Greenpeace, however, is estimating that 20,000-25,000 MW is technically and environmentally viable offshore by 2030. It puts potential at 10,000 MW for the Gulf of Cadiz on the Atlantic coast of Andalucia, 7500-15,000 MW along the Mediterranean coast, "a few hundred" megawatts off the Canary Islands west of Morocco, and 500 MW "near shore" around Spain. Greenpeace acknowledges that technical advances are first needed to make turbine construction in depths of more that 30 metres viable.
The Greenpeace report, "There's Something in the Sea Wind," calls on the Spanish government to draw up an offshore wind plan, set a higher wind tariff for offshore generation, and to fast-track 2000 MW of test bed sites. The lobby group also envisages offloading excess wind power into desalination plant as well as into hydrogen production.
"The report is possibly exaggerated but it's helpful support nonetheless," says Rüdiger Wolf of German developer Umweltkontor, which is behind plans for a 250 MW offshore project at Cabo Trafalgar, one of only two publicly announced offshore projects in Spain, both in the Gulf of Cadiz (Windpower Monthly, May 2003).
Sea bed studies in the gulf by Umweltkontor's affiliate, Offshore Wind Power Development, indicate restricted potential, Wolf says. "A third is lost due to environmental impact and a third due to foundation design difficulties." Regarding depths, he adds, technological advances would have to include floating platforms as well as pile driving in deep sea beds "and that's 20 years down the road." Wolf has also worked closely with a German wind-hydrogen project. "Technically there were no problems but costs proved prohibitive," he says.
Meantime, the parliament of Andalucia said in July it will draw up specific guidelines for regional offshore development. "Planning for such public sites is only to be welcomed," comments Wolf. "But it should be there right from the start, maybe involving an auctioning process like in Britain." The growth of one of the two offshore proposals to five times its original size may well have prompted Andalucia's sudden interest in guidelines. Corporación Energía Hidroeléctrica de Navarra has revealed it is looking at 1000 MW, rather than the widely reported 200 MW for its project.
With zero offshore capacity and the Cadiz projects already five years on the table, the most immediate prospect for offshore wind generation is far from the mainland. In the Spanish Canary Islands off the north-west African coast, a public consortium is negotiating with turbine manufacturers to install a 1.5 MW-2 MW prototype in the port of Las Palmas, with a view to larger installations. The research and development project, scheduled to finish next year, is lead by technology agency Instituto Tecnológico de Canarias (ITC).
ITC's Gonzalo Piernavieja says near shore sites can help repower the Canary Islands' older wind turbines onshore, and surplus generation can power desalination plants. He maintains, however, that the Canaries' deep waters will restrict any major offshore development.