The system will be based on Areva's existing Greenergy Box, which produces hydrogen and oxygen by electrolysis when supply outstrips demand and recombines them to generate electricity when most needed.
This can smooth out the energysupply model or provide emergency backup if required. One unique feature of the Greenergy Box is that the fuel cell and storage tanks are combined in a single container, making it easy to install, according to Jerôme Gosset, vice president of Areva's Energy Storage business unit.
The Greenergy Box also has a greater power range than existing hydrogen fuel-cell systems and a longer duration than batteries, which typically last two-to-three hours. While the Greenergy Box's current maximum capacity is only 100kW, Areva envisages coupling up to five together to give 500kW.
Such a system coupled to a wind or solar installation of a few megawatts would be a perfect match, Gosset said. A 1MW system is on the drawing board if there is sufficient demand, he added.
Areva already has a Greenergy Box connected to a 560kW photovoltaic solar plant in Corsica, feeding into the island's grid. Set up in 2012, this pilot project shows the system can be used to manage the solar production profile, Gosset said.
On the basis of these results, Areva and Schneider will now target other, similar markets, such as France's island territories, which are aiming to displace expensive fossil-fuel imports by incorporating more wind and other renewables into their grids.
As for all such energy-storage systems, cost effectiveness is key. The main challenge is to ramp up production sufficiently to drive costs down, Gosset admitted. The business case for Areva's hydrogen fuel-cell system becomes most competitive at more than five or six hours of storage, when the costs are quickly balanced by the durability of the cell and when batteries are less efficient.
Despite such challenges, a number of short-term energy storage technologies are under development, viewed as an essential complement to an increasing amount of wind and other renewable-energies on the grid.
Utility E.on last year inaugurated its own power-to-gas unit in Germany, in this case capturing wind power when the local grid is congested and feeding hydrogen into the regional gas transmission system as part of the natural gas mix. And earlier this month, E.on announced it is working on a large-scale battery storage system with a capacity of 5MW to better integrate wind and solar into the grid.