Optim Energy LLC won approval of its plan to exit bankruptcy protection, a win for Bill Gates’s private investment firm in its fight with private-equity firm Blackstone Group LP for control of the Texas energy company, the Wall Street Journal reported today. Bankruptcy Judge Brendan Linehan Shannon said that he would sign off on Optim’s plan, which leaves the energy company in control of Gates’s private-equity firm, Cascade Investment. Blackstone had argued Optim’s plan was “a sham,” designed to benefit Gates and his investment firm. Optim had the votes it needs to get the plan approved, but first had to face off with Blackstone for two days last week at a confirmation hearing. Walnut Creek Mining, a Blackstone subsidiary that supplied fuel to Optim’s power plants, argued it was being shortchanged under the plan, recovering only about 1 percent of what it is owed while general unsecured creditors were expected to see a recovery of up to 95 percent.