What are Small-Scale Wind Turbines?
Small-scale wind turbines, also known as micro wind turbines or residential wind turbines, are wind turbines designed for on-site use at homes, farms, and small businesses. Unlike large commercial wind turbines that produce electricity to feed into the electric grid, small-scale wind turbines are used to directly power a home, business, or farm.
Small-scale wind turbines typically have power capacities below 50 kilowatts. They consist of a tower, generator, rotor blades, and tail. As wind passes over the blades, they spin around a rotor which turns an electrical generator to produce electricity. The electricity is then either used directly or stored in batteries.
Some key attributes of small-scale wind turbines are:
- Power output: Usually 1 to 50 kilowatts
- Tower height: Typically 10 to 30 meters
- Rotor diameter: 1 to 10 meters
- Used for on-site energy production
What are the Benefits of Small-Scale Wind Turbines?
There are several potential benefits to using small-scale wind turbines:
Renewable and Sustainable Power
- Produce clean, renewable electricity from wind power.
- Do not generate greenhouse gas emissions.
- Provide energy sustainability and energy independence.
Potential Cost Savings
- Can offset purchase of electricity from utility company.
- Lock in prices since wind power has no fuel cost.
- Eligible for tax credits and incentives in some regions.
Reliable Power Supply
- Provide electricity even when grid power is out.
- Can be used in remote locations without grid access.
- Can be combined with solar panels for round-the-clock power.
Low Maintenance
- Require little maintenance when installed properly.
- Only need infrequent inspections and component replacements.
What Factors Determine the Economics of Small Wind Turbines?
There are several key factors that impact whether or not a small-scale wind turbine will provide a good return on investment:
Wind Resource
- Adequate wind speeds year-round are vital for cost savings.
- Average annual wind speeds of at least 10 mph are recommended at turbine site.
- Prior on-site wind resource assessment is crucial.
Electricity Costs
- Higher utility kWh rates provide greater savings potential.
- Payback period directly correlates with electricity prices.
Incentives and Policies
- Tax credits and rebates can improve economics significantly.
- Net metering policies allow selling excess power back to grid.
- Streamlined permitting helps reduce soft costs.
Turbine Siting
- Proper siting to maximize wind exposure improves production.
- Higher towers capture stronger winds and increase output.
- Avoid obstructions like trees and buildings.
System Size
- Right-sized systems relative to energy usage cut wasted production.
- Excess power generation does not always offset costs.
What Are the Key Challenges With Small Wind Turbines?
However, there are also some key challenges to evaluate:
High Upfront Cost
- Purchase and installation costs currently very high.
- Average costs range from $15,000 to $50,000.
- Long payback periods of 10+ years.
Intermittent Power
- Wind speeds fluctuate, resulting in variable power output.
- May need back-up power or grid connection as a result.
Siting Restrictions
- Permitting and zoning laws may limit tower heights.
- Nearby buildings, trees, etc. can block wind flow.
Noise
- Turbines can generate noise disturbances for neighbors.
- Siting away from dwellings and using sound-reduction methods help.
Maintenance
- Periodic inspections and repairs are required.
- Lightning strikes, icing, component failures can cause issues.
Grid Interconnection
- Selling excess power to grid may require upgrades.
- Advanced inverters needed to sync with grid voltage.
Do Small Wind Turbines Save Money in Real-World Installations?
The financial viability of small-scale wind turbines depends heavily on the specific circumstances. Here are some real-world examples:
Case Study 1: Rural Farm in Iowa
- 50 kW turbine installed on 200 acre corn farm.
- Average wind speeds of 12 mph measured on-site.
- Farm has high electric demand from irrigation pumps and equipment.
- Received 50% cost rebate from state renewable incentive fund.
- Turbine generates 85% of farm's annual electricity needs.
- Savings: Over $11,000 in first year. On track for 9 year payback.
Case Study 2: Urban Home in California
- 2.5 kW roof-mounted turbine installed on suburban home.
- Average wind speeds less than 10 mph at house site.
- Net metering allowed for selling excess power to utility.
- Paid $22,000 total installed cost without incentives.
- Produces only 20% of home's electricity demand.
- Cost: Will not recoup investment costs.
Conclusion: Key Considerations for Financial Viability
Small-scale wind turbines can certainly save money, but several criteria must be met:
- Sufficient wind speeds of 10+ mph
- Favorable electricity rates
- Available incentives and rebates
- Access to net metering
- Right-sized system for energy use
- Good siting and tower heights
Performing a wind resource assessment, crunching the numbers, and evaluating all factors is essential. When designed and installed properly at sites with adequate wind, small-scale wind turbines can absolutely be a smart, cost-saving investment.