Coal fired power has been a cheap source of power and electricity since the beginning of the industrial revolution. Cheap and plentiful, coal's problems were often overlooked because of its very low price. However, as a fuel, solar energy is free and clean. As a result, many people believe that solar power will eventually overtake coal as our main source of electricity. Solar is a newer technology, with problems that likely will be solved over time.

Coal, as with any combustible fuel, emits carbon dioxide (CO2) when it is burned. The amount of CO2 emitted per million British Thermal Units (BTU) produced varies between 205 pounds and 227 pounds, depending on the type of coal being burned in the power plant. In contrast, solar power produces no CO2, a major contributor to global warming.

Sulfur dioxide is the main component of acid rain. Sulfur dioxide rises high in the atmosphere where it combines with water. It then falls back to earth as rain with a sulfuric acid component. The U.S. Environmental Protection Agency (EPA) estimates that 65 percent of annual sulfur dioxide emissions in the United States are from coal fired power plants. Solar power, on the other hand, does not emit sulfur dioxide.

Particulate emissions include soot, smoke and other small particles left over after coal is burned. These particles can become lodged in the lungs and can accumulate on surfaces, making them appear black and sooty. Although modern environmental laws have reduced particulate emissions from coal power plants, these plants still emit some particulate pollution. As a noncombustion power source, solar power emits no particulates as part of the power generation process.

Coal and solar electricity are expected to be roughly the same cost per watt generated by the year 2010. According to Electronics Design Strategy News, the leading solar power provider in Spain will be able to produce power at $0.10 per kilowatt-hour, on a par with the cost of power from a coal fired power plant.

One problem with solar power is that solar generation systems can not generate power at night. Some ideas include utility scale power storage systems which are basically very large batteries. Although this works in theory, in practice there are no utility scale power storage facilities yet. Coal power can produce electricity 24 hours a day and its efficiency is not affected by cloud cover.