Tests Show Significant Gains From Anti-Icing Systems
Anti-icing systems on wind turbines can increase the yearly production of energy with around 10 percent, according to tests made by the utility Skellefteå Kraft at wind farms in the north of Sweden.
– The loss of production on a turbine without blade heating was almost 50 000 euro during one year, says Hans Gedda, a technical consultant, who has been managing the project for Skellefteå Kraft.
At last years Winterwind Hans Gedda presented preliminary results from tests in November and December 2011 at the wind farm Uljabuouda in the northern municipality of Arjeplog.
At this years conference he will describe the findings from expanded testing in Uljabuouda as well as in Jokkmokksliden/Storliden in the Malå municipality during the whole winter season 2011-2012.
There will also be additional data available from the end of 2012.
– Just as our first tests showed there are substantial gains to be made from having anti-icing systems on the turbines, says Hans Gedda.
But he also points out that tests and estimates have to be interpreted with care:
– The results are based on a turbine availability close to 100 precent and properly functioning de-icing system throughout the mesurement period.
– Also, the hub height, weather, landscape and how the turbines are placed – it all affects the severity of the icing.
For example Gedda mentions that icing during November and December 2011 was much less severe than the same months 2012, when stop hours due to heavy icing increased significantly.
In Uljabuouda the utility shut down the anti-icing system (carbon fibres incorporated in the rotor blades, heating the surface) on a Windwind 3 MW turbine while running the system on an identical turbine.
– But after a first trial period we decided to stop that test because the losses were so significant on the turbine with the shut down heating system, says Gedda.
Instead he and the team used a system with reference turbines to get comparisons.
In Jokkmokksliden/Storliden 15 of the 18 Nordex 2,5 MW turbines have anti-icing systems and could be compared with the 3 turbines that haven’t.
The internal power requirement for the anti-icing systems at Jokkmokksliden/Storliden was estimated to 1-1,5 percent of the total output of the turbine, for a month with severe icing.
Corresponding figures at Uljabuouda are 2-2,5 percent.
– An anti-icing system that costs about 100 000-150 000 euro will pay for itself on average after three years of operation, says Hans Gedda.