By David Wagman, Chief Editor
Carbon capture and sequestration represents the “mother of all challenges” facing coal generators, according to Ram Narula vice president and chief technology officer of Bechtel. He made the statement during a Power Engineering Webcast, which took place live from the exhibit floor at COAL-GEN in Louisville, Ky. last month.
Narula and other industry experts made up the Webcast panel that explored what it really will mean to have a carbon capture-ready power plant. The discussion focused on coal units rather than natural gas. The speakers acknowledged, however, that should carbon capture and sequestration become mandatory, as many think will happen, then both fossil fuels will be on the hook to catch and store their carbon emissions.
The enormity of the capture and sequestration challenges was echoed by Paul Thompson, senior vice president of Environmental Services for E.On, COAL-GEN host utility. During a Keynote address, Thompson said the industry has successfully dealt with sulfur dioxide and nitrous oxide emissions. That success has come largely because suitable technology existed and the cost to scrub proved relatively small. By contrast, carbon dioxide emissions dwarf both SO2 and NOX.
“It’s 100 times bigger but with no technology answer today,” he said. E.On may be particularly sensitive to the carbon challenge. Roughly 97 percent of the power generated by operating companies Kentucky Utilities and Louisville Gas & Electric comes from coal.
Several technologies are in development to capture carbon dioxide from coal combustion. These include both pre- and post-combustion technologies. Where much of the uncertainty lies, however, is in issues related to permanently storing the captured carbon dioxide. As the COAL-GEN panel pointed out, legal and policy issues are particularly troublesome. For example, who is liable for the stored carbon? What if stored carbon seeps from one jurisdiction to another? How much storage capacity exists and can these sites by secured for potentially thousands of years into the future? What if one of these sites “burps”?
Justin Zachary, senior principal engineer for Bechtel, said that adding carbon capture equipment will generally require additional plant space of about 500,000 square feet. And almost every part of the existing power plant will be affected by the large amount of equipment that will be added later.
“You may well need an additional cooling tower to accommodate the additional load for the compression of the CO2,” he said. “This is a really an additional plant on top of the one you have.”
Denny McDonald, technical fellow for Babcock & Wilcox, listed equipment and technical considerations for various capture approaches. For oxy combustion, he said provisions would need to be made for air separation unit, a compression/purification unit, moisture removal (depending on fuel), space for mixing oxygen in flues, cooling water and water treatment systems and provision for high plant power load. With post-combustion technologies, his list included CO2 scrubbing equipment (absorbers, regenerators, reboilers), a compression/drying unit, provision for high LP steam requirement and cooling water and water treatment systems.
Make no mistake. The discussion was anything but theoretical. Kyle Nelson, vice president of power production for Sunflower Electric Cooperative discussed his utility’s plans to build two 700 MW supercritical coal units. He said the project has been blocked by Kansas Governor Kathleen Sebelius and several state officials over its carbon dioxide emissions. That makes Holcomb the first coal plant to be rejected solely on the grounds that it will emit CO2. “That’s why it’s important to try to define and quantify what carbon capture really means,” said Nelson. The need for a clear definition is evident.
For more on COAL-GEN, read Steve Blankinship’s reports on pages 20 and 82 in this issue. You can listen to the complete carbon capture and sequestration Webcast discussion at www.power-eng.com.
Senior Editor Teresa Hansen received a much-deserved promotion to become Chief Editor of our sister PennWell publications on the transmission, distribution and finance side of the utilities business. Teresa has been and will continue to be a valued colleague. All of us wish Teresa great success in her new role.
We say hello to Nancy Spring who joins us as Senior Editor, having served as Managing Editor of PennWell’s Electric Light & Power magazine and author of The Executive Digest, a bi-monthly e-newsletter for utility managers and executives. Nancy began her career in the energy industry more than 10 years ago. She will be writing many of Power Engineering’s feature articles. She also will be actively involved in POWER-GEN International, Renewable Energy World North American and NUCLEAR POWER International. And she will edit our quarterly electronic magazine for the global nuclear power industry, Nuclear Power International. Welcome Nancy!