Wind could make rain

Researchers at the Engineering and Physical Sciences Research Council (EPSRC) led by Professor Stephen Salter from the University of Edinburgh, are working on the installation of a specially designed wind turbine at sea. The wind-to-rain project will run for 15 months from April 2003.

The theory is centred on rotating turbine blades being harnessed to pump seawater along the hollow rotors. Water would then spray in small droplets out of the rotor slits. The drops would evaporate and the salt would fall back into the sea whilst water vapour would drift inland increasing the probability of rain, they say.

“[The project] is intended to assess the feasibility of the technology at this early stage, and it will examine the engineering principles of the device – for example spray nozzles and pumping mechanisms – and also study the meteorological potential,” Dr Edward Clarke from EPSRC told edie. “The latter studies will examine the conditions around coastlines near drought regions and determine airflows and onshore wind properties,” he added.

The scientists envisage drought hit lands such as the Sahara becoming areas where agriculture may be able to survive, if their studies can be implemented. It may also hinder the rise of sea levels, an effect of global warming, in the very long term, they say.

“Although there are potential meteorological uncertainties, the potential pay off could be enormous,” says Professor Salter. The wind must blow onshore. The relative humidity must not already be too high. The air must be warm enough to get latent heat for evaporation. To get rain we want the air to rise over higher ground. There must be cloud nucleation particles,” Salter told edie.

Dr Clarke said that if after further research the scheme continues to look promising a small-scale demonstrator might be built. However he acknowledged that such an undertaking would need industrial or government sponsorship.