The leaders of the United States, Canada and Mexico will pledge Wednesday to source half their overall electricity with clean power by 2025, according to administration officials.

The commitment — which will be a joint one, rather than an individual commitment by each nation — represents an aggressive target given the current reliance by the United States and Mexico on fossil fuels for much of their electricity supply. Roughly 59 percent of Canada’s electricity is generated by hydropower operations, with another 16 percent coming from nuclear plants, so it has already surpassed the targeted benchmark.

The new commitment includes not just renewables but also nuclear and carbon capture and storage plants and energy efficiency. Under that definition, 37 percent of North America’s electricity in 2015 came from clean energy sources.

President Obama will travel to Ottawa Wednesday to meet with Canadian Prime Minister Justin Trudeau and Mexican President Enrique Peña Nieto as part of this year’s North American Leaders Summit. The upcoming pledge highlights how collaboration on climate between the United States and Canada has accelerated since Trudeau, leader of his country’s Liberal Party, was elected last fall.

White House senior adviser Brian Deese described it as “an aggressive goal,” but one that “is achievable continent-wide.”

He added that the alignment between Canada, Mexico in the U.S. on climate and energy policy “is stronger than it has been in decades… In all three countries, there is a significant move toward a clean energy economy.”

Roughly 13 percent of U.S. electricity comes from hydropower and other renewable sources, according to the Energy Information Administration, with another 20 percent stemming from nuclear power plants.

Just 22 percent of Mexico’s electricity generation in 2014 came from non-fossil fuels, according to its government, though leaders there have pledged to raise that figure to 34 percent by 2024.

Mexico will also pledge to reduce its emissions of methane, a powerful greenhouse gas, by 40 to 45 percent by 2025. The U.S. and Canada have already set that goal for their own methane output.

Deese said the idea that the U.S. could generate half of its own electricity with clean power by 2025 “is a stretch goal, but one we think is achievable in the United States itself.” But the U.S. would not have to meet that threshold in order to honor its part of the new North American electricity generation target.

CBC News reported Monday that Obama would pledge to generate half of U.S. electricity by clean power by 2025, a report that was incorrect.

Asked whether the president was preparing to make an ambitious climate pledge as part of the upcoming summit, White House spokesman Eric Schultz replied, “We do ambitious well at the White House.”

A new report by environmental experts from the United States, Canada and Mexico last week urged the three countries to work more closely on their climate goals in the wake of the international accord finalized last December in Paris.

“For the first time in recent memory, the national governments of the United States, Mexico, and Canada are politically aligned on climate change,” the group wrote. “The three countries should take this opportunity to explore and launch coordinated climate initiatives that could propel the shift to clean energy across the continent and—through international leadership—accelerate the reduction of greenhouse gas pollution globally.”

Gwynne Taraska, associate director of energy policy at the Center for American Progress and a co-author of the report, said one of the key elements for averting dangerous warming is that countries must meet current climate goals while also setting more ambitious targets for the future. By teaming up, she said, nations can help one another meet those aspirations.

“When countries work together, you improve the odds of success,” Taraska said.

Hillary Clinton has said if she’s elected president she will work to ensure that half of the nation’s electric power will come from clean energy sources by 2030. GOP presumptive nominee Donald Trump has emphasized the need to continue extracting fossil fuels, including coal, to power the nation’s electrical grid and has questioned much of the Obama administration’s effort to forge international climate agreements.

“Shifting half of America’s electricity to clean energy sources is not only achievable – it’s essential,” said Rhea Suh, president of the Natural Resources Defense Council, in a statement. “Avoiding the worst effects of climate change demands nothing less. But we must do it the right way, and that means ramping up our reliance on cost-effective renewable wind and solar power, energy efficiency and other 21st-century technologies.”

Still, Paul Bledsoe, a consultant who worked on climate policy in the Clinton administration, said the U.S. can only meet the administration’s goals if its plan to curb greenhouse gas emissions from existing power plants can withstand a current court challenge.

“These goals are challenging because energy efficiency policies have dramatically reduced new power demand–so little new electricity supply will needed unless many more existing coal power plants are shut down under the president’s clean power plan,” he said in an email, since that will cut “much existing coal power that can be replaced by renewable energy.”