First came President Trump’s freezing of federal support for many renewable energy projects, coupled with cries of “drill, baby, drill.”

Then came the tariffs.

The president’s trade war is expected to drive up the costs of nearly every component of clean-energy production in the United States, from the steel blades of wind turbines to the batteries inside electric vehicles.

Many of those building blocks are imported from the European Union, China and Southeast Asia, where some of the highest tariff rates were assigned.

How that affects the energy mix inside the United States is complicated, experts say. After all, rising costs for these and other materials won’t affect only renewable energy. Many of Mr. Trump’s trade policies, including tariffs on steel and aluminum, will also hit fossil fuels, making it more expensive to build natural-gas export terminals and drill oil wells, despite the president’s pledge to make oil and gas cheaper and more plentiful.

Yet the renewable energy industry is bracing for particularly large effects.

Vanessa Sciarra, vice president of trade and international competitiveness for the American Clean Power Association, a renewable energy trade group, said that “policy whiplash” was endangering Americans’ access to affordable and reliable energy by severing supply chains.

The tariffs are widely expected to reorder the energy landscape far beyond U.S. borders, too.

U.S. oil and gas exports have surged over the past decade, but longer-term prospects for growth abroad were already shaky, with buyers in Europe and Asia trying to reduce their reliance on fossil fuels as part of their pledges to cut emissions of planet-warning greenhouse gases. The possibility that China or the European Union could impose retaliatory tariffs on American fossil fuels might put a further dent in those exports, analysts said.