Electricity Generation: Environmental Pollution Sources And Causes

Electricity generation is a leading cause of environmental pollution, with power plants being the largest source of airborne toxic metal emissions, including mercury, cadmium, and arsenic. Fossil fuel-fired power plants, in particular, are a significant contributor to air, water, and land pollution, releasing harmful nitrogen oxides, sulfur dioxide, and greenhouse gases into the atmosphere. The burning of fossil fuels, such as coal and natural gas, has degraded air quality, contributed to climate change, and harmed biodiversity and human health. While all forms of electricity generation have some environmental impact, coal-fired power is the dirtiest, causing extensive pollution through coal ash and posing risks to groundwater. The transition to renewable energy sources, such as solar, wind, and hydropower, offers cleaner alternatives with lower emissions and less environmental degradation, but even these sources carry some environmental footprint during their construction and operation.

Fossil fuels and coal

The burning of fossil fuels and coal releases harmful substances into the atmosphere, leading to air pollution. These emissions include sulphur oxides, nitrogen oxides, particulate matter (soot), and mercury pollutants. The particulate matter, or PM, resulting from the combustion of fossil fuels, contributes to hazy conditions in cities and scenic areas. When coupled with ozone, PM can trigger asthma and chronic bronchitis, especially in children and the elderly. Additionally, nitrogen oxides (NOx) contribute to ground-level ozone, which irritates and damages the lungs.

Coal-fired power plants also produce ash, which is the solid residue left after burning solid fuels. This ash contains hazardous materials captured by pollution control devices. The disposal of ash sludge, a mixture of ash and water, poses risks to groundwater. Several instances of ash sludge ponds bursting have caused extensive damage and pollution downstream.

The extraction of coal through mining operations also impacts the environment. Surface mining, or strip mining, involves removing the soil and rock above coal deposits, altering the landscape. Mountaintop removal and valley fill mining have significantly affected regions like the Appalachian Mountains. This method of coal extraction can lead to streams being covered with rock and dirt, and the resulting water drainage may contain pollutants harmful to aquatic life. Underground mines, while less disruptive to the landscape, face issues with ground collapse and the drainage of acidic water.

To address the environmental and health impacts of fossil fuel and coal-fired power plants, governments and industries are working towards transitioning to renewable energy sources. Canada, for example, has set emissions reduction goals and is investing in renewable energy sources like tidal energy and geothermal power. The United States, governed by the Clean Air Act and the Clean Water Act, has implemented regulations to reduce pollutants from power plants. Additionally, the coal industry has developed methods to clean coal and remove impurities, aiming to reduce emissions and increase energy efficiency.

Mercury and other toxic metals

Mercury is a neurotoxic metal that can cause severe and irreparable harm to human health, especially to the brain development of young children. It is tied to lower IQ, decreased earning potential, and higher health costs. Mercury is released into the atmosphere when coal is burned in power plants, and it is also emitted during the burning of municipal and medical waste. In addition to mercury, other heavy metals such as lead, chromium, cadmium, and arsenic are also hazardous to human and animal health. These metals can induce acute or chronic poisoning through exposure to water, air, and food.

The industrial activities of the last century have caused a significant increase in human exposure to these heavy metals. High-dose exposure to heavy metals can lead to severe complications such as abdominal colic pain, bloody diarrhea, and kidney failure. Low-dose exposure, on the other hand, can go undetected until diagnosed by its complications. The toxic mechanisms of these heavy metals involve similar pathways, often reacting with biological systems by forming metal cations that have an affinity for vital macromolecules. These metals can also generate free radicals, leading to oxidative stress and disrupting cellular events such as growth, proliferation, differentiation, and damage-repairing processes.

To address the health risks posed by mercury emissions, the Environmental Protection Agency (EPA) in the United States announced the Mercury and Air Toxic Standards (MATS) rule in 2011. The MATS rule required a significant reduction in mercury sources, prompting many coal-fired power plants to convert to natural gas or install costly mercury-capturing filters in their smokestacks. While natural gas reduces the mercury risk, it still contributes to health issues and global warming. The Biden administration has recently moved to reaffirm the MATS rule and restore the standards for regulating mercury emissions from power plants.

In addition to the efforts in the United States, Canada is also transitioning away from coal and other fossil fuel-fired electricity. While Canada's electricity generation mix is already one of the cleanest in the world, with 66% of its electricity coming from renewable sources, it continues to work towards reducing its environmental impact. Canada is investing in renewable energy sources such as solar, wind, and tidal power, and also has nuclear power plants that produce approximately 15% of its electricity. These efforts are crucial in reducing the negative impacts of fossil fuel burning on the environment and human health, including air pollution, water quality degradation, biodiversity loss, and species habitat destruction.

Greenhouse gases

In 2022, about 35% of the world's electricity came from burning coal, which is one of the most greenhouse gas-intensive energy sources globally. Coal-fired power is the dirtiest form of electricity generation. It produces approximately 20% of the world's greenhouse gas emissions and is a significant contributor to climate change and air pollution, harming the health of millions of people annually.

Electric power sector power plants that burned fossil fuels or materials made from fossil fuels, and some geothermal power plants, were the source of about 31% of total US energy-related CO2 emissions in 2022. In contrast, renewable energy sources such as wind power emit far less greenhouse gas per unit of electricity generated. Wind power helps limit climate change as it consumes no fuel and emits no air pollution.

Nuclear power also does not produce any CO2 emissions, although emissions are produced indirectly, for example, during the construction of the plant. Similarly, solar power does not lead to harmful emissions during operation, but the production of the panels creates some pollution. The carbon footprint of manufacturing solar panels is less than 1kg CO2/Wp, and this is expected to fall as manufacturers use more clean electricity and recycled materials.

Canada's electricity generation mix is already one of the cleanest in the world, with 66% of its electricity from renewable sources such as hydroelectricity, wind, and solar. When nuclear is included, over 80% of Canada's electricity comes from sources that positively impact air quality and climate change.

Water usage

Water is essential for the production of electricity, and its usage can vary significantly depending on the energy source and geographic conditions. While some sources, such as photovoltaics, wind power, and run-of-the-river hydropower, consume relatively little water, others like reservoir hydropower and biomass can have a large water footprint.

Hydroelectricity, for example, relies on water for electricity generation, and its main causes of water usage are evaporation and seepage into the water table. The use of water in hydroelectricity can be a concern, especially in regions with water scarcity. However, thermal cycle plants near the ocean can utilise seawater for cooling, minimising the impact on water temperatures and availability for other uses.

Nuclear power plants, on the other hand, have different water considerations. While nuclear power does not typically use cooling towers, dry cooling systems can significantly draw from the water table. Alternative cooling solutions, such as sewage cooling, have been explored to reduce water usage.

The impact of water usage in electricity generation extends beyond the immediate consumption of water. Water scarcity is a pressing issue, with almost 40% of the global population affected. As a result, understanding the water usage of different electricity-generation technologies is crucial for sustainable energy transitions and effective water conservation measures.

Additionally, the burning of fossil fuels and the use of petroleum-based fuels can also harm water quality and biodiversity. This further underscores the importance of transitioning to cleaner sources of electricity, such as hydropower, which has low operating costs and accounts for a significant portion of electricity generation in countries like Canada.

Solar and wind power

However, solar and wind power do have some environmental impacts. The production of solar panels, for example, creates some pollution and requires energy-intensive materials such as plastic, metal, sodium hydroxide, and hydrofluoric acid. The hazardous chemicals used to manufacture photovoltaic (PV) cells and panels must be carefully handled to avoid releasing them into the environment. Some solar panels also use heavy metals and hazardous fluids, which may require special handling for disposal. The disposal or recycling of solar panels is currently a problem, with solar panel waste projected to reach 78 million metric tons by 2050.

Solar power plants can also affect the environment at or near their locations. Land must be cleared for solar power plants, which can have long-term effects on the habitats of native plants and animals. Large solar power plants may require water for cleaning solar collectors and concentrators or for cooling turbine generators, which can affect the ecosystems that depend on these water resources. The concentrated sunlight created by solar power towers can also kill birds and insects that fly into the beam.

Wind power also has some environmental impacts. Wind farms require large amounts of land, with a wind farm using 30 to 141 acres per megawatt of electricity produced. This can result in energy sprawl and impact the landscape. Wind turbines also require large amounts of concrete, the production of which is the third greatest producer of anthropomorphic greenhouse gases. Limestone mining for concrete production can cause ground and surface water pollution and change how water flows over the earth and how heat is absorbed and released. Offshore wind turbines are also changing marine ecosystems. Additionally, wind turbines can cause noise pollution and wildlife death, with birds and bats being killed by the turbines.

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