Final answer:
Switching from coal to natural gas can significantly reduce CO₂ emissions from power generation as natural gas produces less CO₂ per unit of energy. Nuclear power is another low-emission option, contributing only a fraction of the emissions of fossil fuels. Coal not only produces the most CO₂ per unit of energy but also other pollutants.
Step-by-step explanation:
When discussing CO₂ emissions of different power generation options, it is important to consider the impact of various fossil fuels on the environment. Replacing coal with natural gas in electricity generation can significantly reduce CO₂ emissions because natural gas produces less CO₂ per unit of energy. Specifically, according to provided data, natural gas has a much lower carbon-intensity compared to coal, which has historically been the dominant CO₂ producer.
Beyond fossil fuels, nuclear power plants contribute a small fraction of the emissions compared to traditional fossil-fuel-based electricity, with life-cycle CO₂ emissions being only 2% of those from fossil fuels. It is worth noting that the U.S. generates 19.4% of its electricity from nuclear sources, with zero greenhouse gas emissions during operation. In contrast, the coal-burning plants not only produce CO₂ but also other harmful emissions such as sulfur dioxide, nitrous oxide, and mercury.
In terms of reducing CO₂ emissions, switching from coal to natural gas could bring substantial benefits, as natural gas power plants have higher efficiency and lower CO₂ emissions per power output. This is illustrated by the heat transfer to the environment, which is higher in coal power stations, representing a significant loss of energy and a larger contribution to global warming.