>Determining the Renewable Energy Source for You
Choosing the Right Sources of Renewable Electricity for Your Location
Without taking into account financial incentives available
by state and national governments, solar air heating, solar water heating and
micro hydro electric systems have the best financial payback periods. However,
in part due to rebates and people's familiarity with solar electric and wind
power systems, they are the most popular with homeowners and businesses.Selecting what type of renewable energy to use to power your home or business is not always about what you would prefer to have but what is best available and economically most feasible. Here we will discuss reviewing your site for its potential in generating electricity from solar power, wind power and hydro (water) power. We won't be covering solar air heating and solar water heating systems in this article which are exceptionally cost effective for most home owners (please see our article on solar heating technologies).
Ignoring for the moment any rebates or tax incentives offered by your local or national governments and assuming that you site had plenty of resources to provide solar, wind or hydro power, the most cost effective systems for generating electricity are (going from least to most expensive): microhydro electric systems, wind electric systems and solar electric systems. Ironically, the types of systems that are most frequently used go in exactly the oposite order: many solar electric systems, some wind electric systems and few microhydro electric systems. The reason for this reversal is due in part to the actual availability of these energy resources, rebates and incentives, zoning laws at particular a location among other things.
Assessing Wind Power Potential At Your Location
The general rules for determining whether your site is suitable for wind power is less complicated than doing it for hydro electric. Generally speaking, you need at least a 1/2 acre (0.2 hectares) of open land where you can mount the turbine on a tower, and your average wind speed should average 10 mph (16km/h) either annually or during the months you intend to use the turbine.
There are several methods for estimating the average wind speeds for your location, some less accurate than others. Here is a list of possible sources:
- Collect data from your own weather station
- Ask a neighbor who has a weather station
- Rate how wind-whipped your vegetation is with Griggs-Putnam index (see next slide)
- Search for local wind records online
- Call local radio/TV station for wind data
- Call a local/regional airport for data
- Review general wind resource maps provided by NREL (if you're located in the USA) or your national government
When reviewing your location to see if you have at least a 1/2 acre of land available to mount the turbine, keep in mind that the tower also needs to extend the turbine at least 30 feet above nearby (i.e. within 300 feet (91m)) obstructions such as trees, buildings or hills. These obstructions create turbulence in the air around the causing the wind turbine to work very inefficiently. The turbine needs to get up above the turbulence to smoother air flows.
There are exceptions to these rules of thumb, such as people who would like to use small wind turbines for their boats or RVs. In these cases, the location and weather conditions can vary widely from day to day. Usually, in these applications the turbine is used in conjunction with other power sources such a solar electric panels or a generator to charge up a battery bank.
Sizing a Wind Power System to Meet Your Needs
Once you've determined the average winds for your location and determined if you have a suitable location for a wind turbine, you can then select the specific wind turbine to meet your needs. Simply go to the specification page on Alternative Energy Store's website for any wind turbine and look for a chart or table which will tell you how many kilowatt-hours of energy you can expect to product given the average wind speed for your location. If the estimated energy the turbine you selected isn't enough for your needs, go to larger turbine and see if that will meet your needs.
If you find that the turbine you would like to have doesn't supply the energy you need at the average wind speeds you have for your location, then you have a few options besides going with a larger wind turbine. One option is to consider using a hybrid system. That's a system that combines two different renewable energy technologies together, such as a wind turbine and a solar electric system. A benefit to a hybrid system is that the two different technologies frequently compliment each other. For instance, when the sunshine is low due to a rainstorm, there tends to be more wind - providing more power to the wind turbine.
Another option, is to look again at how you can reduce your energy needs in your home. Are there more creative ways you can come up with to reduce how much electricity is used in your home? Review energy star's website for tips on how to further make your home more energy efficient. Consider buying a book that provides even more tips on how to maximize the energy efficiency of your home. The rule of thumb is that for every $1 you spend on making your home more efficient you reduce the purchasing cost of the required renewable energy system by $3 to $5.
