Gasoline prices hit $2 a gallon for the first time since 2015 on Thursday as flooding from tropical storm Harvey knocked out almost a quarter of U.S. refineries, while crude oil prices fell again on the resulting drop in demand. Harvey has battered the U.S. Gulf coast since last Friday, ripping through Texas and Louisiana at the heart of the U.S. petroleum industry. At least 4.4 million barrels per day (bpd) of refining capacity was offline, or almost a quarter of total U.S. capacity, based on company reports and Reuters estimates. Fearing a gasoline supply squeeze, U.S. gasoline prices on Thursday jumped to $2 per gallon for the first time since July 2015. […]