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Test wind turbine near LOFAR meets agreed radio emission norms

Published: Tue, 07/01/2020
Test wind turbine on the horizon of LOFAR’s core station

The test turbine of wind farm “Drentse Monden en Oostermoer” meets the reduction of electromagnetic radiation as agreed in a covenant on the co-existence of a wind farm near the core of the LOFAR radio telescope. This is the conclusion of various measurements conducted since 2 September 2019, and is an important step towards full construction of the wind farm.

In the summer of 2016,  the Radiocommunications Agency Netherlands established that interference in LOFAR’s observations can be caused by both electromagnetic emissions from wind turbines and by reflections of electromagnetic radiation via wind turbines. On 19 September of that year, the wind farm’s initiators and ASTRON entered into the covenant "Co-existence of the wind farm Drentse Monden en Oostermoer and ASTRON’s LOFAR radio telescope" (Dutch: “Convenant co-existentie windpark de Drentse Monden en Oostermoer en de LOFAR radiotelescoop van ASTRON”). The covenant stipulates how LOFAR and the wind farm can co-exist.  Both ASTRON and the wind farm’s initiators made concessions to limit the impact on LOFAR’s scientific program.

In recent years, the parties worked to comply with the covenant’s agreements. A special wind turbine was developed to significantly reduce its electromagnetic radiation. ASTRON’s LOFAR radio telescope conducted measurements of the test turbine in September 2019. The Radiocommunications Agency Netherlands supervised the process in the role of independent expert. The measurements showed that the minimum required emission reduction (35 dB, as per the covenant) is achieved.

The condition in the covenant for the construction and commissioning of the other 44 turbines of the wind farm is therefore met. With a capacity of 175.5 MW, the “Drentse Monden en Oostermoer” wind farm makes an important contribution to achieving the national target of 6000 MW of onshore wind energy. The wind farm will consist of 45 wind turbines spread over six lines in the municipalities “Aa en Hunze” and “Borger-Odoorn” in the province of Drenthe, the Netherlands. The wind farm is expected to be operational in 2021.

The final report of the measurements and the agreement can be found at: https://www.rvo.nl/onderwerpen/bureau-energieprojecten/lopende-projecten/windparken/windpark-dm-en-om (Dutch)

ASTRON will document the specific impact on the scientific program of the LOFAR telescope with the next call for observing proposals to the astronomical community.