The multi-year roadmap comes as Macron is facing fractious "yellow vest" protests by French citizens angry over fuel tax increases designed to finance green initiatives. With his approval ratings plummeting, the French president is expected to announce new measures to make the transition less painful for the poor. But government sources have said he will not walk back on the environment-friendly tax increases.

Officials have already indicated he will announce the closure of France's four remaining coal-fired power plants, part of a pledge to get 40 percent of France's electricity needs from renewable energy sources by 2030. The more delicate question, however, concerns the eventual timeline for shutting down some of France's oldest nuclear reactors, which provide just under 72 percent of the country's electricity needs.