Lignite compositionMined lignite consists of one third elemental carbon that is permeated with residual groundwater, mineral impurities, and sulphur deposited by prehistoric volcanoes.The bonding of two oxygen atoms at combustion results in carbon dioxide emissions weighing as much as the fuel itself.
The energy lost in burning damp lignite and scrubbing sulphur from the flue gases limits power generating efficiency to between 35% for older plants and 43% in advanced designs. The resulting CO2 emissions per kWh are approximately three times those of clean-burning natural gas.
Geological carbon storage in Europe began with CO2 enhanced recovery of oil in the North Sea and natural gas in the Netherlands. The commercial viability of such ventures has been promoted by high carbon taxes in certain countries, beginning with Sweden in 1991 at $100 per ton of CO2. Research on carbon emission reductions was commensurately initiated at the Chalmers University of Technology in Gothenburg and intensified after the Swedish state-owned Vattenfall AB bought four major lignite power stations in eastern Germany in 2002. Guest article from Jefffrey H. Michel |