1) Gas from shale 
Synthetic petroleum products produced from coal, natural gas, shale, tar sands or other sources.
synfuel 1. Synthetic fuel which is a liquid fuel synthesized from a nonpetroleum source; such as, coal, oil shale, or waste plastics. 2. Fuel that is artificially made as contrasted to that which is found in nature. Synthetic gas made from coal is considered to be more economical and easier to produce than synthetic oil. When natural gas supplies...