The pledge was made on the eve of the so-called "Three Amigos" summit on 29 June in the Canadian capital Ottawa, by the presidents of the US and Mexico, Barrack Obama and Enrique Peña Nieto, and Canada’s prime minister, Justin Trudeau.
The clean energies include nuclear and carbon capture and storage (CCS) systems, as well as wind, solar and hydro.
The agreement also contains measures to facilitate and cut the costs of transmitting and trading energy across North America.
The 50% goal by 2025 is a significant step up from the current collective figure of around 37%.
The US produces around three-quarters of the three countries’ electricity, but only about a third of it comes from clean sources.
Canada, with its large hydro reserves, is producing more than 80% of its electricity from non-carbon sources. Mexico, despite recent rapid growth in onshore wind and solar, is generating less than 20% of its electricity from clean sources.
"We believe this in aggressive goal, but for all three countries, one that we believe is achievable continent-wide," said Brian Deese, a senior adviser to Obama.