Utilities have begun offering direct rebates for electric vehicles in an effort to jump-start sluggish sales in an emerging car market that stands to benefit them financially. Electric companies in Vermont and California have offered customers $450 to $1,200 off their electric bill if they buy a plug-in car. Others have partnered with Nissan to offer $10,000 in rebates. With sales of electric vehicles barely cracking 1 percent nationally, it’s a sign that proponents are