WASHINGTON — All but giving up on Congress, President Obama has spent the year foraging for issues he could tackle on his own, and largely coming up with minor executive orders. But on Monday, he will unveil a plan to take on climate change that may be his last, most sweeping effort to remake America in his remaining time in office.

The far-reaching regulations will for the first time force power plants in the United States to curb the carbon emissions that scientists say have been damaging the planet. By using authority already embedded in law, Mr. Obama does not need Congress — so, in this era of gridlock, he has a chance to transform the nation’s energy sector and, at the same time, his presidency.

“The shift to a cleaner-energy economy won’t happen overnight, and it will require tough choices along the way,” Mr. Obama said Saturday in his weekly radio and Internet address, previewing Monday’s announcement. “But a low-carbon, clean-energy economy can be an engine of growth for decades to come. America will build that engine. America will build the future, a future that’s cleaner, more prosperous and full of good jobs.”

While the administration was still completing crucial elements of the plan, it was already clear that the economic stakes are enormous. The new regulations could eventually shutter hundreds of coal-fired power plants. Critics wasted little time arguing that the president’s unilateral plan abuses his power in a way that will cost jobs and raise energy prices for consumers.