Zero-emissions vehicles are more than just about the amount of horsepower they produce. The truth is, power often takes a backseat to range, or how far a zero-emissions vehicle can go on a single charge. To this day, the threshold seems to be 300 miles on a single charge, something that only a few cars are capable of achieving. One of these cars is the range-topping Tesla Model S P100D, which has a range of 315 miles. Another model that’s expected to break that mark is Honda’s Clarity fuel-cell vehicle, and according to the Japanese automaker, the Clarity FCV will have an EPA rating of 366 miles on a single tank, or the equivalent of 68 mpg combined (city and highway), making it the new standard-bearer for the highest range among zero-emission vehicles.