Thursday, September 07, 2006
CALGARY - We may call it wind power, but in truth it all comes from solar energy.
"Wind is created by the heating of the Earth in different locations and different amounts, which causes bodies of air to shift around," says Sean Whittaker, director of policy and technical issues at the Canadian Wind Energy Association.
With turbines we tap into wind's energy. "Basically, the air passes over the blades of the turbine and creates lift, [which] causes a rotation," Mr. Whittaker says. "It's that rotation that you run through a generator that creates electricity."
Turbines come in two configurations: horizontal axis, which are usually tower-mounted with the blades' axle running at right angles to the tower; and vertical axis, which resemble eggbeaters. Horizontal axis turbines dominate the market.
In Practice
First, you need average wind speeds of at least six metres per second. Then you need to get the turbine into the wind. "The higher the turbine, the higher the wind speed, with less turbulence -- so the turbines can extract more power from the wind," says David Kelly of Calgary-based Sedmek Inc., which specializes in renewable energy.
Experts recommend towers be at least 10 metres above the highest structure within 100 metres, and one to two tower-heights away from occupied structures. "Putting a wind turbine on a tower that's too short is like putting a solar panel in the shade," Mr. Whittaker says.
The Canadian Wind Energy Association has developed guidelines that will help you find a site for your wind turbine and deal with local planning regulations. And Mr. Whittaker strongly urges consulting with neighbours and local municipalities, which may, for example, have height restrictions.
Common concerns include safety, noise and esthetics. Experts say birds occasionally fly into turbines, but statistically, a house cat is more of a risk to birds than a turbine.
Most modern small wind turbines make little noise, Mr. Whittaker says, but it's an important thing to consider, along with looks. "In terms of esthetics ... beauty is in the eye of the beholder," he says. "That's really where it's important to consult with the neighbours."
When it comes to maintenance, Mr. Kelly recommends an annual checkup on items such as blades and bearings.
Pros And Cons
Mr. Whittaker lists energy independence and price stability as key advantages.
"The third pro is that there are no adverse impacts on the environment from wind generation," he says. "This is becoming an increasingly important factor for a number of Canadians."
The high capital cost works against wind turbines, as does their rarity, which can make getting advice a challenge.
Dollars And Cents
The Canadian Wind Energy Association's Web site offers a cost estimator that uses your postal code and electricity demand to calculate the ballpark cost of a wind system.
A one-kilowatt system, Mr. Whittaker says, typically costs $6,000 to $7,000. If you're in a windy location, it could provide 15% to 20% of your home's electricity needs. "The second step is to look at the location. It can't be emphasized enough that it's cheaper to save a kilowatt than to make one," Mr. Whittaker says.
Mr. Kelly agrees conservation comes first. "The cheapest watts you can produce are the 'negawatts' -- the watts you don't use," he says. It's much easier to buy an energy-efficient washing machine than it is to install a renewable energy source, Mr. Kelly says.
"Economically, if you are a substantial dollar amount away from a power line, wind power can make sense," he says. "A five-kilowatt turbine would run a typical house in reasonably windy conditions, if you were careful."
He estimates a one- to five-kW turbine costs $3,000 to $20,000, plus the tower and system equipment.
Need To Know
Just outside Calgary's city limits, Terry Willard's home is powered by a hybrid system that includes 1.4 kW of wind from two turbines and one kW of solar power. Sitting in his backyard on a breezy morning, the nearby turbine sounds like a bird's chatter.
"We haven't been on the grid since the first of March," Mr. Willard says. During the less sunny winter months, the utility grid would provide the family with backup power.
When he began switching to renewable energy in 1998, Mr. Willard's aim was to ensure against any problems arising from Y2K. But as electricity prices increased, he's seen wind power gain economic ground.
He's quick to add that his lifestyle doesn't involve going without the usual household items, and his family doesn't necessarily practice energy conservation. But the system provides enough electricity between March and November to take them off the energy grid.
"I'm not sacrificing a thing -- that's not part of my philosophy," Mr. Willard says. "The biggest thing is that you don't have to compromise if you don't want to."
Resources
- Canadian Tire's Energy Solutions Guide www.canadiantirepower.ca
- Canadian Wind Energy Association www.canwea.ca/
- Climate Change Central energysolutionsalberta.com or climatechangecentral.com
- Natural Resources Canada's Office Of Energy Efficiency oee.nrcan.gc.ca/english/
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