The EPA has issued its sticker for the Nissan LEAF all-electric sedan — let’s break down the numbers. First, the LEAF scored big with its 99 miles per gallon “equivalent,” or MPGe, based on the assumption that 33.7 kilowatt hours of electricity equals one gallon of gasoline. The EPA hasn’t issued its sticker for the LEAF’s big rival, the plug-in hybrid Chevy Volt — but GM has said that the Volt gets about 100 MPGe when it’s in all-electric mode, but about 30MPG when the battery-charging motor kicks in. What about the cost of fuel? EPA pegs the LEAF’s annual electricity cost at $561, though that number will vary depending on regional power pricing differences — but it’s still better than EPA’s annual fuel cost of $867 for the Toyota Prius hybrid. The LEAF’s $561-per-year power cost also brings up useful figures to measure against NRG Energy’s new car charging business in Houston. While it has more expensive public charging options, NRG’s program at the low end promises to install Level 2 car chargers at the homes of new LEAF buyers, and provide all the power they need for three years, at a fixed rate of $49 per month — or $588 per year.