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Energy From Wind Turbines Actually Less Than Estimated?

Willem Post's picture
President, Willem Post Energy Consuling

Willem Post, BSME'63 New Jersey Institute of Technology, MSME'66 Rensselaer Polytechnic Institute, MBA'75, University of Connecticut. P.E. Connecticut. Consulting Engineer and Project Manager....

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  • Jan 10, 2013

The capacity factors and useful service lives of industrial wind turbines are important determinants of levelized wind energy costs. Some recent studies have brought to light the capacity factors are less and useful service lives are shorter than typically used in spreadsheet-based analysis by IWT promoters to obtain bank financing and governmental approvals and sway the lay public, including legislators. 


Lesser IWT Capacity Factors: Based on analyses of actual IWT production results, it appears the capacity factors of wind energy projects in many areas of the world are much less than estimated by project developers. As a result, the capital costs and environmental impacts of implementation would be much greater, because a greater capacity of wind turbines and transmission systems would be required to generate the same quantity of energy. See detailed explanation below.

Shorter IWT Useful Service Lives: in this article, a 20-year life is assumed, instead of the 25 years typically used by IWT project developers to obtain bank financing, federal and state subsidies and “Certificate of Public Good” approvals.




The US-DOE is envisioning the US having at least 20% of its energy from IWTs by 2050. Most of the wind turbines would be located in the Great Plains, where are the good to excellent winds. Currently, about 90% of wind turbine capacity, generating at least 95% of wind energy, is located west of Chicago.


The National Renewable Energy Laboratories, NRELs, have proposed multiple corridors with High Voltage Direct Current, HVDC, lines from the Great Plains to the East Coast, where the people are. Those lines have much less line losses than HVDC  lines, and can be buried, or on pylons, as needed, to satisfy NIMBY concerns.


The implementation of at least 20% wind energy would have major impacts on the US electric power system and would require trillions of dollars.


Wind Energy Production and Transmission: About 90% of all wind turbines are west of Chicago. Transmitting their energy from the Great Plains to the East Coast via the envisioned seven (7) HVDC lines incurs energy losses.


Energy has to be gathered from wind turbines and brought to a substations to raise its AC voltage to the AC transmission level, then it is transmitted to other substations to raise the voltage to that of the HVDC line, then the AC is converted to DC, then the DC is sent to the East Coast via the east-west HVDC lines, then to the north-south HVDC line, then the DC is converted to AC, then the voltage is stepped down to the AC transmission level, then via substations to the distribution systems.


The AC/DC units and transformers will see loads from 0% (wind-still days) to up to 90 – 100% (strong wind days) with an annual average of about 36% (the capacity factor), i.e., at part-load the efficiency of the AC/DC units and transformers is less than at rated load.


This means multiple AC/DC units and transformers at each end of the HVDC lines to minimize losses.


This also means the entire system has to be designed for 100% of the wind turbine capacity, but will be utilized at an annual average of only 36%, much less than the normal 60% for transmission systems. 


Below is a list of assumptions to estimate the overall loss, on an A to Z basis:


Average Capacity factor, CF, of all wind turbines………………………………..0.360

Loss due to gather wind energy to existing and new HVAC lines………………0.990

Loss due to step up Great Plains AC voltage……………………………………….0.985

Loss due to HVAC transmission to west-east HVDC lines………………………..0.990

Loss due to step up to HVDC voltage…………………………………………………0.985

Loss due to AC to DC conversion………………………………………………………0.980

Loss due to HVDC transmission to East Coast north-south HVDC backbone…0.970

Loss due to DC to AC conversion………………………………………………………0.980

Loss due to step down the East Coast HVAC voltage……………………………..0.985

Loss due to HVAC transmission on East Coast……………………………………..0.980

Loss due to distribution…………………………………………………………………..0.960


Net CF at user’s meter…………………………………………………………………….0.296


As a result of the above losses, the average CF of 0.360 at the wind turbine is reduced to about 0.296 at the user’s meter, for a 17.9% loss!! This compares with a US grid loss of 6.7%, on an A to Z basis.


There are additional energy and wear-and-tear losses to accommodate wind energy to the grid:


– increased plant capacity and increased hours of part-load-ramping operation to balance the variable wind energy. 

– increased plant capacity and increased hours of 3,600 rpm spinning operations, which requires about 8% of the fuel consumption at rated output, to instantly provide energy when significant wind energy ebbing occurs. 

– increased plant capacity and increased frequency of plant start/stop operations, to provide energy when significant wind energy ebbs or surges are predicted to occur.


Wind Turbine Replacement Scenario: As the above NREL-envisioned IWT build-out proceeds to achieve 20% wind energy by 2052, and assuming a 20-year life, almost all of the existing 52,000 MW of IWTs would need to be refurbished or replaced during 2012 – 2032, if economically/technically viable, plus the new IWTs built during 2012 – 2032 would need to be refurbished or replaced during 2032 – 2052, etc.


Wind Turbine Capacity: Assuming a life of 20 years, onshore capacity factor of 0.30 and offshore of 0.38, energy production growth at 0.9%/yr (due to electric vehicles?), a spreadsheet-based analysis shows, it would take about 425,000 MW of IWTs, onshore and offshore, to provide about 1,170 TWh in 2052, about 20% of the total US production in that year.


Wind Turbine O & M Costs: Below URLs show 2011 estimates of US wind turbine O & M varying by region: about $26,000/MW in Texas and Southwest; about $30,000 – $32,000 in the Great Plains and Midwest; about $40,000/MW in Pennsylvania, New York, Maine, etc. Offshore would be about $50,000 – 60,000/MW. 


These US costs have been steadily rising from an average of about $22,000/MW in 2008 to an average of about $31,000/MW in 2011, despite claims they would be declining by wind energy proponents.


Note: For proper comparison, O & M cost should include variable costs, such as labor, parts, crane rental, consumables, etc., plus fixed costs, such as insurance, administation, etc.


Note: Other major O & M costs result from increased spinning, start/stop, balancing and grid operations due to wind energy being on the grid.


Grid Level Costs: As RE build-outs take place, more becomes known regarding grid level costs. The below OECD study quantified the levelized costs of the grid level effects of variable energy, such as wind and solar, on the grid. It includes the costs of wind energy balancing, PLUS the costs of grid connection, reinforcement and extension, PLUS the costs of back-up (adequacy), i.e., keeping almost all EXISTING generators fueled, staffed, and in good working order to provide energy when wind energy is minimal, about 30% of the hours of the year in NE, about 10-15% of the hours of the year in the US.


In the US, the costs of the 3 PLUSSES for onshore IWTs are minimal when the annual wind energy on the grid is only a few percent, because most grids have some spare capacity to absorb variable wind energy. As the wind energy percentage nears 3 – 5%, the spare capacity is used up and the costs of the 3 PLUSSES are about $7.5/MWh at 5%, about $16.30/MWh at 10%, and about 19.84/MWh at 30%. This is significantly greater than the about $5/MWh usually mentioned by IWT promoters. See page 8 of below URL. Corresponding costs for offshore wind turbine plants would be significantly greater.

These costs are a significant part of the US annual average grid price of about 5 c/kWh. Mostly, they are “socialized”, i.e., charged to rate payers, not to wind turbine owners. As a result, wind turbine owners, with help of other subsidies, such as the 2.3 c/kWh production tax credit, can underbid other low-cost producers, causing them to sell less energy and become less viable over time, i.e., future investors would be less willing to invest in such producers, unless compensated with “capacity payments”, that also will be charged to rate payers, not wind turbine owners. 

The 40-year cost for new, refurbished and replaced IWTs, back-up (adequacy), balancing, grid connection, grid reinforcement and extension would be about $2 TRILLION, unsubsidized, with further annual capital costs after 2052 to maintain the 425,000 MW of IWTs as an on-going energy producer. 


Economic Impact of NREL Build-out: The increased capital cost of IWT build-outs, refurbishments/replacements, balancing plants and grid reorganization, and the impact of the lesser CFs and shorter lives would greatly increase the US levelized cost of energy.


If US wind energy goals were increased to 30% or even 40%, levelized costs, and various other adverse impacts, would be proportionately greater.


Unless developing nations, i.e., China, India, Brazil, etc., handicap themselves in a similar manner (which appears unlikely, based on the outcome of COP-18 in Dohu, Qatar, in 2012), the US, with a low-growth economy and huge trade and budget deficits, would be at an even relative greater economic disadvantage than at present.


Add to that situation wind energy not being anywhere nearly as effective regarding CO2 emission reduction as increased energy efficiency, one may wonder if the Western World is on the right course regarding CO2 emission reduction. 


Note: It is common practice among utilities to perform levelized cost analyses of energy systems. The annual cost of (Owning + O&M) is estimated and summed for, say 20 years, and the annual energy production, MWh, is estimated and summed for 20 years to obtain the 20-year average or levelized cost, $/MWh. Such analyses become more complex, if various financing aspects, subsidies, depreciation, renewable energy credits, aging factors and replacements of equipment, etc, are applied.




Wind turbine plant energy densities are less than 2 W/m2, as measured at the wind turbine, less losses to transmit the energy to the user. Here is an offshore example.


Offshore Example: The Anholt offshore wind power plant has 111 Siemens wind turbines, 3.6 MW each, for a total of about 400 MW, on 88 km2, 14 meter deep water, capital cost $1.65 billion; inaugurated on September 3, 2013; energy density = 400 MW x CF 0.40/88 km2 = about 1.82 W/m2; the CF of 0.40 as measured at the wind turbine is assumed, less losses to transmit energy to the user.


Onshore Example West of Chicago: Onshore wind plants west of Chicago have an average CF of about 0.38, as measured at the wind turbine i.e., about 0.36/0.40 x 1.82 = 1.64 W/m2.


The capacity, MW, required for 50% of US energy from wind = (0.5 x 4,000 TWh/yr)/(8,760 hr/yr x {0.36 – 0.73 x 0.36 AC/DC conversion and HVDC transmission losses}) = about 878,000 MW. Land area required for proper wind turbine spacing would be 878,000/1.64 = 535,232 km2. 


Wind turbines have a life of about 20 years, so there will be a big replacement/repair industry to keep the entire enterprise going. The area would become unfit for human occupation. For health reasons, people’s residences need to be about 2 miles from 3 MW turbines. Most fauna would avoid the area. Agriculture remains feasible. 


See David JC MacKay’s book “Sustainable energy; without the hot air”, pgs. 43 and 284 for more data about energy densities. 




Germany has set the ambitious goals of increasing renewable energy to 35 percent of total power consumption by 2020 and 80 percent by 2050 while phasing out all of Germany’s nuclear power plants by 2022. RE was 20.3% in 2011, 21.9% in 2012.


Germany, after it closed about 50% of its nuclear plant capacity, is rapidly building out CO2-emitting coal and gas plants to offset the loss of the CO2-free nuclear energy, and rapidly building out renewable energy facilities.


At the end of 2012, Germany had about 31,000 MW of IWTs producing about 7.3% of its total generation and 32,800 MW of PV solar systems producing about 4.6% of its total generation.


Balancing Wind Energy: The domestic build-out of grid transmission and distribution systems and of balancing plant capacity to integrate the variable, intermittent RE, including offshore wind energy, are about 5-10 years behind schedule, because of NIMBY and huge costs, i.e., as the ENERGIEWENDE proceeds, Germany needs to increasingly rely on exports to and imports from nearby countries to use THEIR spare balancing capacity to balance its increasingly-erratic, domestic energy production. Current capital cost estimates for onshore grid expansion are about $26 billion. 


There exists a 580 km-long, underwater, HVDC line from the northern tip of Holland to the southern tip of Norway; capacity, 700 MW; voltage, 900,000 V; cable resistance at 50 degrees C, 29 ohm; cable losses at rated load, 2.5%; capital cost, 600 million euro; in service 6 May 2008.


When, on windy days, Germany sends its excess wind energy to the Netherlands to avoid disturbing its own grid too much, variations on the Dutch grid are sensed by the hydro plants in southern Norway. 


They reduce and modulate the flow to the hydro turbines to counter the variations; a part-load-ramping mode that saves water and is CO2-free. 


The Dutch have a large component of gas turbines on their grid that also reduce their outputs and modulate; a part-load-ramping mode that is inefficient (more Btu/kWh, more CO2/kWh) and  NOT CO2-free.


NOTE: Denmark has been using the hydro plants of Norway/Sweden for that purpose for at least 4 decades. On windy days, it has much excess energy, which it exports to Norway/Sweden at low prices, after subsidizing it at high prices!! No wonder household electric rates, about 31.5 eurocent/kWh, are the highest in Europe.


Impact on Electric Rates: As a result of the existing RE build-outs, German household rates increased from 13.94 to 28.50 eurocent/kWh, from 2010 to 2012, a 104.4% increase, and industrial rates increased from 6.05 to 16.10 eurocent/kWh, from 2010 to 2012, a 166% increase. According to a recent study for the federal government, electricity will cost up to 40 eurocents/kWh by 2020, a 40% increase over 2012 prices.


Among european nations, German households have the second highest electric rates; 28.5 eurocent/kWh (energy, plus fees, plus taxes), after Denmark (32 eurocent/kWh), courtesy of RE. US low electric rates are the envy of heavy industry elsewhere, including Germany. France’s are among has the lowest.


EEG Payments and Charges: EEG payments to RE generators are rapidly increasing. They were 5.6, 7.6, 8.8, 10.5, and 12.8 billion euros from 2006 to 2010; estimated at 23.6 b in 2014.


The 2011 charges, a.k.a. “apportionments”, reflect the energy production of the renewable systems installed PRIOR to 2011.


The EEG apportionments on household electric bills were 0.8, 1.0, 1.1, 1.3, 2.05, 3.53, 3.592, 5.227, 6.24 eurocent/kWh, excl. 19% VAT, from 2006 to 2014, with  annual increases of 1.5-2.5 eurocent/kWh to follow.


The below 3-part article by DER SPIEGEL staff reveals much of what is wrong with Germany’s ENERGIEWENDE.


Germany’s Wind Energy: Energy transmission facilities between North Germany and South Germany were not that important before the IWT build-out in North Germany and the PV solar system build-out in South Germany. As a result of these build-outs, there frequently is excess wind energy in the North and excess solar energy in the South.


Germany is planning to build HVDC lines from North Germany to South Germany. Because of NIMBY concerns, these lines are about 10 years overdue. There will be losses similar to the above NREL scheme.


Germany had been dumping its excess wind energy into the Polish grid, i.e., “unplanned energy flows”, for some years AND NOT PAYING FOR THE BALANCING which cost Poland money AND destabilized its largely coal-based grid. Poland told Germany it would build a big switch unless it stopped.


They finally agreed: Two GERMAN grid operators, who were causing the problems, are paying for the transformers at the border; at least 15 million dollars. Poland, the innocent party, is paying nothing. Poland will be getting excess wind energy from Germany, only if and when it agrees and its system can take it.


Germany exports a significant quantity of its variable wind energy (17.54 TWh during Jan-Oct 2012) at very low prices to the Netherlands, because it cannot use it on its own grid. Fortunately, the Netherlands has a large capacity of CCGTs and OCGTs for balancing it.


Germany already practices curtailment of wind energy production, but IWT owners, a politically well-connected group, have complained about losing revenues, and CCGT plant owners have complained about their reduced outputs, inefficiently produced, adversely affecting their plants’ economic viability.


Germany’s Solar Energy: About 22,000 MW of Germany’s 32,800 MW of PV solar systems (end 2012) are in South Germany. On a sunny summer day, from an output of about 0 MW at 6 AM, the PV solar output increases to about 16,000 MW at about noon, and back down to about 0 MW at 6 PM. As this would create major disturbances on the grid and, as PV solar panels cannot be turned off, Germany has to export part of the PV solar energy from about 10 AM to about 2 PM.


Germany has been exporting the excess PV solar energy to France and the Czech Republic at very low prices, after subsidizing it at 30 – 60 eurocent/kWh; France and Czech Republic net energy exports to Germany were 10.3 TWh and 4.8 TWh, respectively, during Jan-Oct 2012. 


France has a significant hydro capacity for balancing part of the excess PV solar energy, but the Czech Republic is building a big switch. Any excess energy not wanted gets grounded!!! 



Energy Flows: The Danish Wind Energy Association claims all wind energy is consumed in Denmark. That claim is invalid, according to NORPOOL grid energy flow analyses. 


This study shows, during 2005 wind energy production was 18.7% of Danish demand, wind energy consumption in Denmark was 13.6% of demand, with the difference 5.1% exported, or 5.1/18.7 = 27% of the wind energy is exported. For 2006, the corresponding numbers were 17%, 10.3%, 6.7%, 6.7/17 = 39%.


However, whereas energy is exported to the NORPOOL grid during strong-wind periods, energy, mostly from Norway’s hydro plants and Sweden’s hydro and nuclear plants, is imported from NORPOOL during other periods. During more windy years, Denmark may have a surplus energy trade balance, during less windy years, a deficit. 


During strong-wind periods, traditional generation and its fuel consumption would show reductions, based on hourly or 15-minute records, if all wind energy stayed in Denmark. However, the Danish system cannot ramp up and down, i.e., lacks sufficient flexibility, to keep pace with all the wind energy variations, especially during strong-wind periods; the energy the Danish system cannot, or for various reasons, does not balance, is exported to NORPOOL; the hydro plants of Norway (98% hydro) and Sweden (53% hydro) perform most of the balancing function of NORPOOL. 


As Denmark rapidly increases its future wind energy production to meet RE goals, the energy consumed within Denmark would not materially change, i.e., exports to NORPOOL and other grids would have to increase, unless Danish energy consumption is augmented by measures, such as adding electrically-heated hotwater storage tanks to district heating systems, charging several hundred thousand plug-in hybrids, increasing electric space heating, increasing supply management (reduce outputs of traditional generators, feathering turbine rotors) and demand management (varying hybrid vehicle charging rate, turning on/off selected demands of users), etc. 


Money Flows: Energy flows have time-varying prices. As wind energy is generated mostly at night, it is likely, Denmark exports energy at low prices at night and imports at high prices during the day, which, depending on the quantities and prices, may yield a dollar deficit or surplus for a year.




Sometimes California wind speeds suddenly decrease to near zero, or a cloud bank passes over solar arrays in the desert. The result is a rapid decrease in wind or solar energy that could cause instabilities and blackouts in the grid.


To prevent such instabilities and blackouts, quick-ramping OCGTs are kept in synchronous spinning mode (3,600 rpm), i.e., consuming fuel at about 6 to 8 percent of consumption at rated output, but not sending energy to the grid, to instantly make up for the missing energy.


Some generators, such as OCGTs and slower-ramping CCGTs, are started and stopped more frequently and/or operated in part-load-ramping mode 24/7/365 (instead of more steadily, near rated output), due to the variable, intermittent wind and solar energy.


The increased spinning, start/stop and part-load-ramping operations 24/7/365 have high Btus/kWh and high CO2 emissions/kWh. The extra fuel and extra emissions offset a significant part of what wind and solar energy was meant to reduce.




A study was performed of the performance of the 21 IWT facilities on eastern Australian grid which is geographically, the largest, most widely dispersed, single interconnected grid in the world.


Whereas, the NRELs rely on subjective computer models to “predict” IWT wind energy production over large areas, this study (second URL, behind a paywall) relies on 5-minute, time-averaged, operational data. The results are grim, but not unexpected.


The study focuses on the year 2010, which was, apparently, not significantly different from other years. The study:


– uses an unusually low wind energy production standard of 2% of installed capacity for the Minimum Acceptable Level (MAL).  

– relies on data provided by the grid operator that covers average power output over five minutes. Shorter time periods are preferable and instantaneous output is ideal.


For 2010, the combined output of all 21 IWT facilities failed to produce 2% of installed capacity 109 times. The longest period was for 70 minutes. One wind farm, described as typical, failed 559 times in the six months. The longest period was for 2.8 days. 


Not only does the entire fleet fail frequently, but also it fails throughout the year. Clearly, such performance would be unacceptable for any traditional method of generating electrical power.


After analyzing the data, the authors stated wind energy cannot be used for base load, and that the installed capacity of required back-up must be at least 80% of IWT installed capacity. 


In Eastern Australia the required back up is OCGTs which are far less efficient than CCGTs. As CCGTs are less quick-reacting than OCGTs, the latter need to operate in synchronous spinning mode 24/7/365 (using 6-8 % of their rated fuel consumption while sending no energy to the grid) to instantly provide energy when wind energy is ebbing. 



Danish Offshore: Offshore turbines are located in very windy areas. Their capacity factors range from 0.235 to 0.484, with an average of 0.391.


CFs in Europe: This URL has detailed information regarding energy conditions, wind energy, CFs in Europe.


Below are the averaged CFs in some widely-dispersed geographical areas for the 2006 – 2011 period.


Sample calculation: US wind energy CF in 2011 = 119,747 MWh/(46,919 MW, end 2011 + 40,180 MW, end 2010)/2 x 8,760 hr/yr) = 0.314; based on AVERAGE installed capacity. The US 6-yr average CF, similarly calculated, is 0.289; this is a more accurate value, as it evens out varying winds from year to year.


Germany, onshore                   0.187; dismal, but rising due to offshore IWTs

Denmark, including offshore     0.251; rising due to offshore IWTs

The Netherlands                      0.228

The US                                    0.289; a high value due to excellent winds in the Great Plains.

Texas                                      0.225

Ireland                                     0.283; Ireland and Scotland have the best winds in Europe.                 Spain                                       0.241

China                                       2009, 0.153; 2010, 0.152; 2011, 0.161; 2012, 0.166

Australia                                  0.300

UK, 2012                                 0.275; rising due to offshore IWTs



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.


Most Northeast wind turbine project owners claim CFs of about 0.32 or better to make their proposed projects look good on paper, to get government approvals and subsidies, and to delude lay legislators and lay public. Usually, real world CFs are less.


The AWEA, EIA, NREL and US-DOE all publish CFs of 0.25-0.30 for the Northeast, New York and Pennsylvania, based on actual production data. There are a few sites with better than average wind conditions, such as Marsh Hill, MA, and Lempster, NH, with CFs greater than 0.30. See below. 


U.S. average annual capacity factors for 2011 


U.S. average annual capacity factors by project and state for 2011 and 2012


The 2011 CFs of the NE states were: MA, 0.177; ME, 0.276; NH, 0.314; RI, 0.222; VT, 0.206.

The 2012 CFs of the NE states were: MA, N/A ; ME, 0.243; NH, N/A ; RI, N/A ; VT, 0.231


New York: 19 facilities; 2009, 0.189; 2010, 0.227; 2011, 0.236; 2012, 0.235


Pennsylvania: 17 facilities, 789 MW end 2011, 0.273; 23 facilities, 1335 MW end 2012: 0.300 (estimate)  


New Hampshire: Lempster Wind LLC; 24 MW; 66,092 MWh (2011); CF 0.314


Rhode Island: Portsmouth Wind Turbine; 1.5 MW; 2,912 MWh (2011); CF 0.222


Maine: Maine’s plans to have 2,000 MW of IWTs by 2015 and 3,000 MW by 2020 may need to be reviewed, as energy production is well below expectations. About 400 MW was in operation at the end of 2012.


Production and CFs for 2012, as reported by IEA/DOE.


Mars Hill        42 MW         133,284 MWh          CF 0.3613

Stetson I       57 MW         107,152 MWh          CF 0.2140

Stetson II       26 MW           41,943 MWh         CF 0.1837

Kibby Mtn    132 MW         264,180 MWh          CF 0.2278

Rollins            60 MW        126,887 MWh          CF 0.2408

Record Hill     50.5 MW      110,099 MWh          CF 0.2487


Total            367.5 MW      783,545 MWh         CF 0.2427



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

– Only projects with at least a full year of operation are included.

– Excludes: Fox Islands 4.5 MW; Beaver Ridge 4.5 MW; Bull Hill 34.2 MW, on line October 31, 2012 




CFs less than promised are likely due to:


– Turbulent winds entering 373-ft diameter rotors varying in speed AND direction under all conditions; less turbulent in the Great Plains and offshore, more turbulent, if arriving from irregular upstream or hilly terrain. 


– 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 turbulent winds entering the rotors; for the 3 MW Lowell Mountain IWTs rotor-starting wind speed with undisturbed winds is about 7.5 mph, greater with turbulent winds.


– IWT self-use energy consumption up to about:


up to 4% 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. 


up to 8% 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, reducing the IWT CF of about 0.25 or less, to about 0.2425 or less.


– CFs declining up to 1%/yr, based on UK and Denmark experience, due to aging IWTs having increased maintenance outages, just as a car.


– Reduced production occurs due to 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

* Upstream, hilly terrain causing irregular wind speeds and directions entering the rotors

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


– In the prevailing wind direction should be at least 7 rotor diameters 

– Perpendicular to the prevailing wind direction should be at least 3 rotor diameters. 


Note:  In case of the 63 MW Lowell Mountain, Vermont, ridge line 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.


Lowell has less than 3 diameters, hence there is flow interference. It it true, the interference is minimal, if the wind is perpendicular to the ridgeline, but during many hours of the year that is not the case. See URLs.


Flow interference, increased noise, increased wear and tear, such as rotor bearing failures, and lesser CFs will be the result.


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.


US bird kill = 1 bird/day x 39,000 IWTs x 365 days/yr = 14,235,000 birds/yr.

US bat kill = 2 bats/day, or 28,470,000 bats/yr, for a total of 42,705,000 animals/yr.


Note: Irregular air flows to the rotor cause significant levels of unusual noises, mostly at night, that disturb nearby people. Details in this article.  


The net effect of all factors shows up as real-world ridge line CFs of 0.25 or less, instead of the vendor- predicted 0.32 or greater, i.e., much less than estimated by IWT project developers to obtain financing and approvals. 


Government Regulator 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.



Bolton Valley Ski Resort 


Since October 2009, the Bolton Valley Ski Resort has had a Vermont-made, 100 kW “community” wind turbine, project capital cost $800,000 (includes a $250,000 gift from the Clean Energy Development Fund); vendor-predicted energy production 300,000 kWh/yr, for a CF = 0.34; vendor-predicted estimated useful service life 20 years. 


A recent check of the Bolton Valley website in January 2013 indicates actual energy production from October 2009 to-date (39 months or 3.25 yrs) was 509,447 kWh, for an actual CF = 509,447 kWh/(3.25 yr x 100 kW x 8,760 hr/yr) = 0.179, 47.4% less than the vendor-predicted CF of 0.34 to obtain VT-PSB approval. Like selling a car and telling the new owner it will do 34 mpg, whereas it actually does only 18 mpg. Also, an early red-flag indication of poor CFs on Vermont ridge lines that should have been heeded by the VT-PSB and VT-DPS. 


Value of energy produced = (509,447 kWh x $0.125/kWh)/3.25 yr = $19,594/yr; if annual O&M and financing costs, amortized over 15 – 20 years, are subtracted, this value will likely be negative, i.e., a CEDF-subsidized, money-losing project. 


Sheffield Mountain

Vermont Electric Cooperative, VEC, purchased energy from the Sheffield Wind LLC project (16 IWTs, each 2.5 MW = 40 MW) since it came on line in October 2011.


Under two Power Purchase Agreements, PPAs, VEC purchased 2 x 20,124 MWh in 2012, for a VEC-calculated CF = 0.23, less than the vendor-predicted CF of 0.32 or better, to obtain VT-PSB approval. In Mar 2013, CF = 0.249, a winter month.


Note: The Maine ridge line IWTs had a 2012 CF = 0.234; data source FERC website. See above.


VEC paid 10 c/kWh for the energy and received 5.5 c/kWh by selling Renewable Energy Credits, RECs, to out-of-state entities that should have reduced their CO2 emissions, but likely did not want IWTs to destroy their ridge lines.  


Lowell Mountain

The Green Mountain Power 63 MW Lowell Mountain wind turbine facility with (21) 3 MW Danish, Vestas V-112 wind turbines, 367.5-ft (112 m) rotor diameter, 275.6-ft (84 m) hub height, total height (275.6 + 367.5/2) = 459.3 ft, stretched along about 3.5 miles on 2,600 ft high ridge lines, has nothing to do with community-scale wind, everything with industrial, utility-scale wind. The housings, 13 ft x 13 ft x 47 ft (3.9 m x 3.9 m x 14 m), on top of the 280-ft towers, are much larger than a Greyhound bus.


Gaz Metro of Quebec, Canada, owns GMP (and CVPS). It recently acquired Central Vermont Public Service Corporation. It now controls at least 70% of Vermont’s electrical energy market.


The GMP name for this facility is “Kingdom Community Wind”. GMP is using blatantly deceptive PR to soft-soap/deceive 



Exclusion Zone: The blasting, clearing, road building, and foundation areas of the Lowell project directly impacts 159 acres of land. The Lowell project land area includes a total of about 2,700 acres that remain undisturbed and acts as a buffer zone.


As wind turbines’ capacity, MW, increased from 500 KW to 3,000 kW, their environmental impact is much greater. About a 1.25 mile (2 km) distance from a residence is needed for IWTs 2 MW and up to minimize adverse:


– infrasound and low frequency noise impacts on nearby people, especially pregnant women and children.

– impacts on the ambiance, quality of life and property values of nearby residences.


Lowell would need an exclusion zone of (3.5 m + 2.5 m), length x 2.5 m, width x 640 acres/sq m = 8,125 acres. 


Example of Property Value Degradation: Assessment reduction due to Georgia Mountain wind turbine noise = $409,900 – $360,712 = $49,188


Lowell and the Grid: GMP claims to be all about renewables, but it recently entered into an agreement with the Seabrook nuclear power plant to buy 60 MW of steady, near-CO2-free nuclear energy at 4.66 cents/kWh, much less than the cost of the HEAVILY-SUBSIDIZED Lowell wind energy, which is variable and intermittent energy, i.e., junk energy, and only partially CO2-free. To make the wind energy useful on the NEK grid, it requires:


– voltage regulation

– extra, quick-ramping/quick-starting, OCGT spinning plant capacity*

– extra OCGT/CCGT balancing plant capacity*

– grid modifications


* Because the annual wind energy percent on the NE grid is small, about 1%, the owners of existing generators do not yet “see” adverse impacts on their operations. As the percent increases, owners will “see” increasingly adverse impacts and will demand to be compensated, as happened on other grids with a greater percent, say 3-4 %, i.e., present owners are free-loading off other generator owners.


Voltage Regulating Facility: Lowell wind energy varies with the cube of the wind speed; double the wind speed, eight times the energy.  According to ISO-NE, because the variations of the wind energy voltage are too excessive for the NEK grid, a 27.5 MVAR voltage regulating facility needs to be installed by GMP. It will be located adjacent to the Jay Peak 46 kV Switching  Station, housed in a 40’ x 68’ x 45’5” tall building, surrounded by 70’ x 90’ x 8’ tall fencing.


The voltage regulating is performed by a Hyundai-supplied, 62-ton, synchronous-condenser system, operating at 3,600 rpm and at no load, 24/7/365 (high-speed idling, year-round), plus electrical systems to modify the variable wind energy by adding or subtracting reactive energy to satisfy below-criteria voltages on the 115 kV transmission system.


It requires an 800-hp motor to get it up to speed and maintain it there. The system will cost about $10.5 million and be operational by the Spring of 2014. During all of 2013 and part of 2014, Lowell will be operated in curtailed mode, as required by ISO-NE.


S-C systems have energy losses of about 3%, i.e., 97% efficient, plus the facility has its own levelized (Owning + O&M) costs, which will adversely affect the project economics. Energy loss of only the S-C system = 800 hp x .746 kW/hp x 8,760 hr/yr x 0.03 = 156,839 kWh/yr; that energy is subtracted from the energy fed to the grid.

*Newly-developed systems are available from GE, Siemens, Vestas, that perform two functions: vary the pitch of the blades, based on wind velocity, as measured at the nacelle, to more-efficiently obtain energy from the wind, and, using partially-charged batteries that absorb and supply energy, to reduce voltages variations. The resulting processed outputs are collected from each IWT and fed, via a substation, into the grid. The likely net effect, claimed by Vendors, is an increased CF and less disturbance of the grid.


Capital Cost: GMP calculated the Lowell capital cost at about $160 million, plus about $10.5 million for a synchronous-condenser system, per ISO-NE requirements, to minimize voltage variations and instabilities of the Northeast Kingdom grid, for a total of about $170.5 million.  


The above capital costs may not include transmission upgrades ($10,280,000) and substation upgrades ($3,160,000 or $17,420,000) of which Vermont Electric Cooperative paid 41% and GMP 59%. See page 14 of URL.


Lowell sends wind energy, via the upgraded transmission and upgraded Jay substation, into the often, heavily-loaded 115,000 V line between Highgate and Newport, north of Lowell, causing it to be overloaded. 


Transmission upgrades ($10,280,000) and substation upgrades ($3,160,000 or $17,420,000); Vermont Electric Cooperative paid 41% and GMP 59%. 


As a result of upgrading the 115,000 V line between Irasburg and Johnson (capital cost not yet published), south of Lowell, some wind energy can also be sent via that line. This eases the burden on the Highgate-Newport line, and thus Lowell can more often operate at a greater output.


On rare occasions, when the wind blows very hard, say about 30 MPH, the Lowell wind turbines may produce energy at a high MW (and make a lot of noise), but likely not at the rated value of 63 MW.


On many occasions, mostly during summer and at dawn and dusk, the Lowell turbines produce minimal energy. 


Because of variable wind conditions in New England, even on ridge lines, about 30% of the hours of the year, wind energy is minimal. 


This means it cannot be relied on, and almost all other generators need to be staffed, fueled, and kept in good operating condition to deliver energy to the grid when wind energy is minimal.


Production: GMP estimated the Lowell production at 63 MW x 8,760 hr/yr x CF 0.336 = 185,570 MWh; or 180,003 MWh, adjusted for 3% voltage regulation losses. It is unclear why this value is different from 2) below.


Note: The $10.5 million synchronous-condenser plant is about 97% efficient, i.e., reduces the Lowell output by about 3%.


1) Production (standard rotor) = 63 MW x 8,760 hr/yr x CF 0.2842 = 156,844 MWh/yr; per GMP claim filed with PSB.

2) Production (large rotor) = 63 x 8,760 x 0.3587 = 197,959 MWh/yr; per GMP claim filed with PSB. 


More Likely Energy Production: Based on 5 years of Maine ridge line production results, the Lowell CF is likely to be about 0.25 or less. More likely production = 63 MW x 8,760 hr/yr x 0.25 x 0.97 = 133,831 MWh/yr, or 134/5,800 x 100% = 2.3% of Vermont’s annual consumption.


Wind Turbine O & M Cost: Below URLs show recent estimates of US wind turbine O & M varying by region: about $26,000/MW in Texas and Southwest; about $30,000 – $32,000 in the Great Plains and Midwest; about $40,000/MW in Pennsylvania, New York, Maine, etc.


Lowell = (63 MW x $40,000/yr)/(180 million kWh/yr) = 1.4 c/kWh, using GMP production estimates; 1.89 c/kWh, using a CF of 0.25.


Note: During the first 6 months of operation, the Lowell CFs were: 0.202; 0.218; 0.167; 0.162, 0.223; 0.195, for an average of 0.193, mostly due to ISO-NE-mandated curtailments, i.e., GMP has fewer RECs to sell, and higher maintenance costs per/kWh.


Other major O & M costs result from increased spinning, start/stop, balancing and grid operations due to wind energy being on the grid. 


Energy Cost: GMP calculated the levelized Lowell energy costs, based on a vendor-provided CF of 0.336 and a vendor-provided 25-year life, at 10 c/kWh, heavily-subsidized; it would 15 c/kWh, unsubsidized, per AEI/US-DOE.


More Likely Energy Cost: A percentage of the 10 c/kWh, say 40%, is due to the site preperation (land acquisition, blasting, road building, foundations, site runoff, connection to the grid, etc.) and the rest, 60%, is due the IWTs (mast, nacelle, rotor, etc.). Only the part associated with the wind turbines is affected by a lesser CF and a shorter life.


More likely energy cost = (0.60 x 10 c/kWh x CF ratio 0.336/0.25 x Life ratio 25/20 x S-C system 1/1.03) + (0.40 x 10 c/kWh) = 14.1 c/kWh, heavily-subsidized; it would be 21.2 c/kWh, unsubsidized, per AEI/US-DOE.



– NE grid prices have averaged about 5-6 c/kWh (there are occasional spikes, as shown by below ISO-NE data), have been at that level for about 3 years, are likely to stay there for some decades, as a result of abundant, domestic, low-cost, low-CO2-emitting natural gas.


– Hydro Quebec and Vermont Yankee pricing is about 5.5-6 c/kWh, inflation and or grid price adjusted; 24/7/365, steady, near-CO2-free energy.


– GMP bought 60 MW of steady, near-CO2-free nuclear energy at 4.66 cents/kWh, inflation and or grid price adjusted. Smart move, now that Lowell has become a PR disaster and will likely be a financial fiasco as well.


CO2 Emission Reduction: GMP claimed 25-yr CO2 emission reduction, shown below, is based on 0.5 metric ton CO2/MWh, NE grid intensity, CF = 0.336 and 25 yr life.


Realistic 20-yr energy production, accounting for aging at 0.5%/yr, lesser CF of 0.25, shorter life of 20 years, 3% synchronous-condenser losses, is shown below. 


                                            Energy Production               CO2 Emission Reduction

                                                   MWh                                   metric ton                             

GMP 25-year Claim                   4,639,250                             2,319,625                  


Realistic 20-year                      2,522,860                             1,261,430

Less pre-production*                                                                100,000

Net**                                                                                    1,161,430



** Pre-production CO2 emissions are for mining, processing, manufacturing the wind turbines, excluding shipping, site preperation, erecting, interconnecting to the grid.

*  Not adjusted for wind energy-induced grid inefficiencies, because New England annual wind energy is only 1%. At future greater annual wind energy percent on the NE grid, CO2 emission reduction effectiveness declines, as confirmed by a study of the Irish grid which shows at 17% annual wind energy, effectiveness is 0.526, which would reduce the net CO2 emission from 1,161,430 to 563,512 metric ton.


Conclusion: The GMP CO2 emission reduction claim is at least 1.997 higher than the more likely reduction. In the future, with 17% annual wind energy on the NE grid, that claim will be even more extravagant, i.e., at least 4.116 higher than the more likely reduction.  


GMP’s Optimistic Assumptions: GMP used a vendor-predicted CF of 0.336, but that value is much greater than the average CF of 0.234 of six ridge line IWT facilities in Maine, based on FERC production data. 

For comparison: New York State, 19 facilities    2009, 0.189; 2010, 0.227; 2011, 0.236; 2012, 0.235. See below URLs. 


GMP used a vendor-predicted 25 year life, instead of a 20 year life. 


GMP used optimistic vendor-predicted values to:


– obtain bank financing and federal and state subsidies  

– obtain “Certificate of Public Good” approvals from the VT-PSB

– make Lowell look good on paper to befuddle the gullable lay public, including legislators

– polish its “greenness” in the eyes of the public


Failure to base approval decisions on realistic spreadsheet-based analyses is a malfeasance of a public trust, which has legal consequences.


Note: CFs were a closely guarded business secret, until it became known IWT owners have to report quarterly energy production to the Federal Energy Regulatory Commission, FERC.


Based on the FERC data, the CFs on ridge lines are about 0.25 or less, instead of the 0.32 or better claimed, largely due to overestimating wind speeds and quality, aging of the IWTs and various outages and curtailments. See URLs.


GMP Made Whole, Others Pay: Whereas Lowell Mountain may have significantly greater levelized energy costs than the above 10c/kWh, this would not affect GMP’s bottom line, as it would roll all its costs regarding Lowell Mountain mostly into its household rate schedules, subject to PSB approval, after pro forma hearings. 


Because the business records of this heavily-subsidized project are “proprietary”, it is likely, the lay public will never learn what the real costs were, and legislators do not dare investigate lest they be seen as less green.



The VT-PSB, VT-DPS, etc., likely knew CFs on Vermont ridge lines would be less than the vendor-predicted values (the evidence was on the FERC website, and they are on my email distribution list), but rooted for and/or approved the above three projects anyway, after pro forma hearings.  


It should be obvious to the VT-PSB (it is supposed to serve/protect the public) and other government entities, whereas IWT project developers make claims of IWTs having:


– CFs of 0.32 or greater, this claim should be discounted to at most 0.25, based on real-world ridge line results in Maine and in Vermont.


– Useful service lives of 25 years, this claim should be discounted to at most 20 years, based on real-world useful service life results.


The spreadsheet levelized energy cost analyses prepared by IWT project developers, currently based on their dubious claims, should be revised to better reflect the real world, rather than an “Alice in Wonderland” world.


Failure to base approval decisions on real-world, spreadsheet-based analyses is, as a minimum, a lack of due diligence, or, if facts were known to the VT-DPS, as is the case with the Lowell Mountain and Sheffield Mountain approvals, a malfeasance of a public trust; both have legal consequences.

John Miller's picture
John Miller on Jan 10, 2013

Willem, just a few years ago the DOE was using a standard estimate of 38% for onshore average wind power capacity factors.  The DOE reduced their estimate to 33% more recently.  Your data clearly shows this estimate needs to be further reduced in the near future.  A couple years ago a business contact in Texas indicated the local Utility companies typically budgeted-planned for annual average wind capacity factors of about 20% (vs. your actual of 22.5%).  These relatively low capacity factors were likely contributing issues to why T. Boone Pickens abandoned/sold his ‘American Wind Alliance’ investments in Texas and Minnesota large farm projects over the past couple years.

Another factor often not discussed related to wind power unpredictable-variable performance is the impact on affected Utility companies peaking power generation thermal efficiency performance.  If wind power is allow to uncontrollably supply a local power grid, sufficient natural gas peaking power must be on-line and idled-hot standby to quickly stabilize power grids when wind farm power supplies decrease or drop off line and local power grid voltages drop.  This operation directionally makes natural gas peaking power plants less efficient (more fuel consumption per KWH) and/or requires feathering-idling wind turbines to reduce their output in order to reasonably stabilize local grids; which contribute to lower capacity factors.

Another factor not well communicated to the general public is why wind (or solar) power costs are at least 20% greater than coal, natural gas and nuclear on average even though the wind (and sun) energy is free.  As you are aware, the 25% +/- capacity factor you have identified for wind power means that over 3-times the total power generation capacity must be installed vs. coal/natural gas baseload plants that typically have capacity factors greater than 85%.  This makes the capital costs of renewable wind (or solar) for a given power generation-delivered capacity significantly greater than fossil fuels.  Even with the added fossil fuels costs, wind power apparently cannot compete without perpetual 2.2 cent/KWH subsidies (adjusted for inflation) and additional tax credits in the future. 

John Miller 

Randy Voges's picture
Randy Voges on Jan 10, 2013


On a related note (and speaking of Vermont) have you seen this?

Things are getting interesting in California, too.

John Miller's picture
John Miller on Jan 11, 2013

AE, despite California’s apparent leadership in all things environmental such as wind power, they still appear to import about 20% of their electric power from adjacent State’s (Re. EIA data) and pay about 25% more for average retail electric power than the U.S. average (Additional EIA data).   

John Miller

Michael Goggin's picture
Michael Goggin on Jan 11, 2013

John, Willem, I don't expect DOE will be updating its wind capacity factor numbers from 33% because, despite your best efforts to cherry pick data, wind's capacity factor in the U.S. is actually 33% (page 41):

Regarding the myth that wind doesn't produce the expected emissions savings, I'd kindly ask that you stop repeating this lie until you can explain the following DOE data that directly contradicts your claim. I posted this comment more than 6 months ago on another one of Willem's spam posts on this website, and to date he hasn't been able to offer any explanation for why the data directly contradicts his claim:

"Unfortunately for Mr. Post, repeating a myth does not make it true. Regular readers of EnergyCollective have probably seen a nearly identical posting from Mr. Post almost a dozen times already. In fact, since everything in this posting has already been debunked, I'll just copy and paste the previous debunkings below. However, I would be curious how Mr. Post would attempt to explain away this inconvenient truth, which conclusively tests and refutes his entire hypothesis:

The Department of Energy collects detailed data on the amount of fossil fuels consumed at power plants, as well as the amount of electricity produced by those power plants. By comparing how the efficiency of power plants has changed in states that have added significant amounts of wind energy against how it has changed in states that have not, one can test the hypothesis that wind energy is having a negative impact on the efficiency of fossil-fired power plants. The data clearly shows that there is no such relationship, and in fact states that use more wind energy have seen greater improvements in the efficiency of their fossil-fired power plants than states that use less wind energy. Specifically, coal plants in the 20 states that obtain the most electricity from wind saw their efficiency decline by only 1.00% between 2005 and 2010, versus 2.65% in the 30 other states. Increases in the efficiency at natural gas power plants were virtually identical in the top 20 wind states and the other states, at 1.89% and 2.03% improvements respectively. The conclusion that adding wind energy actually increases fossil plant efficiency makes intuitive sense, because adding wind energy to the grid displaces the output of the most expensive, and therefore least efficient, fossil-fired power plants first."

Michael Goggin's picture
Michael Goggin on Jan 11, 2013

Thanks Willem, now I understand why your math is wrong. The majority of wind plants finish construction and become operational near the end of the year, so simply averaging the MW capacity at the start and end of the year significantly overstates the MW that were actually online on average over that year. That explains why your capacity factors are lower than the real DOE/LBNL data.

DOE's data are based on actual fuel use at power plants, so your claim that they use estimates for fuel use data is simply false.

John Miller's picture
John Miller on Jan 11, 2013

Michaelgoggin, your analysis that shows adding variable wind power to state-wide power systems increases average fossil fuel power plant thermal efficiency appears to be questionable.  Granted the EIA data may show increased efficiency of coal power plants in states that have significant amounts of wind power generation, but this factor may be ignoring the actual variables that affect power system efficiencies.  Coal plants are primarily baseload (constant) capacity and are not directly affected by variable wind on an hour-to-hour or day-to-day basis.  Natural gas intermediate-peaking plants are most affected.  I am not sure what time frame you evaluated, but over the longer term (years) all fossil fuel power plant efficiencies routinely improve due to retiring older-inefficient power capacity, continuously improving in-service power plant equipment efficiencies and installing new state-of-art, high efficiency power generation capacity.  Also, improved power grid controls (or smart grids) have further increased total and fossil fuels power generation efficiencies.  Are you sure you have taken these factors into account when arriving at you comment that “adding wind energy actually increases fossil plant efficiency and makes intuitive sense”?

Alan White's picture
Alan White on Jan 11, 2013

CF will  only significantly change once the platform for wind is changed. big blade windmills are so 13th century and bigger is not getting any better. one aspect of the CO2 debate that gets lost is the amount of energy that it takes to produce all the components in a current 400 ft windmill. That energy is never recaptured or replaced with new energy from the unit being online. 

Nw technology is on the horizon for wind and one that will make more power not kill birds and not make a whoosh noise. these will raise the CF to levels that they shoud be. to be profitable for everyone. 



Randy Voges's picture
Randy Voges on Jan 12, 2013

Dovetailing with John and Willem's comments, it's important to distinguish between capacity resources and energy resources (I also alluded to this in Anna Leidreiter's post).  Capacity resources are dispatched by the transmission system operator and must generate power within a defined range, and they face penalties for deviating from it.  Energy resources (i.e., wind and solar) are not under this obligation; they put out whatever they can, although it's possible they may be curtailed in order to keep the system stable.  In fact it's useful to think of energy resources not as generators, but rather as negative load.  Anyway, because most of the generation is capacity, it isn't too difficult to accommodate the available energy resources.  The more energy resources you have (the technical term is 'penetration level'), the more flexible the system has to be to maintain stability.  The issue gets really challenging for an island grid (think Hawaii).

Would be nice for someone from an RTO (ERCOT, PJM, MISO, etc.) to expound on this further in a post; they could do it better than I could.


Paul O's picture
Paul O on Mar 16, 2013


In this era of deficits and tight resources, should we be throwing so much money at wind farms? As I see it and have opined elsewhere, wind power is a very poor and il-adviced stand alone source/ replacement for carbon based generation of electricity. We should be pouring money into research for stand alone base load replacement for current carbon based power generation.

What really irks me is the way and (expensive) manner that variable energy (aka Capacity Resources) interests are being allowed to dominate the energy debate, without due dilligent questioning, how and why are they not required to publish their Quarter-hour grid operations data, when they are being funded by public funds?

It is also irkesome to witness the virulent response of Wind Energy adherents when someone points out the "Emperor Has No Clothes"  flaws of wind energy. There is a near tangible religious fervor in the attitude by which casters of doubt on the suitability of wind power are being attacked.

Oscar Fleury's picture
Oscar Fleury on Jan 14, 2013

Mr Post wrote:

"Add to that situation wind energy not being anywhere nearly as effective regarding CO2 emission reduction as increased energy efficiency..."

" "

From the first statement it occurs that wind energy CO2 emissions are understated.

From the second statement it occurs that wind energy CO2 emissions are overstated.

This kind of contradiction is inevitable in a complex system of lies designed to mutually consolidate false truths over time.

Hence, Mr Post would be well advised to acknowledge the well known fact that it is almost impossible to lie to everybody all the time...

Leo Klisch's picture
Leo Klisch on Jan 14, 2013

Birds of prey, such as eagles and hawks, account for about one-third of deaths from wind turbines across the United States, said Don Gorney, a well-known Indianapolis birder and former president of the Amos W. Butler Audubon Society. Warbler species account for another third, he said, and all other species account for smaller proportions of deaths. Gorney believes wind farms are compatible with bird conservation if sensible guidelines are followed. Homoya, the Purdue researcher, agreed. "It's interesting to point out that (one) study found that in terms of gigawatt-hours of electricity produced, there are roughly 13 times more bird deaths associated with fossil fuel energy production than with wind farms."

Leo Klisch's picture
Leo Klisch on Jan 14, 2013


  agreed, our population and lifestyle are putting way to much pressure on the natural world we love and depend on. Hard to know which direction to turn. Even efficiency seems to get far less attention than it deserves but most people and corporations seem to need ridiculously short payback times on projects even if they have billions of $ setting around. Thanks for your input on wind power - we need skeptics no matter what the plan or idea. I think the biggest question on any analysis like yours is knowing for certain the accuracy and quality of the inputs/data.

On another note I would like your reaction to the below article in "journal of Power Sources"


Leo Klisch's picture
Leo Klisch on Feb 4, 2013

Willem, the link for the study is below. Now I recognize that the organiztion behind the study may make you skeptical of it's objectivity but it seems complete even though the assumptions could be challanged.

thanks for your input. 

Also you may be interested in GE's latest turbine - use smart planet link below.,fossil-fuel,and...

Alan White's picture
Alan White on Mar 11, 2013


   yes in fact it has been invented for I did it. Windshine electric generators are the next generation in power production from wind. I know you will like the design and just contact me at and I will let you know what is possible for the future. 

Leo Klisch's picture
Leo Klisch on Mar 16, 2013

Last year Iowa got 24.5% of there power from wind in the state. Would be interesting to see how the Iowa utilities manage their grid. Their grid may be more interconnected than most. Based on wikipedia info the average capacity factor calculates to 31%. They have 5137mw wind operating. If all were running to max on a particular day with average load the percent contribution of wind would be 79%. Given the peaks and valleys of daily load, I would think that there are many hours were wind output is equal or greater than the Iowa only load. Iowa does export power so they handle the high wind days by exporting which would not affect the CF or they feather the turbines. Now if the whole MISO region was at 24.5%, balance and stability could be a problem. But because the MISO region is big enough to have varying weather, it could allow a much higher percent wind. The monthly output in 2012 varied from a high of 1490 Gwh in January to 643 Gwh in July. If a person really cared to dig into it and the info was not trade secrets, one could relate CF to age of turbines or other factors. I think the lower output in July could easily be made up with residential, farm and commercial ground and roof mount PV. If this raises the cost of power it will incentivise more efficiency, demand response, CHP, biogas etc. projects to lessen the need for CCGT or storage backup.

Clayton Handleman's picture
Clayton Handleman on Feb 13, 2014

I am trying to better understand issues about use of HVDC from great plains to the east coast.  I have been able to find little referenced information on efficiency of HVDC.  A portion of your post has a good deal of detail but no references to ascertain where the data came from.  Can you point me to some technical literature on efficiency of HVDC including up and down conversion.  My interest is both in state of the art and technology trends. 

I spent a number of years designing inverters and watched them go from low 90’s to high 90’s percent conversion efficiency.  I am interested in better understanding where we are on the learning curve with HVDC. 

Thank you in advance

Clayton Handleman's picture
Clayton Handleman on Feb 13, 2014


Of interest to me is the portion of your post below.  There is a lot there and I have been through a good bit of the reference material you post trying to find a source for those numbers.  I have also been looking through the references that they reference.  I am guessing that you could quickly point me to where you found this information and it would be much appreciated.  Thank you.


Energy has to be gathered from wind turbines and brought to a substations to raise its AC voltage to the AC transmission level, then it is transmitted to other substations to raise the voltage to that of the HVDC line, then the AC is converted to DC, then the DC is sent to the East Coast via the east-west HVDC lines, then to the north-south HVDC line, then the DC is converted to AC, then the voltage is stepped down to the AC transmission level, then via substations to the distribution systems.


The AC/DC units and transformers will see loads from 0% (wind-still days) to up to 90 – 100% (strong wind days) with an annual average of about 36% (the capacity factor), i.e., at part-load the efficiency of the AC/DC units and transformers is less than at rated load.


This means multiple AC/DC units and transformers at each end of the HVDC lines to minimize losses.


This also means the entire system has to be designed for 100% of the wind turbine capacity, but will be utilized at an annual average of only 36%, much less than the normal 60% for transmission systems. 


Below is a list of assumptions to estimate the overall loss, on an A to Z basis:


Average Capacity factor, CF, of all wind turbines………………………………..0.360

Loss due to gather wind energy to existing and new HVAC lines………………0.990

Loss due to step up Great Plains AC voltage……………………………………….0.985

Loss due to HVAC transmission to west-east HVDC lines………………………..0.990

Loss due to step up to HVDC voltage…………………………………………………0.985

Loss due to AC to DC conversion………………………………………………………0.980

Loss due to HVDC transmission to East Coast north-south HVDC backbone…0.970

Loss due to DC to AC conversion………………………………………………………0.980

Loss due to step down the East Coast HVAC voltage……………………………..0.985

Loss due to HVAC transmission on East Coast……………………………………..0.980

Loss due to distribution…………………………………………………………………..0.960


Net CF at user’s meter…………………………………………………………………….0.296


As a result of the above losses, the average CF of 0.360 at the wind turbine is reduced to about 0.296 at the user’s meter, for a 17.9% loss!! This compares with a US grid loss of 6.7%, on an A to Z basis.

Clayton Handleman's picture
Clayton Handleman on Feb 13, 2014




Clayton Handleman's picture
Clayton Handleman on Feb 14, 2014

Found something, not as detailed as I would like but based on an operating system –

They say that for 1000km line 500kV, 3GW they are seeing 5.8% line loss and 1.3% conversion loss.


Clayton Handleman's picture
Clayton Handleman on Feb 14, 2014

“Is that for AC or DC line?”

There is a hyperlink to the paper.  Keep me honest, check it out to make sure you believe it.

“Make sure to check if ALL A to Z steps are included, i.e., from wind turbine to user’s meter.”

I hope to have time.  At this point I think your 17% conclusion is pretty much demonstrated to be a SWAG and your conclusions based upon it are not on such solid ground.




Clayton Handleman's picture
Clayton Handleman on Feb 14, 2014

“Does the voltage up come before the AC/DC conversion, or after?”

Its a good question.  This group of ABB papers is the most informative I can find on the topic online so far.  Maybe Roger Faulkner will jump in.



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Thank Willem for the Post!
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