At 240 MW, Petra Nova is the world's largest post-combustion carbon capture facility installed on an existing coal-fueled power plant.
At 240 MW, Petra Nova is the world's largest post-combustion carbon capture facility installed on an existing coal-fueled power plant. | Photo courtesy of NRG Energy, Inc.

World's Largest Clean Coal Plant Opens In Texas

Long synonymous with oil, Texas has a new distinction - home to the world's largest clean coal plant.

The $1 billion project southwest of Houston allows a 240-megawatt (equivalent) coal-fired power plant to capture about 90% of its carbon dioxide emissions for use in enhanced oil recovery. This produces significant reductions in greenhouse gasses associated with climate change.

The project is a joint venture between NRG, the largest independent power producer in the United States, and JX Nippon Oil & Gas Exploration, the largest Japanese oil company. The Department of Energy spent $190 million to support the development of the technology.

“NRG is very focused on decarbonizing our fossil fuel fleet - the process here is very evolutionary and helps to make coal sustainable and also ensure a diversified power grid,” said David Knox, an NRG spokesperson. “The conversion was carried out without any increase in cost for the consumer.”

The plant’s engineering allows carbon dioxide (CO2) to be pumped via a pipeline to the West Ranch oil field located some 80 miles away. There the captured carbon dioxide is injected into oil wells as part of an enhanced oil recovery (EOR) strategy.

The mature West Ranch field was producing 300 barrels of oil per day before the start of this project. The carbon dioxide injections will allow production to increase to 15,000 barrels per day. Given current technology, the field is believed to have about 60 million barrels of recoverable oil.

The Petra Nova project is 60% larger than the world's next largest such plant, the 150-megawatt plant located in Saskatchewan, Canada.

“Some 20% of conceptual design and detail engineering was completed before we broke ground on Petra Nova, and as this carbon capture technology develops, the costs related to the technology will come down," Knox said.

Experts note such projects are going to be feasible only in specific geographies where a coal plant is in relative proximity to a large and mature oilfield. Additionally, the conversion can great increase the size of the facility.

“In West Texas, they use CO2 taken from a natural formation in Colorado. At Petra Nova we are using captured carbon dioxide for EOR which was the big challenge,” Knox said.

Such clean coal projects have drawn criticism from environmental groups.

“These so-called success stories are always based on enhanced oil recovery,” said Max Gruenig, the President of the U.S. Ecologic Institute, “so once the field is gone or no longer used, then what?”

NRG maintains that this project is just one important step to a low-carbon dioxide emission future. The company is also funding a $20 million dollar “XPrize” to encourage the development of a commercially viable usage for C02. Some 27 teams are currently competing in that endeavor.

Elsewhere around the country, the success of the Petra Nova project is attracting notice.

“Here in Montana we are certainly encouraged by what is going on with Petra Nova in Texas,” said Jim Atchinson, the executive director of the Southeastern Montana Development Corporation.

A large coal-fired power plant in Colstrip, Montana, will see two of its four units shut down by 2022. Atchinson is working on a diversification plan for the community and ways for the plant to remain competitive in the face of pressure from new regulations.

“The low oil price likely means any opportunity is still a way off but, this is still very much on the table and part of our diversification strategy," he said.