EROEI - Running out of Easy

Rome ran out of wood. We're running out of easy.

Yesterday was summer solstice. Seemingly the last day you’d think about heating a home. However, despite the sun’s longest daylight journey of the year, up in the mountains where I live it still drops below 15c each night. So, there’s always a need for firewood, just in case poor weather socks in. And that got me thinking. Years ago, when I harvested deadfall and aged trees it was a pretty physical, yet enjoyable, exercise that would take me less than a kilometer or two from my homestead. My truck, my chainsaw, axe/hatchet, a come-along, and later my dog, would trek up a local forest service road in the early morning, usually in June or July. Sometimes August or September if I was daring. By noon or mid afternoon there would be a cord or more of bucked birch, sometimes fir, always plentiful and dry. A short drive home and I’d come back one or two more times, so I’d have a three to four cord supply every winter. Splitting and stacking were backyard chores that could span a few weeks if need be. Pretty easy pickings.

I carried on with this approach for about a decade, eventually with the assistance of a second set of hands as my own capacity slowed. Being up in the bush is always enjoyable regardless of the reason, but I noticed a worrisome trend over the last few years of harvesting. I had to venture further, sometimes 20-30km to find decent quantities. Additionally, the favoured/select species available were becoming rare. Birch is now an appreciably rare, and highly prized, find. What used to be a one weekend per year task morphed into a three to four weekend job, easily taking three to four times the fuel, time, and effort obtaining a larger volume of lower heat quality firewood to provide the same total seasonal heating capacity.

This problem is actually very common. Ancient Rome faced the same issue in the late stages of their empire. Wood was their primary heat source, and their primary building material. As the forests around Rome were stripped progressively further away, longer hauling distances, more animal power, more animal feed, more labourers/soldiers to harvest and protect their take, and more land for food – these became existential boundaries and they compounded upon themselves, resulting in an energy and resource crisis. So much so that the diminishing energy contributed to the decline and collapse of the empire.

The above examples illustrate the concept of energy return on energy invested (EROEI). It is simply the ratio of energy put into the effort of obtaining energy. This ratio underlies everything. And I do mean everything. From single cells to entire civilizations. Any functioning system consumes energy, and how efficiently it does so is driven in part by how effectively the end user puts it to work (such as the decision to operate a high or low efficiency automobile) - but more importantly by how efficiently the basic energy resource is obtained. Because for every unit of energy resource harvested an amount of energy must be expended in the harvesting. The less effort (energy) to obtain a resource, the more of it that can be put to work to the benefit of the user (an amoeba or an empire!).

At the dawn of the petroleum age oil was harvested that literally seeped out of the ground, the effort to collect it was as low as it could get. The EROEI of oil in the 1930s was around 100:1 – for every barrel (of equivalent energy) spent harvesting, 100 barrels were obtained. This was a tremendous and real return on effort. The surplus energy from such easy extraction created an explosion of growth, choices and benefits to multitudes of people. This bonanza literally pulled many societies into a new world. On a per capita basis, each of us was a monarch compared to our pre-industrial ancestors.

Obviously, as with wood, as time went on and as civilization reaped the benefits and grew, and as consumption rates increased, the supply of ground seepage abated, and we learned new methods to harvest, primarily drilling. Since drilling added a layer of complexity and additional effort, and as wells started drilling deeper, into more complex terrain, and eventually offshore, the EROEI naturally declined over time. By the early 1970s the ratio had declined to a few dozen to one. Today the ratio is on the order of 10-20:1 for conventional oil (liquid drilled sources). Unconventional sources, such as tar sands are as low as 3-5:1. Some estimates for certain extraction methods approach 1:1 which is the point of energetic futility.¹

Despite technological advances to both end use and oil production that do show improvement compared to their ancestral technologies, the reality is that EROEI has declined steadily as civilization has consumed most of the high ratio ‘good stuff’. This is clearly (and logically) indicated by the simple fact that we’ve expanded our extraction technologies into very creative and complex methods that literally squeeze drops from stone, or that we travel further from shore placing ever more complex floating rigs far out at sea. Had there been an abundant (some hopeful folks would argue ‘inexhaustible’) supply of high EROEI oil, no investment (energy and $)² would take place for these hard to reach and low benefit sources.

So, for all our end-use technological bang-for-your-buck amazements, each new layer of complexity to squeeze a bit more out of a bit less, each new generation of improved fuel efficiencies, dollar per seat-mile cost reductions, etc., will always bump up against the hard reality of diminished and continuously diminishing basic energy harvesting efficiency. This is a non-negotiable, non-partisan, global reality.

For every extra BTU of energy required to get energy, that BTU is no longer available to the end-user. On a global scale an EROEI less than 8:1 is generally considered the threshold below which civilization no longer has a surplus of available energy to maintain the complexity, and diversity, we see in all the benefits that have been developed.

For a civilization tuned to growth and expansion, the prospect of degrowth and contraction is daunting indeed. After all, it is in our nature to believe in positive growth or at least constant standards of living, and it is also in our nature to disbelieve or refute risks to our wellbeing that are not obvious or that occur too slowly for us to recognize. Awareness of what’s on or over the horizon is itself a form of adaptation. The physics aren’t going to change, so it must be us that adapt.

These days I rely on the good service of younger locals who are keener and more able than I to carry on the essential task of collecting wood (I’m not so prideful to not admit my limitations), and I limit my excursions into the bush to more recreational endeavours, such as mushrooming or just simply hiking. Regardless, building community to facilitate adaptation is my goal, and my privilege.

Notes:

1. The strict measure of EROEI is a subject of continuous discussion, primarily around the definition of where one begins and ends the energy expenditure chain of the oil extraction/production/refining system (at the well, at the refinery, at the gas pump?). For simplicity, I use relative measures for the numerical values in this writing.

2. It is worth noting that very few economists or advisors to policy makers understand the basic physics behind energy and the disconnect between energy and money, nor do they understand the concept of an energy cost to obtain energy. Most of these folks treat oil, gas, coal etc. simply as consumables that magically appear, or worse, commodities to be traded for money. At any rate, they do not factor EROEI into oil infrastructure investment models. As such, they are blind to the real cost and this is one of the major reasons most recent investments have failed financially.