Renault, along with Nissan and Nuvera, is developing a power train using fuel cells with reformers. This technology directly produces the hydrogen from a variety of fuels on board the vehicle, solving the problem of very high-pressure or cryogenic storage. They have been working together on this technology since 2002 which can be used immediately, without waiting for a hydrogen distribution network to be established.
The power train consists of the following four components:
- A fuel tank that can contain gasoline, diesel and ethanol, all of which can be used to supply the reformer. This option was chosen to reduce concerns about the future availability of hydrocarbons. It also means that motorists can choose the cheapest available type of fuel.
- The reformer, which 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. 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 fuel cell.
- The fuel cell, which generates electric power by combining hydrogen and oxygen. The only by-product of this electro-chemical reaction is water, which is then returned in a closed circuit to the reformer that needs water to operate. The water produced by the fuel cell is reinjected into the system.
- The electric power generated by the fuel cell is transformed to the appropriate voltage by the power electronics and then drives an electric motor.
Renault presented this information, on the progress it has made in fuel cell research, at the 16th World Hydrogen Energy Conference that was held in Lyons, France between June 13 and 16, 2006.
I do not know if the following is the specific technology used by Renault, but it must at least be a derrivitive. Nuvera make metalic bipolar plate PEM fuel cells. The specific fuel cell they gave specifications for was 75 Kw. From the Nuvera website:
Metallic Bipolar Plates - Metallic stacks are best suited for transportation applications because of their resistance to shock and vibration and are significantly lower in manufacturing cost than graphite stacks. Nuvera was the original metal stack manufacturer and, today, is the only metal stack manufacturer that is capable of using uncoated metal plates, which is a feature of our patented approach that will offer cost advantages during manufacturing.
Nuvera's fuel cell stacks use direct water injection (DWI) technology.
They have achieved electrical efficiencies of 50 to 55 percent (not necessarily on the Renault fuel cell).
Nuvera has demonstrated that onboard reformers are environmentally responsible (whatever that means)
The Star (Substrate Transportation Autothermal Reformer) fuel processor, developed by Nuvera specifically for the automotive market in conjunction with the U.S. Department of Energy, utilizes advanced catalysts developed by Nuvera and its catalyst partners. A revolutionary technology in both size and operation, Star may well become the first gasoline fuel processor in a realistic form for automotive deployment.
Today, Nuvera is a recognized world leader in fuel-processing technology design. Our fuel processors range in size from 500 W to 250 kW and lead the industry in size, efficiency, and flexibility. In fact, using our proprietary steam, autothermal, and partial oxidation technologies, we remain one of the only companies in the world capable of converting virtually any hydrocarbon fuel (gasoline, natural gas, propane, methanol, Diesel, and jet fuel), renewable fuel (ethanol), and synthetic fuel into hydrogen. Additionally, our innovative technology is set to crack the last remaining barrier to onboard fuel processing - start-up time.
Lastly, by working with the world's leading catalyst companies, we have developed specialized catalysts for use in our fuel processors. We have also developed technology that allows us to optimize process conditions and reactor designs to facilitate the efficient removal of harmful contaminants - such as carbon monoxide and sulfur - from the hydrogen stream produced by our fuel processors.
At the present time, we are working with Renault, among other leading automakers around the world, to demonstrate Star's effectiveness in laboratory trials. Pre-commercial units could be placed in demonstration fuel cell vehicles as early as 2010.
Renault presents progress in its research into fuel cells, Renault press release, June 13,2006