The energy return on energy investment is

• A. High
• B. Medium
• C. Negligible
• D. Low

Answer: (D)

Energy return on energy investment (EROI) compares how much usable energy you get from a resource to how much energy you had to put in to obtain it. If the energy you produce is only a small amount larger than what you used to extract, process, and deliver it, the return is considered low. In real-world systems, exploring and drilling, refining, transporting, and maintaining energy production all consume substantial energy. As resources are tapped more deeply or of lower quality, those input costs rise and the net energy gained drops. So, overall, the typical net gain is relatively small, making the energy return on energy investment low.