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."
