Electricity and the Environment

Electricity and the Environment

Although electricity is a clean and relatively safe form of energy to use, there are environmental impacts associated with the production and transmission of electricity. Nearly all types of electric power plants have some impacts or effects on the environment, some more than others.
The Two Coal-fired Power Plants of the Crystal River North Steam Complex in Crystal River, Florida

Source: Ebyabe, Wikimedia Commons author (GNU Free Documentation License) (Public Domain)
Hunter Power Plant, a Coal-Fired Power Plant South of Castle Dale, Utah

Source: Tricia Simpson, Wikimedia Commons author (GNU Free Documentation License) (Public Domain)
The United States has laws to reduce these impacts. Perhaps the most important such law is the Clean Air Act, which established regulations for the control of air emissions from most power plants. The Environmental Protection Agency (EPA) administers the Act and sets emissions standards for power plants through various programs, such as the Acid Rain Program. The Act has resulted in a substantial reduction of emissions of some of the major types of air pollutants in the United States.
The Impact of Power Plants on the Landscape
All power generators or plants have a physical footprint (the area where they are placed or located). Some can be located inside, on, or next to an existing building, so the impact of their footprint is very small. Most large power plants require clearing land to locate the power plant and any necessary fuel storage areas (in the case of hydro-power dams, a reservoir forms behind the dam). Some plants may also require the construction of access roads, rail, pipelines, transmission lines, and access to cooling water supplies or reservoirs.
Besides the physical footprint, many power plants are large physical structures that have impacts on the visual landscape. Some people may not like this especially where the landscape is relatively natural or pristine.
In general, the larger the area disturbed, the greater the real and potential impacts on the landscape.
Fossil Fuel-, Biomass-, and Waste-Burning Power Plants
In the United States, fossil fuels (mainly coal, oil, and natural gas), materials that come from plants (biomass), and municipal and industrial wastes are used to generate most of the electricity we use; about 70% in 2010. Emissions that result from the combustion of these fuels include:
Carbon dioxide (CO2)
Carbon monoxide (CO)
Sulfur dioxide (SO2)
Nitrogen oxides (NOX)
Particulate matter (PM)
Heavy metals such as mercury

Nearly all combustion byproducts have negative impacts on the environment and human health:
Carbon dioxide is a greenhouse gas and a source of global warming.1
SO2 causes acid rain, which is harmful to plants and to animals that live in water, and it worsens or causes respiratory illnesses and heart diseases, particularly in children and the elderly.
NOX contributes to ground level ozone, which irritates and damages the lungs.
PM results in hazy conditions in cites and scenic areas, and, along with ozone, contributes to asthma and chronic bronchitis, especially in children and the elderly. Very small, or “fine PM” is also thought to cause emphysema and lung cancer.
Heavy metals such as mercury can be hazardous to human and animal health.

Power Plants Use Air Emission Controls
Power plants are required to meet standards that limit the amounts of some of the substances that they release into the air. There are different ways that power plants meet these standards:
Coal-fired plants can use coal that is low in sulfur content. Coal can also be pre-treated and processed to reduce the types and amounts of undesirable compounds in combustion gases.
Particulate matter emissions are controlled with devices that clean the combustion gases that exit the power plant:
“Bag-houses” use large filters
Electrostatic precipitators use charged plates
Wet scrubbers use a liquid solution
SO2 emissions are controlled by wet and dry scrubbers, which involves mixing lime in the fuel (coal) or by spraying a lime solution into the combustion gases. Fluidized bed combustion can also be used to control SO2.
NOX emissions can be controlled by several different techniques and technologies, such as low NOX burners during the combustion phase or selective catalytic and non-catalytic converters during the post combustion phase.
Some Plants Also Produce Liquid and Solid Wastes
The coarse solid residue that results from the burning solid fuels is called ash. The largest particles collect at the bottom of the boiler ("bottom ash") and are removed and quenched with water. Smaller and lighter particulates ("fly ash") are collected in air emission control devices, and are usually mixed with the bottom ash. The resulting "sludge," which contains all the hazardous materials that were captured by the pollution control devices, may be stored in retention ponds, sent to landfills, or sold for use in making concrete blocks or asphalt. Many coal-fired power plants have very large sludge ponds. Several of these ponds have burst and caused extensive damage and pollution downstream of the pond.
Most Power Plants Produce Greenhouse Gases
Greenhouse gases contribute to the “greenhouse” effect. Scientists know with virtual certainty that increasing greenhouse gas concentrations tend to warm the planet.2
Power plants that burn fossil fuels and materials made from fossil fuels and some geothermal power plants are the sources of about 40% of total U.S. carbon dioxide (CO2) emissions.
Nuclear Power Plants Produce Different Kinds of Waste
Nuclear power plants are not a source of greenhouse gases or other emissions, but they do produce two kinds of radioactive waste:
Low-level radioactive waste — This includes items that have become contaminated with radioactive material, such as clothing, wiping rags, mops, filters, reactor water treatment residues, and equipment and tools. Low-level waste is stored at nuclear power plants until the radioactivity in the waste decays to a level where it is allowed to be disposed of as ordinary trash or it is sent to a low-level waste disposal site.
Spent (used) nuclear fuel — The spent fuel assemblies are highly radioactive and must initially be stored in specially designed pools resembling large swimming pools (water cools the fuel and acts as a radiation shield) or in specially designed dry storage containers. An increasing number of reactor operators now store their older spent fuel in dry storage facilities using special outdoor concrete or steel containers with air cooling.
Electric Power Lines Also Have a Footprint
Power transmission and distribution lines carry electricity from power plants to customers. Most transmission lines are strung above ground on large towers. The towers and lines impact the visual landscape, especially when they pass through pristine natural areas. Trees near the wires may be disturbed and have to be managed to keep them from touching the wires and these activities can affect native plant populations and wildlife. Power lines can be placed under the ground, but this is more expensive and may result in a greater disturbance of the landscape than overhead lines.
1. U.S. Environmental Protection Agency, Climate Change State of Knowledge.
2. Intergovernmental Panel on Climate Change.
 
Also on Energy Explained
Electricity in the United States
Use of Electricity
How Electricity Is Delivered To Consumers
Energy Use in Homes
Energy Use in Commercial Buildings
FAQs
What percentage of world energy consumption and electricity generation comes from renewable energy? — http://www.eia.gov/tools/faqs/faq.cfm?id=527&t=3
How much carbon dioxide (CO2) is produced per kilowatt-hour when generating electricity with fossil fuels? — http://www.eia.gov/tools/faqs/faq.cfm?id=74&t=11
How much of U.S. greenhouse gas emissions are associated with electricity generation? — http://www.eia.gov/tools/faqs/faq.cfm?id=77&t=11
What percentage of world energy consumption and electricity generation comes from renewable energy? — http://www.eia.gov/tools/faqs/faq.cfm?id=527&t=3
 Learn More
Power Plant Emissions — http://www.eia.gov/cneaf/electricity/epa/epat5p1.html
U.S. Emissions Data — http://www.eia.gov/environment.html
How clean is my electricity? — http://www.epa.gov/cleanenergy/energy-and-you/how-clean.html
Climate Change Information — http://www.epa.gov/climatechange/
What Is the Impact of Electricity Generation on the Environment? — http://www.epa.gov/cleanenergy/energy-and-you/


Last Reviewed: July 1, 2011
« Factors Affecting Electricity Prices Hydrogen »