Dozens of nations agreed in 2023 to triple renewable energy capacity by 2030 as part of efforts to limit global warming.

But announcements and construction starts of new wind and solar projects grew 11 percent in 2025 -- down from 22 percent in the previous year, as wind development projects faced hurdles, Global Energy Monitor (GEM) said.

"Wind developers experienced political barriers and a streak of failed wind power auctions in wealthy nations," GEM research analyst Diren Kocakusak said.

US President Donald Trump has blocked wind projects, and made no secret of his antipathy towards renewables, though the global slump was not attributable to any one country, Kocakusak said.

GEM's research also found that just a small fraction of wind and solar growth came from rich G7 countries, with the "centre of gravity" now shifting "decisively toward emerging and developing economies."

As has been the case for years, China is expanding renewable capacity on a scale unmatched elsewhere.

It accounted for around a third of global capacity growth in 2025 -- 1.5 terawatts -- more than growth in the next six countries combined.

But that was not enough to set the world on track to meet the 2030 goal.

- 'Disappointing developments' -

Even if all the projects currently announced and under-construction proceed, the world would still fall short.

GEM's research has found almost 40 percent of planned projects begin operations after their announced start date, or are put on hold or scrapped.

However, Kocakusak said that did not mean the goal was out of reach.

"Momentum appears to be slowing, but that's not due to a lack of potential," he told AFP.

There is still "enough time" for countries to ramp up capacity, and solar projects that have not yet been announced could be completed before 2030, he said. Wind projects can take longer to get up and running.

More than 3.5 terawatts of wind and solar projects have also been announced without a confirmed start date, and could help meet the 2030 goal if they come online quickly enough.

Some wealthy countries are supporting renewable growth, with Japan seeking to revise wind auction guidelines and Britain boosting investment.

These policies sit alongside "disappointing developments", though, like reports Germany may limit grid priority for renewables, Kocakusak said.

"Whether the 2030 tripling target is achieved will depend on the level of commitment and implementation from countries and developers," he said.