The economic argument for using wind power to make hydrogen, rather than using it to offset electricity generation from fossil fuel or nuclear plant, lies in avoidance of imbalance penalties. These are incurred when wind stations exceed, or fail to produce, the production they were committed to deliver to the grid in day-ahead schedules. The technical argument is to avoid situations on windy days when high volumes of wind power could overload local distribution networks.
Gas Natural's Antoni Julià says the pilot system will produce hydrogen at up to 60 cubic metres an hour (measured at atmospheric pressure, though it will be compressed to 20 cubic metres). When wind output drops to below the level scheduled a day ahead, the hydrogen gas stored will power a 55 kW gas generator to make up the difference.
Including compressors, generator, storage tanks and other elements, the overall investment exceeds EUR 900,000. "Such a project is the only way to acquire in-the-field knowledge of converting wind to hydrogen, with hands on experience of tubes, bolts and all," says Julià.
The site chosen for the project is the semi-public Sotavento showcase wind plant in Galicia in northern Spain, where six turbine technologies generate power alongside one another. The brand of the turbine selected is confidential "in order to avoid unfair publicity," says Julià. While Gas Natural owns 292 MW of wind assets, it has no stake in Sotavento other than the hydrogen project.