Bob Dylan told us the answer to the world’s political problems was blowing in the wind, Donovan memorably failed to catch the wind and now a professor of Dynamics at England’s Nottingham University wants us to store the wind.
Seamus Garvey of the Midlands-based university’s Department of Mechanical, Materials and Manufacturing Engineering, believes the future of energy is storing it as compressed air in giant bags under the sea. He even has the backing of a major power company which has decided to invest in his ambitious scheme.
Ireland’s west coast, the professor points out, is one of the best places in the world for harvesting renewable energy, largely because of the strong winds. It is also an ideal location for large, offshore wind turbines and wave-energy converters.
The island has easily enough natural power to supply its entire energy demand several times over until well past 2050. The main obstacles are how to make the systems cheap and unobtrusive, and ‘how to keep the lights on’ when the wind is not blowing.
The academic proposes a single solution – integrated compressed air renewable energy systems (Icares). The idea is that wind turbines, wave-energy converters and tidal turbines should compress air rather than generate electricity directly. When the wind is strong, some compressed air is used to drive large high-speed generators and the rest is stored in flexible containers under water. When the wind is less strong, the stored air is resurrected and used to keep the generators turning.
Bigger is better for wind turbines, but conventional designs have hit a ceiling in size. Scaling up these machines further will raise the cost per unit power. By contrast, these turbines only become practical at 200m diameter and improve steadily above that.
Being able to store energy was not important in the past because the output from power stations could be controlled. However, when more than a quarter of the total electricity supply is from intermittent renewables such as wind, there will be times when the total power being generated by the wind turbines exceeds demand across the country.