Bob is right on - the internal combustion engine's awful efficiency makes even partial-electric (a.k.a. plug-in hybrid) cars a better choice. I recall electric motors can yield upwards of 95% efficiency, compared to well below 30% for an ICE (even worse before they're warmed up!)
The comparisons I've seen for cost per mile indicated the break-even point for gas vs. electricity was $1/gallon, so anytime gas costs more than that, driving on electricity saves you money. Going from memory here, apologies for that.
All comparisons I have seen also favor electricity over gasoline for well-to-wheels (total system) energy efficiency, and for well-to-wheels greenhouse gas production. Somewhat surprisingly, even the US's coal-heavy power mix for generating the electricity yields less GHG's per mile through an electric car, again because of the huge disparity in engine efficiency vs. the venerable ICE.
I say if you can find a way to charge your HAH overnight, it's worth it. You may eventually find a larger battery pack aftermarket kit (like Hymotion and others are working on for Prius and Ford Escape) for converting to a full plug-in hybrid that can drive 20 or more miles on all electric. I did find one link about the plug-in world: http://www.calcars.org/vehicles.html