posted on Feb, 21 2008 @ 02:10 AM
The various attempts to develop the world's oil shale deposits, over a period of over 150 years, have experienced successes when the cost of shale
oil production in a given region was less than the price of crude oil or its other substitutes. According to a survey conducted by the RAND
Corporation, a surface retorting complex (comprising a mine, retorting plant, upgrading plant, supporting utilities, and spent shale reclamation) is
unlikely to be profitable in the United States until crude oil prices range between US$70 to US$95 per barrel (in 2005 dollars). Once commercial
plants are in operation and experience-based learning takes place, costs are expected to decline in 12 years to US$35–US$48 per barrel. After
production of 1,000 million barrels, costs are estimated to decline further to US$30 – US$40 per barrel. Royal Dutch Shell has announced that its
in-situ extraction technology in Colorado could be competitive at prices over US$30 per barrel, while other technologies at full-scale production
assert profitability at oil prices even lower than US$20 per barrel. To increase the efficiency of oil shale retorting, several co-pyrolysis processes
have been proposed and tested.
A critical measure of the viability of oil shale as an energy source is the ratio of the energy produced by the shale to the energy used in its mining
and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI). A 1984 study estimated the EROEI of the various known oil shale
deposits as varying between 0.7-13.3. Royal Dutch Shell has reported an EROEI of three to four on its in-situ development, Mahogany Research Project.
An additional economic consideration is the water needed in the oil shale retorting process, which may pose a problem in areas with water scarcity.