Coal is a non-renewable source of energy. Burning coal emits harmful gases and waste such as carbon dioxide, sulfur dioxide, nitrogen oxides, sulfuric acids, arsenic, and ash, and has led to major environmental impacts like acid rain in some regions. Coal excavation requires a significant amount of energy and coal is generally transported from remote locations over long distances, leading to higher carbon emissions. Lignite causes problems in transportation and storage due to its high moisture and ash content, and is susceptible to spontaneous combustion. It is also difficult to crush, pulverize, and combust. It has a lower heating value, which means that more fuel must be handled to produce a given amount ofpower (Table 8.3).

8.8