Coal stockpiles grow at Europe's ports.

Coal is piling up at ports across Europe, depressing both the cost of the fuel and price of electricity. Stockpiles at three European ports - Rotterdam, Amsterdam and Vlissingen - are near the highest since 2013.

Supplies built up during a warmer than usual winter and as governments tried to reduce emissions from the most polluting fossil fuel. The result is that inventories of the commodity are unusually high when they should be depleted from a season of high heating demand. Cheaper coal is one of the factors pushing...