EROEI and Civilization’s Forced Decline
EROEI (Energy Return on Energy Invested) is possibly the most important ratio to human existence. This measure is foundational to our civilization, yet understood by few.
EROEI is why we’re able to support 8 billion humans, why atmospheric CO2 is 425ppm and also why human civilization will eventually collapse.
It’s an essential metric that explains why we have computers, retirement funds and air travel. It’s essential to our progress as a species. This has been true since the dawn of agriculture and is even more so in a post-industrialized world.
To help broaden understanding of this deceivingly simply measure, I’m writing the following primer on EROEI.
What is EROEI?
EROEI is a metric used to evaluate the efficiency of energy production systems. It measures the amount of energy obtained from a particular source compared to the amount of energy invested to harness that energy. The formula used is:
Example of EROEI: Solar Panels
Consider a solar panel system:
- Energy Invested: This includes the energy used in manufacturing the solar panels, transporting them, installing them, and maintaining them over their lifespan.
- Energy Produced: This is the energy the solar panels generate during their operational lifetime.
If a solar panel system uses 1,000 units of energy for its entire process (from manufacturing to operation) and generates 10,000 units of energy in its lifetime, the EROEI would be 10. This means that for every unit of energy invested, ten units of energy are returned.
EROEI in Agriculture: An Example of Caloric Return Versus Energy Investment
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