If oil shale was viable USA would have exploited it some 50 years ago and till today it's not viable.
Scientists’ best estimates of the Energy Return on Investment (EROI) of oil shale suggest it is very inefficient compared to conventional fuel and emits up to 75% more greenhouse gases (GHGs. However, differences in the way energy efficiency is calculated can cause confusion over its potential use, according to the US study.http://ec.europa.eu/environment/inte...pdf/276na3.pdfFully accounting for all energy used is also vital in assessing GHG emissions. Emissions from oil shale, which result from the direct energy input and as a product of the extraction reaction, are estimated to be 1.25 -1.75 times higher than for conventional crude oil. Oil shale production also requires large amounts of land and up to three barrels of water per barrel of oil produced. These environmental costs together with the low EROI lead the researchers to conclude that, although the energy accounting process needs rigourous review, there is little economic or environmental incentive to use oil shale as a fuel source.