The Obama administration has decided to revive a controversial loan guarantee program at the Energy Department, administration officials said on Thursday, even as the program remains under Congressional scrutiny after losing hundreds of millions in taxpayer money on investments in failed green energy start-ups like the solar module maker Solyndra.

This time, though, the program would devote as much as $8 billion to helping industries like coal and oil make cleaner energy. Although the program, which does not require Congressional approval, would support a wide range of technologies, it could help coal-fired power plants find a way to keep their emissions from escaping into the atmosphere, department officials said.

Officials say the federal subsidies are necessary to support the development of technologies that are too complex, unproven and expensive for investors and private companies to pursue on their own, assertions that have already stirred criticism from opponents who see the program as too risky and a misuse of taxpayer money.

The program’s renewal comes just as the administration is releasing stringent environmental rules that would severely restrict air pollution at new coal plants.