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Electric car and induction cooker have brought us into a new revolution on the energy use. Most of us might consider electricity as a clean source of energy. It is true that electricity does not cause pollution as fossil fuels do, but if we track down on how electricity is generated, we will discover that the electricity generation process do pollute the environment. In fact, electricity is not as clean as we think it is.

electricity sources

As the major source of electricity (41%), the coal burning process emits air pollutants such as CO₂, SO₂, NOx, particulate matter, CO and VOCs. In which CO₂ is a greenhouse gas. SO₂, NOx, particulate matter and CO are hazardous to human health whereas NOx and VOCs contribute to secondary pollutants. Besides, coal plants require a huge amount of cooling water and will emerge thermal pollution when discharging the cooling water. Not to mention the coal mining draws great negative effect on ecosystem and landscape.

Natural gas is a relatively clean burning fossil fuel in compare with coal, however natural gas is mainly methane which the leakage of natural gas is one of the methane emission sources. Besides, burning natural gas also emit CO₂. Both methane and CO₂ are greenhouse gases. In addition, the process of drilling for natural gas also emits air pollutants and causes harm to ecosystem and water resources.

Nuclear power reactor does not emit air pollution during operation, still the by-product of nuclear power generation, radioactive waste is hazardous to human health and environment. On the other hand, renewable energy such as solar energy, hydroelectric and wind energy do have some indirect negative impacts on environment. Toxic materials and chemicals are used to produce PV cells in solar panel. Besides, the beam of sunlight created by solar power tower can kill birds and insects. Last but not least, solar power plant, hydroelectric dam and wind turbine cause negative impacts on the habitat and ecosystem nearby.

To sum up, it is true that electricity is a comparative clean energy. In which, the electric generation by renewable energy have the minimum impact on the environment among all. We should encourage renewable energy but at the same time, never consider it as no environmental impact hence take for granted. Thus, do not forget to switch off the light next time you leave the room!

Lim Shuang Ao