A wrong-way bet on the price of wood pellets has jeopardized America’s biggest exporter of the fuel, even though demand has never been higher among the European and Asia power plants burning wood instead of coal. Enviva said its gambit to buy pellets from a customer, and resell them for more, backfired when prices fell, and that nine-figure losses could trigger a default with its lenders by year-end. Enviva’s shares are down about 60% since it warned investors earlier this month that the trade risked its ability to remain a going concern. The ...