OPEC is forecasting an unlikely winner amid an energy shift away from hydrocarbons, predicting the cartel itself will dramatically boost its influence in the global oil market over the next two decades.

In its annual report on long-term energy trends, the Organization of the Petroleum Exporting Countries said it expects global oil demand to grow steadily over the next two decades. By 2045, it predicts its members’ oil will constitute 39% of global crude consumption, up from about 33% now. The group said it expects the Middle East—dominated by OPEC members like Saudi Arabia and the United Arab Emirates—to ship 57% of the world’s crude exports by 2045, up from 48% in 2019.

The group’s market-share gains will come as production by other big producers, including the U.S., ebbs amid falling investment in new hydrocarbon development, according to the report. Non-OPEC supply is forecast to “plateau and peak” in the late 2020s, OPEC said. American oil production is expected to fall by 1.5 million barrels a day by 2045 compared with 2019, the report said.

The forecast, contained in OPEC’s closely followed World Oil Outlook, underscores what some oil-company executives and energy-market analysts say is an underappreciated dynamic behind many richer economies’ push to transition from fossil fuels to lower-emission energy sources: Despite that shift, demand for oil and natural gas is expected to continue for years to come.

In the short term, that holds potential benefits for players who haven’t committed to curtailing their own oil and gas output—like OPEC.