How Green is Green?
Comparing the Environmental Impacts of Wind Power and Coal Power
Robert E. Beauford, April 16, 2011
Technological change to more sustainable technologies does not eliminate the need for ongoing environmental responsibility. Any form of power generation will involve compromises with the environment. Facilities require a physical area of land upon which to be erected, metals and other construction materials with which to be assembled, materials to build and maintain wires for power distribution, and so on. This is true regardless of the fundamental technology employed. In order to better understand both the environmental costs and benefits of a post carbon energy infrastructure, a quantitative comparison of the environmental impacts of coal and wind power generation was undertaken. The specific question addressed is as follows: ‘When compared in real human health and environmental terms, how beneficial is the change to wind power versus traditional coal based power generation?’ In addition, this study examines the question ‘Is wind power a realistic answer to future electrical energy needs?’
Wind power generation has been an economically viable alternative to more historically dominant electrical generation processes since the mid to late 1990’s. In the few years since the beginning of its expansion in the marketplace, wind energy has emerged as not only the fastest growing ‘green’ energy technology, but as the fastest growing technology within the energy sector as a whole, including traditional sources. In just a few years, it has grown to represent almost 2 ½ percent of global power consumption, and has been doubling in installed generation capacity about every 3 years.2
Coal power, by contrast, is the oldest and currently largest electrical power generation technology employed at an industrial level today. Coal provided about 54% of US electrical power in 2009, and is the single largest air polluter in the US.1
2. Scope of Comparison
The intention of this study was to examine the environmental impact of each technology in an operational phase. As a result, only brief and sporadic attention has been given to ‘setup’ costs of generation facilities. The focus is on ongoing resource consumption, emissions, and environmental and human impacts during the operational, or power generating, phase of the facilities for each technology. Regional scope is primarily limited to the US, due to the ready availability of data. This introduces some possibly non-negligible biases, since emissions standards, age of generation facilities, installed emissions controls, and employed technologies may vary substantially for different world regions. The differences were not examined. Also, despite the assumption of basic equivalence in facility maintenance, setup, and so on in this survey, facility construction cannot truly be equated for coal and wind power generation facilities. Coal power plants require an entire mine infrastructure, railroad facilities, and substantial water supply infrastructure in addition to actual power generation facilities.
For purposes of comparison, a ‘typical’ coal fired electrical power generation facility will be assumed to be a 500 megawatt (MW) coal plant. This is not accurate in terms of actual average output of generation facilities in the US, but is an accepted and consistent norm in all literature that was reviewed. There were, as of 2010, 594 operating coal power plants in the US.3 They range in capacity from less than 100 MW to about 3000MW, though the largest of these represent a very small number of plants.4 The average capacity of US coal fired power plants is about 667MW, or about 1/3 larger than the ‘typical’ plant used for comparative purposes.5,6
There are, as of yet, no ‘typical’ wind power plants. Most are in the 100MW to 800MW range. A 20 thousand megawatt facility has been proposed and is in the initial phases of construction in China. Wind power projects, called ‘wind farms’ are often unit scalable, and unlike coal fired power stations, may be expanded slowly and steadily over time.
Ongoing Consumable Inputs
A typical coal fired power generation facility requires the annual availability of about 2.2 billion gallons of water.1 Coal power generation is the second largest consumer of water in the US, following only agriculture in demand.7 In addition, a plant requires about 1.4 million tons of coal to remain in operation, and will require approximately permanent storage for about .14 million tons of toxic solid non-combustible wastes.1,8 A substantially larger permanent storage location is required per year for the deposit of up to 14 million tons of overburden removed in order to gain access to fuel. This last number is highly variable, ranging from as little as a few million tons to well over 25 million tons of waste rock per plant per year.
Wind power has no ongoing consumable inputs beyond facility maintenance.
CO2 Greenhouse Gas Emissions
Typical U.S. coal fired power plants annually emit about 3.7 million tons of CO2 each,1 not including emissions form mining or transport of fuel. This is the largest single industry source of greenhouse gas emissions, both in America and in the world. Globally, coal combustion generates about 20% of all CO2 emissions, and in America it represents over 20% of all greenhouse gas emissions combined.9 If mining and transport emissions are combined with power generation emission, the US figure is closer to 30% of total greenhouse gas emissions.10
Wind power generation produces no CO2 or other greenhouse gas emissions.
Acid Gas Emissions
About 10,000 tons of sulfur dioxide are produced by each typical U.S. coal fired power plant each year, as well as substantial quantities of hydrogen chloride, hydrogen fluoride, and other acid gasses.1 Coal power generation is responsible for about 65% of all US sulfur dioxide emissions.11 SO2 and other acid gasses not only contribute to acid rain, but also directly attack respiratory health, damaging lung tissue and increasing the likelihood of both lung and heart disease.12 In China, the World Bank has estimated that over 50,000 annual deaths are directly attributable to coal power generation, out of about 650,000 deaths attributed to pollution, and that over 400,000 new cases of chronic bronchitis are directly attributable to acid gas and particulate coal plant emissions.13 In the US, though the majority of coal power plants still employ no acid gas reduction technology, SO2 emissions have substantially declined since the early 1980s, largely due to the elimination of high sulfur coal as generation fuel.14 This reduction illustrates the effectiveness of Federal environmental enforcement in protecting public health, and encourages more of the same.
Wind power generation, by contrast, produces no acid gas emissions.
Airborne Particulate Emissions
A typical US coal fired power plant emits about 500 tons of small airborne particles annually.1 These particles, which are primarily composed of unburned or non-combustible remnants of power plant fuel, can be transported substantial distances by wind. Because many of these particles are small enough to pass directly into the bloodstream through the lungs, the effects on public health can be significant.15 In addition to substantially elevated incidence of chronic bronchitis, asthma, and heart attacks (38,000/year), between 23,000 and 30,000 annual US deaths are attributable to these particulate coal emissions.15,16,17 The cumulative negative health effects of coal particulate emissions is roughly quantifiable in terms of hospital admissions (21,850 per year), emergency room visits (26,000 per year), and lost work days (3,186,000 per year).15 In addition, ‘black carbon,’ which is largely coal power plant particulates, has emerged as a substantial climate change factor, and is contributing substantially to global ice mass loss due to a lessening of reflectivity of glaciers and ice sheets.18
Wind power generation results in no measurable particulate emissions. Large fragments of windmill blades, however, are occasionally lost and flung for appreciable distances. This is primarily due to people shooting at them.
Nitrogen Oxide (NO(x)), Carbon Monoxide, Hydrocarbons, and Other Toxic Emissions
A typical US coal fired power plant annually produces 10,200 tons of nitrogen oxide, 720 tons of carbon monoxide, 220 tons of hydrocarbons, and 76 other known toxic air pollutants not previously mentioned in this report.1,19 Overall air pollution from coal plants is greater than from any other industrial source.19 Interactions between many of these chemicals are poorly or not at all understood. Nitrogen oxide emissions from a single plant are equivalent to the annual output from 500,000 modern cars.1 Coal power is the second largest nitrogen oxide emitter in the US after automobiles. NO(x) emissions damage lung tissue directly and are a major contributor to the formation of ozone, which causes further respiratory illness.20,21 It should be noted that the formation of near surface ozone as a pollutant is entirely bad for people and the environment, and does nothing to replace or contribute to the upper atmospheric ozone upon which we depend for existence on this planet.
Wind power generation produces no nitrogen oxide or related emissions.
Mercury, Heavy Metals and Radionuclides
US coal fired power plants are the largest contributors to mercury pollution in the nation24,25, producing about 170 pounds of airborne mercury per typical plant per year.1 Very low levels of mercury exposure produces significant negative health effects in children exposed during fetal development, infancy, or early childhood. A single event of exposure to relatively small levels of mercury can produce a lifetime drop in IQ of 5 points. Researchers have found blood concentrations of mercury adequate to pose a significant threat to infants in about 1 out of every 6 US women.22,23,24 In addition to mercury, coal power plants emit significant quantities of arsenic, lead, cadmium, and several other dangerous metals.26,27 While 225 lbs. of arsenic emitted annually from a typical coal power plant may seem an insignificant amount, exposure to only 50 parts per billion of arsenic in drinking water has been found to produce cancer in 1 out of 100 people.27
It is interesting to note that a single typical US coal fired electric power plant also emits an amount of uranium and thorium that is roughly equivalent to the airborne emission from all US nuclear power plants combined. Surprisingly, this amount is still so close to background radiation levels that no resulting health risk has been documented.28,8
Wind power generation produces no heavy metal or radionuclide emissions.
Ensuring a Fair Comparison
In order to be sure that this is a fair examination of the comparative environmental impacts of coal and wind power generation, examination of the specific suspected negative environmental impacts of wind power generation should also be undertaken. A substantive search of existing literature produces only two accusations of negative environmental or health impacts from wind power generation. These, along with some of the known impacts of coal power generation are listed below. The following two section will address these wind related issues: affects on wildlife, and affects on communities adjacent to the generation facilities.
Coal Power, Environmental Problems
Effects on Wildlife (Including Birds and Bats)
Effects on wildlife, from coal power generation, are widespread and profound. Along with 2.2 billion gallons of water drawn in to the typical US coal plant each year, comes about 21 million fish eggs and juvenile fish which are destroyed. As many as 1.5 million adult fish are trapped against intake screens, though many of these survive the experience.1 Fuel production, through coal mining, is astoundingly destructive to the landscape and to habitat. Uncounted wildlife of all types are destroyed.30,31 Unlike most human activities that damage or reduce carrying capacity of a habitat area, when it is said that habitat is ‘destroyed’ by surface mining for coal, the phrase is truly accurate. In West Virginia, a common method of accessing and mining coal is referred to as ‘mountain top removal and valley fill.’32,33 The process is exactly what it sounds like, and has resulted, in that state alone, in the destruction of about 300,000 acres of hardwood forest and over 1000 miles of streams.33 The same particulate emissions, heavy metals, and acid precipitation that negatively affect human health also kill or injure insects, plant life, fish and other aquatic life, birds, and mammals.30,31 The total annual U.S. loss in terms of animal, fish, and bird life due to coal power generation has not been clearly quantified, but is unquestionably in the high millions.
Wind power has been criticized for contributing to the deaths of birds. Several scientific studies have been done on this issue, and the results confirm that this is a problem, though a minor one.34,35 The results should be understood within the context of overall bird mortality rates. The highest estimates of US bird kills due to impacts with windmill blades falls around 60,000 individuals. Bat deaths may be as high as 3 times this number. Most studies estimate 1/10th to ½ of this figure, or about 6,000 to 30,000 individuals. By contrast, coal and gas extraction are estimated to kill between 30 and 40 million birds each year. Impacts with electric lines kill about 174 million, pesticides kill about 67 million, legal hunting kills over 100 million, cars kill about 100 million, and domestic cats kill well over 100 million.36,37
Noise and Health Effects on Communities Adjacent to Generation Facilities
Communities in the immediate vicinity of coal mining and power generation facilities have been well studied in order to understand the health impacts of the industry. Unfortunately, these communities, which provide the most to the coal power industry, share a disproportionate percentage of the negative impacts that come from the process. Coal industry communities show substantial percentage increases in kidney disease41,43, heart disease 41,43,45, chronic obstructive pulmonary disorder and other lung diseases38,41,43,45, hypertension41,43,45, asthma38,45, lung cancer 38,44,45, infant mortality38, cerebral vascular disease45, and possibly other cancers and diabetes mellitus38,45.
Wind power generation has a cleaner health record. Some residents of communities immediately adjacent to wind power generation facilities have reported feelings of stress or annoyance in response to the ‘swishing’ sound from the generator blades. While these feelings may be valid, studies comparing these populations with control groups in surrounding areas have consistently found that the percentage of annoyed and stressed persons does not exceed the background levels of annoyed and stressed people in the overall regional populations.39,40
4. Discussion and Implications of the Present Results
A fact based comparison between the environmental and health impacts of wind versus coal powered electrical generation leaves little doubt that wind power is astoundingly cleaner, healthier, better for the environment, and that it contributes less to global climate change. Questions have been repeatedly raised, however, regarding the practicality of wind as a large scale source of electrical power, and misconceptions dominate the public dialogue. Several of these misconceptions need to be remedied.
Since the mid-1990s, wind power generation has taken enormous leaps forward, both in technology and application. First, the effectiveness of individual windmills is increasing. 600 to 750 kilowatt generators have been largely replaced, in modern installations, by 3 megawatt generators. 10 megawatt generators are already in existence, and are soon to be employed in significant numbers in offshore wind farms. It is reasonable to expect that further technological increases will emerge. Secondly, the world community’s understanding of the requirements and potentials of wind power generation has expanded dramatically with the ongoing incorporation of large scale wind generation facilities in to national power grids. There are far fewer unknowns in 2011 than there were in 1998.
82 nations now have active wind power generation programs, and the technology has grown to supply about 2.5% of the world’s electrical power demands.46 Wind power is the fastest growing electrical generation technology on the planet, and installed generating capacity is doubling about every 3 years. Many predictions, both from inside the wind power industry and from outside sources, suggest that wind power will supply about 20% of US power consumption by 2030, and may represent between 20 and 30% of overall global power supplies by that date.47,51 Several countries, including Denmark, Spain, Portugal, and Ireland, are well beyond the US in terms of percentage of power generated from wind. Experience in these countries has established, not only that intermittency, or variation in wind speed and availability, does not affect the utility of wind power generation in a modern power grid, but also that a modern power grid can absorb the replacement of 20% or more of overall electrical generation capacity by wind power without any substantial restructuring or compensation for regional flux.48,49,50
Aggressive development of wind technology is proceeding around the world. Various European institutions have begun earnest exploration of the necessities for building a power grid that is composed entirely of integrated renewable sources, and China has committed to truly vast wind projects that are expected to supply an unparalleled amount of emission free renewable energy.
Taking into account the various recent advances in technology, rapid global expansion and success in applying the technology, and the level of future commitment expressed by world governments for this sustainable technology, it is very likely that wind power will represent 30% or more of global power generation within the first half of the 21st century.
1 Union of Concerned Scientists, Coal vs. Wind, 2009 (April 2011), web site http://www.ucsusa.org/clean_energy/coalvswind/c01.html
2 World Wind Energy Association, World Wind Energy Report 2009 (April 2010), web site http://www.wwindea.org/home/index.php
3 U.S. Energy Information Administration, Count of Electric Power Industry Power Plants, by Sector, by Predominant Energy Sources within Plant, Report Revised April, 2011 (April 2011) website http://www.eia.doe.gov/cneaf/electricity/epa/epat5p1.html
4 MIT Energy Initiative, Largest Coal-Fired Power Plants of Top Coal-Based U.S. Electric Utilities (April, 2009), web site http://web.mit.edu/mitei/docs/reports/table-plants.pdf
5 Energy Justice Network, FACT SHEET: “Clean Coal” Power Plants (IGCC), April 2007 (April, 2011) web site http://www.energyjustice.net/files/coal/igcc/factsheet-long.pdf
6 U.S. Energy Information Administration, Form EIA-860 Database, Report revised January 4, 2011 (April 2011) web site http://www.eia.doe.gov/cneaf/electricity/page/eia860.html
7 Center for Media and Democracy, SourceWatch, Water consumption from coal plants, Modified January 31, 2011 (April, 2011) web site http://www.sourcewatch.org/index.php?title=Water_consumption_from_coal_plants
8 United States Geological Survey, Fact Sheet FS-163-97, Radioactive Elements in Coal and Fly Ash: Abundance, Forms, and Environmental Significance, October, 1997 (April 2011) web site http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html
9 Pew Center on Global Climate Change, Coal and Climate Change Facts (April, 2011) web site http://www.pewclimate.org/global-warming-basics/coalfacts.cfm
10 U.S. Environmental Protection Agency, INVENTORY OF U.S. GREENHOUSE GAS EMISSIONS AND SINKS: 1990-2009, April 2011 (April 2011) web site http://epa.gov/climatechange/emissions/downloads11/US-GHG-Inventory-2011-Complete_Report.pdf
11 Center for Media and Democracy, SourceWatch, Sulfur Dioxide and Coal, Modified January 12, 2011, (April 2011) web site http://www.sourcewatch.org/index.php?title=Sulfur_dioxide_and_coal
13 The World Bank, Environment in East Asia and Pacific, Air Quality Management, 2011 (April 2011) web site http://go.worldbank.org/YN2QSMAF60
14 U.S. Environmental Protection Agency, Air Trends, Sulfur Dioxide, December 17, 2010 (April 2011) web site http://www.epa.gov/airtrends/sulfur.html
15 Abt Associates, The Particulate-Related Health Benefits of Reducing Power Plant Emissions, October 2000 (April 2011) web site http://www.abtassociates.com/reports/particulate-related.pdf
17 Lockwood A. H., Welker-Hood K., Rauch M., Gottlied B., Physicians for Social Responsibility, Coal’s Assault on Human Health, November, 2009 (April 2011) web site http://www.psr.org/resources/coals-assault-on-human-health.html
18 University of Iowa - Health Science, ScienceDaily, Black Carbon Implicated in Global Warming, 30 Jul. 2010. (April 2011) http://www.sciencedaily.com/releases/2010/07/100729144225.htm
19 The American Lung Association, Toxic Air: The Case for Cleaning Up Coal-fired Power Plants, March, 2011, (April 2011) web site http://www.lungusa.org/assets/documents/healthy-air/toxic-air-report.pdf
22 Mahaffey K., Cliffner R. P., and Bodurow C., National Institute of Environmental Health Sciences, Environmental Health Perspectives, 112(5): 562-570, Blood Organic Mercury and Dietary Mercury Intake: National Health and Nutrition Examination Survey, 1999 and 2000, November 19, 2003 (April 2011) web site http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.6587
23 Agency for Toxic Substances and Disease Registry, Center for Disease Control, Toxicological Profile for Mercury, March, 1999 (April 2011) web site http://www.atsdr.cdc.gov/ToxProfiles/tp46.pdf
24 National Wildlife Federation, Mercury Pollution from Coal-fired Power Plants, (April 2011) web site http://www.nwf.org/en/GlobalWarming/PolicySolutions/~/media/PDFs/Global Warming/Policy-Solutions/NWF Mercury Fact Sheet FINAL.ashx
26 U.S. Environmental Protection Agency, News Releases from Headquarters, EPA Proposes First National Standard for Mercury Pollution from Power Plants / Mercury and air toxics standards represent one of strongest health protections from air pollution since passage of Clean Air Act, March 16, 2011 (April 2011) web site http://yosemite.epa.gov/opa/admpress.nsf/bd4379a92ceceeac8525735900400c27/55615df6595fbfa3852578550050942f!OpenDocument
28 Gabbard A., Oak Ridge National Laboratory, Coal Combustion, Nuclear Resource or Danger, February 5, 2008 (April 2011) web site http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html
29 (reference deleted)
31 National Wildlife Federation, Poisoning Wildlife, The Reality of Mercury Pollution, September, 2006 (April 2011) web site http://www.nwf.org/nwfwebadmin/binaryVault/PoisoningWildlifeMercuryPollution1.pdf
32 Wake Forest University, Science Daily, Mountaintop mining poisons fish. March 1, 2011 (April 2011) web site http://www.sciencedaily.com/releases/2010/02/100226214742.htm
33 PBS, Independent Lens, Razing Appalachia, Mountaintop Removal Mining: The Facts, May 14, 2003 (April 2005) web site http://www.pbs.org/independentlens/razingappalachia/mtop.html
34 offshorewind.Biz, Wind Turbines and Birds Might Mix, March 30, 2011 (April 2011) web site http://www.offshorewind.biz/2011/03/30/wind-turbines-and-birds-might-mix-usa/
36 U.S. Department of Agriculture, Wildlife Damage Management, Table G. Animals Taken by Wildlife Services - FY 2009, (April 2011) web site http://www.aphis.usda.gov/wildlife_damage/prog_data/2009_prog_data/PDR_G_FY09/Basic_Tables_PDR_G/Table_G_FY2009_Short.pdf
38 Hart J. T., National Institute of Health, Pub Med Central, The Health of Coal Mining Communities, 1971 (April 2011) web site http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2156484/pdf/jroyalcgprac00261-0018.pdf
39 Ontario Ministry of Health and Long-Term Care, Ministry Reports, The Potential Health Impact of Wind Turbines, May 20, 2010 (April 2011) web site http://www.health.gov.on.ca/en/public/publications/ministry_reports/wind_turbine/wind_turbine.pdf
40 Colby W. D., Dobie R., Leventhall G., Lipscomb D. M., McCunney R. J., Seilo M. T., Wind-Turbine Sound and Health Effects: An Expert Panel Review, December, 2009 (April 2011) web site http://www.windturbinesyndrome.com/img/WindTurbineNoise.pdf
41 West Virginia University Health Sciences Center, ScienceDaily, Chronic Illness Linked To Coal-mining Pollution, Study Shows, March 27, 2008 (April, 2011) web site http://www.sciencedaily.com/releases/2008/03/080326201751.htm
42 (reference deleted)
43 Hendryx M., Ahern M. M., Am J Public Health, 98(4):669-71, Relations between health indicators and residential proximity to coal mining in West Virginia, April, 2008; epub Feb 28, 2008.
44 Hendryx M, Fedorko E, Anesetti-Rothermel A. Geospat Health, 4(2):243-56, A geographical information system-based analysis of cancer mortality and population exposure to coal mining activities in West Virginia, United States of America. May, 2010.
45 Physicians for Social Responsibility, Coal’s assault on human health, November 2009, (April 2011) web site http://www.psr.org/resources/coals-assault-on-human-health.html
46 World Wind Energy Association, World Wind Energy Report 2009, March, 2010 (April 2011) web site http://www.wwindea.org/home/images/stories/worldwindenergyreport2009_s.pdf
47 U.S. Department of Energy, National Renewable Energy Laboratory, DOE/GO-102008-2567, 20% Wind Energy by 2030, July 2008 (April 2011) web site http://www.nrel.gov/docs/fy08osti/41869.pdf
48 Sinden G., Environmental Change Institute, Oxford University Centre for the Environment, Characteristics of the UK wind resource: Long-term patterns and relationship to electricity demand, in press (April 2011) web site http://www.eci.ox.ac.uk/publications/downloads/sinden06-windresource.pdf
49 McMillen S., Wind Power is Not Intermittent, March, 2009 (April 2011) web site http://www.recombinantrecords.net/docs/2009-03-Wind-Power-Is-Not-Intermittent.html
50 Kutscher C.F., American Solar Energy Society, Tackling Climate Change in the U.S., January, 2007 (April 2011) web site http://ases.org/images/stories/file/ASES/climate_change.pdf
51 U.S. Energy Information Administration, Summary Statistics for the United States, 1998 through 2009, Report Revised April, 2011 (April 2011) website http://www.eia.doe.gov/cneaf/electricity/epa/epates.html