Coming not so soon and probably not to a house near you is the home solar hydrogen refuelling station - Honda's latest idea in its drive to make hydrogen the fuel of choice for zero-emission cars.
The Japanese carmaker believes hydrogen fuel-cell vehicles offer the best long-term alternative to fossil fuels, and the US arm of the company is showing a refuelling breakthrough that it says points to a home version down the road.
Among the world's carmakers, Honda is widely seen as the hydrogen leader, tempted by the idea of a car that uses no petrol and emits only water vapour. Others like General Motors put more effort into battery-powered electric vehicles such as the upcoming Chevrolet Volt.
One of the big barriers to hydrogen car deployment is the lack of refuelling infrastructure, leading Honda to bet that the future lies in combining a public station network with a more modest home option.
Honda's home option will comprise a solar-powered hydrogen refuelling station using solar panels.
"Customers can choose how they interact with both of them based on their annual miles and their habits," said Stephen Ellis, fuel cell manager at the Honda's North American headquarters in Torrance, California.
"The key thing to remember is that with five-minute refuelling you are good for another 240 miles," Ellis added.
That range comes from the "fast-fill" public station, of which there are just a handful in Southern California, where Honda leases 15 FCX Clarity hydrogen-powered vehicles and is set to distribute more in coming months.
Eight hours of home solar refuelling would guarantee a smaller range of 50km or about 16,000km a year - enough for an average commuting car.
At the Los Angeles research and development centre, engineers refuelled the sleek FCX Clarity sedan with a new single-unit station connected to a solar array that replaces a two-unit system, cutting costs and improving efficiency by 25 per cent.
"This is wonderful progress, the biggest progress," said chief engineer Ikuya Yamashita.
The station uses a 6kW solar array, composed of 48 panels and thin film solar cells developed by a Honda subsidiary. It breaks down the water into hydrogen in what Honda calls a "virtually carbon-free energy cycle".
The FCX Clarity's hydrogen "stack" - or the electricity generator - is around the size of an attache case, tucked between the two front seats, and is a fifth of the stack size developed a decade ago.
The car is likely to be sold commercially around 2018 in the luxury large sedan category, while the solar hydrogen refuelling system could move beyond the research stage and into the market-ready phase around 2015. "A lot of this work is not necessarily for today's economic situation," said Ellis. "This is for tomorrow, when most people feel energy prices will be higher."
