Various government entities, eager to show their greenness regarding global warming, passed laws to subsidize renewable power, so-called “green power”, as if there is such a thing. Some governments even passed laws that declare hydropower as non-renewable, but, on reflection of its implications, reverse themselves and passed laws that declare hydropower IS renewable, as recently did Vermont’s legislature.
President Andrew Jackson, Democrat, Populist: “When government subsidizes, the well-connected benefit the most”. The renewables subsidies to the politically-well-connected often result in uneconomic wind power projects, some of which are described in this article.
EXAMPLE: UNIVERSITY of MAINE WIND POWER A DISMAL FAILURE?
The University of Maine, UM, decided to have a 600 kW wind turbine made by RRB Energy Ltd, an Indian company, at its Presque Isle Campus. The purpose was to generate power and to use the wind turbine as a teaching tool for the students. Because it is almost impossible to obtain operating data from the vendors and owners of wind farms (they claim “trade secrets”, whereas in reality they want to obfuscate wind power’s shortcomings, or a too good subsidy deal), UM decided to make available all of its wind turbine data.
The data from the UM website were used to perform some analysis.
Capital Cost and Power Production
Estimated capital cost $1.5 million
Actual capital cost $2 million; an overrun of 33%.
The project was financed by UM cash reserves and a $50,000 cash grant from the Maine Public Utilities Commission.
Predicted power production 1,000,000 kWh/yr,
Predicted capacity factor = 1,000,000 kWh/yr)/(600 kW x 8,760 hr/yr) = 0.190
Actual power production after 1 year 609,250 kWh
Actual capacity factor for 1 year = 609,250 kWh/yr/ (600 kW x 8,760 hr/yr) = 0.116; a shortfall of 39%
Value of power produced = 609,250 kWh/yr x $0.125/ kWh = $76,156/yr, minus O&M and financing costs amortized over 20 years, this value will likely be negative; a dismal outcome.
Actual power production after 1.5 years 920,105 kWh
Actual capacity factor for 1.5 years = (920,105 kWh/1.5 yrs)/(600 kW x 8,760 hr/yr) = 0.117
Operation and Maintenance
According to the European Wind Energy Association: "Operation and maintenance costs constitute a sizable share of the total annual costs of a wind turbine. For a new turbine, O&M costs may easily make up 20-25 percent of the total levelized cost over the lifetime of the turbine."
Power Used by the Turbine, or Parasitic Power
Parasitic power is the power used by the wind turbine itself. During spring, summer and fall it is a small percentage of the wind turbine output. During the winter it may be as much as 10-20 % of the wind turbine output. Much of this power is needed whether the wind turbine is operating or not. At low wind speeds, the turbine power output may be less than the power used by the turbine; the shortfall is drawn from the grid.
Two little-wind days were selected; a summer day and a cooler winter day to show that in summer the parasitic power is less than in winter. In winter, the wind speed has to be well above 4.5 m/s, or 10.7 miles/hour, to offset the parasitic power and feed into the grid. Speeds less than that means drawing from the grid, speeds greater than that means feeding into the grid.
This will significantly reduce the net power produced during a winter. On cold winter days, even at relatively high wind speeds of 10.7 miles/hour, or greater, power is drawn from the grid, meaning the nacelle (on big turbines the size of a greyhound bus) and other components required significant quantities of electric power; it is cold several hundred feet above windy mountain ridges.
14 May, 2010, wind speed 2.9 m/s (6.9 miles/hour), net power output -0.3 kW.
20 Nov, 2010, wind speed 4.5 m/s (10.7 miles/hour), net power output -5.6 kW.
Below is a representative list of equipment and systems that require electric power; the list varies for each turbine manufacturer.
- rotor yaw mechanism to turn the rotor into the wind
- blade pitch mechanism to adjust the blade angle to the wind
- lights, controllers, communication, sensors, metering, data collection, etc.
- heating the blades during winter; this may require 10%-20% of the turbine's power
- heating and dehumidifying the nacelle; this load will be less if the nacelle is insulated.
- oil heater, pump, cooler and filtering system of the gearbox
- hydraulic brake to lock the blades when the wind is too strong
- thyristors which graduate the connection and disconnection between turbine generator and grid
- magnetizing the stator; the induction generators used to actively power the magnetic coils. This helps keep the rotor speed constant, and as the wind starts blowing it helps start the rotor turning (see next item)
- using the generator as a motor to help the blades start to turn when the wind speed is low or, as many suspect, to create the illusion the facility is producing electricity when it is not, particularly during important site tours. It also spins the rotor shaft and blades to prevent warping when there is no wind.
Grid Power Failures
No-wind and Little-wind Conditions:
Wind turbines are not operating or are kept turning on grid power. If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, as described above.
Medium Wind Conditions:
Wind turbines are operating. If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, as described above. Wind turbines may not be allowed to feed into the grid, but may be operated to supply only parasitic power.
Too-high Wind Conditions:
Blades are feathered, rotor is locked. If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, as described above.
The huge difference between predicted and actual capital cost and capacity factor would be disastrous for a commercial installation. Because this is for “teaching purposes” such a detail is apparently not that important. The capital cost and any operating costs in excess of power sales revenues will likely be recovered by additions to tuition charges.
UM should find less expensive ways to educate students in all areas, not just wind power. Cost per university student in the US is already well over 2 times that of Europe, a real competitive disadvantage.
EXAMPLE: BOLTON VALLEY SKI AREA WIND POWER A DISMAL FAILURE?
In the New England, the Jeminy Peak Ski Area was the first to have a wind turbine; its wind turbine is a 1,500 kW unit made by GE. The Bolton Valley Ski Area decided to be the first in Vermont to have a wind turbine. It decided to have a 100 kW wind turbine made by Northern Power Systems, Barre, Vermont. The purpose was to generate power and by selecting a Vermont wind turbine, it would likely be favorably considered for a Clean Energy Development Fund subsidy.
The data from the Bolton Valley Ski Area website were used to perform some analysis.
Capital Cost and Power Production
Actual capital cost $750,000-$800,000; different websites have different values.
Estimated useful service life 20 years.
The CEDF provided a $250,000 cash subsidy to the politically-well-connected Bolton Valley Ski Area.
Predicted power production 300,000 kWh/yr
Predicted capacity factor = 300,000 kWh/yr)/(100 kW x 8,760 hr/yr) = 0.34
Actual power production after 17 months (1.4 yr) 204,296 kWh from October 2009 to-date
Actual capacity factor for 17 months = 204,296 kWh/1.4 yr/ (100 kW x 8,760 hr/yr) = 0.17; a shortfall of 50%.
Value of power produced = 204,296 kWh/1.4 yr x $0.125/ kWh = $18,241/yr, minus O&M and financing costs amortized over 20 years, this value will likely be negative; a dismal outcome.
It is somewhat like selling a car and telling the new owner it will do 34 mpg, whereas it actually does only 17 mpg.
It appears the Bolton Valley Ski Area made a mistake selecting a 100 kW wind turbine to reduce its power costs. The value of the revenue will be grossly insufficient to justify the project.
It seems the CEDF should do more due diligence before giving the people's money to such projects.
In the Great Plains wind power without significant subsidies pays, i.e., is comparable to coal, gas and nuclear power, because there are many areas with capacity factors of 0.40 or greater, capital costs are about $2,000/kW and O&M costs are not high.
In New England much greater subsidies will be required to make wind power pay because there are few areas on suitable ridgelines with capacity factors greater than 0.35 and capital costs, based on Maine wind farms, are about $2,500/kW, or greater, and O&M costs are high, especially in winter, outages due to freeze-ups and icing of the blades, etc., during winter are not infrequent.
EXAMPLE: WIND FARM FREEZE-UP IN NEW BRUNSWICK, CANADA
A $200-million wind farm in northern New Brunswick, consisting of 33 units @ 3 MW each made by Vestas, a Danish company, owned and operated by GDF SUEZ Energy, a French company, is frozen solid, cutting off a potential supply of renewable energy for NB Power. The 25-kilometre stretch of wind turbines, located 44 miles northwest of Bathurst, N.B. has been completely shutdown for several weeks due to heavy ice covering the blades. The same happened during the 2009-2010 winter.
About Willem PostWillem Post BSME New Jersey Institute of Technology, MSME Rensselaer Polytechnic Institute, MBA, University of Connecticut. P.E. Connecticut. Consulting Engineer and Project Manager. Performed feasibility studies, wrote master plans, and evaluated designs for air pollution control systems, power plants, and integrated energy systems for campus-style building complexes. Currently specializing in energy efficiency in buildings.
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