'Energy bags' would solve wind flow dips

ENGINEERING WIND FARMS: THE NEXT GENERATION of offshore wind farms built here could incorporate energy storage devices that solve the problem of intermittent wind energy.

Speaking at a recent Engineers Ireland seminar, UCD graduate and professor of dynamics at the University of Nottingham, Seamus Garvey, said that the wind farms – featuring larger turbines and new tower designs – could be combined with compressed air energy storage devices that store power until it is needed.

Garvey proposes a design using robust and durable turbine blades that are larger than current ones, combined with floating turbine towers that are moored to the seabed. This would reduce the cost of the turbines by as much as 80 per cent, he has calculated.

The deep oceans surrounding Ireland – off the west coast, for example – make it an ideal location for second-generation wind farms. Integrating these with wave and tidal farms and energy storage devices would bring the cost of electricity produced in line with, or below, coal power.

This could dramatically increase Ireland’s potential to export cheap, clean energy to the UK or Europe through the appropriate interconnectors, according to Garvey. It would also provide an opportunity to develop an indigenous wind industry, providing hundreds of associated manufacturing and services jobs, he added.

The compressed air storage devices that he proposes using, called “energy bags”, are made of steel or polymer, and would draw air from solar-powered heat exchangers. They would store the air until a time of peak energy demand, and they would then release the air, which would turn the wind turbine to generate electricity.

Having received a €300,000 grant from power giant E.On last year for the construction of two prototype energy bags, Garvey is currently part of a consortium of 12 engineering companies from Britain, Germany, Denmark and elsewhere that has applied for €12 million in EU research funding.

The cost of trialling a new turbine design combined with an energy bag would cost a fraction of the estimated €7 billion being invested in Irish wind power, or the €6 billion Ireland spent on imported fuel last year, said Garvey.

It could then be scaled up and integrated with trial wave and tidal projects, such as those being planned off the Mayo coast.