Lignite
Lignite, or brown coal, is the lowest rank of coal, a soft, brown, combustible sedimentary rock formed from peat with high moisture and low carbon (25-35%), used mainly for electricity generation, though its low energy content and high water/ash make it dirty and less efficient than higher coals, requiring local use due to transportation costs and significant environmental impact.
Characteristics & Formation
Appearance: Dark brown, earthy, crumbly, resembling compressed wood or dirt.
Formation: Plant matter (peat) in swamps undergoes millions of years of heat and pressure, turning it into lignite.
Composition: High moisture (up to 66%), low carbon (25-35%), low energy content (around 7,000 Btu/lb).
Uses & Significance
Primary Use: Almost exclusively for steam-electric power generation in power plants.
Advantages: Abundant, accessible, and provides low-cost, reliable energy, especially where large deposits exist (like North Dakota).
Disadvantages: High moisture and ash content reduce boiler efficiency; it's a significant source of greenhouse gases and pollutants, requiring more fuel for the same power compared to other coals.
Characteristics & Formation
Appearance: Dark brown, earthy, crumbly, resembling compressed wood or dirt.
Formation: Plant matter (peat) in swamps undergoes millions of years of heat and pressure, turning it into lignite.
Composition: High moisture (up to 66%), low carbon (25-35%), low energy content (around 7,000 Btu/lb).
Uses & Significance
Primary Use: Almost exclusively for steam-electric power generation in power plants.
Advantages: Abundant, accessible, and provides low-cost, reliable energy, especially where large deposits exist (like North Dakota).
Disadvantages: High moisture and ash content reduce boiler efficiency; it's a significant source of greenhouse gases and pollutants, requiring more fuel for the same power compared to other coals.
