American Electric Power’s decision to shut down an ambitious experiment aimed at capturing greenhouse gases from a coal-fired power plant was a disappointing setback to efforts to control harmful global warming emissions from coal, among the world’s most abundant fuels.

It was also a predictable result of Congress’s failure to enact climate change legislation that would have placed a price on emissions and given businesses compelling economic reasons to clean up their plants and develop new technologies. Without industrywide federal standards in place, state utility regulators would not have allowed A.E.P. to recoup its investment through higher prices, making the whole project untenable.

Coal-fired power plants produce one-third of the nation’s emissions of carbon dioxide. Policy makers have other tools to help lower these greenhouse gas emissions, including regulations requiring more efficient plants. What they do not have is breakthrough technologies.

The A.E.P. project, located at a 31-year-old coal-fired plant in West Virginia, was the country’s most advanced attempt to strip carbon dioxide from the flue gases and store it permanently underground in deep-rock formations under the plant. The company had completed a small pilot program, and the Energy Department had promised to pay for half the final $668 million bill. But A.E.P. would have been on the hook for the rest.