More than one way to fall off a cliff

Also published at

Wonkometer Warning MH-225The “energy cliff” is a central concept in ecological economics, and it’s based on a very simple ratio. But for me this principle was a slippery thing to grasp, and I eventually realized some of the most common graphs used to illustrate the Energy Cliff were leaving me with a misleading mental image.

This column takes a closer look at Energy Return on Energy Invested (ERoEI, EROEI or simply EROI) and the Energy Cliff, concluding with the question of how and whether the Energy Cliff might be experienced as a historical phenomenon.

The Energy Cliff as a mathematical function

Below are two frequently used versions of the Energy Cliff graph, based on the pioneering work of Charles Hall. They illustrate the relationship between Energy Return on Energy Invested and the percentage of energy production that is “surplus”, i.e., not needed by the energy sector for its own work and therefore available for use by the rest of society.

Chart accessed via

Chart accessed via

Chart from Tim Morgan, Life After Growth, Kindle edition, locus 980

Chart from Tim Morgan, Life After Growth, Kindle edition, locus 980

In each case the EROEI is shown on the horizontal axis with lowest values at the right. The apparent suddenness of the drop-off in surplus energy depends on the relative scales of the axes and maximum value shown for EROEI, but in each case the drop-off becomes nearly perpendicular as EROEI falls below 10 – thus the name “Energy Cliff”.

Simple enough, eh? But after seeing this graph presented in several books and essays, I still found the concept hard to master. I kept asking myself, “How does that work again?” or “Why does energy supply drop off so suddenly?”

The problem, I realized, is that the impression these graphics leave in my mind is at odds with the intent. As these examples show, the “Energy for society” or “Profit energy” dominates the graphic visually, and the “Energy used to procure energy” or “Cost energy” seems like such a small sliver that it couldn’t possibly be that important. Mathematically naïve as that impression may have been, it nevertheless made it difficult for me to retain a clear understanding of the Energy Cliff.

The solution for me was to play with the graph until I felt I understood it clearly, using imagery that reinforced the understanding.

It was most helpful, I found, to present the graph not as an unbroken continuum between the two variables, but as a bar chart showing discrete values of Energy Return on Energy Invested: 1, 2, 3, 4, etc up to 50.

The Energy Cliff as a Bart Chart

Visualizing the numbers this way minimizes the tendency to see the surplus energy, or Net energy output, as one massive block. Just as importantly, it allowed me to easily focus on the relationship between specific values of Energy input and Net energy output.

For example, at the far right end of the graph is the ERoEI value 1. This corresponds to a bare break-even scenario. An oil well with this ERoEI would not be worth drilling: we would use up one barrel of oil to drill and operate the well, and it would spit out exactly one barrel in return, leaving us with no surplus energy for our efforts.

An ERoEI of 2 corresponds to a Net energy output of 50%. To return to our Proverbial Oil Corp., we burn one barrel of oil to drill and operate a well, and the well spits out two barrels, leaving us with a net gain of 1 barrel or 50% of the Total energy output.

Our oil wells with ERoEI of 3 give us 3 barrels total for every one we invest, for a net energy gain of 2 barrels or 66.6%, wells with ERoEI of 4 give us a net energy output equal to 75% of their total energy output, wells with ERoEI of 5 give us a net energy output equal to 80% of their total energy output, and so on.

We can also see clearly that the Energy input and Net energy output percentages change very slowly for ERoEI values above 20 – at which point Energy input is 5% and Net energy output is 95% of Total energy output).

There is another simple tweak to this chart that can vividly illustrate the sudden drop-off: animation. (And since most of us use supercomputers capable of guiding a moon mission for our morning reading, why not throw in some animation?)

The animated Energy Cliff – click chart to set in motion

The animated Energy Cliff – click chart to set in motion

By focusing attention on just a narrow range of ERoEI values at a time, this moving bar graph illustrates the fact that Net energy output changes slowly throughout most of the range, and then drops off suddenly and swiftly.

The animated graph relies on the element of time as a key facet of the presentation. That begs the question: can the Energy Cliff chart be read as a function of time?

The Energy Cliff as a historical phenomenon

It is easy to look at the Energy Cliff graphic as a chronological progression, given the convention of viewing timelines with past on the left and future on the right. That would be a mistake – there is no element of time in the chart – but it might be a useful mistake if made consciously.

It’s true that ERoEI rates have been declining slowly for the past 50 years, and many new energy technologies today have ERoEI rates of 10 or lower. And in fact, the Energy Cliff chart is sometimes presented as evidence that an impending energy crisis is mathematically inevitable. While that would be an unwarranted extrapolation from a graph of a simple exponential curve, it isn’t hard to cherry-pick data that graphs to a shape similar to the Energy Cliff.

Consider the following table of ERoEI rates over time.

Selected ERoEI rates over time

This table starts with EROEI rates before the industrial age, and finishes with rates that could plausibly represent the collapse of industrial society. When graphed these numbers show a drop-off much like the Energy Cliff, with the addition of a steep slope going up at the outset of industrial civilization. The values are roughly scaled chronologically, to represent the length of time during which very high EROEI prevailed – basically, the 20th century.

Net Energy over time - chart 1 copy


The numbers cherry-picked for this chart include, crucially, an EROEI for photovoltaic panels in Spain as calculated by Charles Hall and Pedro Prieto, which was the subject of spirited discussion recently on Resilience. At 2.45, this EROEI is far below the level needed to support a highly complex economy. If this number is correct and turns out to be representative of photovoltaics more generally, then the scenario suggested in the above chart is plausible. As high EROEI petroleum sources are depleted, we turn to bottom-of-the-barrel resources like tar sands, and then to solar panels which are even less energy-efficient. Complex industrial society soon collapses, and the vast majority of us must return to the fields.

For a very different picture, we could use the EROEI for solar panel installations presented by Ugo Bardi in Resilience, from a study by Bhandari et al. In this view, photovoltaics in Spain have an EROEI of 11–12, safely out of the drop-off zone of the Energy Cliff. In this scenario we’d have no need for last-ditch fossil fuels from tar sands, solar panels would produce enough surplus energy to create more solar panels and keep industrial society rolling cleanly along, and the Energy Cliff would be a mathematical function but not a historical reality.

Net Energy over time - chart 1 copy


These two charts are equally over-simplified, ignoring other renewable resource energy technologies with widely varying EROEI rates such as hydro-electric generation. It’s unknown how long we might stretch out the dwindling supply of high-EROEI fossil fuels, or whether there will be a collective decision to clamp down on carbon emissions and leave fossil fuels in the ground. And I’m unqualified to make any judgment on whether the Hall/Prieto or the Bhandari assessment of photovoltaics is most realistic.

In presenting these two different charts I merely want to illustrate that while the Energy Cliff graph of a mathematical function is simple and direct, extrapolating from this simple function to forecast historical trends is fraught with uncertainty.

Top graphic: “The Fool” in the Rider-Waite Tarot deck dances gayly at the edge of a precipice.


Tractor-trailers hauling oil and water on North Dakota highway.

‘Are we there yet?’ The uncertain road to the twenty-first century.

Also published at

What made the twentieth century such a distinctive period in human history? Are we moving into the future at an ever-increasing speed? What measures provide the most meaningful comparisons of different energy technologies? Is it “conservative” to base forecasts on business-as-usual scenarios?

These questions provide handy lenses for looking at the work of prolific energy science writer Vaclav Smil.

accounting_for_energy_1Smil, a professor emeritus at the University of Manitoba, is not likely to publish any best-sellers, but his books are widely read by people looking for data-backed discussion of energy sources and their role in our civilization. While Smil’s seemingly effortless fluency in wide-ranging topics of energy science can be intimidating to non-scientists, many of his books require no more than a good high-school-level knowledge of physics, chemistry and mathematics.

This post is the first in a series on issues raised by Smil. How many posts? Let’s just say, to use a formulation familiar to anyone who reads Smil, that the number of posts in this series will be “in the range of an order of magnitude less” than the number of Smil’s books. (He’s at 37 books and counting.)

The myth of accelerating change

In early 2004, I wrote a newspaper column with the title “Got Any Change?” Some excerpts:

Think back 50 years. If you grew up in North America, people were already travelling in cars, which moved along at about 60 miles per hour. You lived in a house with heat and running water, and you could just flick a switch to turn on the lights. You turned on the TV or radio to get instant news. You could pick up the phone and actually talk to relatives on the other side of the country.

For ease of daily living and communication, things haven’t changed much in the last 50 years for most North Americans.

My grandparents, by contrast, who grew up “when motorcars were still exotic playthings”, really lived through rapid and fundamental changes:

The magic of telephone reached into rural areas, and soon my grandparents adjusted to the even more astonishing development of moving pictures, transmitted to television sets in the living room. The airplane was invented about the time my grandparents were born, but they lived long enough to fly on passenger jets, and they watched the live newscasts as astronauts landed on the moon. (“Got Any Change?”, in the Brighton Independent, January 7, 2004)

As it turns out Smil was working on a similar premise, and developing it with his customary authority and historical rigor. The result was his 2005 book Creating the Twentieth Century: Technical Innovations of 1867-1914 and Their Lasting Impact. This was the first Smil book I picked up, and naturally I read it while basking in the warm glow of confirmation bias.

In the course of 300 pages, Smil argues that many world-changing technologies swept the world in the twentieth century, but nearly all of them are directly traceable to scientific advances – both theoretical and applied – during the period 1867 to 1914. There is no other period in world history so far, he says, in which so many scientific discoveries made their way so rapidly into the fabric of everyday life.

Most of [these technical advances] are still with us not just as inconsequential survivors or marginal accoutrements from a bygone age but as the very foundations of modern civilization. Such a profound and abrupt discontinuity with such lasting consequences has no equivalent in history.

For anyone alive in North America today, it’s easy to take these advances for granted, because we have never known a world without them. That’s what makes Smil’s book so valuable. In detail and with clarity, he outlines the development of electrical generators, transformers, transmission systems, and motors; internal combustion engines; new industrial processes that turned steel, aluminum, concrete, and plastics from scarce or unknown products into mass-produced commodities; and the ability to harness the electromagnetic spectrum in ways that made telephone, radio and television commercially feasible within the first few decades of the twentieth century.

Ship docked at St. Mary's Cement plant at sunset.

The Peter R Cresswell docked at the St. Mary’s Cement plant on Lake Ontario near Bowmanville, Ontario. The plant converts quarried limestone to cement, in kilns fueled by coal and pet coke. Photo from July, 2015.

Energy matters

There is a good deal in Creating the Twentieth Century on increasingly efficient methods of energy conversion. For example, Smil writes that “Typical efficiency of new large stationary steam engines rose from 6–10% during the 1860s to 12–15% after 1900, a 50% efficiency gain, and when small machines were replaced by electric motors, the overall efficiency gain was typically more than fourfold.”

But I found it odd that Creating the Twentieth Century gives little ink to the sources of energy. Smil does note that

for the first time in human history the age was marked by the emergence of high-energy societies whose functioning, be it on mundane or sophisticated levels, became increasingly dependent on incessant supplies of fossil fuels and on rising need for electricity.

Yet there is no substantial examination in this book of the fossil fuel extraction and processing industries, which rapidly became (and remained) among the dominant industries of the twentieth century.

Clearly the new understandings of thermodynamics and electromagnetism, along with new processes for steel and concrete production, were key to the twentieth century as we knew it. But suppose those developments had occurred, but at the same time only a few sizable reservoirs of oil had been discovered, so that petroleum had remained useful but expensive. Would the twentieth century still have happened?

Perhaps we shouldn’t blame Smil for avoiding a counterfactual question about epochal changes a century and more ago. After all, he has devoted a great deal of attention to a more pressing quandary: how might we create a future, with the scientific knowledge that’s accumulated in the past century and a half, while also faced with the need to move beyond fossil fuel dependence? Can we make such a transition, and how long might it take? We’ll move to those issues in the coming installments.

Top photo: Trucks hauling crude oil and frac water near Watford City, North Dakota, June 2014.

The Conquest of a Continent

A review of

The Conquest of a Continent

Siberia & The Russians

by W. Bruce Lincoln, Random House, 1994
Originally published in 1994

Siberia and Canada have much in common by way of geography and history. Europeans were first attracted to both regions by the lustrous furs to be taken in the taiga, tundra and boreal forests. In each case, trappers and traders soon proved it possible to deplete animal populations, even in seemingly limitless regions, unless attention was paid to conservation. In the ensuing centuries, prospectors in both countries found precious minerals, heavy metals, and petroleum in the most inhospitable of locations, spurring engineers to learn about permafrost, meltwater bogs, and shifting ice floes.

In both countries, colonizers have overwhelmingly clustered in a narrow band along the southern borders. Finally, the ways of the peoples who have made the northern lands their homes for millenia have been generally ignored by the newcomers.

If Siberians and Canadians have a great deal to learn from each other, there was little opportunity for contact for most of this century. But in the last few years, many Canadian companies with experience in resource extraction and arctic construction techniques have been welcomed in Siberia, while travelling delegations of native peoples have shared perspectives on preserving their cultures in an industrial age.

With these new opportunities for interchange, a familiarity with Siberia’s history is essential to many people. W. Bruce Lincoln’s new book tells part of this story ably, although Lincoln gives us only fleeting glimpses of the native peoples of Siberia, and almost no sense of how their cultures fare today or how they have contributed to Siberia’s history.

Lincoln’s opening sentence provides a controversial if succinct interpretation of history: “Nations are born of battle, and conquest makes them great.” The gory opening chapters on the Mongol armies, who exited history’s centre stage as quickly as they entered, may lead some readers to conclude that the book will equal the average action movie in its insights into the human condition.

Deeper into the book, however, Lincoln rounds out the story, even though the tales for the most part remain chilling. We learn about the slow progress of Siberian industry, as hundreds of thousands of workers carve railways through mountains and dig mineshafts in rock-hard permafrost. Lincoln weaves together many threads of political economy, to illustrate how the maneuverings of empire-building politicians in Europe often resulted in the starvation of prisoners thousands of miles away.

With only a few brief exceptions, each brutal regime seemed to beget an even more brutal regime, until the Bolsheviks, desperate to create an industrial colossus out of the reach of rival armies, sacrificed forced labourers by the hundreds of thousands. In the process, land and people suffered equally: “Siberia’s Soviet masters had transformed the fragile ecology of the tundra and taiga . . . into some of the most noxious surroundings on earth.” While Russia’s most recent rulers are seeking technical help to make Siberian industry more productive, the whole world, and especially the circumpolar countries, have an interest in helping Siberian industry clean up its act.

Lincoln’s book relates hundreds of tales of conquest in Siberia, but very little that could pass for greatness. With a lot of luck, perhaps the greatness will yet come.

Review originally published in the 150th Anniversary Edition of the Globe & Mail, March 5, 1994.

Inuvik History

Inuvik History Project

In 2006 I was approached by Dick Hill, the first mayor and long-time resident of Inuvik, Northwest Territories, to work with him in transforming his extensive notes and photos into a history of the community. The result was a two-volume set published in July 2008 and launched at the community’s 50th Anniversary celebration.

My role included writing and editing, research in digital photo archives from Ottawa and Yellowknife, scanning and touch-up of photos and slides, design, layout, and liaison with the printer.

Inuvik: A History is approximately 240 pages, with a selection of photos, maps and illustrations in black and white. Inuvik In Pictures is 48 pages, with full colour pictures throughout.

More information on these books is available here.
Below: front and back cover of Inuvik: A History

Cover photographs for Inuvik: A History

Front Cover, top, Inuvik from the air, 1995, photo by Staffan Widstrand/Corbis; Olympic skiers Sharon & Shirley Firth, photo by Dick Hill; loading gravel at Twin Lake gravel pit, 1955, photo by Curt Merrill; RCMP officer Gerry Kisoun, photo by Raymond Gehman/Corbis. Back cover photographs show the ‘Ice Worm’ Carnival, 1960s, photo by Dr. Norris Hunt; and author Dick Hill.

Below: front and back cover of Inuvik In Pictures


Cover photographs for Inuvik In Pictures:

Front Cover, top, raising the first large warehouse, 1956, photo by Curtis Merrill. Bottom left: Prime Minister and Mrs. Diefenbaker in Inuvik, 1961, NWT Archives. Bottom centre: civil servant housing, photo courtesy of Dr. N.E. Hunt Collection, Inuvik Centennial Library. Bottom right: Bill Nasogaluak at the Great Northern Arts Festival, 1992, photo by Tessa Mcintosh, NWT Archives.
Back Cover photographs: top row, left to right, Johnny Semple; Peggy Curtis; Nap Norbert; Cece McCauley; Rose Anne Allen. Second row, Cynthia Hill; unidentified; Martha Kupfer; unidentified. Third row, Billy Day, Doug Billingsley, Diane Baxter. Fourth row, Peter Clarkson, Victor Allen. Fifth row, Louis Goose.

The Arctic Grail

No oil slicks on the carpet, please

Launching Pierre Berton’s The Arctic Grail

Originally published in November, 1988

As photo opportunities go, the book launch for Pierre Berton’s The Arctic Grail was one of the most elaborate in publishing history. As arctic voyages go, the trip to a Beaufort Sea oil rig was somewhat less demanding than picking up Berton’s tome for an armchair expedition.

The Arctic Grail is an account of the romantic age of arctic exploration. Nineteenth-century audiences snapped up reports of their heroes fighting bitter blinding blizzards over vast uninhabited ice fields.

But a warm sun rose in a clear sky as two helicopters left Inuvik, 350 kilometres north of the Arctic Circle. As we flew north over the Mackenzie Delta, three-metre spruce gave way to one-metre scrub willow; soon we saw only lichens and lakes, and it seemed we were far from civilization.

The illusion was dispelled when we reached Tuktoyaktuk – Inuvialuktun* for “looks like caribou.” Herds of oil tanks flanked a winding shoreline, dwarfing the houses, the Catholic Church, even The Bay.

Berton closes his saga in 1909, when the motor age was just beginning. Eighty years later, prospectors are staking claims at the ends of the earth, oil companies are pumping gas from beneath the ice pack, and 20,000 horsepower icebreakers are making test runs through the Northwest Passage.

If thirst for petroleum sparked new interest in the north, it also made Berton’s book launch possible – the author and most of his entourage were escorted from Calgary by Gulf Canada Resources Limited. When the helicopters set us down on a deck 40 nautical miles from shore, our hosts began a tour of the Molikpaq oil rig.

Here came the day’s moment of high adventure – a crane lifted a dozen of us over the water to a tug boat. We stood on a swinging two-metre ring, clutching a rope rigging, while sparkling waves bobbed beneath us – more fun then the CNE**, and absolutely free. Gulf employees patiently followed photographers’ directions to put Berton in just the right position for the cameras.

Several hundred blinks of the shutter later the party was reunited in the dining hall, where we toasted our exploits with Carl Jung De-alcoholized Wine – the town of Tuktoyaktuk and Gulf’s northern facilities being “dry” zones.

Early explorers in Berton’s account were too stubborn to follow Inuit advice: “Could any proper Englishman traipse about in ragged seal fur, eating raw blubber and living in hovels made of snow?” They caught chills when their wool uniforms got sweaty, and suffered scurvy because they cooked the vitamins out of their meat.

As guests of Gulf we had no such worries. We filed past the fresh salad bar in stocking feet (no oil slicks on the carpet, please), and our musk-ox and caribou were served well-done.

Written during a stint as reporter for the Inuvik Drum, and published in NOW, Toronto, November 17, 1988.

* The original version stated “Inuktitut”, the more general name for Inuit languages, instead of “Inuvialuktun”, the language of the Inuvialuit of Canada’s western arctic region.

** CNE = Canadian National Exhibition, known to generations of Toronto youngsters for its amusement park rides.