At a time when Russia’s wielding its energy industry like a hammer (and sickle), a new report illustrates how powerful that weapon is.

A study published Wednesday by the Centre for Research on Energy and Clean Air calculates that Russia earned $66.5 billion from fossil fuel exports since its troops invaded Ukraine on Feb. 24, with Germany as the biggest buyer.

Using data on ship movements, real-time tracking of gas flows through pipelines and estimates based on historical monthly trade, the researchers figured Germany paid Russia about 9.1 billion euros ($9.65 billion) for fossil fuel deliveries in the first two months of the war.

Earlier Wednesday, Russia shut off gas shipments to Poland and Bulgaria over their support of Ukraine in the war and threatened other countries with similar measures. Germany’s Economy Minister Robert Habeck called that an example of “the reality where energy is used as a weapon” and said his country is trying to diversify its supplies, reduce consumption and switch to renewable energy “so that we are not defenseless.”

At an international forum on offshore wind energy in Atlantic City, New Jersey, U.S. Energy Secretary Jennifer Granholm stressed the importance of the world turning its back on Russian energy and find other, cleaner sources.

“Russia is waging a war in Ukraine and the imperative (is) to move away from Russian oil and gas,” Granholm said. “For the world to move away from Russian oil and gas screams that there is an imperative that we electrify.”

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Latest developments:

► More than half of the 90 howitzers the U.S. promised to send Ukraine have been delivered, Pentagon Press Secretary John Kirby said Wednesday.

►Trevor Reed, a Marine held captive in Russia for nearly three years, will be allowed to return home to the U.S. in an extraordinary prisoner exchange between the countries at a time of heightened tensions.