All of them are the current biggest sources of electrical energy.
3 of them will be explained.
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1) Natural gas:
it was the largest source, 38 % approx., of the USA electricity generation. It is used in steam turbines and gas turbines to generate electricity.
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2) Nuclear energy:
It was the source of 19% of the U.S. electricity generation in 2021. Nuclear power plants use steam turbines to produce electricity from fission.
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3) Coal power:
It was the 2nd.-largest energy source for US electricity generation in 2021.