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This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.

Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".

Thursday, May 5, 2011

Wind Energy: A Growing Source of Renewable Energy

Summary.  Wind energy plays a small but growing role in the world’s energy economy.  The European Union has the objective of reducing greenhouse gas emission by 80-95% by 2050.  China’s 12th Five Year Plan, covering 2011-2015, includes the goal of rapidly expanding its presently small wind generating capacity.  The United States, with no national energy policy currently in place, has several short term fiscal incentives to stimulate private development of renewable energy including wind energy.


The burning of fossil fuels is recognized as being a major contributor to the increase in man-made greenhouse gases accumulating in Earth’s atmosphere.  The United Nations-sponsored Intergovernmental Program on Climate Change and other organizations conclude that the increase in greenhouse gases leads to warming of the average global temperature, which is predicted to produce several adverse consequences impacting our life on the planet.

The world’s nations have gathered in conference to attempt unified responses to the threats posed by global warming.  The most recent was the Cancun conference in November 2010.  In response to the perceived problem, most nations have undertaken to slow the growth of atmospheric greenhouse gases, and even to achieve a leveling off of their concentration at a new, elevated, level.  This involves ambitious programs to reduce burning fossil fuels, and to substitute alternative sources of energy in their place.  One contribution to this endeavor is large scale development of wind power for generation of electricity.  Aside from the energy required to manufacture the wind turbines used and the transmission lines that carry the resulting electricity, wind power is deemed to have no emissions of greenhouse gases when operating.

In this post development of wind power is described in Europe, China and the U. S.

Wind World-wide

According to the Global Wind Energy Council, world-wide wind generating capacity for electricity is predicted to grow to a total of about 450 gigawatts (billion watts, GW; see Note 1) within 5 years, and to about 1,000 GW in 10 years (reported by BTM Consult ApS).   At present the world-wide generating capacity is almost 200 GW, which is 22.5% higher than in 2009.


The European Union (EU) has 27 member nations.  The European Commission, its executive body, issued its Roadmap for moving to a low carbon economy in 2050 (see the post) on March 8, 2011.  The goal set forth in the Roadmap is to reduce greenhouse gas emissions by 80 to 95% from the emission level of 1990, by 2050.  The Roadmap builds on an earlier EU initiative to reduce greenhouse gas emissions by 20% by 2020.  Achieving these objectives requires concrete policy decisions to be implemented in each of the member nations.  It envisions reductions in emissions of 1% per year until 2020, then 1.5% per year from 2020 to 2030, and finally 2% per year until 2050.  These should provide about 25% reduction in emissions by 2020, about 40% by 2030, and about 60% reduction by 2040.  This is shown in the following graphic.

Relative greenhouse gas emissions charted at 5 year intervals by economic sector.  Actual results shown through 2010; projected results thereafter.  The red line shows projected results using policies in place prior to the Roadmap.  The remaining projections include technologies and policies to be implemented under the Roadmap.  Source: European Commission, “A Roadmap for moving to a competitive low carbon economy in 2050” March 8, 2011

The Roadmap envisions major reductions in emissions coming from the electric power sector, by developing renewable sources including wind power.  Today all renewable sources for power generation in the European Union are already 45% of the total; the Roadmap envisions virtually 100% renewable power by 2050.
In the near term, the members of the EU have the goal of generating 21% of their electricity from renewable sources by 2010.  As seen in the graphic below, slightly less than half of non-hydro renewable electricity generation in 2005 was from wind energy.

Historical renewable electricity energy provided by sector in Europe, 1990-2005, Twh/yr (billion Kwh).
Purple, cross striped (narrow band at top): Offshore wind.
Purple, vertical stripes: On-shore wind.              Yellow: Solar photovoltaic cells.
Orange-brown cross striped: Geothermal electricity.
Gray cross striped: Biowaste.                 Green, dotted: Solid biomass.                Pink: Biogas.
Source: European Commission, Renewable Energy Road Map, 2007

Although most wind energy in Europe is land-based, off-shore wind energy projects are also being developed, mostly in the North and Baltic Seas.  A European transnational grid is being developed to connect these resources.


China recently released its 12th Five Year Plan, covering the years 2011-2015, including its plans for expanded energy production and use.   The five year plans are determined by the central government, and their implementation likewise is administered centrally. 

From 2010 to 2015, overall electric generating capacity will increase from about 1000 GW to about 1400 GW (see Note 1).  This increase includes a major and growing amount of generating capacity from coal, a very slight increase in hydroelectric generating capacity, and increases totaling about 1% of total capacity in 2010 to about 3% of total capacity in 2015, for renewable energy. 

According to a cited report from the Chinese Wind Energy Association, China is adding wind-generated electric power to its energy mix at a rapidly expanding pace, even as the share that wind generation contributes remains quite small.  At the present time, China’s total wind generating capacity is 45 GW.  It added 18.9 GW of new capacity in 2010, representing a 73% increase over the previous year.  Under the 12th five Year Plan covering 2011-2015, China plans to install 70 GW of new wind generating capacity by 2015, and for the following five year plan, 150 GW by 2020. 

Much of this new wind capacity is manufactured within the country.  Sinovel Wind Group Co. is a specialized enterprise that manufactures on-shore, off-shore and intertidal wind generators.  In 2010 it provided 4.4 GW of capacity, making it the largest wind manufacturer in China, and No. 2 in the world.  The company has subsidiaries placed in Spain, Australia, Canada, the U.S.A. and Brazil.

According to the International Energy Agency’s World Energy Outlook 2010, during the period 2008-2035 about 9% of newly added energy demand in China will be delivered by renewable sources other than hydroelectric, including wind.  However, as noted above, the majority of the increases remain fossil fuel-derived energy.

United States

The U. S. is the only major emitter of greenhouses in the world without a national energy policy in place.  The U. S. Environmental Protection Agency is in the process of preparing administrative rules governing emissions in an atmosphere of active political debate and concerted opposition from affected interests.   As of 2010 35 states and the District of Columbia have put renewable portfolio standards, mandates or goals in place, which would govern the role of renewable energy sources within their respective boundaries.  Since the various programs differ, and 15 states have no policy in place, this creates a disparate and confusing regulatory framework across the country.

As of 2009, the role of wind power in the generation of electricity (excluding transportation and building heating) is shown in the following graphic

It is seen that wind generation accounted for 1.7% of all electricity generation in the U. S., as of 2009.  (It is worth noting in passing that solar energy contributed a very small amount to electricity generation.)

According to the American Wind Energy Association, 35% of newly added generating capacity in the U. S. since 2007 is wind power.  The annual rate of increase in wind-based electricity generating capacity was 61% in 2008 and 28% in 2009.  The net summer electricity generating capacity in the U. S. is shown in blue in the following graphic.
Total wind energy generation (green line, left scale) and net summer generation capacity (blue bars, right scale) in the U. S. 1999-2009. Source: U. S. Energy Information Agency  

It is seen that installed power generating capacity (blue) and total energy generated from wind (green; see Note 1) are increasing rapidly.  Nevertheless, according to the U. S. Energy Information Agency (USEIA), wind generation constituted less than 1% of the total energy consumed in the U. S. in 2009.  Based on the average electricity usage per household in 2008, the total energy generated by wind in 2009, 73,700 million Kwh, would have been sufficient to supply the electricity needs of 6,700,000 households (see Note 2).  The wind energy generated in 2009 represents 5.4% of all residential electricity used
in the U.S. in 2009.

A projection by USEIA of generating capacity that may be installed in the coming years is shown below. 

Source: U. S. Energy Information Administration

Planned wind energy installations are shown in lavender.  It is seen that as of the date of preparation, 2009, wind facilities decrease significantly after 2011.  This may reflect the expiration of tax incentives explained below.  From the point of view of combating the emission of greenhouse gases, projected new installations fueled by fossil fuels (coal, red; and natural gas, orange) are much larger and highly significant.  Newly commissioned fossil fuel plants will continue in operation for several decades, making continued additions to the atmospheric burden of greenhouse gases each year.

The USEIA projects an increased role for renewable sources in the generation of electricity over the coming decades, increasing to 17% of overall electricity production by 2035 , up from 9% in 2008; wind power will be a major contributor to this growth.  A strong impetus for use of renewable sources is to contribute to the decarbonization of our energy economy.  This is viewed as a significant factor for minimizing the effects of global warming.  In general, the capital costs for installing renewable sources, including wind, are evaluated as being more costly than fossil fuel-driven sources.  Much of this cost comes from the fact that land areas in the U. S. that provide abundant sources of renewable energy, such as wind and solar power, are distant from the ultimate consumers, so that costly transmission lines must be built.  But balancing this initial outlay, the cost of operating the facilities is much lower once built, since no fuels need to be purchased.

These effects may be overcome by continuing to offer favorable tax credits for installing new renewable energy facilities.  The Federal Renewable Electricity Production Tax Credit has contributed to an eight-fold increase in wind energy production in the years  since 2001.  The Federal Energy Policy Act of 2005 provides interest-free financing to government entities intended for wind energy.  The USEIA projects that extending this credit beyond its expiry would have a significant favorable effect going forward.  Additional factors guiding installation of new renewable generation facilities are the Renewable Portfolio Standards or goals that many states have put in place, as well as marketable certificates for renewable energy that may be traded among providers.

The U. S. Energy Information Agency’s Annual Energy Outlook 2011 issued April 2011 presents a comprehensive analysis of U. S. Energy production and consumption foreseen through 2035.  Its Reference case is based on current policies and laws without assuming extension of provisions that expire at various points in time.  Its No Sunset case builds on the Reference case by assuming extension of favorable tax and other fiscal policies during the period of the analysis.  Its Extended Policies case includes the assumptions of the No Sunset case and adds to it the extension of current federal energy efficiency policies.

The following graphic presents historical and projected contributions to all forms of renewable energy other than hydroelectric power through 2035 under the Reference case.

Electricity generation from all renewable sources projected for the Reference case beyond 2009.
Source: U. S. Energy Information Agency: Annual Energy Outlook 2011

In the years immediately preceding and following the cutoff year 2009 the most significant increase occurs with wind-derived electricity generation (blue).  This sector then shows a sharp break at about 2012 and remains essentially constant thereafter.  This stark behavior is due to the fact that under the Reference case favorable tax credits expire at that time, as discussed above.

The following graphic shows projections for the total amount of renewable electricity generated under the Reference, No Sunset, and Extended Policies cases.  Beyond about

Total renewable electricity generation per year over 2005-2009 (historical data) and 2010-2035 (projection) under three cases.  The kilowatt-hours generated are higher than in the preceding graphic, presumably because hydroelectric power is included here.
Source: U. S. Energy Information Agency: Annual Energy Outlook 2011

2023 the No Sunset case, which includes extensions of favorable tax credits, leads to a significant increase in generation compared to the Reference case.  By 2035, considering electricity generation from all sources, the Reference case provides 14% whereas the No Sunset case provides 16%, displacing generation from fossil fuel-derived generation.  (The Extended Policies case falls below the No Sunset case because, it is proposed, its increased efficiencies lower the demand for electricity so that less needs to be  generated.)

On April 19, 2011 the U. S. Secretary of the Interior, Ken Salazar, approved construction of the first off-shore wind energy project in the U. S.  The project, by Cape Wind Associates, is to be installed in Nantucket Sound off the south coast of Massachusetts, and envisions 130 turbines arrayed across 25 square miles in the shallow waters of the Sound, generating up to 420 MW (0.42 GW) of power.  This should supply about 75% of the immediate region’s electricity needs. This project had previously gone through many years of environmental and permitting review at various levels of government.

Conclusion.  The perceived dangers accompanying increased atmospheric concentrations of greenhouse gases provide an impetus for the nations of the world to work toward an emissions-free energy economy.  The European Union, striving to attain 80-95% reductions by 2050, has significant wind energy installed, with plans to expand.  China, with a centralized economy, building on an initial small base, intends drastically to expand its wind energy generating capacity, while also expanding its fossil fuel-driven electricity generation.  The U. S., with no central energy policy in place, has short-term fiscal incentives to stimulate private development of wind energy; these incentives are not considered secure in the long term.  The disparate array of state renewable portfolio standards currently in place make it difficult for enterprises to plan and install new wind energy facilities.

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Note 1.  A watt is a unit of power, quantifying the rate at which energy is provided or consumed.  It is a small unit. 

A kilowatt (1,000 watts, Kw) is a more manageable unit of power.  10 100-watt light bulbs represent 1 Kw; an electric toaster would be 1-2 Kw.

Generating capacity is the rate at which an installation provides power, such as in millions of watts (megawatts, MW) or billions of watts (gigawatts, GW); please note these are watts, not kilowatts.

Energy is a measure of total work done, given by power x time and for electricity is watt-hours.  Again this is usually given in terms of kilowatt-hours, Kwh.  10 light bulbs burning for 1 hour would be 1 Kwh.

Note 2. According to the USEIA, in 2008 the average annual usage of electricity for a U. S. household was 11,040 kWh, with a state-by-state range of 6,200 (lowest) to 15,600 (highest).  The total residential electricity consumption in the U. S. in 2009 was 1,363 billion Kwh.  Commercial and industrial electricity usage is in addition to this amount.

© 2011 Henry Auer


  1. Hi! Keep it up! This is a good read. I will be looking forward to visit your page again and for your other posts as well. Thank you for sharing your thoughts about wind energy tax credits. I am glad to stop by your site and know more about wind energy tax credits.
    Opponents declare that by using RECs a customer can claim energy “reduction” even if they do not actually reduce their end-use at all - or even increase it. Proponents counter that more REC purchases drive increased production of renewable power which can replace conventional production.
    Despite this growing demand and support for renewable energy, a fragile economy, volatile commodity pricing, and the lack of national energy policy have combined to pave a challenging road for renewable energy advocates and stakeholders. Economies of scale and new manufacturing processes are making alternative energy production more competitive, but until it achieves parity through innovation or regulatory policy, the success of green energy companies may largely depend on their ability to optimize Green Energy and Cleantech tax incentives to attract investors and maintain sustainable balance sheets.

  2. Great article Henry! Wind energy has become a stable source of energy worldwide as its energy generating capacity continues to increase over the years. Although wind speed is not constant, improvements in technology lessens the variation of energy generated from wind power.

  3. Hi there! great stuff here, I'm glad that I drop by your page and found this very interesting. Thanks for posting. Hoping to read something like this in the future! Keep it up!

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