Renault is focusing on the development of an on-board multi-fuel reformer to produce the hydrogen to power the fuel cell, thereby sidestepping the current problems with very high-pressure, cryogenic, or materials-based storage, as well as the need for a hydrogen distribution network.

Renault will present an update on its work on fuel-cell vehicles at the 16th World Hydrogen Energy Conference in Lyons, France, which opens today.

Renault, Nissan and Nuvera Fuel Cells have been working together on this solution since 2002.

The chemical processes of the on-board reformer. Click to enlarge.

The on-board reformer transforms the liquid fuel into reformate, a hydrogen-rich gas that can be used to supply the fuel cell. The process has six distinct stages with five primary systems: a burner, an autothermal reformer (ATR), a high temperature shift (HTS) system, a preferential oxidation system (PROX), and a low temperature shift (LTS) system.

First, the cracking phase breaks down the long hydrocarbon molecule chains into simpler molecules: hydrogen, water, carbon, etc. In the next five stages, the gas is purified until it is ready for use with the 45 kW fuel cell.

The reformate emerges with about 40% H 2 and 100 ppm CO, the rest being water, CO 2 and nitrogen. At maximum power output, the hydrogen production rate is about 1.4 g/second, according to Renault.

The reformer can run on gasoline, diesel and ethanol, so Renault had to design a special multi-fuel tank for all three. Trenault chose the multi-fuel approach to reduce concerns about the future availability of hydrocarbons. It also means that motorists can choose the cheapest available type of fuel.

When Renault announced its Renault Commitment 2009 in February, it confirmed that the group was preparing a broad range of alternative technologies, of which the fuel cell is just one part. (Earlier post.)