EXAMPLES OF WIND TURBINE SYSTEMS TO LEARN FROM

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, reversed 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 wellconnected often result in uneconomic wind power projects, some of which are described in this article.

 

Vendors, owners, financiers often claim “trade secrets”, whereas in reality they want to obfuscate wind power’s shortcomings, a too-generous subsidy deal, or other insider’s advantage. It would be much better for all involved, if there were public hearings and full disclosure regarding the economics of any project receiving government subsidies, to ensure the people’s funds receive the best return on investment.

 

EXAMPLE: UNIVERSITY of MAINE WIND TURBINE A DISMAL FAILURE?

 

The University of Maine, UM, decided to install a 600 kW wind turbine made by RRB Energy Ltd, an Indian company, at its Presque Isle Campus. Results from a 20-month wind resource assessment indicated the campus receives enough wind for a community wind project, not a commercial wind project. 

 

Community wind power is defined as locally-owned, consisting of one or more utility-scale or a cluster of small turbines, totaling less than 10 MW, that are interconnected on the customer or utility side of the meter. The power is consumed in the community and any surplus is sent to the utility which supplies power as needed.

 

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, owners and financiers of wind facilities, UM, to its credit, decided to make available all of its wind turbine operating data. 

 

http://www.ppdlw.org/umpi.htm

http://www.umpi.edu/wind/timeline

http://www.windtaskforce.org/profiles/blog/show?id=4401701%3ABlogPo...

http://nwcommunityenergy.org/wind

 

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 subsidy from the Maine Public Utilities Commission.

Estimated useful service life about 20 years.

 

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; if O&M and financing costs amortized over 20 years are subtracted, this value will likely be negative. 

 

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; dismal.

 

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." 

 

Energy Used by the Turbine (Parasitic Energy)

 

The wind turbine itself uses parasitic energy. During spring, summer and fall, it is a small percentage of the wind turbine production. During the winter, it may be as much as 10 - 15 % of the wind turbine production. Much of this energy is needed whether the wind turbine is operating or not. At low wind speeds, the turbine production may be less than the energy used by the turbine; the shortfall is drawn from the grid. 

 

http://windfarmrealities.org/?p=1594

http://windfarmrealities.org/?p=1284

http://windfarmrealities.org/wfr-docs/harrison-viability-ontario.pdf

 

Two low-wind-speed days were selected; a summer day and a cooler winter day to show that in summer the parasitic energy 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 energy and feed into the grid. Speeds less than that means drawing energy from the grid, speeds greater than that means feeding energy into the grid. 

 

This will significantly reduce the net energy production during a winter. On cold winter days, even at relatively high wind speeds of 10.7 miles/hour, or greater, energy is drawn from the grid, meaning the nacelle (on big turbines the size of a greyhound bus) and other components require significant quantities of energy; it is cold several hundred feet above windy mountain ridges.

 

Summer day: 14 May 2010, wind speed 2.9 m/s (6.9 miles/hour), net power output  -0.3 kW. During summer days, wind energy production is minimal, i.e., wind turbine draws energy from the grid for many hours.

 

Winter day: 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 - 15 % of the turbine's power

http://www.slideshare.net/WinterwindConference/further-development-...

- Heating and dehumidifying the nacelle; this load will be less if the nacelle is well-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)

 

NOTE: 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.

 

Conclusions

 

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 competitive disadvantage.

  

EXAMPLE: BOLTON VALLEY SKI AREA WIND TURBINE A DISMAL FAILURE?

 

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. 

 

http://northernpower.kiosk-view.com/bolton-valley

http://www.northernpower.com/pdf/specsheet-northwind100-us.pdf  

 

Capital Cost and Power Production

 

Actual capital cost $800,000.

http://www.boltonvalley.com/upload/photos/552Wind_Tower_Info_Sheet.pdf

 

The CEDF provided a $250,000 cash subsidy to the politically, well-connected Bolton Valley Ski Area.

Estimated useful service life about 20 years. 

 

Predicted power production 300,000 kWh/y

Predicted capacity factor = 300,000 kWh/y)/(100 kW x 8,760 h/y) = 0.34

 

Actual power production after 17 months (1.4 y) 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 h/y) = 0.17; a shortfall of 50%

Value of power produced = 204,296 kWh/1.4 y x $0.125/ kWh = $18,241/y; if O&M and financing costs amortized over 20 years are subtracted, this value will likely be negative.

 

NOTE: It is somewhat like selling a car and telling the new owner it will do 34 mpg, whereas it actually does only 17 mpg. 

 

Update: A recent check of the Bolton Valley website in January 2013 

 

Actual power production after 39 months (3.25 y) was 509,447 kWh from October 2009 to-date.

 

Actual capacity factor for 39 months = 509,447 kWh/(3.25 y x 100 kW x 8,760 h/y) = 0.179; a shortfall of 47.4% of the 0.34 promised.

 

Value of power produced = (509,447 kWh x $0.125/kWh)/3.25 y = $19,594/y; if O&M and financing costs amortized over 15 - 20 years are subtracted, this value will likely be negative.

 

On April 2, 2011, the Bolton website showed the following readings: 

 

19.7 mph windspeed, 21.2 kW output 

22.3 mph windspeed, 22.5 kW output 

23.4 mph windspeed, 24.5 kW output 

 

Those outputs are much lower than the ones stated on page 6 of the NPS specifications. Outputs should be about 55 - 65 kW for these wind speeds, minus parasitic losses, which appear to be about 11 - 12 kW at temperatures below 32 F.

 

May be the wind speed indicator reads high. Adding in some weeks of downtime further reduces power production and CF. This may explain the shortfall in power production and the low CF.

 http://www.northernpower.com/pdf/Northwind100GeneralSpecification.pdf

 

Conclusions

 

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 donating the people's money to such projects. 

 

In the Great Plains wind power with moderate 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 less than $2,000/kW and O&M costs/MWh costs are low.

 

In New England much greater subsidies would 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, O&M costs/MWh are high, especially in winter; frequent snow plowing at 2,000-plus ft elevation and outages due to freeze-ups and icing of the blades, etc., are common.

 

EXAMPLE: MAINE RIDGE LINE CFs BELOW EXPECTATIONS

 

Maine plans to have 2,000 MW of IWTs by 2015 and 3,000 MW by 2020. About 400 MW were in operation at the end of 2012, about 906 MW at end 2016.

 

All US IWT owners connected to the grid have to report their quarterly outputs, MWh, to the Federal Energy Regulatory Commission, FERC. The data is posted on the FERC website, and, with some effort, can be deciphered.

 

Capacity Factors less than Estimated: Below are some numbers regarding the much less than expected results of the Maine ridge line IWTs for the 12-month periods indicated in the below table.

 

http://www.coalitionforenergysolutions.org/maine_wind_thru_3q2012m1...;

http://www.windtaskforce.org/profiles/blogs/maine-wind-sites-produc...

 

	MW	Oct 2011-Oct 2012	Dec 1011-Dec 2012
Mars Hill*	42	0.353	0.3613
Stetson I	57	0.254	0.2140
Stetson II	26	0.227	0.1837
Kibby Mtn		0.238	0.2278
Rollins	60	0.238	0.2408
Record Hill	51	0.197	0.2462
Weighed avg.		0.247	0.2427

 

*Uniquely favorable winds due to topography.

 

Example: The Maine weighted average CF = (42 MW x CF 0.353 + 57 x 0.254 + 26 x 0.227 + 132 x 0.238 + 60 x 0.238 + 50.5 x 0.197)/(42 + 57 + 26 + 132 + 60 + 50.5) = 0.247; excluding Mars Hill, the weighted average CF is 0.234. 

 

Note: CF reduction due to aging is not yet a major factor, as all these IWTs were installed in the past 5 years.

 

Causes for Lesser Capacity Factors: The lesser, real-world CFs are likely due to:

 

- Winds entering 373-ft diameter rotors varying in speed AND direction under all conditions; less so in the Great Plains and offshore, more so, if arriving from irregular upstream or hilly terrain, as on ridgelines. 

 

- Turbine performance curves being based on idealized conditions, i.e., uniform wind vectors perpendicularly entering rotors; those curves are poor predictors of ACTUAL CFs.

 

- Wind testing towers using anemometers about 8 inch in diameter; an inadequate way to predict what a number of 373-ft diameter rotors on a 2,500-ft high ridge line might do, i.e., the wind-tower-test-predicted CFs of 0.32 or better are likely too optimistic.

 

- Rotor-starting wind speeds being greater than IWT vendor brochure values, because of irregular winds entering the rotors; for the 3 MW Lowell Mountain IWTs rotor-starting speed with undisturbed winds is about 7.5 mph, greater with irregular winds.

 

- IWT self-use energy consumption up to about:

 

2% for various IWT electrical needs during non-production hours; in New England, about 30% of the hours of the year (mostly during dawn and dusk hours, and most of the summer), due to wind speeds being too low or too high, and due to outages. This energy is drawn from the grid and treated as an expense by the owner, unless the utility provides it for free. 

 

4% for various IWT electrical needs during production hours; power factor correction, heating, dehumidifying, lighting, machinery operation, controls, etc. 

 

NOTE: In case of the 63 MW Lowell Mountain, Vermont, ridge line IWT system, a $10.5 million synchronous-condenser system to correct power factors was required, by order of the grid operator ISO-NE, to minimize voltage variations that would have destabilized the local rural grid; self-use energy about 3% of production.

 

http://windfarmrealities.org/u-minn-and-vestas-reality-check/

http://theenergycollective.com/willem-post/53258/examples-wind-powe...

http://en.wikipedia.org/wiki/Synchronous_condenser

  

- Reduced production for various other reasons, such as:

 

* Curtailment due to the grid’s instability/capacity criteria being exceeded

* Curtailment due to excessive noise; nearby people need restful sleep for good health

* Curtailment due to excessive bat or bird kill

* Flow of an upwind turbine interfering with a downwind turbine’s flow. As a general rule, the distance between IWTs: 

 

- In the prevailing wind direction should be about seven rotor diameters 

- Perpendicular to the prevailing wind direction should be about three rotor diameters. 

 

Note: In case of the 63 MW Lowell Mountain, Vermont, ridgeline system, 21 IWTs, with 373-ft diameter rotors, are placed on about 3.5 miles of 2,500-ft high ridge line. Construction drawings indicate the spacing varies from about 740 ft to about 920 ft, or 1.96 to 2.47 rotor diameters.

 

New England ridgeline directions are from SW to NE, as are the prevailing winds. 

GMP opting for the greater diameter rotor, to increase the CF, worsened interference losses, i.e., likely no net CF increase, but an increase in lower frequency noises that are not measured with standard dBA testing. 

 

http://www.wwindea.org/technology/ch02/en/2_4_1.html

http://www.windpowerengineering.com/construction/wider-spacing-lead...

http://www.nrel.gov/wind/pdfs/day1_sessioniv_04_shermco_alewine.pdf

  

 

NOTE: Irregular airflows to the rotor cause significant levels of unusual noises, mostly at night, that disturb nearby people. See URL.

http://www.windtaskforce.org/profiles/blogs/wind-turbine-noise-adve...

 

Government Regulators Lack of Due Diligence: It appears regulators: 

 

- Did not ask the right questions on their own (likely due to a lack of due diligence and knowledge of power systems), or 

- Ignored/brushed aside the engineering professionals, who gave them testimony or advised them what to ask, or 

- Received invalid/deceptive answers from subsidy-chasing IWT project developers and promoters, or 

- Kowtowed to wind energy-favoring politicians allied with wind energy oligarchs, i.e., not hinder IWT build-outs, or 

- Did all of the above.

 

The developers told Maine regulators their IWT projects would have CFs of 0.32 or greater, and 25-year lives, to more easily obtain bank financing, federal and state subsidies, and "Certificate of Public Good" approvals. Once they get approval, there is no accountability for poor performance. Meaningful players in the IWT smoke-and-mirrors game, including regulators, know this. All understand IWTs are about subsidy chasing and tax sheltering, not about efficient, high-quality energy production. 

 

Because of subsidy-chasing by IWT project developers, and politicians wanting to be seen as doing something about climate change and global warming, the vetting process of proposed IWT projects by boards of political appointees is much compromised, which is creating distrust, resentment, anxiety and division among the lay public, and especially among the many thousands of people “living” nearby the IWTs, whose quality of life is greatly compromised.

 

http://theenergycollective.com/willem-post/98061/irelands-wind-ener...

http://theenergycollective.com/willem-post/61309/lowell-mountain-wi... 

 

EXAMPLE: NEW YORK STATE WIND CFs BELOW EXPECTATIONS

 

Below is the URL of a table that shows the performance of New York State's wind turbines.

 

http://www.dailyenergyreport.com/wp-content/uploads/2011/06/NY_CF20...

http://www.windaction.org/faqs/31912 ;

http://www.windaction.org/faqs/35069

 

The Vendor promises were capacity factors of 30% to 35%, before installation.

 

The reality, after installation:

 

Installed capacity, MW: 1,162 in 2008; 1,274 in 2009; 1,274 in 2010; 1,348 in 2011

Production, MWh: 1,282,325 in 2008; 2,108,500 in 2009; 2,532,800 in 2010; 2,780,700 in 2011

Capacity factors: 18.4% in 2008; 19.8% in 2009; 22.7% in 2010; 24.3% in 2011

 

The 2006-2011 average CF was 0.249, much less than predicted before installation.

 

The data for the table was obtained from the 2011 New York ISO Gold Book.

 

http://www.nyiso.com/public/webdocs/services/planning/planning_data...;

http://www.nyiso.com/public/webdocs/services/planning/planning_data...

 

The low CFs are not unique to NY State. It has replicated itself in The Netherlands, Denmark, England, Germany, Spain, Portugal, Ireland, etc. See above section "Worldwide CFs Below Expectations".

 

http://energynumbers.info/capacity-factors-at-danish-offshore-wind-...

http://en.wikipedia.org/wiki/Wind_power_in_Germany

 

UNSUBSIDIZED wind energy costs have bottomed out to about: 1.5-2 times annual average grid prices in the Great Plains, 3 times grid prices on 2,500 ft high ridge lines in New England, 4-5 times grid prices offshore, such as Cape Cod.

http://theenergycollective.com/willem-post/47519/base-power-alterna...

 

The production is invariably less than promised. Add this to the fact that the CO2 emissions reduction is much less than claimed by wind energy promotors, as shown in below articles, makes further subsidies and investments in wind energy an extremely dubious and expensive proposition. See URLs.

 

http://theenergycollective.com/willem-post/64492/wind-energy-reduce...

http://www.clepair.net/IerlandUdo.html ;

http://docs.wind-watch.org/BENTEK-How-Less-Became-More.pdf

http://www.clepair.net/windSchiphol.html ;

http://www.clepair.net/Udo-okt-e.html

http://www.clepair.net/Udo-curtail201205.html

. 

EXAMPLE: KIBBY MOUNTAIN, MAINE, CFs BELOW EXPECTATIONS 

 

The Kibby Mountain, Maine, 132 MW wind turbine facility, capital cost $320 million, is owned by TransCanada and was built, after a lot of destruction, on one of the most beautiful ridge lines in Maine.  It was placed in service on 10/31/2009.TransCanada, an energy conglomerate, and Vestas, a Danish wind turbine company, claimed that the capacity factor would be 0.32, or greater.

 

Its FERC designation is “Trans Canadian Wind Development, Inc.”, in case you want to look up the below data.

 

In 2009 and 2010, the facility had a lot of startup problems and its energy production was negligible.

 

In 2011, it had a capacity factor of 22.5% for the first 9 months.

For the 3rd quarter of 2011, it was 14.42%. Monthly capacity factors were as follows:

 

July       18.48%

Aug       12.31%

Sept      12.41%

 

Why are the CFs so low?

 

Winds on ridge lines have highly-irregular velocities AND directions. This does not show up when one performs wind velocity testing with an anemometer, but when rotors are 373 feet in diameter (a football field is just 300 ft long), one part of a rotor will likely see a different wind velocity AND direction from another part. This leads to highly-inefficient energy production and low CFs. Wind vendors are very familiar with this, but do not mention it. However, all is explained in this article.

 

The VT-DPS and Senate and House Environment and Energy Committees, and all others, should finally read this article, before "leading" Vermont into an expensive energy la-la-land.

http://theenergycollective.com/willem-post/61309/lowell-mountain-wi...

 

EXAMPLE: FREEZE-UP OF WIND FACILITY IN NEW BRUNSWICK, CANADA

 

A $200-million wind facility 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 which has a 20-year Power Purchase Agreement with GDF Suez Energy. 

 

The 18-mile stretch of wind turbines, located 44 miles northwest of Bathurst, N.B., has been completely shutdown for several weeks due to heavy ice covering on the blades. The same happened during the 2009-2010 winter.

 

For the 5th year in a row, the three New Brunswick wind turbine plants (150 + 99 + 45 = 294 MW) have UNDERPERFORMED.

 

In 2012, owner/vendor-promised production 904,000 MWh, for a CF of 0.35; actual production 694,000 MWh, for a CF of 0.27. The utility is not complaining, because the production shortfall enables it to by energy from the grid at about 5.5 c/kWh, about half the price of 10.5 c/kWh it HAS to pay, by law, for wind energy! 

 

A fourth proposed wind turbine plant has been put on hold, because of grid reliability/coping issues.

 

http://www.canada.com/technology/Northern+Brunswick+wind+turbines+f...

http://www.windaction.org/news/c48/?sort=title&startnum=121

http://bjdurk.newsvine.com/_news/2009/01/26/2357728-wind-energy-is-...;

http://www.cbc.ca/news/canada/prince-edward-island/story/2009/07/23...

http://www.theglobeandmail.com/report-on-business/industry-news/ene...

http://www.energy.gov.yk.ca/pdf/overcoming_icing_effects_wind_turbi...

  

EXAMPLE: RESIDENTIAL WIND TURBINES A DISMAL FAILURE?

 

The residential wind system is for a recently built LEED Platinum house in Charlotte, Vermont, capacity 10 kW, grid-connected, 80-ft mast, all-in cost $40,500, or $4,050/kW. The project received a CEDF cash subsidy of $12,500

 

Power production is about 6,286 kWh/yr; 6,094 kWh is used, 192 kWh is sold to the utility as part of "net-metering" 

Capacity factor = (6,094 + 192) kWh/yr/(10 kW x 8,760 hr/yr) = 0.0712 

The owner pays the utility $9/mo. for standby power. 

Useful service life is about 10-15 years after which it will need to be replaced or refurbished. 

 

Levelized cost of buying electricity from the utility for 25 years is about $0.230/kWh 

Levelized cost of wind power with no incentives is about $0.701/kWh, base on a 15-year $40,500 mortgage at 5%/yr 

http://www.coalitionforenergysolutions.org/residential_wind.pdf

 

Conclusions

 

Residential wind power systems are very uneconomical investments.

The legislature enacting subsidies for such projects is a grossly inefficient use of the people’s money.

It appears the CEDF should do more due diligence before donating the people's money to such projects. 

 

Another Example of Small Wind: Middlebury College Turbine.

 

Bergey; 10 kW; on a 100 ft mast; 22 ft dia rotor; $ 45,000 to install; 50% paid for by DOE; production about 8,000 kWh/yr for about 10 - 15 years.

 

CF = 8,000 kWh/(8,760 hr/yr x 10 kW) = 0.091; miserable. 

 

$45,000/$4,500/kW = 8 kW of PV panels would produce: 8 x 8,760 x CF 0.143 = 10,021 kWh for 25 years.

   

EXAMPLE: GERMAN SOLUTION FOR LOW-WIND AND ICING CONDITIONS

 

Germany is very marginal for wind power, especially in the south. its national average wind power CF is 0.187, lower than the Netherlands (0.228) and Denmark (0.251).

 

A solution is to have wind turbines with very tall masts and oversized rotors. One such unit is the Enercon-82, capacity 2 MW, hub height 138 m (460 ft), rotor diameter 82 m (273 ft), for a total height of about 600 ft. The unit requires a substantial foundation. The installed cost is about $2,600/kW. 

 

The units have a fan in each blade with an electric heater that circulates warm air through the uninsulated, hollow blade to keep it warm in winter to prevent icing that impairs blade aerodynamics, as on an airplane wing, and to prevent excessive noise. 

 

Five of them are located on a flat hill in the Hof District of Bavaria, Germany. Total project cost about 18 million euros, or $26 million. A 25-year mortgage at 5%/yr to pay off the capital would have annual payments of $26 million/amortization factor of 14.09 = $1,845,280/yr.

 

However, an investor may want to make a profit, not just pay off the mortgage. Say 8%/yr for taking the risk to borrow the money, create the project and pay the borrowed money back over 25 years from risky future cash flows.

 

The gross capacity factor is 22,500 MWh/yr/(10 MW x 8,760 hr/yr) = 0.257 

The net CF is 10 - 15 % less, say 10% less, due to parasitic power. 

Unit power cost = $1,845,280/(22,500,000 kWh/yr x 0.90) = $0.091/kWh, excludes O&M of about 0.015/kWh, and insurance and risk premium.

 

The wholesale price of electricity in Germany is about $0.050/kWh, which means the cost of Hof District wind power in Bavaria is at least $0.106/$0.055 x 100 = 93% greater than wholesale,