Skip to main content
Scientific American

September 20, 2013

Running the numbers on EPA’s new CO2 regulations: combined cycle stacks up well

Existing technology like combined cycle generation could be used to meet EPA's stricter CO2 emissions limits

By David Wogan

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American

Word started getting out late Thursday evening about the US Environmental Protection Agency's carbon dioxide regulation for new natural gas and coal power plants. The New York Times has a rundown of the expected announcement (it hasn't been officially announced at the time of posting). While carbon capture technology is being discussed for coal plants, it looks like combined cycle generation might be enough to get some power plants under the limit without needing any capture tech - at least for natural gas. This is because you're extracting extra work through a steam turbine (in addition to the gas turbine) from the same unit of fuel.

Here is a breakdown of the CO2 regulations and how combined cycle generation stacks up (via my Twitter stream):

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

I used EIA's emissions factors and heat rates for these calculations. I only found data for natural gas in my quick search of EIA and EPA, so if anyone has heat rates for coal-fired combined cycle feel free to send them in and I'll update this post.

Update: Costa Samaras sent over CO2 emissions rates for coal-fired plants from a NETL analysis (PDF). Looks like even the IGCC plants from GE, Shell, and ConocoPhillips won't hit the EPA targets without capture technology.

David Wogan is an engineer and policy researcher who writes about energy, technology, and policy.

David's academic and professional background includes a unique blend of technology and policy in the field of energy systems. Most recently, David worked at Austin Energy, a Texas municipal utility, implementing a Department of Energy stimulus grant related to energy efficiency. Previously, David was a member of the Energy & Climate Change team at the White House Council on Environmental Quality for the Obama Administration.

David holds two Master's degrees from The University of Texas at Austin in Mechanical Engineering and Public Affairs. While at UT, David was a researcher in the Webber Energy Group, where his research focused on advanced biofuel production to offset petroleum use in the transportation sector. David holds a Bachelor's of Science degree in Mechanical Engineering from The University of Texas at Austin, where he researched nuclear non-proliferation measurement technology.

David is a 2013 Aspen Institute Journalism Scholar, joining a select group of journalists from Slate, ABC News, and The New York Times.

David lives in Austin, Texas. Follow along on Twitter or email him at david.wogan@me.com.

More by David Wogan