The Narva Oil Shale Mine in northeastern Estonia has long been one of the world’s major sources of shale oil. Oil shale is a fine-grained sedimentary rock containing organic material that can be heated to produce fuel. Extraction at Narva has been declining, falling to about 8.5 million tons in 2024 from over 10 million in recent years. Estonia is now transitioning away from oil shale, aiming to end oil-shale–fired electricity by 2035 and its energy use by 2040. As those processes wane, new indu