What limits the exploitation of oil shale?

• A. The extraction process requires excavation of soils and heating.
• B. It yields insufficient energy.
• C. It is too costly to transport.
• D. It has no environmental impacts.

Answer: (A)

Oil shale isn’t oil you can just pump out. The oil is bound in kerogen within rock, so to get usable liquid fuel you must first expose the shale and then heat it to drive off the liquids. That means large-scale excavation of soils and rock followed by substantial heating in processing plants or underground. This combination is extremely energy-intensive and expensive, which makes the overall recovery economics and net energy return unfavorable compared with conventional oil. In short, the heavy digging and heating required to access the kerogen is the main factor that limits exploitation.