Running on air and water
Fuel cell developed by the Fever project. The only waste emitted by this 100% clean system of energy production: water.
Zero emissions, over a range of 500 km, 120 km/h top speed. This is the performance of a prototype of a clean car produced by a European partnership. "Fever" is an electric car powered by a fuel cell which consumes only hydrogen and oxygen.
An experimental vehicle, modelled on a Renault Laguna estate.
Two problems remain to be solved: size and cost.
In fifteen years' time, three fourths of cars on the road will have to consist of hybrid vehicles, in which electric power is coupled with internal combustion. The remaining 25% will be fully electric. For this purpose, a particularly economical and clean vehicle could be developed from the prototype produced by the six European partners in the Fever project. The vehicle's special feature is that is has an engine powered by a fuel cell that is very environmentally friendly.
Electrolysis in reverse
"In a fuel cell, it is the recombining of hydrogen with the oxygen in the air which produces an electric current and water", explains Jean-Claude Griesemann, project coordinator and head of research at Renault. "The fuel cell principle is the reverse of electrolysis in which a current causes water to break down into hydrogen and oxygen." With the aid of a catalyst, the hydrogen introduced into the first chamber in the fuel cell releases electrons, which are captured by a metal plate resulting in an electric current. The hydrogen nuclei, or protons, then pass through a semi?permeable membrane and recombine, in the second chamber, with the oxygen in the air. The water thus formed is the only waste produced by this completely clean system of energy production.
Various specialists with mutually complementary knowhow worked on this prototype for five years. The Italian partner De Nora produced the fuel cell and Ansaldo, likewise Italian, assembled the secondary systems and the hydrogen tank with the fuel cell. Air Liquide of France manufactured the hydrogen tank, Volvo of Sweden carried out the simulations and the Paris School of Mines defined the system's operating parameters. The prototype was based on a modified Renault Lagune estate.
"The main problems lay in understanding the physical phenomena which take place inside the system", explains Jean?Claude Griesemann. "One of the difficulties is maintaining the balance between the pressures of air and hydrogen on either side of the membranes during all the transitional stages. Any sudden imbalance could break the membranes - and thus destroy the cells. Another difficulty is linked to managing the water, both that required for gas humidification and cooling and that produced by the fuel cell. Too much water in the circuits would prevent proper gas circulation, for example. Temperature control is also a problem, because any heating means energy consumed at the expense of electricity production."
The lessons of a prototype
The experimental vehicle demonstrated the feasibility, and above al the qualitative and quantitative performances, of such a system: zero emissions, much higher energy production than for internal combustion engines, a top speed of 120 km per hour and a range which is limited only by the quantity of hydrogen carried (500 km for 8 kg of liquid hydrogen). The remaining problems to be solved prior to industrial production are space (the system's current size only leaves room for two passengers) and cost. The objective viewed as economically reasonable would be to get down to EUR 100/kg which is equivalent to twice the price of the engine - some good quality fuel cells at present cost up to EUR 100 000/kw.
In addition to working on the Fever, De Nora and Air Liquide are also cooperating with other partners on the EU's HYDRO?GEN project. Coordinated by the French car manufacturer PSA, this aims to develop another type of vehicle using a new generation of fuel cells and compressed hydrogen.
The mass production of this explosive gas, together with its transport and distribution, is in fact the main obstacle to use of the fuel cell. Manufacturers (in particular Volkswagen, coordinator of the CAPRI initiative) are therefore looking at the possibility of producing the hydrogen directly in the vehicle itself by means of a "reformer". A common operation in gas industries, reforming involves oxidising a hydrocarbon, using high?temperature steam and air, and a catalyst, in order to obtain hydrogen, carbon monoxide and a lighter hydrocarbon. With methanol, the reformer produces hydrogen and carbon dioxide only. This solution has the advantage that it can be used immediately in the existing distribution network, and methanol can also be produced from very diverse sources. Vehicles designed in this way would no longer have zero emission, but the system's excellent energy efficiency would still result in a major reduction in the CO2 emissions of these vehicles.