EROEI

 
EROEI: Energy Return On Energy Invested

I didn't hear this term until relatively recently, but when I did, it rang a bell.

EROEI is a measure of net gain. As ER and EI are always positive numbers, EROEI must also be positive. But an EROEI of one (where ER equals EI) is a watershed, break-even value. For values greater than one, a net gain is achieved. Values between zero and one represent net loss.

Any (local) venture - be it a hummingbird, a steam shovel, a corporation - with an EROEI substantially greater than one tends to thrive. With an EROEI close to one, it's living on the perilous edge. An EROEI between zero and one, and it's operating at a loss.

In an economy that depends on growth, if we're not getting more out than we're putting in, we're on Skid Row.

I find it to be a dang useful concept in life, as a focus of assessment, for just about any decision. Energy is a catch-all term... expenditures of time, effort or  assets, had best bring a return (I'll accept pleasure, joy and yum as countable toward the ER side!).

But in TEOTWAWKI circles, it is often noted that the EROEIs of 'fossil fuels' - those miracles of useful energy - are dropping like rocks in the post-peak-everything environment. Ditto for virtually anything, including the 'harvest' of renewable resources. Despite advances in extraction technologies, we're spending more and more energy to extract each calorie.

NOTE: Fracking is not an exception. Even early data confirms that it is following the same EROEI curve as any other limited resource. One expects BOTH initial boom AND eventual bust. As demand continues to grow exponentially, the curve can't help but compress.

I have some questions...

EROEI is a context number. ER is fairly straightforward. Let's say the energy equivalent of a barrel of crude. But what we accept as the EI is critical to the full result. Do we mean energy required for extraction machinery? For transport (including the pro-rated transport infrastructure?)? Refinement? Transport, again? 

It's hard to imagine that the numbers include much more than these, and I've not heard if there's even that much.

But there is more... the so-called hidden costs. 

How much to feed, clothe and transport workers all along the way? How much goes to infrastructure necessary to use the fuels (pumping stations, roads and automobiles; railways and trains; ships, harbors, nav aids and shipyards; power plants and factories, homes and other clients of the grid? How much to loss; to spills, inefficiency and entropy? How much to remediation (evironmental impact and clean-up, medical costs related to pollution, accidents, etc.). Ultimately, how much to climate change, ocean acidification and rise? Every barrel we extract has a share in each of these.

This is supposed to be a plus-sum game. GROWTH = ER > EI, right? So long as EROEI > 1, we're okay, right? Right??

But if EI is grossly underestimated, what then is our trajectory?



Note: It's interesting to note that sustainability depends on an EROEI of one. Neither growth nor its opposite are sustainable for a successful species.