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-well-connected 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 POWER 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%3ABlogPost%3A3650&xgs=1&xg_source=msg_share_post

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

 

Operation and Maintenance

 

According to the European Wind Energy Association: "Operation and maintenance costs constitute a sizable share of the total annual costs of a wind turbine. For a new turbine, O&M costs may easily make up 20-25 percent of the total levelized cost over the lifetime of the turbine." 

 

Power Used by the Turbine (Parasitic Power)

 

Parasitic power is the power used by the wind turbine itself. During spring, summer and fall it is a small percentage of the wind turbine output. During the winter it may be as much as 10-20 % of the wind turbine output. Much of this power is needed whether the wind turbine is operating or not. At low wind speeds, the turbine power output may be less than the power used by the turbine; the shortfall is drawn from the grid. 

 

Two little-wind days were selected; a summer day and a cooler winter day to show that in summer the parasitic power is less than in winter. In winter, the wind speed has to be well above 4.5 m/s, or 10.7 miles/hour, to offset the parasitic power and feed into the grid. Speeds less than that means drawing from the grid, speeds greater than that means feeding into the grid. 

 

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

 

14 May, 2010, wind speed 2.9 m/s (6.9 miles/hour), net power output  -0.3 kW.

20 Nov, 2010, wind speed 4.5 m/s (10.7 miles/hour), net power output -5.6 kW.

 

Below is a representative list of equipment and systems that require electric power; the list varies for each turbine manufacturer.

 

- rotor yaw mechanism to turn the rotor into the wind

- blade pitch mechanism to adjust the blade angle to the wind

- lights, controllers, communication, sensors, metering, data collection, etc.

- heating the blades during winter; this may require 10%-20% of the turbine's power

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

- 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 POWER A DISMAL FAILURE?

 

In the New England, the Jeminy Peak Ski Area was the first to have a wind turbine; its wind turbine is a 1,500 kW unit made by GE. The Bolton Valley Ski Area decided to be the first in Vermont to have a wind turbine. It decided to have a 100 kW wind turbine made by Northern Power Systems, Barre, Vermont. The purpose was to generate power and, by selecting a Vermont wind turbine, it would likely be favorably considered for a Clean Energy Development Fund subsidy. 

 

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/yr

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

 

Actual power production after 17 months (1.4 yr) 204,296 kWh from October 2009 to-date

Actual capacity factor for 17 months = 204,296 kWh/1.4 yr/(100 kW x 8,760 hr/yr) = 0.17; a shortfall of 50%

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

 

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

 

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 windspeeds, minus parasitic losses which appear to be about 11-12 kW at temperatures below 32F. May be the windspeed indicator reads high. Adding in some weeks of down-time 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 may have 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. Jeminy Peak appears to have made a better decision with its 1,500 kW turbine from GE.

 

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 about $2,000/kW and O&M costs are not high.

 

In New England much greater subsidies will be required to make wind power pay because there are few areas on suitable ridgelines with capacity factors greater than 0.35 and capital costs, based on Maine wind farms, are about $2,500/kW, or greater, O&M costs 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: 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_CF2008-2010_final.jpg

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

 

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

 

The reality, after installation:

 

Installed capacity, MW: 1035.5 in 2008; 1,274 in 2009: 1,274 in 2009; 1,348 in 2010

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

Capacity factors: 14.1% in 2008; 18.9% in 2009; 22.7% in 2010

 

Because no wind turbines were added during 2010, the 22.7% capacity factor of 2010 is the best proof of the lack of performance of the New York State wind turbine facilities.

 

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_reference_documents/2011_GoldBook_Public_Final.pdf 

 

This reality is not unique to NY State. It has replicated itself in The Netherlands, Denmark, England, Germany, Spain, Portugal, Ireland, etc. 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-reduces-co2-emissions-few-percent

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

 

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-wind-turbine-facility-vermont

 

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.

 

http://www.canada.com/technology/Northern+Brunswick+wind+turbines+frozen+solid/4286952/story.html

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

http://bjdurk.newsvine.com/_news/2009/01/26/2357728-wind-energy-is-not-reliable-according-to-ferc- 

http://www.cbc.ca/news/canada/prince-edward-island/story/2009/07/23/pei-wind-turbine-gearboxes.html

http://www.theglobeandmail.com/report-on-business/industry-news/energy-and-resources/why-peis-wind-plan-is-dying/article1752506/

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

 

EXAMPLE: EXPENSIVE POWER FROM WIND FACILITY IN LONG ISLAND SOUND

 

Cape Wind Associates, LLC, plans to build and operate a wind facility on the Outer Continental Shelf offshore of Massachusetts. The wind facility would have a rated capacity of 468 MW consisting of 130 turbines @ 3.6 MW each made by Siemens AG, a German company, maximum blade height 440 feet, to be arranged in a grid pattern in 25 square miles of Nantucket Sound in federal waters off Cape Cod, Martha’s Vineyard, and Nantucket Island. 

 

The Massachusetts Department of Public Utilities approved a 15-yr power purchase agreement, PPA, between the utility National Grid and Cape Wind Associates, LLC. National Grid agreed to buy 50% of the wind facility’s power starting at $0.187/kWh in 2013 (base year), escalating at 3.5%/yr which means the 2028 price to the utility will be $0.313/kWh. The project is currently trying to sell the other 50% of its power so financing can proceed; so far no takers, because significant quantities of less expensive power from other renewables is available.

 

A household using 618 kWh/month will see an average wind power surcharge of about $1.50 on its monthly electric bill over the 15 year life of the contract; if the other 50% of power is sold on the same basis, it may add another $1.50 per month. Tens of thousands of households and businesses will all be chipping in to make the owners of Cape Wind Associates richer.

 

Power production is estimated at 468 MW x 8,760 hr/yr x CF 0.39 = 1.6 GWh/yr. 

The capital cost is estimated at about $2.0 billion, or $4,274/kW. Federal subsidies would be 30% as a grant.

 

http://green.blogs.nytimes.com/2010/12/09/wind-farm-would-link-northeastern-grids/

http://www.southcoasttoday.com/apps/pbcs.dll/article?AID=/20101123/NEWS/11230310

http://theenergycollective.com/brighterenergy/47584/america-moves-step-closer-its-first-offshore-wind-farm

http://www.env.state.ma.us/dpu/docs/electric/10-54/73010tntst.pdf

http://www.nrel.gov/docs/fy10osti/40745.pdf

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

http://finance.yahoo.com/news/Wanted-Buyer-for-apf-120662485.html?x=0&sec=topStories&pos=1&asset=&ccode=

 

EXAMPLE: RESIDENTIAL WIND POWER 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. 

 

EXAMPLE: ACCOMMODATING GRID POWER FAILURES

 

If grid power fails, then a wind turbine can provide its own parasitic power of there is enough wind. Three conditions are described: 

 

No-wind and Little-wind Conditions, Wind turbines are not operating or are turning on grid power: 

 

If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, especially in winter, as described above.

 

Medium Wind Conditions, Wind turbines are operating: 

 

If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, as described above. Wind turbines may not be allowed to feed into the grid, but may be operated to supply only parasitic power.

 

Too-high Wind Conditions, Blades are feathered, rotor is locked and facing the wind: 

 

If a grid power failure, emergency back-up power (batteries or diesel-generator) is needed to provide parasitic power, as described above.

 

EXAMPLE: GERMAN SOLUTION FOR LOW-WIND CONDITIONS

 

Germany is very marginal for wind power, especially in the south. its national average wind power CF is 0.167, lower than the Netherlands (0.186) and Denmark (0.242).

 

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. 

 

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 10-20% less, say 15% less, due to parasitic power, O&M outages, etc. 

Unit power cost = $1,845,280/22,500,000 kWh/yr/0.85 = 0.082/kWh, excludes O&M of about 0.015/kWh and insurance and risk premium, i.e., making a profit.

 

The cost of baseload power in Germany is about $0.055/kWh, which means the Hof District wind power in Bavaria is at least $0.097/$0.055 x 100 = 76% higher than grid prices; if making a profit is included the percentage will be higher.    

 

A technical success? Maybe. An economic success? No. 

 

EXAMPLE: POWER PLANT CYCLING IN COLORADO AND TEXAS

 

Because the NEEG has very minor wind power penetration, there would be no data to study fuel consumption and CO2 emissions related to cycling plants to accommodate wind power, as there are in other jurisdictions. Accordingly, a recent study of Colorado and Texas, both states with significant wind facilities, would be used to illustrate some impacts of wind power on plant operations.

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

 

Power Plant Cycling In Colorado  

 

Public Service of Colorado, PSCO, lacks sufficient gas-fired CCGT capacity for cycling to accommodate wind power. Instead, it is attempting to use coal plants for cycling for which they were not designed and for which they are highly unsuitable. The results have been significantly increased pollution and CO2 emissions per kWh.

 

Fuel consumption in Btu/kWh is called heat rate; for a coal plant operated near rated output it is about 10,500 Btu/kWh for power delivered to the grid. It is lowest near rated output and highest at very low outputs. If a plant is ramped up and down (cycled) at a percent of rated output, its heat rate rises. See Pages 26, 28, 35, 41 of the Bentek study.  

 

On Page 28, the top graph covering all PSCO coal plants shows small heat rate changes with wind power during 2006. The bottom graph shows greater heat rate changes with wind power during 2008, because during the 2006-2008 period 775 MW of wind capacity was added. For the individual PSCO plants doing most of the cycling, the heat rate changes are much higher. 

 

On Page 26, during a coal plant ramp down of 30% from a steady operating state to accommodate state-mandated “must take” wind power, the heat rate rose at much as 38%.

 

On Page 35, during coal and gas plant ramp downs, the Area Control Error, ACE, shows significant instability when wind power increased from 200 to 800 MW in 3.5 hours and decreased to 200 MW during the next 1.5 hours. The design ramp rates, MW per minute, of some plants were exceeded.

 

On Page 41, during coal plant cycling across the PSCO system due to a wind power event, emissions, reported to the EPA for every hour, showed increased emissions of 70,141 pounds of SOX (23% of total PSCO coal emissions); 72,658 pounds of NOX (27%) and 1,297 tons of CO2 (2%) than if the wind power increase had not caused the plants to be cycled. 

 

Those increases of CO, CO2, NOX, SOX and particulate per kWh are due to instabilities of the combustion process during cycling; the combustion process can ramp up and down, but not too rapidly. As the varying concentration of the constituents in the flue gases enter the air quality control system it cannot vary its chemical stoichiometric ratios quickly enough to remove the SOX below EPA-required values. These instabilities persist well beyond each significant wind event. 

 

PSCO does not release hourly wind generation data. Such baseline information is critical for any accurate analysis and comparison of alternatives to reduce such emissions; deliberately withholding such information is inexcusable.

 

Power Plant Cycling In Texas

 

The Texas grid in mostly independent from the rest of the US grids; the grid is operated by ERCOT. The grid has the following capacity mix: Gas 44,368 MW (58%), Coal 17,530 MW (23%), Wind 9,410 MW (12% - end 2009), Nuclear 5,091 MW (7%). Generation in 2009 was about 300 TWh. By fuel type: Coal 111.4 TWh, Gas CCGT 98.9 TWh, Gas OCGT 29.4 TWh, Nuclear 41.3 TWh, Wind 18.7 TWh.  Summer peak of 63,400 MW is high due to air conditioning demand. 

 

Wind provides 5% - 8% of the average generation overall, depending on the season. Its night contribution rises from 6% (summer) to 10% (spring). Texas capacity CF = 18.7 TWh/yr/{(9,410 + 7,118)/2) MW x 8,760 hr/yr)} = 0.258. Texas has excellent winds and should have a statewide CF of 0.30 or greater. Explanations for the low CF likely are:

 

- grid operator ERCOT requires significant curtailment of wind power to stabilize the grid. 

- vendors, developers and financiers of wind power, eager to cash in on subsidies before deadlines, installed some wind turbine facilities before adequate transmission capacity was installed to transmit their wind power to urban areas.

 

Much of the gas-fired capacity consists of CCGTs that are owned by IPPs which sell their power to utilities under PPAs. That capacity is not utility-owned and therefore not available for cycling to accommodate the more than 10,000 MW capacity of wind power. Instead, utilities are attempting to use coal plants for cycling for which they were not designed. The results have been significantly increased pollution and CO2 emissions.

      

Unlike PSCO, ERCOT requires reporting of fuel consumption by fuel type and power generation by technology type, including wind power, every 15 minutes. The 2007, 2008, 2009 data shows rising amplitude and frequency of cycling operations as wind penetration increased. In 2009, the same coal plants were cycled up to 300 MW/cycle about 1,307 times (up from 779 in 2007) and more than 1,000 MW/cycle about 284 times (up from 63 in 2007) from one 15-minute period to the next. The only change? Increased wind power penetration.

 

On Page 69:  The ERCOT cycling of plants to accommodate wind power produced results similar to the PSCO system; increased cycling due to wind power resulted in significantly more SOX and NOX emissions than if wind power had been absent. CO2 emission reductions due to wind power are minimal at best.  

 

Remedy for Colorado and Texas Cycling Problems

 

A way out is for PSCO and ERCOT is to retire older coal plants that have efficiencies of about 30% and emit about 2.15 lb of CO2/kWh and replace them with utility-owned, gas-fired CCGTs that have efficiencies of up to 60% and emit about 0.67 lb of CO2/kWh. The CCGTs have short installation periods and capital costs of about 1,250/kW. 

 

If wind were entirely absent, this measure would reduce the most CO2/kWh at the least $/kWh and would produce power at the least $/kWh. 

 

If some of the new units were cycled to accommodate wind power, their Btu, NOX and CO2 per kWh would increase, mostly offsetting the CO2/kWh reduction due to wind power, as shown above.

 

In addition their operation as cyclers would incur an additional owning cost, because their CFs would be about 0.70, instead of about 0.85 - 0.90 as base-loaded units, as shown above.

 

http://theenergycollective.com/willem-post/47519/base-power-alternatives-replace-base-loaded-coal-plants

http://theenergycollective.com/willem-post/46977/impacts-variable-intermittent-power-grids