Why is natural gas a better solution to generate electricity than combustion of coal?
The main reason that natural gas is considered a better fuel than coal for production of electricity is that it burns more cleanly, or, technically, combusts more completely, and thus results in emission of fewer pollutants. Incomplete combustion of coal results in emission of both greenhouse gasses and particulate matter. It is possible to install scrubbers on older coal-fired plants to reduce emissions, but this increases the cost of energy production. In the past, coal was often produced by strip-mining with little environmental mitigation, but more recently coal mining has become less environmentally harmful, while the most recent method of extracting gas in North America, which has made gas more accessible and less expensive is hydraulic fracturing or "fracking", something which may make natural gas less benign than it is now considered.