The figure had increased strongly in previous years as Europe's biggest economy aims to reach a goal of green power accounting for 80 percent of its energy mix by 2030.

But last year power from sources such as wind, solar and hydroelectric accounted for 58.8 percent of the mix, up just slightly from a figure of 58.5 percent in 2024, according to the energy regulator.

The figure had been just 43 percent in 2021.

The share of wind power, which remained Germany's biggest energy source, fell slightly while solar rose due to growth in production capacity, the regulator said.

The group Environmental Action Germany said last year's near stagnation in renewables' share was in part due to a lack of wind in the first half of 2025.

But the NGO nevertheless fears a looming slowdown in the green power shift under Merz's coalition, which took power last year, Constantin Zerger, the group's head of energy and climate protection, told AFP.

He said that Economy Minister Katherina Reiche "has announced several times that she wants to slow down the expansion of renewables, which is of course very, very dangerous".

Critics point to measures ranging from a planned expansion of gas power to proposals to scrap some solar subsidies as evidence that Reiche is seeking to slow the green shift and prioritise helping big business.

Merz has pushed back at criticism he is undermining the climate change fight, saying that his government is taking a more pragmatic approach to the energy transition that aims to keep costs manageable.

In the previous government, the Greens party helmed the economy ministry and pushed ambitious measures to accelerate the transition -- which were hailed by environmentalists but caused unease among businesses about extra burdens.

Last year the share of solar energy in Germany's energy mix passed that of lignite, also known as brown coal, for the first time.

But the share of two other fossil fuels, coal and natural gas, rose.