COAL Peat (Scotland) Earth During the Carboniferous Period, Million yrs ago North America 300 million years ago Ancient Swamps Carboniferous plants Ancient Swamps Ex/ Coal World reserves of coal = ~1 trillion metric tons World use of coal = ~7.7 billion metric tons/year COAL Difference between Reserves and Resources World Coal Consumption = ~8 billion metric tons/yr World Coal Production = 7.7 billion metric tons/yr Coal Exports Coal Imports Changing Cost of Coal: Affected by Natural Gas Availability Coal use dates back 5000 years Used extensively by Romans Major use in England in 1200s; start of underground mining In 1700, 5/6 of coal was mined in England Led to Englands Industrial Revolution Surface Mining is now 2/3 of US production Globally, 60% is still mined underground Surface Mining (New South Wales, Australia) Open Pit Mining Open Pit Mining in India Strip Mining Strip Mine Reclamation (N Dakota): active mining is lower right, reclamation is upper left. Mountain Top Removal A critical Augur Mining Modern Underground Mining Coal Plant, Germany Coal plants are about 35% thermodynamically efficient, at best. Older grandfathered plants can be much less. Coal Washing removes soil and rock Removing Soot Integrated Gasification Combined Cycle Turning coal into coke: Coke is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace. It is there to reduce the iron oxide (hematite) in order to collect iron. Existing power generation could capture >95% of carbon in coal using CCS (CO2 Capture and Storage), also known as Geologic Carbon Sequestration. The added cost is about 2-4 cents per kilowatt-hour (~30%)