CHEYENNE, Wyo. (AP) - Forty-seven entries from seven countries have been submitted for a $20 million competition to capture and use greenhouse emissions from power plants.

Proposals include turning carbon dioxide into products as common as cooking oil or as exotic as graphene, a substance much stronger than steel. Other ideas include using carbon dioxide to produce biofuels.

The NRG COSIA Carbon XPRIZE announced the entrants Wednesday. The first round of competition happens only on paper. The second round involves demonstrations in a lab.

The third and final round uses real emissions from a coal-fired power plant in Wyoming and a gas-fired power plant in the Canadian province of Alberta.

The winner will demonstrate the most profitable way to make products from CO2 to defray the cost of keeping the gas out of the atmosphere.