what is energy return on investment eroi 
energy return on investment eroi is a ratio for describing a measure of energy produced in relation to the energy used to create it for instance the ratio would illustrate how much energy is used to locate extract deliver and refine crude oil relative to how much useable energy is created the energy return on investment eroi is a key determinant of the price of energy because sources of energy that can be tapped relatively cheaply will allow the price to remain low understanding energy return on investmenteroi is important because if the cost of an energy plant is more than the revenues gained from selling electricity that plant is not economically viable eroi can also help organizations and governments compare different energy sources for profitability such as nuclear vs solar power 