WIND TECHNOLOGY
Wind turbines are used to produce energy by capturing the kinetic energy present in wind. A wind turbine has three main parts: 1) the turbine (which consists of rotor blades and the rotor), 2) the shaft, and 3) the generator. The rotor blade acts as a barrier to the wind and movement of wind causes this blade to move in a circular motion. The rotor blade is attached to a shaft, which then turns a generator that produces electricity.
Both vertical and horizontal axis wind turbines are available. For more information about turbine basics, calculating power requirements, design considerations, incentives and rebates, wildlife concerns, aesthetics, social impacts, and regulatory requirements please refer to WorleyParsons report available on the BEES website. Wind studies suggest the potential for small wind turbines in Canada’s alpine is good.
Issues to consider when installing a wind turbine at a typical alpine location include:
- Capital cost: The most expensive component of a wind turbine system is the batteries, which need to be replaced approximately every 10 years. The capital cost of a wind turbine designed to provide heating requirements is prohibitive. There are Provincial and National incentives and rebates available to assist with capital costs.
- Difficulty in assessing sites for installation: Sites are remote and access with heavy equipment is by helicopter, which is expensive. Wind characteristics and other meteorological data should be monitored for a year prior to installation of a wind turbine.
- Difficultly in maintaining the turbine: Wind turbines sized for alpine application will be mounted on a tower that can be lowered for maintenance so that helicopter servicing is not required.
- Noise: Wind turbines produce mechanical and aerodynamic noises at the level of 30 to 54 decibels. Newer turbine designs produce less noise than in the past. Mounted on a ridge 500 meters away from the hut, the noise from a turbine may be negligible.
- Negative effects on wildlife (birds, bats): The key is to site a wind turbine away from migratory routes. Actual effects to wildlife in the alpine environment are not known.
- Visual impact on the natural landscape: There is no doubt that a wind turbine has a visual impact. The question is whether the public is willing to make a trade off between the negative visual impacts and using a renewable energy. Some restrictions may apply inside Provincial and National Parks.
- Blade icing due to humidity: Ice riming is a common problem with wind turbines in cold regions. The type of icing varies significantly based on the meteorological characteristics of a specific region. This may be less of an issue on the east side of the continental divide where the climate is drier compared to BC’s interior or coastal regions. Icing on turbine blades may impact site safety from falling ice, cause changes to the balance and aerodynamic integrity of the blades, result in increased maintenance or equipment damage due to increased structural loads, and cause false readings from turbine control equipment and sensors. Turbine blade coated with low-adhesion black paint can help minimize the amount of ice build-up on blades. Blade heating would not be practical for use in alpine conditions.
- Snow loading: The amount of snow received at a site is a determining factor to scheduling maintenance on the turbine. Vent covers on the turbine require specialized design to resist entry of spindrift.
- Material failure due to the cold: This includes metals, plastics and wiring. A higher grade, non-brittle material such as stainless steel can be used instead. Use standard hot-dip galvanized bolts. Use wiring rated for cold temperatures.
- Freezing of lubrication fluids: A synthetic lubricant rated for cold temperatures is best for cold, alpine conditions.
- Battery capacity declines with temperature drop: Batteries can be sized to take into account any loss due to temperature drop. Store batteries in the warmest available location to achieve best performance.
- Frost jacking may impact structural integrity of the tower: The best solution is to anchor into bedrock.
- Air density will increase as temperature decreases: As density increases, the power output increases. This can be advantageous for an alpine location and should be taken into consideration during design.
- High wind speed and wind gusts: High wind speed may cause structural damage to a wind turbine and its tower. Wind turbines function best with a steady wind without gusts, however turbines built for harsh environments are more robust.
Wind turbines in alpine locations are most suitable for low load application (lighting & communications & ventilation) and generally unsuitable for heating loads (refer to section in this report: Heat Energy Systems Cost Comparison).
A renewable energy users survey administered by BEES and Parks Canada in 2009 indicated that of the three renewable energy sources: solar, micro-hydro, and wind, people were most in favour of solar and least in favour of wind. They cited noise and problems with wildlife as the main reasons they didn’t like wind power (BEES, 2009).
TRENDS
Popular areas of research today in the wind energy field include: optimization of rotor blades to increase the aerodynamics of the turbine, decreasing losses in mechanical components of the system, lowering noise produced, and making turbines more cost-effective.
PRECEDENT
Wind turbines are being installed to power eight research stations in Antarctica. They will replace diesel generators. Wind speeds in the Antarctic reach up to 200 mph making wind turbines an ideal way to produce power in this isolated place. The Proven 6 Turbine has been successfully installed and operated in the Antarctic and is an effective and emission-free choice for this location.
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