Dr. Largen

• Nonrenewable resources
• available in finite, limited quantities
• depleted by use
• natural processes do not replenish within reasonable period of time
• on human time scale
• include
• minerals
• copper, tin, aluminum, radioactive ores
• fossil fuels
• coal
• oil
• natural gas
• Renewable resources
• available in potentially unlimited quantities
• term is not used exclusively to describe energy resources
• replaced by natural processes fairly rapidly
• on a scale of days to decades
• can be used forever
• as long as they are not overexploited in short term
• must be used in sustainable manner
• gives them time to replace or replenish themselves
• include
• non-energy
• trees
• fishes
• fertile agricultural soil, fresh water
• energy
• solar
• wind
• geothermal
• hydroelectric

• Nonrenewable resources
• must differentiate between deposits that can be extracted and those that cannot
• resource
• naturally occurring substance
• of potential use to humans
• can potentially be extracted using current technology
• reserve
• known deposits that can be extracted profitably with existing technology
• under certain economic conditions
• resource
• total amount changes only by amount that is used each year
• reserve
• an economic concept
• amount changes as
• technology advances
• as new deposits are discovered
• as economic conditions vary
• reserves are smaller than resources

• general
• definition
• formation
• specific types
• formation
• resources and reserves
• use patterns
• use issues
• General definition
• partially decayed remains of plants, animals and microorganisms that lived millions of years ago

• General formation
• ~300 million years ago
• much of earth’s climate was mild and warm
• plants grew year round in vast swamps
• as swamp plants and aquatic microorganisms died
• fell into or sunk in water
• decomposed very little due to lack of oxygen
• covered by layers of sediment
• over great periods of time
• heat and pressure that accompanied burial of organic material by sediments
• converted non-decomposed organic material into carbon-rich materials we now call fossil fuels

• Types
• coal
• oil
• natural gas

• Coal
• formation
• types
• reserves
• extraction
• use patterns
• use issues

• Coal
• formation
• ~300 million years ago
• tropical freshwater swamps covered many regions of earth
• conditions in swamps favored extremely rapid plant growth
• resulting in accumulations of dead plant material under water
• decay was inhibited due to low oxygen concentrations
• partially decayed accumulated plant material was covered by sediments
• especially when geologic changes in earth caused some swamps to be submerged by seas
• over vast periods of time, heat and pressure that accompanied burial
• converted non-decomposed plant material into carbon-rich rock called coal
• types
• occurs in different types, or grades, dependent on
• varying amounts of heat and pressure to which it was exposed during formation
• exposed during formation to
• higher heat and pressure
• drier (lower water content)
• more compact (harder)
• higher heating value (=higher energy content)
• lower heat and pressure
• wetter (higher water content)
• less compact (softer)
• lower heating value (=lower energy content)
• three most common grades
• lignite
• bituminous
• anthracite
• lignite
• characteristics
• moist, water content of ~45%
• soft, woody texture
• produces little heat compared to other types
• heat value of 7000 BTU/pound
• dark brown in color
• contains ~20 noncombustible compounds
• contains ~35% carbon
• uses
• often used to fuel electric power plants
• deposits
• sizable deposits found in western US
• largest US producer is North Dakota
• cost to mine (1997) $10.91/2000 pounds
• bituminous
• characteristics
• moderately dry, water content of 5-15%
• moderately hard
• although its also called a soft coal
• produces nearly twice the amount of heat as lignite
• heat value of 12,000 BTU/pound
• dull to bright black with dull bands
• contains ~20-30 noncombustible compounds
• contains ~55-75% carbon
• uses
• extensively by electric power plants
• produces a lot of heat
• deposits
• found in US in Appalachian region, near Great Lakes, in Mississippi Valley, in central Texas
• cost to mine (1997) $24.64/2000 pounds

• highest grade of coal
• characteristics
• very dry, water content of 4%
• very compact
• called hard coal
• produces twice the heat of lignite
• heat value of 14,000 BTU/pound
• dark, brilliant black in color
• contains ~1 noncombustible compound
• contains ~95% carbon
• anthracite
• uses
• electric power generation and other industrial uses such as production of steel
• deposits
• in US, most is located east of Mississippi River, particularly in PA

• Coal
• deposits and reserves
• coal is most abundant fossil fuel in world
• found mostly in Northern Hemisphere
• found in seams or veins
• underground layers that vary in thickness from 2.5cm to >30m in thickness
• easily located
• geologists believe most (if not all) major deposits have been located
• known, proven world reserves
• location
• ~66% located in US, Russia, China, India
• with US accounting for 24% of those
• could last
• ~200 years at present rate of consumption
• ~65 years if rate of consumption increases by 2% per year

• known US reserves
• location
• throughout US
• more in eastern 1/2 of continental US
• could last US
• ~300 years at present rate of consumption

• unknown, unproven world reserves
• additional coal reserves that are currently too expensive to develop
• for example, deposits at depths >5000 feet would cost more to extract than would be offset by current price of coal
• location
• ~85% are located in US
• could last
• ~1000 years at present rate of consumption
• ~149 years if rate of consumption increases by 2% per year
• unknown, unproven US reserves
• could last US
• ~400years at present rate of consumption
• known AND unknown world reserves
• could last
• ~200-1000 years depending on rate of consumption

• Coal extraction
• two basic types of coal mines
• surface mines
• also called strip mining
• used when overburden is 30-100 meters thick
• overburden = rock/earthen material on top of vein/seam of coal
• results in best utilization of coal reserves
• it removes most of coal in a vein
• can be profitably used in a vein as thin as 1/2 meter
• have increased globally
• in US, from 30% of coal extracted in 1970 to 60% of coal extracted currently
• advantages over subsurface mining
• less expensive
• safer for miners
• allows more complete removal of coal
• disadvantage over subsurface mining
• disrupts land more extensively
• adverse environmental impacts
• subsurface mines
• employed when overburden is thick, >~30-100 meters
• account for ~40% of current coal extraction
• advantage over surface mining
• disrupts land less extensively
• less potential for adverse environmental impacts
• disadvantages over surface mining
• more expensive
• less safe for miners
• less complete removal of coal

• Coal use patterns
• provides
• ~21% of world’s commercial energy
• ~22% of US’s commercial energy
• used to
• generate
• ~62% of world’s electricity
• ~53% of US’s electricity
• make
• ~75% of world’s steel

• many analysts project a decline in coal use over next 40-50 years because of
• its high CO₂ emissions
• harmful human health effects
• availability of less environmentally harmful ways to produce electricity
• Coal use issues
• coal contains
• small amounts of sulfur
• which is released into atmosphere as SO₂ when coal is burned
• SO₂ is a greenhouse gas
• trace amount of mercury and radioactive materials
• which are released into atmosphere when coal is burned
• most abundant fossil fuel
• produces highest environmental impact from
• land disturbance
• air pollution
• greenhouse gas emissions (SO₂ CO₂)
• release of toxic mercury particles
• release of thousands of times more radioactive particles into atmosphere per unit energy produced than does a normally operating nuclear power plant
• water pollution
• human health impacts
• occupational
• coal mining is one of most dangerous jobs in world
• during 20th century, ~90,000 American coal miners died in mining accidents
• though death rates declined in latter part of century
• between 1870 and 1950, 30,000 miners died in PA alone
• equivalent of one man per day for 80 years
• occupational
• miners have increased risk of black lung disease
• lungs become coated with inhaled coal dust restricting oxygen exchange, causing ~2000 deaths per year

• land disturbance
• in US, thousands of square kilometers have been disturbed by mining
• only about 1/2 of that has been reclaimed

• types
• open trenches
• topsoil removal/erosion
• landslides caused by lack of vegetation
• mountaintop removal
• land subsidence
• trailing dumps

• acid mine drainage
• produced when rainwater seeps through iron sulfide minerals exposed in waste mines and
• carries sulfuric acid to nearby streams and lakes
• air pollution
• many elements taken up by ancient plants were concentrated in coal formation process
• such as uranium, lead, cadmium, mercury, rubidium, thallium, zinc
• released when coal is burned
• as gas into atmosphere
• are concentrated as in fly ash
• coal is responsible for ~25% of all atmospheric mercury pollution in US
• acid deposition
• both sulfur oxides (SOx) and nitrogen oxides (NOx) form acids when they react with water
• SOx and NOx emissions react with water in the atmosphere to form
• an acid which falls from atmosphere to surface, known as acid deposition or acid precipitation
• greenhouse gases
• coal contains up to 10% sulfur by weight
• unless sulfur is removed by washing or flue-gas scrubbing
• it is released during burning and oxidizes to sulfur dioxide (SO₂) or sulfate (SO₄)
• ~18 million metric tons SOx released annually in US (~75% of total US emissions)
• high temperatures and rich air mixtures used in coal-fired burners also
• oxidize nitrogen compounds (mostly from atmosphere) into nitrogen oxides (NOx)
• ~5 metric tons of NOx released annually in US (~30% of total US emissions)
• combustion of coal produces CO₂
• ~one trillion metric tons released annually in US (~50% of total US emissions)
• making coal a cleaner fuel
• desulfurization systems
• clean power plants’ exhausts
• chemicals react with pollution and pollution settles out (precipitates)
• modern "scrubbers" remove ~98% of sulfur
• expensive, adds to cost of coal energy
• clean coal technologies
• new methods for burring coal such as fluidized bed combustion
• mixes crushed coal with particles of limestone in a strong air current during combustion
• takes place at lower temperatures so there are fewer nitrogen oxides produced
• sulfur reacts with calcium in limestone and precipitates out
• new methods for burring coal such as fluidized bed combustion
• process is more efficient than traditional coal burning
• produces more heat for a given amount of coal
• therefore, reduces CO₂ emissions
• converting goal into gaseous and liquid fuels
• solid coal can be converted into synfuels
• synthetic natural gas (SNG)
• by process of coal gasification
• liquid fuel such as methanol or synthetic gasoline
• by process of coal liquefaction
• most analysts expect synfuels to play only a minor role as a energy resource in the next 30-50 years