At a newly built dock along Germany’s Elbe River, tankers from the United States unload liquefied natural gas to fuel factories and homes. In central Spain, a forest of wind turbines planted atop mountains helps power the energy grid. In French government buildings, thermostats have been lowered in winter to save electricity.

In the three years since Russia’s invasion of Ukraine ignited an energy crisis across Europe, the continent has transformed how it generates and stores power. Russian natural gas, long Europe’s energy lifeline, has been replaced with other sources, notably liquefied natural gas from the United States. Wind and solar power generation has leaped around 50 percent since 2021. New nuclear power plants are being planned across the continent.

But Europe’s energy security remains fragile. The region produces far less natural gas than it consumes and is still largely dependent on other countries, especially the United States, to help keep the lights on. Natural gas, which drives the price of electricity, is roughly four times as expensive as in the United States. High energy costs have strained households and forced factories to close, weakening Europe’s economy.

A dependence on Russia

The 2022 invasion of Ukraine revealed Europe’s dependence on energy from Russia, especially natural gas, which accounts for around 20 percent of Europe’s energy consumption.

“The energy appeared cheap, but it exposed us to blackmail,” Ursula von der Leyen, president of the European Commission, the European Union’s executive arm, told the World Economic Forum last month.