15 December 2010

Carbon Capture: A Tough Nut to Crack

By Karin Rives
Staff Writer

Washington — Populations grow, emissions increase, global temperatures continue to rise. What to do?

Emission cap-and-trade schemes and renewable energy alone likely won’t be able to bend the carbon curve — the term climate-change experts like to use to describe a reduction in greenhouse gas emissions.

For that reason, governments and companies increasingly are looking for new and unconventional solutions to the climate problem.

Capturing emissions of carbon dioxide, the main greenhouse gas, and storing them in huge underground repositories for thousands of years is one proposal on the table. The U.S. government is spending $4 billion and private industry is contributing $7 billion to investigate potential carbon storage sites and technologies nationwide.

Ten major demonstration projects are under way, along with more than 50 smaller projects — most of which were initiated in the last two years. The goal is to bring between five and 10 commercial projects online by 2016.

One involves converting an idled oil-fired power plant in Illinois to coal, a cheaper fuel, and installing a boiler that uses oxygen instead of air during combustion. That creates a form of carbon dioxide gas that can be easily captured and compressed into a transportable liquid.

Federal funding supports the new plant, pipelines and a yet-to-be-determined storage site in the Midwestern state. The retrofitted plant will capture nearly 1 million tons of carbon dioxide annually.

“These new technologies will not only help fight climate change, they will create jobs now and help position the U.S. to lead the world in carbon-dioxide capture technologies, which will only increase in demand in the years ahead,” Energy Secretary Steven Chu said when announcing the funding.

STORAGE CAN LAST 5,700 YEARS

The United States produced nearly 7,000 million metric tons of greenhouse gas emissions in 2008, according to the U.S. Environmental Protection Agency (EPA). Factories and other so-called stationary pollution sources accounted for nearly half of those emissions.

A new study from the U.S. Department of Energy estimates that as much as 20,000 billion tons of carbon dioxide emissions could be stored for up to 5,700 years in North American saline rock, oil and gas reservoirs and dormant coal fields. If used, this could allow the U.S. to cut emissions while continuing to take advantage of its large coal reserves.

But the cost of trapping emissions, turning them into a liquid and transporting the liquid to underground storage sites kilometers away is very high. Building a national network of pipelines and retrofitting U.S. power plants and other buildings could easily cost tens or hundreds of billions of dollars, studies have estimated.

BUILD A MARKET AND THEY WILL COME

The EPA and the Department of Energy concluded in an August 2010 study that coal-fired power plants are the best candidates for carbon capture and storage (CCS). The nation’s 600-some coal plants supply nearly 50 percent of the energy consumed in America, and produce 40 percent of all carbon dioxide emissions.

Because of the cost involved with CCS, the agencies also concluded that such technology will be deployed on a wide scale only when driven by a national policy to reduce greenhouse gas emissions. What’s needed, they wrote, is a “stable, long-term, market-based framework to channel private investment into low-carbon technologies.”

Howard Herzog, a senior research engineer at the Massachusetts Institute of Technology and a world-renowned carbon capture specialist, agreed.

“We’re not sending enough signals to the market to make CCS technology competitive, so essentially all projects need government support in one way or another,” he said. With a commercial market possibly 20 years away, it will be important to use interim policies, such as a small surcharge on electric bills, to sustain funding for a handful of carbon capture and storage initiatives, he said.

“It will allow capacity-building in the private sector,” Herzog said, “so that when the market is ready in 20 years, we can have large-scale projects come on hand fairly quickly.”

Worldwide, there are now between 20 and 30 “serious” projects under way that try to capture emissions from power plants, he said.

(This is a product of the Bureau of International Information Programs, U.S. Department of State. Web site: http://www.america.gov)