The energy crisis that’s led to electricity shortages and blackouts in Europe and Asia may be heading for the U.S.

Electric companies are alerting customers about winter price hikes and an energy hedge fund warned of potential gas shortages. Ernie Thrasher, chief executive officer of Xcoal Energy & Resources LLC, said said utility executives have told him they’re anxious that fuel shortages this winter could trigger blackouts.

“These utilities are worried the assets that they have can’t get enough fuel,” Thrasher said in an interview. “There are people of high authority at large utilities that are deeply concerned.” He declined to name the companies, saying they come from almost every region in the U.S.

The global economic recovery from the pandemic has driven up demand for power, triggering shortages and higher prices for natural gas, especially in Asia. That’s prompted utilities to use more coal, which as a result is also now in short supply around the world. U.S. utilities are switching away from gas and expected to burn about 23% more coal this year.

The U.S. has enough gas to get through a normal winter, said James Shrewsbury, co-chief investment officer of e360 Power LLC, a gas and power hedge fund in Austin, Texas. But sustained low temperatures could create gas shortages. “If we get a prolonged cold this winter, there will be problems.”

Increased demand is bumping up against mine output that’s been falling for years. The growing urgency to fight climate change has made suppliers reluctant to increase production capacity for the dirtiest fossil fuel. Now, U.S. utilities’ stockpiles are shrinking and it’s not clear whether U.S. miners will be able to meet their increasing calls for more fuel.

Power producers including Duke Energy Corp. are already warning customers that bills will spike this winter. Duke’s Piedmont Natural Gas unit said Tuesday that high gas prices and low production will raise customer bills by about $11 a month in North and South Carolina. And Xcel Energy Inc. told Colorado regulators last month that its natural-gas customers will also see price hikes of about $11 a month due to tight supplies, an increase in gas exports and damage from Hurricane Ida.

A representative for Edison Electric Institute, the trade group for U.S. investor-owned electric utilities, didn’t respond to a request for comment.

The New York State Public Service Commission is monitoring utilities in the state to ensure they have enough fuel this winter but said it expects they’ll be in position to meet demand.

“The utilities have hedged approximately 70%” of their residential electricity needs, which should protect against price swings, the agency said in a statement.