The sweeping tariffs that President Trump announced on Wednesday could hobble the use of giant batteries that energy companies are increasingly installing to help them tap more wind and solar power and make the broader electric grid more reliable.

Over the past five years, grid batteries have become one of the biggest growth industries in the U.S. energy sector. In states like Texas and Arizona, companies have been installing stacks of lithium-ion cells the size of shipping containers. They can soak up excess wind and solar energy and save it for when it’s needed. In California, the use of batteries to store solar power for the evening hours has helped utilities reduce the amount of natural gas that is burned.

Yet the majority of America’s lithium-ion batteries are still imported, and 69 percent of those imports came from China in 2024, according to BloombergNEF. Mr. Trump’s latest round of tariffs, when combined with earlier trade moves, will impose a 64.5 percent tax on grid batteries from China, and that rate would rise to 82 percent next year.

“This will throttle U.S. energy storage deployment,” Jason Burwen, vice president of policy and strategy at the battery developer GridStor, wrote in a social media post. “Bad for business, bad for grid reliability.”

Energy companies were expected to install a record 18,200 megawatts of grid battery capacity this year, enough to store the entire output from 18 large nuclear reactors for a few hours, according to the U.S. Energy Information Administration. Together, batteries, wind and solar power were expected to make up 93 percent of capacity added to the grid.

Those batteries help address renewable energy’s biggest weakness: the fact that the wind and sun aren’t always available. In states that rely heavily on solar power like California and Texas, a boom in battery installations has helped reduce the risk of blackouts during the hot summer months by working together with gas plants to provide power when demand spikes.

But batteries aren’t just useful for adding more renewables: Utilities also use them to smooth out small disruptions in the flow of electricity, say, if a power plant unexpectedly tripped offline. Or, they can be used to reduce congestion on transmission lines.

Companies have largely been installing grid batteries because the price of lithium-ion technology has plummeted (the batteries are similar to those found in electric cars). Tariffs could reverse that trend.

“Batteries are the only major clean tech sector where imports still overwhelmingly come from China,” said Antoine Vagneur-Jones, head of trade and supply chains at BloombergNEF. “So the impacts of these tariffs are going to be a lot bigger for batteries than they are for other technologies.”

In recent years, the United States has started to build up a domestic battery supply chain. After the 2022 Inflation Reduction Act passed, the Biden administration poured billions of dollars into new battery factories and offered tax credits for both domestic manufacturers and the use of batteries in both grids and electric vehicles.

But many of those factories face an uncertain future now that President Trump and Republicans in Congress are looking to roll back a variety of clean energy policies.

Teasing out the precise effects of tariffs on the energy mix is complicated, Mr. Vagneur-Jones said. Right now, batteries often compete with natural gas plants as a technology to fill in the gaps left by fluctuating wind and solar power.

But it won’t always be so easy for many power companies to increase their use of gas: There is a lengthy global backlog for new gas turbines, and a company trying to build a new gas plant from scratch today may have to wait until 2030 or beyond. The oil and gas industry is also being hurt by new tariffs on steel and aluminum, which can affect everything from the steel pipe used to line new gas wells to power transformers.

“It’s always tempting to say these tariffs are good for fossil fuels, bad for clean energy,” Mr. Vagneur-Jones said. “But I think it’s just bad for everyone.”