Due to go on sale from 2018, the lightweight two-seater car is being funded with the help of a £2m grant from the Welsh government. It uses a carbon composite chassis and a powertrain comprising only 18 moving parts, with a total kerb weight of just 580kg – half the weight of a supermini.

The Rasa uses an 8.5kW fuel cell (equivalent to 11bhp), which combines hydrogen with oxygen to form water and electricity to drive the motors positioned in each of the four wheels. More than 50% of the kinetic energy produced under braking is recovered and turned into electricity to boost acceleration via a bank of super-capacitors. 

The result is a range of up to 300 miles on 1.5kg of hydrogen, said to equate to an estimated fuel economy of 250mpg, and a top speed of 60mph. Well to wheel CO2 emissions are around 40g/km, said to be the lowest for any vehicle, and water is the only exhaust output.

A public 12-month trial of 20 Rasa prototype cars will take place later this year and the model will then be offered on sale from 2018 on a “strategically planned phased roll-out by region”.

Riversimple also says the Rasa will be marketed using a “sale of service” ownership model similar to leasing. This will see the customer pay a fixed monthly fee that covers all repair, maintenance, insurance and fuel expenses as well as fixed mileage allowance. Customers will simply exchange or return the Rasa at the end of the ownership period.

Hugo Spowers, founder of Riversimple Movement Ltd, said: “The Rasa engineering prototype marks another key milestone in bringing an affordable and highly-efficient hydrogen-powered car to market. We really have started from a clean sheet of paper. The Rasa gives us the opportunity to introduce customers to a more convenient concept of motoring, a lightness of ownership that neither places a burden on the pockets of motorists or the surrounding environment. The car is simple, light and fun in every respect.”