Environmental Engineering Reference
In-Depth Information
Fuel
Energy content
Air-dried wood
ca. 15 MJ/kg
Subbituminous coal (anthracites) > 22.1 MJ/kg
Bituminous coal (anthracites)
> 26.7 MJ/kg
Crude oil
42-44 MJ/kg
Unconventional Oil and Gas: Scraping the Barrel
Conventional oil and gas - those reserves that are extracted using long-standing
technologies such as vertical wells - are the 'low-hanging fruit' of the fossil fuel sector.
Obviously, a term such as 'conventional' is subject to change: what is unconventional
today may well be conventional sometime in the future, as new extraction, refining and
transportation methods are developed. There are currently four main types of
unconventional oil and gas: tar sands, shale gas, shale oil and coal bed methane.
Tar sands are a kind of immature petroleum, in which the organic matter has not yet
been transformed into oil by heat and pressure. These sandy sediments contain bitumen, a
type of petroleum that is too viscous to transport by pipeline without dilution. Shale gas
and oil are trapped in shale rock that is too densely compacted to allow extraction using
conventional drilling technology. Coal bed methane (CBM) is found in coal seams that are
too deep or of too poor a quality for commercial mining.
Reserves of unconventional oil and gas are both immense and widely distributed, but
because of the greater costs and additional technology required to extract them, many are
not yet competitive with conventional sources. However, a steadily rising market price for
crude oil, growing uncertainty about the global supply, and rapidly growing demand from
Asia have spurred on the unconventional oil and gas sector. Thanks to shale gas fracking
in the United States and bitumen melted out of the Alberta tar sands, the United States is
poised to overtake Russia as the world's largest gas producer, and Canada has become the
Nuclear Fuels
There's more to heavy metal than long hair and shrieking guitar solos. In chemistry, the
term refers to metallic elements that have a large number of protons in their nucleus.
