By Jason Palmer
Science and technology reporter, BBC News
The car may be rolled out in small to medium UK cities starting in 2010
The manufacturer of a hydrogen car unveiled in London on Tuesday will make its designs available online so the cars can be built and improved locally.
The Riversimple car can reach 80km/hr (50mph) with a range of 322km (200 miles). Fuel consumption is claimed to be equivalent to 300 miles per gallon.
The cars will be leased with fuel and repair costs included, at an estimated £200 ($315) per month.
The company hopes to have the vehicles in production by 2013.
Next year, it aims to release 10 prototypes in a UK city which has yet to be confirmed.
Riversimple has in partnership with gas supply company BOC to install hydrogen stations for the cars in the city where the prototypes are launched.
'Open source' model
The car itself is an amalgam of high-efficiency approaches in automotive design.
Its four motors are powered by a fuel cell rated at just 6kW, in contrast to current designs that are all in excess of 85kW - required because the acceleration from a standing start requires a great deal of power.
Riversimple's solution is to power the car also from so-called "ultracapacitors", which store large amounts of electric charge and, crucially, can release that charge nearly instantly to provide the power needed to accelerate from rest.
The ultracapacitors are charged as the vehicle brakes to a halt, converting the energy of the moving car into stored energy.
Under the bonnet is a comparatively tiny fuel cell
Without a combustion engine, gearbox, or transmission, and with a shell made of carbon fibre composites, it weighs 350kg.
The company claims that it is closer to market than any of its start-up competitors, but what sets them apart is an unusual business model.
"Riversimple has effectively rethought the whole of what in the business school world we call the 'value chain' of the auto industry," said John Constable, chair of the Riversimple project.
The company asserts that in the leasing model, the vested interest for the manufacturer is in producing long-lasting, fuel-efficient, high-quality products, since it bears the cost of both hydrogen and repairs.
Its partnership with BOC is designed to resolve the chicken-and-egg question of who would build the infrastructure required to refuel hydrogen cars when there are none on the road. Meanwhile, would-be hydrogen car buyers are concerned about the dearth of refuelling stations.
"You can incrementally put in a template package of one refuellling point and 50 cars in different cities, and each city one by one can build an urban hydrogen infrastructure, and that incrementally builds a nationwide infrastructure," said Hugo Spowers, the former race car designer who conceived the Riversimple idea in 1999.
The company will distribute the engineering designs to the 40 Fires foundation, a not-for-profit organisation that will make the designs "open source".
The idea, they say, is to allow local manufacturing in small plants. This stands in contrast to the "economies of scale" that drive current plants to huge sizes and workforces.
In addition, designs can be adjusted for local markets, using locally sourced parts or materials.
The agreement will be such that if the designs are improved by a local manufacturer, those improvements will be sent back, so that what the company refers to as its "network of manufacturers" can contribute to the overall development of the product line.