Air force tests wind turbines at airports

The airport of La Palma in Spain's Canary Islands will soon be the first in the world with a wind plant -- and a further four developments are planned on Spanish soil for the airports of Lanzarote, Tenerife Sur, Melilla and Jerez de la Frontera, according Jesús Maellas of the Instituto Nacional de Tecnica Aeronautica (INTA), the research and development arm of Spain's air force. The project developer is Spain's civil aviation and airport managing body, Aeropuertos Españoles y Navigación Aerea (AENA), whose renewables department commissioned INTA to supervise this, and other energy projects, as part of a push to promote the use of clean energy throughout Spanish airports.

Foundations for the La Palma project -- two MADE 650 kW turbines -- are being poured. INTA will use the turbine to throw light on the effect of electromagnetic and visual interference from turbines on aviation navigation, a particular fear of Britain's Ministry of Defence (page 40). "On this small scale we have no evidence that wind turbine activity causes interference with electronically assisted communication and navigation," says Maellas. INTA has opened a line of investigation to study interference. "But as we seem to be the first, we have no data from other countries to go on," he says.

Maellas is convinced the La Palma project is safe as the airport does not use complicated ILS (Instrument Landing System) and VOR (Very-high-frequency Omni Range) -- apparatus that a wind plant might disturb. Instead, the airport's main navigation aid -- a non-directional beacon -- is situated far enough away to discount interference, he says. But even where ILS and VOR systems are used Maellas believes wind turbine electromagnetic emissions are negligible and will be proven not to interfere with aviation instrumentation.

Other problems that INTA has taken into account include visual interference and noise pollution, which have been minimised by situating the turbines as far as possible from the runway and terminal building. But one of the main problems is how to rig the turbine with beacon lights. "Red lights on the tips of the blades cannot be lit constantly, otherwise at night the turbines will look like a Ferris wheels," says Maellas. "We are now working on a system for lighting the blade tip only as it reaches its highest point during rotation."