Why do power plants emit such a high percentage of pollutants?

Because they burn fossil fuels, and in this process large amounts of polluting gases (such as carbon dioxide, sulphure dioxides, nitrogen oxides) are released into the atmosphere. Carbon dioxide is especially problematic, because it is a greenhous gas: most of it cannot be re-absorbed by natural processes therefore increasing the global warming effect.

Power plants are highly controversial because of their ability to emit a high percentage of pollutants. Why they emit a high amount of pollutants is because most power plants burn what is known as fossil fuels. Fossil fuels were originally the decayed remains of animals and plants that through over the course of time, became part of natural gases and sediments such as coal and oil. These organisms were buried thousands to millions of years ago (hence the term fossil) and through time, mixed with petroleum and other forms of fuel that humans use to create energy to run power plants and forms of industry.

Fossil fuels release large amounts of harmful pollutants including sulfur dioxide and nitrogen oxides into the environment. The ways by which fossil fuels are harmful include the way in which they are collected; drilling into the earth for oil or coal which greatly damages the landscape and ecosystem of plant and animal life. When fossil fuels are emitted into the environment after being use in power plants and factories, their release results in a large amount of carbon dioxide emissions which prevents certain heat from leaving the atmosphere, trapping the heat and accelerating global warming.