Utilities push to grow but know little about how to keep air clean

By Phoebe Sweet

Tuesday, Dec. 18, 2007 | 7:07 a.m.

As debate over solutions to global warming rages here and in Congress, carbon jargon has started to fly.

There are calls for something called cap and trade, carbon taxes, capture, sequestration.

While environmentalists and power companies discuss solutions to the climate crisis, invoking the specter of greenhouse gases produced by burning fossil fuels, many observers scratch their heads and try to understand what the two sides are talking about.

Take carbon capture and sequestration, for example.

The technology involves removing carbon dioxide, a greenhouse gas that causes global warming, from power plant emissions and storing it underground.

There are potentially three ways to do this: through integrated gasification combined cycle technology, oxy-fuel combustion or post-combustion carbon capture technology.

Strip away the jargon and what you have left is more perplexing than the jargon itself.

Utilities, which want to keep building coal-fired plants - which emit twice the greenhouse gases of natural gas-fired plants - are promising their customers a cleaner approach through carbon-capture technology. But they don't know how much it will cost. They don't know when it will be ready or how much water it will use.

And although they are sure it will work somewhere someday, they aren't sure whether it will ever work in Nevada.

One thing power companies say they know for sure: They can't do it now. The technology is too expensive and not ready for commercial use, they say. So even for plants that are proposed for eastern and Southern Nevada, the new carbon capture technology will have to be added later. "The technology is very promising," says Starla Lacy, director of environmental services for Sierra Pacific Resources, parent company of Nevada Power Co. "I think it's important to point out there are a lot of options. We're going to do everything we can to promote the research ... so it can be viable and commercially available as quickly as possible."

Sierra Pacific Resources is participating in a pilot project and supporting research with industry groups to advance the technology, Lacy said.

Environmentalists would like utilities to stop relying on cheap coal altogether. But they say if coal must be used then power companies should adopt capture and sequestration technology today.

"We should not be rushing into building 19th-century technology in Nevada when we have vast amounts of renewable energy resources available here," said Lydia Ball, a regional representative of the Sierra Club. "Capturing and sequestering carbon emissions is a technology available today. And the cost of implementing it should not be passed on to the ratepayer down the road because the utilities want to invest in outdated coal technology today."

Although experts from the utility industry and the environmental community disagree on whether carbon capture is ready, they agree that the technology is new and constantly evolving.

Utility executives acknowledge they don't know what it will look like in two years, five years, 10 years, because research advances are being made every day. So they can't predict what they will use tomorrow at power plants proposed today.

Three main kinds of carbon capture technology are being studied now.

The first, "integrated gasification combined cycle," (IGCC), converts coal to liquid fuel, then captures and stores the carbon dioxide produced.

Environmental groups consider this method the most promising. Clean-air advocates say it is ready to be used today. But it is incredibly expensive and utilities say the technology is untested on a commercial scale and not ready for large power projects.

A second technology being researched would burn coal using pure oxygen rather than regular air, making carbon dioxide easier to capture. Sierra Pacific Resources' Lacy characterized research of that technology as still theoretical.

Sierra Pacific Resources and two other power plant developers with Nevada proposals have promised a third kind of technology, carbon capture, that would be installed long after plants are built. That technology, also called post-combustion capture, uses chemical scrubbers to separate and remove the carbon dioxide from flue gases.

George Peridas, a carbon capture expert with the Natural Resources Defense Council's Climate Center, said a plant retrofitted to trap carbon emissions uses about 40 percent more energy than an IGCC plant.

And adding post-combustion technology to a conventional coal plant would more than double water use, according to a recent report from the Energy Department's National Energy Technology Lab.

The electric utility industry is already second only to agriculture as the nation's largest water user, according to Sandia National Laboratories.

Even if technology advances by the time the eastern Nevada plant near Ely opens in more than five years, it is unclear whether Nevada is the best site for carbon capture and sequestration.

Once the carbon dioxide from a power plant is trapped, it must be injected into the ground and stored for hundreds of years, a process some scientists say could be risky.

Peridas said underground storage is safe, and a recent Intergovernmental Panel on Climate Change report says there is a 99 percent chance the carbon dioxide will stay underground for 100 years and a greater than 99 percent chance it will stay put more than 1,000 years.

But not enough research has been done on Nevada's geology to know whether carbon dioxide could be stored in the state at all. Carbon dioxide is typically kept in saltwater aquifers or in spent oil and gas fields as a way to extract more of the fossil fuels.

"There is evidence that safe sequestration may never be technologically ... feasible at these coal plant sites," according to Nevadans for Clean and Affordable Reliable Energy, a group of mostly environmentalists that opposes the coal plants. It cites an Energy Department study indicating Nevada has poor potential for storage of carbon dioxide in aquifers or oil wells. The group is critical of agreements between the three companies proposing coal plants in the state and Nevada's environmental commission in which developers agree to install carbon capture technology when it's commercially viable.

Lacy acknowledged Sierra Pacific Resources does not yet know whether it will be possible to store carbon dioxide underground near its proposed 1,500-megawatt Ely Energy Center.

"We want to explore the ability to inject it close by. We're not interested in building a pipeline," Lacy said. She was referring to the possibility that the company would have to pipe carbon dioxide to another state if storage in Nevada were not possible.

Lacy and Joe Lucas, executive director of the coal lobby group Americans for Balanced Energy Choices, say funding for carbon capture and storage research will be key to advancing the technology over the next decade.

Lucas said potential investment in carbon capture research could be as beneficial as the $5 billion in federal spending on research that reduced mercury, sulfur and nitrogen pollution from 1970s power plants.

He said the federal government should set aside at least $17 billion over the next 10 years for development of commercial-scale carbon capture and sequestration technology.

"Technology," Lucas said, "has always provided the solution to problems with coal-based power."