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The U.S. and Mexico will commit to joining Canada in boosting their use of wind, solar and other carbon-free sources of electricity, helping North America meet an ambitious goal of generating at least 50 percent of its energy from "clean" sources by 2025.

The pledge is set to be made as part of a summit of North American leaders Wednesday in Ottawa, Canada.

"We believe this is an aggressive goal but one that is achievable by all three countries," said Brian Deese, a senior adviser to President Obama on energy matters.

The goal applies across the continent, meaning it's an average for Canada, Mexico and the U.S. together. The goal, which would need to be adhered to by the president who succeeds Obama in January, is "achievable if all three countries respectively make ambitious progress toward executing and in effect exceeding the targets" set in last year's Paris climate accord, Deese said.

The commitment will apply to any electricity generated without producing carbon dioxide emissions, including nuclear as well as renewable wind, solar and hydro power. Deese said it also could apply to power from plants using carbon-capture technology to siphon off emissions.

The Sierra Club's Michael Brune said the plan demonstrates "North American unity behind a consensus for strong global climate action."

Over the past year, the U.S. derived about a third of its power from carbon-free sources, including nuclear that provided 19.9 percent, according to April data from the Energy Information Administration. About 37 percent of North America's electricity came from carbon-free sources in 2015, largely because Canada already obtains more than half its energy from clean sources.

Deese declined to speculate on how much of the 50 percent goal would need to be from the U.S.

It's a "doable" goal, said U.S. Energy Information Administration head Adam Sieminski. The agency forecasts growing use of wind and solar electricity even with new regulations slashing greenhouse gas emissions from power plants.

The target is a strong pledge for Obama and Mexican President Enrique Peña Nieto. The Obama administration had previously said it aimed for the U.S. to get a fifth of its electricity from renewable sources by 2030. Mexico last year promised to get 35 percent of its power from renewable sources by 2024.