At the very end of the original "Back to the Future" movie, the character of Doc comes back from the year 2015 and has converted the DeLorean time machine to run on power generated by a home appliance called Mr. Fusion. He threw household garbage into it saying, "I need fuel" as young Marty McFly looked on in amazement.Well, despite that tongue-in-cheek prediction of the future, Mr. Fusion didn't come true, but we can drive a futuristic car today. The 2018 Clarity is the latest Honda to use a fuel cell powered by compressed hydrogen and is available for lease at $369 per month.Through a chemical process, the fuel cell creates electricity, so the Clarity is essentially an electric car that doesn't need to be plugged in. Honda claims a range of 366 miles on a full tank of hydrogen. But where do you get hydrogen?"The goal is to have over 100 stations by 2020," said Fred Aikins, a spokesman for True Zero , one of the companies installing hydrogen dispensing pumps around California. He added that currently there are 31 stations - run by True Zero and others - statewide.They're often tucked into corners of conventional gas stations, and a fill-up is quick and easy, which is the beauty of replenishing an electric car this way. Though after topping up the Clarity test car I was driving at a Pure Fuel outlet, the car's trip computer wasn't quite promising the range that Honda and the EPA do in the official rating. My estimated range was shown to be only 287 miles, not 366. As the saying goes, "your mileage may vary."The price may vary too. Dispensed high-pressure gaseous hydrogen is measured in kilograms, and now that hydrogen has moved beyond the testing phase, market rates apply. So a fill-up is comparable to filling up a gasoline car at current pump prices.When the test Clarity's fuel gauge showed just over one-quarter tank remaining, I topped it up at a cost of $48.46, based on a pump price of $16.58 per kilogram. But Honda includes $15,000 worth of hydrogen as part of the three-year Clarity lease. So for now, free fuel for three years if you lease one.But even though hydrogen for fuel cell cars is now more available than it used to be, some may not be ready to make the leap to something so unconventional. (In addition to the Clarity, Toyota and Hyundai both also have them on the market.)For those buyers, there are two other versions of the Clarity: a pure EV battery electric and a plug-in hybrid. The plug-in offers 47 miles of battery range (officially), or you can go as far as you want with gasoline, just like any other car.The pure plug-in version of the Clarity gets an 89-mile range. The flexibility of power in one model is what helped the Clarity score the Green Car of the Year Award at the Los Angeles Auto Show, with Green Car Journal publisher Ron Cogan saying the three variations are an ideal way to offer alternative power in one design.So you can skip the gas pump, and use hydrogen, the "fuel of the future," or you can use regular electricity from the wall, or even a bit of gasoline in the case of the PHEV Clarity. They're several choices, from one car.