Chevron Corp., which said late last week that it is looking for a buyer for its Hawaii operation, including its refinery and 60 gas stations, could fetch anywhere from $75 million to $300 million, an industry source told PBN. But any possible buyer would have to fork over quite an investment to bring Chevron’s Kapolei refinery, the smaller of the two oil refineries in Hawaii, up to par with environmental regulations, the source said. “So whoever buys it, will have to invest in that at a cost…