Home TECH TOOLS WIND DESIGN
Much has been written on the subject of wind turbine selection. We will provide some pointers here, but do suggest that you investigate the following resources for more in-depth information:
- "Windpower for home and business, Renewable Energy for the 1990's and beyond" , by Paul Gipe, copyright 1993 by Paul Gipe. Chelsea Green Publishing Company.
- "Site Analysis for Wind Generators, Part 1: Average Wind Speed", by Mick Sagrillo, copyright 1994 by Mick Sagrillo, Home Power Magazine Issue #40, April/May 1994.
- "Tower Economics 101" by Mick Sagrillo, copyright 1993 by Mick Sagrillo, Home Power Magazine Issue #37, October/November 1993.
Wind Turbine System Sizing Pointers:
|Turbines may be sized differently depending on whether you are off-grid, net metered, or commercially selling electricity (like under the S.O.C. for instance). Practically any rural property can support a wind turbine, but knowing your wind will help you decide what kind of output you can expect from a given wind turbine. The Ontario Wind Atlas can provide good general wind information for you to use, but the best way is still to install wind test equipment at your location for at least one year. We can help you discover how a given range of wind turbines will perform at your location by plotting their performance based on the Wind Atlas data.
We typically advise wind sizing as follows:
- Wind-only off-grid applications: 125% of load
- Wind/Solar off-grid applications: 60-75% of load
- Wind net metered: 40-80% of load
- Wind commercial: Based on specific site wind data.
Once you know your load requirements and your wind resource, we suggest you read information below on wind turbine installation to familiarize yourself with some of the technical considerations of installing a wind turbine.
Wind Turbine Installation Pointers:
- Ensure proper distance (typically 125% of tower height) from any overhead wires, buildings or property lines as required by code, or bylaw!
- Installing a wind tower correctly involves respecting the physical forces that will affect the tower. Wind turbines inherently catch wind, and therefore create large horizontal shear force loads on the tower and guy lines. Also, the furling mechanism of a given turbine will increase the force applied against the furling motion. Knowing and understanding these loads will go a long way to ensuring your machine stays up and running even during those high wind winter storms. Don't rely solely on manufacturers installation data that are based on average soil conditions or temperate climates that don't ever freeze. Installations of turbines larger than 5 kW should always include a soil test done by a qualified engineer.
- Equally important is the grounding method used for the tower. All tower components, including the outside anchor points should be grounded to a ground loop buried in the ground with proper ground rods (please refer to your CEC manual). Separate grounding or surge protection must be applied to the turbine wiring. This keeps any electrical surges from entering your conditioning equipment or traveling even further into your home. Many turbine manufacturers will not warrant lightning damage if you have not installed proper lightning protection.
- Ensure you have a proper diversion load. Wind turbines must maintain their electrical load on the generator. This keeps the machine from over-speeding and causing damage (try holding a toy pinwheel out the window of a moving vehicle and you will see the effects of over-speeding). Many turbine manufacturers are now including diversion loads as standard equipment with their turbine controller, but if not, make sure that you match both the resistance requirements and capacity of the diversion load to the turbine.
After you have addressed the above four issues, the rest of a wind turbine installation becomes very standard:
- properly size your wiring runs (see our wire calculator for example)
- install adequate over-current and isolation devices
- properly size your inverter (and batteries where applicable)
As with any system installation, ask lots of questions of your installer, read all manuals, register all your products (where applicable), and follow the required maintenance schedule. Wind turbines are designed to last a long time. The single greatest threat to their long term survival is neglect!