The benchmark natural-gas price soared to a nearly four-month high, bolstered by rising demand from power generators that are pivoting away from coal. This year, utilities will retire 4.3% of the nation’s coal-fired electricity-generation capacity that is either outdated or unable to meet new environmental regulations, according to the U.S. Energy Information Administration. As a result, the burden of making up that shortfall will fall on gas-fired facilities, boosting overall demand and prices for gas. U.S. natural-gas inventories posted a smaller-than-expected increase last week, according to EIA data released Thursday. That coincided with above-normal temperatures in the East and Midwest, highlighting the role power-plant demand will play in the natural-gas market this summer when air-conditioning use could force generators to run hard. Natural-gas futures Thursday rallied 2.5% to $3.008 a million British thermal units, the highest level since Jan. 16 on the New York Mercantile Exchange. […]