Environmental Science
Intermediate

Energy Payback Ratio

Energy produced over a lifetime divided by energy to build it.

Formula

EPR=EgeneratedEinvestedEPR = \frac{E_{generated}}{E_{invested}}

Variables

E_{generated}Lifetime output
E_{invested}Embodied energy

Example

Higher EPR = greener technology

Did You Know?

Modern solar panels pay back their energy in 1-2 years.

energysustainability