This story originally referred to the energy produced by wind turbines in “kilowatts.” The correct unit is “kilowatt-hours.” Correction added February 16, 2011.
Ron Watson has a cautionary tale for farmers considering buying a wind turbine.
“It’s going to put out half of what you would expect,” said the farmer from Beaver Creek, Sask.
Watson has operated a 20 kilowatt wind turbine on his farm since August 2009. Power generation from the 4,100 kilogram turbine has been disappointing.
“We’re definitely not getting out of it what we were told we were going to get,” he said.
The turbine generates twice as much power as the farm needs when it is operating at full capacity, but there are many days when it doesn’t spin.
He had expected it would be more than capable of handling his farm’s needs, but estimates it produces half the power he thought it would.
The turbine, perched on a hill 24 metres above the nearby South Saskatchewan River, produced an average of 25 kilowatt-hours of energy per day last month.
The three houses and shop on his farm used 95 kilowatt-hours of energy per day.
Watson’s experience mirrors the findings of a Saskatchewan Research Council report that compared measured production at 10 wind turbine sites with estimated production at 40 sites using the best models available.
“Measured annual energy production from the turbines averages 48 percent of that predicted by the models using the manufacturer’s published power curves,” Kelly Winder wrote in the Small Wind Turbine Performance Investigation report, which was distributed only to study participants.
He attributed 12 percentage points of the 52 percent shortfall to turbine failures, 16 percentage points to lower than normal winds during the measuring period and the remainder to misrepresentations of the power curves by turbine manufacturers and other factors such as site selection and installation.
Winder said 200 people are participating in the province’s net metering program, 85 to 90 percent of which operate wind turbines.
He agreed with Watson that prospective buyers should budget on generating half of the power the manufacturers claim the turbines will produce.
“If they’re still happy with it, then go ahead. The chances are they will be pleasantly surprised.”
Darryl Jessie, president of Raum Energy of Saskatoon, which has sold more than 150 turbines on the Prairies, said he has reservations about the methodology used in the SRC study.
He said it measured data at only 10 sites, which is a small proportion of the number of turbines operating in the province.
As well, he added, some of the turbines are located on sites that were chosen more for advertising wind energy than for optimum power generation.
Jessie said the data collection period was inadequate and the SRC used a wind speed averaging technique to calculate its power curves, while Raum relies on instantaneous wind speed, which he feels is a superior measure.
He said Raum turbines are now better than the 2007 models that the SRC analyzed. The company no longer sells that 1.3 kilowatt machine, he added.
Jessie said the company is working to improve the performance of its turbines and believes new models, such as the 3.5 kilowatt machines, will fare “a lot, lot better” in future SRC studies.
He acknowledged some companies have intentionally misrepresented their power curves to make a quick buck but insisted Raum isn’t one of them.
“I don’t know of anyone saying definitively that your power curve is way off,” he said.
“We always tell our customers that we’re not perfect but when something goes wrong, we’ll be there and we’ll take care of it.”
That has certainly been the experience of Dave Burback, who owns a 3.5 kilowatt Raum turbine on his acreage near Grandora, Sask.
He experienced a series of initial mechanical setbacks shortly after commissioning the turbine in October 2009. The braking system didn’t work, the inverters were not properly synchronized with the turbines and the turbines failed.
It was a new product and Burback expected glitches.
He said Raum fixed the problems and there have been no issues since the first four-month rocky period.
However, he isn’t happy with the turbine’s energy output. He expected it to produce 3,000 kilowatt-hours of energy a year but his meter shows 1,700 kilowatt-hours of production.
He said he needs to be patient and not judge the turbine after one year of operation, especially a wet year with limited wind production.
“I’m still positive. I’m still satisfied with my purchase.”
Watson also said he doesn’t regret his purchase. He believes the turbine will eventually pay for itself, especially considering the incentives he received from the provincial and federal governments.
However, he thinks wind turbine manufacturers have plenty of room for improvement. One advancement he would like to see is a properly functioning governor that allows turbines to operate all day during windy spells rather than shutting down to prevent damage to the equipment.
“I would say they’re in the Model T stage, let’s put it that way,” said Watson.