Some people have tried repeatedly to get Fuelly to add MPGe and to account for electricity. Fuelly has responded that they are not going to add anything at this point. They said to just use Voltstats.
"Yeah, I'm sorry the site isn't designed to report that. We're set up to share and compare MPG. kWh/mile doesn't fit in with that scheme, and we're not going to completely reshape the site for a couple of vehicles. At our current moment in history people use MPG to compare the fuel economy of vehicles, so we're going to stick with that."
"We're going to take our time with this, and we might not add kWh tracking. Fuelly is a free service that we run on the side because we believe people should think about their fuel usage. We can't be all things fuel economy to all people. Some folks are going to disagree with how we do things—some are going to want more features than we offer. We're ok with that."
2012 Blue Topaz Volt - 11/18/11 to 11/17/14 - 36,806 EV miles. Now waiting for the Bolt/Model 3!