This interesting item (text & photo below) was posted by John Hughes on the ans-pie list today....
To me, it illustrates one of the problems which large-scale wind power use in Canada is likely to encounter -- imagine the disaster of an ice-storm destroying a large fraction of a wind farm with several thousand windmills ( the number required to replace a nuclear power station like Pickering), just a couple of years after their installation.... high-priced imported electricity makes up the short fall while utilities struggle for months, trying to repair the broken blades, one by one, in a hazardous, freezing weather environment, liable to cause many worker injuries...
....last month, John also posted this bit of information, from http://www.kemijoki.fi/jaaneste.htm, worth repeating here (in Canada) (grammar corrected from original text):
The ice formation on the wind power plant's rotor deteriorates the balance and aerodynamic properties of the blades. Due to this the output of the plant can diminish even by 50 %. Ice formation is a remarkable problem for the economy of wind energy production, especially in the arctic areas of Nordic countries, northern America and Russia, but also in Europe's mountain areas. The main parts of the ice prevention system are:
Blade heating elements.... Ice detector.... Anemometer.... Temperature sensors.... Control unit
By expending some percentage of the power production for blade heating, it is still economical to produce wind energy in arctic conditions.
...it would be interesting to know whether in fact any of the windmills already installed in Canada use such ice prevention systems, and also what the total heat output from a wind farm with several thousand windmills might be, in a freezing rain situation... sounds like a very efficient way of heating the environment !!
Wind farm closed after blade snaps, boaters warned
Wednesday, 23 January, 2002, 12:23 GMT
Wind farm closed after blade snaps
The blade sits at the top of a 93-metre-high column
A turbine propeller blade has folded in half at the UK's first electricity-generating offshore wind farm, at Blyth, in Northumberland.
It will not be known until data are gathered from a companion turbine whether high winds in the region are to blame for the breakdown.
The turbine operators, Amec Wind, hope to carry out an investigation with the unit's Danish makers, although bad weather has so far hampered plans for an inspection.
Small boats have been warned to stay away after a blade onone of the two 93-metre-high turbines snapped.
Dr Chris French, a lecturer in marine electrotechnology at Newcastle University, said it could be a long and tricky job to fix the blade.
Dr French told BBC News Online: "Before there is any attempt to take anything off, they will want to look at some of the data that come back from the instrumented turbine.
"I would also think a huge crane barge will be needed to come alongside to carry out the repair work.
"They are going to have to wait for a suitable gap in the weather before work can start.
"I cannot believe the turbines would have been installed without stress testing being carried out first, so I suspect a materials abnormality.
"These are the first offshore wind turbines of their type in the UK, if not the world, so we should not be too pessimistic about what has happened."
The turbines were opened in December 2000, just under a kilometre off Blyth, in a £4m operation by Hexham company Amec Wind.
The turbines were switched off when the fault was discovered, and an inspection by makers Vestas of Denmark is due on Wednesday.
An Amec spokesman said that although there had been windy weather no cause of the fault had yet been determined.
The turbines, opened by Energy Minister Helen Liddle, can generate enough power for 3,000 homes.