Yet, Varo executives are confident that their foothold in European energy markets will help secure their future. Now that Germany is cut off from Russian natural gas, they figure, it will be hungry for a green alternative to generate electricity and to power factories that need a lot of energy like steel mills or chemical plants. The German border runs through a roadway just outside the biogas plant’s gate. “We are in the right ZIP code,” Dev Sanyal, Varo’s chief executive, said in an interview.

Varo, which had about 2,100 employees and an annual revenue of $26 billion in 2022, is an 11-year-old company that earns about $500 million a year refining crude and distributing and trading oil products. Yet the company’s owners — Carlyle, a private equity firm based in the United States, and Vitol, a commodities trading giant — realized that the business needed to prepare for changes ahead. Last year, they brought in Mr. Sanyal, who led the gas and renewable energy business at BP to shift direction.