Quick Facts About Wind Energy

Quick Facts About Wind Energy

wind turbines
<p>Wind farm in dryland wheat country of Sherman County Oregon. Photo by John Hay</p>

Small wind energy refers to wind turbines under 100 kilowatt (Kw) in size. 101-999 kw are considered medium size. Large wind turbines are greater than 1000 kw in size. The wind turbines north of Lincoln are 660 Kw each. The new ones built at Bloomfield Nebraska are 3000 Kw (3 Megawatt (MW)) each and stand ~500 feet tall. (the state capitol is only 419 feet tall).

At home we measure electricity in kilowatt hours (kwh) a 100 watt light bulb running 10 hours would use 1000 watt hours or 1 kilowatt hour of electricity.

Buying a small wind turbine

  1. Assess your electricity consumption, cost, and your utility tariff
  2. Be more energy efficient reduce your consumption
  3. Estimate or measure wind resource
  4. Select turbine size (model) and tower height
  5. Investigate incentives & economics
  6. Get zoning approval
  7. Complete a utility interconnection agreement
  8. Obtain building & electrical permits
  9. Order turbine and tower
  10. Install the turbine
  11. Commission the turbine
  12. Perform periodic inspections & maintenance

Source: Tony Jimenez- National Renewable Energy Lab

Estimating How Much a Wind Turbine Produces Annually

  • Wind turbine Size in Kw = X
  • Number of hours in a year = 24*365=8760
  • Annual Capacity Factor = 0.05-0.25 (0.25 is for very good sites with high towers, 0.15 would be closer to realistic for most sites, 0.05-0.01 is for pour sites, short towers with building and trees)
  • (X * 8760)*CF = Estimated Kwh per year produced by the small wind turbine

For example

2.4 kw * 8760 * 0.15 = 3153 kwh per year
3153 kwh * (electricity rate per kwh) = $ amount of electricity produced per year 3153 * 0.08 = $252

So $252 dollars is the value of electricity produced. Remember this is assuming you can get retail rate for all electricity and does not include cost for maintenance. Also consider if your goal is to produce your electricity renewably you may add some value to the electricity produced and your desire for a wind turbine will go beyond simple payback.

Alternate estimating method: Take your wind speed at turbine height and compare it to manufacturers energy chart to determine kwh per month.

Incentive and economics

This website has a list of federal and state incentives- Database of State Incentives for Renewables & Efficiency.

Incentives as of today in Nebraska:

  1. 30% Federal income tax credit
  2. Net metering in selected utilities, (statewide net metering is being proposed)
  3. Low interest loans through the State Energy Office currently wind, solar will not qualify.

Examples of wind turbine equipment prices

  • 1 kw Bergey turbine $2700 add 80Õ tower $2200 total (this one for battery charging), ~ $4900
  • 2.5 kw Proven turbine with 80' SSV tower and grid interconnection inverter, ~ $28,600
  • 2.4 kw Skystream turbine with 45Õ tower and grid interconnection inverter, ~ $12,500
  • 6 kw Proven turbine with 80Õ SSV tower and grid interconnection inverter, ~ $40,850
  • 10 kw Bergey turbine with 100Õ tower and grid interconnection inverter, ~ $40,550
  • Prices will vary depending on many factors and these are not meant to be exact prices
  • Towers a large part of the cost and self supporting (SSV) and monopole towers are more expensive than lattice towers with guy wires.
  • Maintenance is done every 6 mo to a year. Lightning strikes are possible, so have included in homeowners insurance. Estimate for maintenance is approximately $0.01 - $0.02 per kwh produced.
  • Some very small turbines can cost < $5000, These are usually charging batteries or for a specific load., A similar calculation can be done to estimate kwh production per year.

Some Examples Built around Lincoln

  • South of Lincoln on Hwy 77 just 2 miles south of the Crete corner there is a 10 KW wind turbine on a 120 foot tower at the school.
  • A 2.4 kw turbine is on a somewhat short monopole tower at the Rogers Memorial Farm, this is a research project for an electrical engineering student.

By John Hay, UNL Extension Educator

bioenergy.unl.edu