Environmentalists warn that the proposal, signed by a bipartisan group of 13 governors, could increase reliance on fossil fuels and fail to bring consumer prices down.By Marianne Lavelle, Kiley BenseRising electricity costs and the rapid build-out of energy-hungry data centers across the mid-Atlantic region brought a bipartisan group of governors to the White House Friday for an agreement on a joint action plan meant to “ensure data centers pay their fair share.” The proposal also would extend a wholesale price cap that is now in place, possibly shielding consumers from further increases.