Small Wind Turbines
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Energy source:
Wind
Name of the technology:
Wind machine, Wind turbine or Wind generator
Date of arrival on the market:
Windmills have existed for centuries.
Today, wind turbines are used mainly to produce electricity, but some are still used for water pumping.
Maturity of the technology:
They have been on the market for several decades. In recent years, the cost has decreased and the reliability and productivity have increased.
Type of energy produced:
Mechanical (e.g.: pumping water)
Electrical
Example of typical usage:
Wind generators or wind power plants connected to an electrical network
Stand-alone systems with energy storage
Payback period and/or benefits:
In 2007, depending on the quality of the wind resource at the site and excluding incentive programs for the production of renewable energy or the value of environmental credits, the net cost of energy from small wind turbines was 10 to 30 cents/kWh. In comparison, net cost of energy from modern large wind power plants was 5 to 10 cents/kWh.
Design, Installation, Operating And Maintenance Costs
Range of products that can be used in a system:
Different models of wind turbines are available in the 100 W to 5 MW range (Enercon has a 6 MW wind turbine).
- Small wind turbines have a capacity range of about 100 W to 100 kW; the diameters of the rotors range from about 1 m to 15 m, respectively. This large range of products is divided into three sub-markets depending on whether we refer to:
- micro-electrification or small capacity wind turbines (100 W-1 kW),
- auto production (1-50 kW) or
- community electrification ( >50 kW).
- In the 100 kW to 600 kW range, we refer to wind turbines of average size.
- From 600 kW to a few MW, we are in the large wind turbine category.
Considerations relating to the size of the system:
Wind turbines of all these capacities are available on the market.
Do not confuse the wind turbine's capacity (rated output capacity set by the manufacturer) with the energy produced by the installed system. A wind turbine with a rated capacity of100 kW (power is measured in kW) can produce 100 kWh in one hour if the wind is blowing at the right speed. The energy produced annually by a wind turbine (energy is measured in kWh) depends mainly on the rated capacity of the wind turbine and the number of hours in the year during which the wind blows with sufficient force to make the wind turbine work.
The FU (Utilization factor) is the relationship between the wind turbine's annual energy production divided by the maximum quantity of energy that the wind turbine would have been able to produce if the wind had blown at the right speed all year long, non-stop. The FU is a value between 0 and 1, or a percentage. The FU may be calculated for different periods; annual, seasonal or monthly. The typical FU of a modern wind turbine lies in the 0.15 to 0.35 range.
Evaluating the cost of the system: The wind generator vs. the rest of the system:
Beyond the cost of the wind generator, the cost of the rest of the system must not be neglected. Wind generators exclude more often than not the tower, foundation, installation and activation. The storage systems, inverters, as well as the control, regulation and distribution panels for each system are generally considered to be optional modules. Similarly, the choice of position, type of soil, local regulations, potential objections from neighbours, permit application and interconnection problems are part of the cost of the rest of the system.
Read the technical specifications carefully before finalizing the design of the wind energy system.
Typical specific technology performance (kWh/kW/year; kWh/m2/year):
The energy produced annually by a wind turbine depends on the wind conditions at the site and on the design of the system. The energy produced annually by a modern wind turbine is within 1,300 to 3,000 kWh/kW/year. It can also be measured by unit of rotor swept area (in kWh/m2/year) which should be in the range of 1,000 to 1,500 kWh/m2/year.
Consult the data sheet provided by the manufacturer. It should contain, at the least, the Power-Speed curve for the machine as well as its production under different wind conditions.
Cost range for usable energy (including installation and operation):
In 2007, depending on the quality of the wind resource at the site, and excluding incentive programs for the production of renewable energy or the value of environmental credits, the net cost of the energy supplied by small wind energy is between 15 and 30 cents/kWh.
Expertise, skills and training required for design, installation and operation:
Even in the case of small wind turbines, it is strongly recommended to use the services of an experienced installer in order to ensure proper operation and system profitability for the planned life of the project.
Operational requirements and maintenance (e.g.: annual maintenance, major repairs, labour, etc.):
Consult the user guide provided by the manufacturer. An average annual cost of between 1 and 1.5 cents/kWh is generally associated with the maintenance and operation of large modern wind turbines. For small wind turbines, the maintenance costs per kWh will be higher than for large wind turbines. An experienced certified installer will give you a correct evaluation of this important budgetary item for the life span and performance of your system.
Specific technological limitations and impact on design:
A wind turbine will not operate if there is no wind.
A mechanism to protect against possible mechanical breakdown due to excessive wind should be an integral part of the wind turbine.
It may be necessary to include a storage system for the energy captured in order to supply prioritized demand in periods during which the wind turbine is outside of its normal operating range. If the wind turbine is connected to a power grid, as is the case with auto production, the grid replaces the storage system to supply priority demand when the wind turbine is not operating or is not available.
Required permits and authorizations:
Guidelines for the development of a small wind energy project are available on the Canadian Wind Energy Association (CanWEA) website. Permits and authorizations fall under the jurisdiction of municipal, provincial and regulatory authorities in your area.
http://www.smallwindenergy.ca/downloads/Small_Wind_Siting_Guidelines.pdf
Wind turbine certification:
Contrary to the accomplishments in the large wind energy market, the current gaps in product certification are slowing the growth of the market for small wind turbines in North America. Certification for small wind energy was recently identified as an action priority by a group of North American stakeholders involved in promoting small capacity renewable energy. A North American organization, the "Small Wind Certification Corporation" was formed in 2006 and is actively working towards establishing continental certification standards in order to better support the development of the industry and the labelling for small wind energy products with a view to facilitating the consumer's task. The AWEA and the CanWEA are members of the SWCC working group. They suggest certification markers that must be approved by authorized certification agencies.
Warranties and system life span:
A small wind energy project should be financed on the basis of a life span of less than 20 years.
Manufacturers' warranties will be of a shorter duration, typically 1-2 years.
The life span of a wind energy system should coincide with a cost benefit analysis; from 8 to 20 years depending on the manufacturer and model and typically 25 years for a large wind turbine. Certain components will need to be replaced during that period of time. Read the manufacturer's documentation carefully with regard to these matters.
Evaluating wind energy potential:
Consult the Canadian Wind Energy Atlas (http://www.atlaseolien.ca/en/index.php). . .
For a large project, it may be necessary, for financial reasons, to install your own anemometer tower for better definition of your wind energy site. .
Useful software for evaluating project prefeasibility:
Wind savings worksheet (Canadian Wind Energy Association) (http://www.smallwindenergy.ca/calculator/home.php )
RETScreen (www.retscreen.net)
Synergies
Technology inputs and outputs:
The wind turbine's rotor transforms the kinetic energy of the air into the mechanical energy of rotation.
A wind generator converts the mechanical energy of rotation into electricity.
A multi-blade wind turbine supplies mechanical energy to the shaft of a pump used to feed livestock by transforming the rotational movement into an alternating linear movement.
Links To Other Sources Of Information And Recommendations
More information (hyperlinks):
http://www.smallwindenergy.ca/en/SmallWind.html
http://www.canwea.ca/Fact_Sheets_eng.cfm
http://www.smallwindenergy.ca/en/SmallWindAndYou
/ConnectingToTheGrid/NetMetering.html
http://www.awea.org/faq/sagrillo/index.html
Manufacturers, suppliers and representatives:
Wind turbine manufacturers and representatives
300 W to 1 kW systems:
http://www.smallwindenergy.ca/en/Resources/Manufacturers/Mini.html
http://www.smallwindenergy.ca/en/Resources/DealersInstallers/Mini.html
1 kW to 30 kW wind turbines:
http://www.smallwindenergy.ca/en/Resources/Manufacturers/Small.html
http://www.smallwindenergy.ca/en/Resources/DealersInstallers/Small.html .
30 kW to 300 kW wind turbines
http://www.smallwindenergy.ca/en/Resources/Manufacturers/Medium.html
http://www.smallwindenergy.ca/en/Resources/DealersInstallers/Medium.html
Comments - Recommendations:
Above all, do not confuse the power (kW) and the energy (kWh) produced by a wind energy system. Ten kW will do the same work (supply the same quantity of energy) in one hour as one kW will for 10 hours.
Remember that stand-alone systems always need an emergency backup system.
Do not forget that the cost of setting up a system is not limited to the cost of the wind turbine; the profitability of your project could be compromised.
Do not underestimate the difficulties and delays to obtain all the construction permits and authorizations. There are no possible shortcuts to a successful project.
Support from competent and experienced advisors is a wise investment for any sizeable project.
Modified: 03-31-2008
