Titel: BOREAS VII – Summary of a cold climate wind energy conference (2005), Vindforsk teknikrapport 1:08
Författare: Göran Ronsten
Utgivare: Elforsk, Vindforsk
Årtal: 2008
Ämnesord: Vindkraft i kallt klimat
Sökord/Keywords: de-icing, Wind energy in cold climates, meteorology.
Rapport (Pdf)
Sammanfattning/Abstract: This report covers presentations made at the BOREAS VII – a conference on icing and its effects on wind energy production held in March 7-8, 2005. The report was prepared by Göran Ronsten at the Swedish Defence Research Agency (FOI) within the wind energy program of Elforsk as report “Elforsk informerer, VINDKRAFT – 3/05, Rapport från BOREAS VII”. The current report is translation of this report. The report has been translated by Annova Forskningskonsult’s Ann Salomonson into English and checked by the author to be available on the Winterwind 2008 web page:
http://www.winterwind.se/.
Introduction
BOREAS VII¹ was arranged on March 7-8, 2005, by the Finnish Meteorological Institute (FMI) in Saariselkä in Finnish Lapland. The number of participants at BOREAS conferences has steadily increased from 30 to the present level of above 60. More than half of the participants were from the R&D sector. Manufacturer of peripheral equipments were relatively well represented, while producers of wind turbines were conspicuous by their absence, except for VESTAS. There were also a number of developers of wind energy in cold climate.
One third of the participants were from Finland, one sixth from Norway and the other half from 13 different countries, including USA, Canada, and Japan. One reason why FMI managed to keep a high number of participants was the ongoing cooperation within COST727, “Measuring and forecasting atmospheric icing of structures”².
Summary and conclusions
The interest in icing seems to increase concurrently with the society being more sensitive to disturbances in the electricity supply and communication. As BOREAS VII was coordinated with COST727, the circle of BOREAS participants has been widened to include also traditional national meteorological institutes and universities. Therefore, many interesting synergetic effects arose when the challenges could be elucidated not only from a wind energy point of view. At the BOREAS VII conference, participants from COST727 presented topics that included everything from ice layer with a thickness that can be counted in number of atomic layers to icing on power lines where the ice weight corresponds to a heavy traffic jam along the entire power line!
Among other things, COST727 evaluates present and future ice detectors. In order to measure icing it is necessary to agree on what parameters, besides wind velocity and temperature, that are most important to measure. Today, the importance of atmospheric humidity is questioned due to the fact that its correlation with icing is ambiguous. Instead, the drop size distribution in relation to the diameter of the ice covered object and the liquid water content of air are considered important icing parameters. Unfortunately, both drop size distribution and the liquid water content of air are difficult and expensive to measure.
The ultimate goal of COST727 is to bring about continuous synoptical³ ice observations to support the development of icing analyses and forecasts. Such analyses and forecasts are today in regular use within civil as well as military air traffic. Verifications of analyses and forecast tools, for example from temperature and icing measurements in high masts, are not currently being carried out.
Only after the above items have been made, is it meaningful to develop reliable icing and low temperature frequency maps, which can describe the assumed losses at an intended wind farm site. In combination with the wind energy resource is it then possible to estimate the losses in energy production that is caused by icing and low temperature. After doing this, a wind energy exploiter, or owner, will be able to judge which type of de-icing equipment is most economical to order, if any.
BOREAS VII gave the participants a good review of the current situation of the topic “Measuring and forecasting
atmospheric icing structures”. Several work and group meetings of the COST727 were arranged in connection with the conference, and also a preparatory meeting at the prospect of the continuation of the IEA R&D Wind, Annex XIX, Wind energy in Cold Climates”.
¹ http://www.fmi.fi/research_meteorology/meteorology_13.html
² http://cost.cordis.lu/src/action_detail.cfm?action=727
³ Simultaneous measurements over a large area