Bituminous Coal
-42% of world’s electricity (46 in U.S. & 70 in China)
-high heat content, large supplies, high sulfur content
-most abundant fossil fuel but by far the dirtiest
-process of making it available degrades land and pollutes water and air
-pollutes air when burned especially without expensive pollution control devices
-releases SO2 and soot
-fine particle pollution kills more than 24,000 a year
-power/industrial plants= largest emitters of CO2
-emits radioactive material and toxic, indestructible mercury into atmosphere
-produces toxic ash
-ample supplies in many countries
-high net energy yield
-low cost when environmental costs are not included
-severe land disturbances and water pollution
-fine particle and toxic mercury emissions threaten human health
-emits large amounts of CO2 and other air pollutants when produced and burned
Conventional Oil
-makes up 30% of the world’s estimated supply of oil
-extraction: drilling vertical/horizontal wells into deposits (underground rock formaions), big $$$
to find and extraction= decreases net energy yield
-goes to refinery/ refining- separate oil into different components with different boiling points,
also decreases net energy field
- high net energy yield, relatively inexpensive
-causes air and water pollution and releases greenhouse gasses
-Petrochemicals: comes from crude oil distillation; used as raw materials in industrial organic
chemicals, cleaning fluids, pesticides, synthetic fibers, paints, medicines, computers/ add to ecological
footprint
-Huge business, world is very dependent
-World: 34% U.S.: 40%
-ample supply for several decades, high net energy but decreasing, low land disruption, efficient
distribution system
-water pollution from oil spills and leaks, environmental costs not included in market price,
releases CO2 and other air pollutants when burned, vulnerable to international supply interruptions,
loss of biodiversity
Natural Gas
-mixture of gases of which 50-90% is methane; contains smaller amounts of heavier gaseous
hydrocarbons such as propane and butane, and small amounts of highly toxic hydrogen sulfide
-heats space and water to produce electricity and propel vehicles
-versatile fuel w/ high net energy yield
-more plentiful than oil, fairly low cost, lowest environmental impact of all fossil fuels
-World: 21% US: 23%
-creates CO2 and other air pollutants but much less than others
-Conventional: lies above most reservoirs of crude oil, but those found in deep sea and remote
land areas where natural gas pipelines have not been built is usually burned off because it costs too
much to build pipelines to distribute it
-Liquefied petroleum gas (propane and butane liquefied under high pressure) stored in
pressurized tanks for mostly rural areas; the rest of the gas (mostly methane) is purified and pumped
into pipelines for distribution
-Liquefied natural gas- high pressure/very cold temp., shipped overseas in refrigerated liquid
tanker ships, heated and converted back to gas for distribution through pipelines
*low net energy yield; more than one third of its energy content is used to liquefy it,
process it, ship it, and reconvert it*
-At current consumption rates, reserves of natural gas should last the world 62-125 years/US 82118 years
-Unconventional: in coal and shale(limestone) beds; however, to retrieve causes environmental
impacts: scarring of land, large water use, and potential pollution of drinking water from aquifers/ also
in icy, cage like structures of water molecules (methane hydrate), found under artic permafrost, too
costly to use
-Energy Policy Act: excluded natural gas companies from regulation under US water pollution
control law
Oil Shale
-oily rocks; supply of heavy oil/contains combustible mixture of hydrocarbons (kerogen)
-extracted by crushing oil shales after being heated in a large container becomes shaile oil
-heated to increase flow rate and processed to remove sulfur, nitrogen, and other impurities
-72% of the world’s estimated oil shale reserves are in rock formations under government land
in Colorado, Wyoming, and Utah;
- US Bureau of Land Management estimates that the deposits contain an amount of potentially
recoverable heavy oil 4 times the size of Saudi Arabia’s conventional oil reserves & 11 times the size of
Alberta’s tar sand reserves
-Estimated global shale oil supply is 240 times larger than conventional crude oil
-oil shale deposits are locked up in rock of very low grade causing a lot of energy and money to
mine and convert kerogen to shale oile= low net energy; lower than tar sands
- energy form oil shale cannot compete in the open market unless the US gov’t (taxpayers)
provide large subsidies and tax breaks
-5 barrels of water per 1 barrel of shale oil (tons of water)
-great environmental impact to mine oil shale than crude oil and it releases 27-52% more CO2
per unit of energy produced
-advantages and disadvantages the same as tar sands
Solar
-Passive Solar: absorbs and stores heat directly from the sun within well-insulated structure
-concrete, bricks, water tanks can be used to store collected energy as heat and release
it slowly throughout the day & night
-has been used for thousands of years
-Active Solar: captures energy from the sun by pumping a heat-absorbing fluid (water or
antifreeze solution) through special collectors, usually mounted on a roof or on special racks to face the
sun; some heat used directly and the rest can be stored in large insulated container, filled with gravel,
water, clay, or heat absorbing chemical, for release as needed
-net energy is moderate (active) to high (passive)
-very low land disturbance
-moderate cost (passive)
-need access to sun 60% of time during daylight
-sun can be blocked by trees and other structures
-high installation and maintenance costs for active systems
-Need backup system for cloudy days
-Photovoltaic (PV) Cells- thin wafers of purified silicon or polycrystalline silicon with trace
amounts of metals that allow them to produce electricity, thickness ranging from less than that of a of
human hair to that of a sheet of paper, when sunlight strikes these transparent cells they emit electrons
and many cells wired together in a panel can produce electrical power, cells can be connected to
existing electrical grid systems or to batteries that store the electrical energy until needed
-can be put on rooftops, side of buildings
-large solar-cell power plants in Portugal, southern Spain, Germany, South Korea, and
southwestern US/ store excess energy for night and cloudy days by using electricity to run pumps that
compress air into underground caverns/ stored pressure as needed to turn turbines and produce
electricity
-excess energy could be used to decompose water and produce H2
-centralized solar cell power plants must be in deserts & require an expensive modernized
regional or national grid system to transfer power they produce to users
-smaller systems can be used for any home or business in any sunny part of the world
-moderate net energy yield
-little or no direct emissions of CO2 and other air pollutants
-easy to install, move around, and expand as needed
-competitive cost for newer cells
-need access to sun
-need electricity storage systems or backup
-high costs for older systems but decreasing rapidly
-solar-cell power plants could disrupt desert ecosystems
Ocean Tides & Waves
-damns can be built across the mouths of some bays and estuaries to capture the energy the
flowing water for hydropower
-there are currently two large tidal energy dams operating ( La Rance on the northern coast of
France & the other in Nova Scotia’s Bay of Fundly)
-cost is very high
-suitable sites limited; small number of rivers have adequate tidal flows
-Verdant Power placed six underwater turbines to tidal flow of the East River near New York
City; act as turbines and generate electricity efficiently/ if successful plan to install and if successful then
300- such a system powers a town in Norway
-large snakelike chains of floating steel tubes have been installed off the coast of Portugal; up
and down motion of chains by waves generated electricity for 15,000 homes in 2006
-equipment is vulnerable to corrosion & storm damage
Hydrogen
-must heat water or pass electricity through it or stripping it from the methane and gasoline
through chemical reaction involving coal, O2, and steam
-no CO2 emissions (as long as the H2 is not produce with the use of fossil fuels)
-can be produced from plentiful water at some sites
-no direct CO2 emissions if produced from water
-good substitute for oil
-High efficiency (45-65%) in fuel cells
-provides more energy per gram does any other fuel
-hardly any H2 in the atmosphere; must be created
-fuel is created with other methods of energy giving it a negative net energy yield
-fuels cells (best way to use hydrogen electricity) are expensive but technology is improving
-CO2 emissions if produced from carbon-containing compounds
-high costs require subsidies
- needs H2 storage and distribution system
See pg. 370 for graph