HAWTs and VAWTs

There are two basic types of wind turbines defined by the orientation if the axis or drive haft that turns the generator – horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT).

Horizontal axis wind turbines are the oldest, most efficient and therefore, the most common of the two types. They consist of two or more vertical blades (three is the most common) attached to a hub which is in turn attached to the horizontal drive shaft and the generator. This whole assembly sits on top of a tower. The blades face into the wind on the windward side of the tower to avoid any disturbance the tower may create. The tower is designed to elevate the blades into the strongest and most consistent wind. Currently, the longest blades are 82 metres long (269 feet) and the tallest towers reach 180 metres or 590 feet.

There are many different vertical axis wind turbine designs, ranging from the Darrius “egg beater” configuration to bladed turbines. Like HAWTs, vanes or blades turn a shaft connected to a generator , although in this case the shaft is vertical and the generator on the ground. There is no tower, and VAWTs  are generally much shorter than HAWTs, The prime advantage of  VAWT configuration is that it faces always faces into the wind, and is therefore better suited to areas where the wind is continually changing direction. Because of their more compact design, VAWTs are commonly used for microgeneration by home, cottage and small business owners and farmers to provide power for their own use or to sell back to grid.

A new development combines a VAWT with solar cells to provide electricity from wind power and solar power at the same time.

Ontario Pours Cold Water on Offshore Wind Farms

Offshore wind farms are viewed as one answer to wind turbine noise, unsightliness, and danger to bats. Makes sense? – put them where no one can hear or see them. As well, offshore winds are far more consistent and reliable than onshore winds. There are more than 40 offshore wind farms in China, Japan and 10 European countries. Their total combined capacity at the end of 2009 was almost 2,000 megawatts. So the question is why aren’t there offshore wind farms in Canada?

The answer is obvious for Alberta and Saskatchewan – neither have an offshore. Sure there are some big lakes but those are well off the grid and the costs of transmission infrastructure and transmission itself would be prohibitive.

British Columbia may soon have an offshore wind farm. On March 17, 2011 NaiKun Wind Energy Group was “granted a federal screening decision, confirming that Canada’s first offshore wind project can be constructed with no significant environmental, social or health effects.”  The project will be located in Hecate Strait Haida Gwaii and Prince Rupert and will comprise up to 110 turbines will a combined installed capacity of 396 megawatts.

Image: Naikun Wind Energy Group

While Ontario doesn’t have a sea coast, it does border on three great lakes: Ontario, Erie and Huron. Until recently four offshore projects were planned, but in February, the Ontario government decided to impose a moratorium “until the necessary scientific research is completed and an adequately informed policy framework can be developed.”  The ministry also said “Offshore wind power development in freshwater lakes is relatively new and presents technical challenges that do not exist in a saltwater environment, such as the need to manage potential impacts to drinking water and the effects of ice build-up on support structures.”

The action be the Ontario government seems to be counter to its previous assertions that wind power will be a more and more important source of electricity as the province’s coal-fired generating stations are phased out.

There is one other example of a wind farm in fresh water, the Vindpark Vänern on Lake Vanern in Sweden. Located 6.5 kilometres off shore and consisting of 10 three-megawatt turbines, the project went on line in May 2010.

While New Brunswick, Prince Edward and Nova Scotia currently do not have offshore wind farms, all three provinces are investigating the possibility.

Backyard wind power? Not so fast

Talk about taking the wind out of urban wind power’s sails.

Graham Findlay in Ottawa was told he cannot install a wind turbine in his backyard, despite support from his neighbours. Besides having to change the zoning of his home, he would have to set up the turbine so that if it fell, it would fall only on his property.

The turbine in question is a ten-meter tall Energy Ball V100, designed for residential areas. According to Ottawa’s current bylaws, wind turbines can only be erected on properties that are at least 0.8 hectares in size; about 8,000 square meters. What does that mean?  For urbanites, it’s checkmate.  According to Ottawa’s Planning and Development Approvals Commissioner, 8,000 square meters is the minimum plot size for country lots. Lots created for average homes are generally around 2,200 square meters.

The Energy Ball V100 is nothing like wind-farm turbines. It’s actually shaped like a ball, and has a very discreet design. It takes a load off of the local power grid; Findlay says it would supply his house with 10 per cent of its energy needs.

In the future, it may be possible to install smaller turbines in urban backyards. The Green Energy Act seems to stipulate zoning rules don’t apply to certain renewable-energy installations.

However, because the Green Energy Act is so new – only passed in May – Ottawa is still getting its ducks in a row about how it will be put into practice.