The Electric Power Research Institute (EPRI) has looked at several technologies available or in development that hold the potential to enable coal-fueled power plants to significantly reduce carbon dioxide (CO2) emissions without employing expensive carbon capture and storage (CCS).
The methods being evaluated by EPRI center on cutting CO2 emissions through more efficient combustion and use of heat. The results of EPRI’s study have been published in a new white paper, “Can Future Coal Power Plants Meet CO2 Emission Standards without Carbon Capture and Storage?”
EPRI’s paper analyzes current and anticipated U.S. and global CO2 emission standards for coal plants, identifies key challenges associated with CCS deployment, and provides detailed descriptions of coal-only technologies that are not ready for commercial deployment but that present significant potential to reduce CO2 emissions.
Slashing CO2 emissions from coal plants is increasingly important following the Aug. 3 issuances of the U.S. Environmental Protection Agency (EPA) of the Clean Power Plan, which calls upon states to curb power sector emissions 32% by 2030.
Current CCS technologies and anticipated near-term commercial offerings will not only increase capital costs but also impose significant performance penalties, challenging the competitiveness of new coal plants, according to EPRI. Many locations worldwide lack suitable geology for CO2 storage, one of several factors expected to constrain CCS deployment, EPRI notes in the white paper.
Today’s most efficient coal-fired plants are the “ultra-supercritical” plants that produce steam at high temperature (above 593*C or 1100*F) and emit approximately 800 kg (1760 lb) CO2/MWh.
But even new ultra-supercritical plants like the American Electric Power (NYSE:AEP) John W. Turk facility in Arkansas, are not capable of meeting EPA’s new plant performance standard.
EPRI looked at several technology options for increasing the thermal efficiency of the processes for generating electricity with coal, including:
•Rankine cycles (used by most of today’s coal plants) with higher steam temperatures;
•Combined heat and power applications (also known as cogeneration); and
•Coal gasification integrated with one of four systems — combined cycles (gas turbine plants), supercritical CO2 Brayton cycles (which use the CO2 instead of water or steam as the working fluid), solid oxide fuel cells (SOFCs), and “triple cycles” (a combination of combined cycles and solid oxide fuel cells or SOFCs).
But none of the options considered in EPRI’s analysis are currently commercially available, economically viable, and suitable for broad deployment.
“While existing IGCC [integrated gasification combined cycle] technology could meet EPA’s standard under certain conditions, more stringent limits in the UK, Canada, and some U.S. states could not be achieved,” EPRI said.
National R &D programs in the United States and elsewhere are making progress, but additional public-private R &D investment is needed to accelerate the deployment of many of these technologies.
“It’s critically important for the electric power industry to have as many generation technology and fuel options as possible,” said EPRI Vice President of Generation Tom Alley.
“Reducing emissions will be one of the key drivers as the industry makes decisions about existing assets and about the designs and fuels used in the next generation of power plants. EPRI research like this can be invaluable in informing those decisions,” Alley went on to say.
EPRI’s members represent more than 90% of the electricity generated and delivered in the United States, and international participation extends to 40 countries. EPRI’s principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.; and Lenox, Mass.
The 16-page report is publicly available but cannot be republished or posted without EPRI’s prior written consent.
For information about the EPRI report contact Senior Program Manager, Advanced Generation, Jeffrey Phillips, 704.595.2738, firstname.lastname@example.org.