration, NRG Energy tapped its Parish plant, an eight-unit facility. Four of the units are coal-fired, with a capacity of 2,640 MW. The technology will work on a 125MW slipstream from one of the coal-fired units, which are fueled with Powder River Basin coal. This low-sulfur coal, together with Powerspan’s ECO multi-pollution control system that NRG Energy plans to install, will provide the low-sulfur environment the technology requires, said Stokes. The four Parish coal-fired units emit approximately 21 million tons of carbon dioxide annually. The Powerspan demonstration system will capture about 1 million tons of CO2 each year of its operation. One appeal of the carbon capture technology was its enhanced oil recovery (EOR)-friendly design. “We chose the Parish plant because we wanted to do the demonstration in Texas for the enhanced oil recovery capability,” said Stokes. There are numerous players in the EOR market looking for sources of carbon dioxide, said Stokes. “And there is a range of ways that we could partner with them. Many companies are looking at the development of a carbon dioxide pipeline PUBLIC POWER 28 SEPTEMBER 2008 http://www.sterlingpadlocks.com

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Public Power - September 2008 Contents Perspective 10 Questions What’s Good About RTOs? Capturing Coal’s Carbon Carbon Safety Valves Greater Glass, Greater Savings Getting Customers to Embrace Compact Fluorescent Lights LEEDing Green Kansas City Shows How to Build Green For Governing Boards Safety Community Broadband Hometown Connections Parting Shot

Public Power - September 2008

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