It’s the nett energy stupid…..

18 12 2012
Or what is the big deal about Energy Return on Energy Invested

Another stinker (must be at least 37° again today), and it looks like another storm in the offing.  In the end, we only got 26mm last night, more lightning than rain…. but all donations gratefully accepted!

There’s so much hype these days about how America will become energy self sufficient because of all the shale deposits being mined.  It’s hard to explain to people new to the energy cliff exactly how much difference good and bad ERoEI makes to the running of our civilisation.  Everything, not least the maintenance of all the stuff that is already here, relies on available surplus energy to keep our living arrangements humming.

Before we discovered energy dense oil and coal and how to exploit it to the max, everything was done by hand.  Or hoof.  I always have to laugh when people say to me it’s impossible to run society on 100% renewable energy.  Exactly how do they think we got to here before oil and coal were exploited to death?  Magic?  Yes my friends, 200 years ago, everything ran on renewables…. biomass for food and firewood, wind and water for power to grind grains, and biomass powered by solar energy.

Speaking of firewood, you would be amazed at how much curry I get from some quarters for burning the stuff in the AGA.  I’m not surprised that some people equate firewood with smoky pollution, because a lot of people who burn wood in places like Launceston and Armidale really are environmental criminals, or just plain lazy sods…. so when I found this chart below (source), I was just staggered…

It’s very obvious with just a cursory glance at this why the industrial revolution was so successful.  With coal at 80:1 and the oil discovered prior to the 1930′s at 100:1, who in their right mind would do heavy work with muscle power?  The jump to less than half that in the next three bars, hydroelectricity and post US Peak petroleum, also clearly shows why there was an energy crunch in 1973 and 1980.  All of a sudden, some 50% of all surplus energy disappeared…..  and it all had to be replaced with ever more imported oil (at least in the US, by far the biggest economy of the time).

But what really caught my eye was the bar for firewood……..  Firewood has today the same ERoEI as imported oil in 2005, the largely accepted year global Peak Oil occurred…!  I cannot wait for the next time some clot starts sparring with me on some ABC forum about my firewood habits; I’ll be able to tell him that firewood is more efficient than NUCLEAR…!  That’s so amazing, even I have difficulty believing it.  Except of course that firewood is used exclusively to generate heat, unlike electricity, an energy source that is unequalled for running computers, lights, TVs and charging your iGadgets, but terrible for making heat….

When you think of how electric heat is made, by burning a fossil fuel a long way away to heat water up and make steam to drive a turbine that drives a generator, and feeding the resulting electricity down some long wires, through 1, 2 and sometimes 3 transformers to your house where you re convert it to heat is complete stupidity.  Compare that to using a gas stove where the fossil fuel is lit directly under the saucepan, and it’s a no brainer as to which method is best.

Enter firewood, which is renewable (it grows on trees!) and, if sustainably replanted, is also Carbon neutral, and yes I can see why firewood has such a high ERoEI.  Just don’t expect to run your laptop off it.

Anyhow, this chart doesn’t have a bar for shale oil, but I expect if there was, it would be right next to the tar sands one…..  The future will not run on shale oil and tar sands, those two terrible fuels are only possible while we still have that good stuff from before 2005……  and after that?  Better start planting lots and lots of trees.



15 responses

18 12 2012

Thanks Mike, very interesting. My previous motto “Think local, act local” has now been replaced by “Live like a peasant”. Which probably means getting rid of the computer! Cheers, Judith

18 12 2012

No no Judith, we are thoroughly modern peasants…!

19 12 2012

fascinating graph Mike. I share your frustration with those who’ve obviously never thought about how we got to the age of fossil fuels! and I’ll definitely be using the firewood has a better EROEI than nukes line.

19 12 2012

It is, however, correct to state that one cannot and will not run *today’s* society on 100% renewables. The society that ran on 100% renewables was a lot smaller, both in terms of geographical distribution and population number and got by with an order of magnitude less than even, dare I say it, yourself.

Also, not sure how I got to be an environmental criminal but I can live with that in my warm house during winter. Since I’m the one sucking up the particulate emissions in the morning as I cycle to work I figure it evens out.

24 12 2012
Greg Bell

I’m suspicious of that graph – 0:1 is surely an error? No energy returned on 1 unit invested? Did they mean 1:1?

24 12 2012

Well it’s possible to get less than 1:1….. and 0:1 may be a poor choice of expression, but it just means zero. Zero ERoEI may be hard to explain, but you have to put a value on the axis to start somewhere.. I just hadn’t thought about it before.

24 12 2012
Greg Bell

I’m just going to be bold and say it’s not a poor choice but is wrong. There’s nothing that we’d do that would yield zero energy returned. Judging from what’s near that horizontal line, I’d say they meant “1:1”.

But a careless error like that makes me doubt the accuracy of the whole chart.

24 12 2012

Oh but there is Greg……. look at this: (

Net Energy

But here is what so many fail to understand. Look at the net energy.

At 20 to 1, an investment of 0.5 units got 10 back out. The net is 9.5 units.

At 1.3 to 1, it took an investment of 7.69 units got 10 back out. The net is 2.31 units.

At 1 to 1, an investment of 10 units got 10 back out. The net is 0 units – all you have done is converted one energy form into another. (And of course at less than 1 to 1, you have actually lost usable energy during the process).

If we wish to net 10 units, then at 20 to 1 we have to produce a total of 10.53 units (you are solving 2 equations here; EROEI = Out/In and Net = Out – In; For EROEI = 20, the solution is Out = 10.53 and In = 0.53). For an economy that requires 10 units of energy to run, we need an excess of 0.53 units to net that 10. (And if you want to pick nits, 10.53 is rounded from 10.5263157894737).

Now drop the EROEI to 1.3. We now have to produce a total of 43.33 – an excess of 33.33 – to get the 10 we need to run the economy (Out = 43.33, In = 33.33; EROEI = 1.3 = 43.33/33.33; Net = 10 = 43.33 – 33.33). Thus, the requirement from dropping the EROEI from 20 to 1 down to 1.3 to 1 requires a production excess of (33.33/0.53), or over 60 times the high EROEI case.

Running Faster to Stay in Place

Therein EROEI illustrates clearly the challenge we face. As EROEI declines, energy production must accelerate just to maintain the same net energy for society. At an EROEI of less than 2, the amount of energy required to net our current energy usage far exceeds even the most optimistic proposals for our production capacity. Others have concluded much the same: The status quo can’t be maintained if EROEI continues to decline.

Many don’t grasp this concept. If they did, they would understand why a falling EROEI is reason for concern.

24 12 2012
Greg Bell

You (or the chart’s creator) are confusing EROEI with nett EROEI. They labelled the y-axis EROEI, which means 0:1 is nonsensical. None of those energy sources listed yield 0 units of energy, though many yield 0 units of nett energy.

3 04 2014
Tony Dickson

Hi Mike, I am glad you put this link onto The Conversation. I wish I had that graph when I was doing battle with Dr. Robinson in Armidale some years ago.
We run our whole farm on about 5kwh/day. All heating requirements are provided by the crap firewood which is unsaleable.
I have developed a plantation management regime based on copsing, which maximises growth rates and ecological values by replicating, to a large extent the structural diversity of natural forest.
Current estimates indicate that the number of species found only in the canopies of eucalypts may be as many as 250,000. The same cannot be said of a nuclear power station, or indeed a wind farm.
You are no doubt aware of the arguments about domestic PV pushing up power prices. An overlooked aspect of such PV investment is the unquantifiable effect it has on encouraging frugality. I have noticed so many people of my acquaintance who could never have told you how much power they used, suddenly becoming “light Nazis” and ordering their domestic habits and discretionary power use around their feed-in tariffs, or lack thereof.
Do you have any data or thoughts on these matters?
Cheers, Tony.

3 04 2014

Hi Tony, welcome to the fray……. boy those fellas on TC have been keeping me busy this afternoon!

I agree with PVs encouraging frugality…. though I struck out with that couple + teenagers’ $1600/qtr power bill! Such wanton consumption I have never seen before… oh to be rich enough to just sign a cheque and pay for it!!

Sorry no data. But we sure live in interesting times…

3 04 2014
Tony Dickson

Yeah, I must get back to work myself.
I had some customers who had a similar bill, plus they were going through a big gas bottle a month and a tonne of my firewood every ten days or so. I gave them the arse. They definitely fell into the catagory of cashed up bogan: a full cool room for their booze next to the spa on the deck and because they liked the outdoors lifestyle, they airconditioned the deck.

The phrase, “age of entitlment” comes to mind.

3 04 2014

wow………….. the mind boggles. Airconditioned deck hey…. even that’s a new one on me!

3 04 2014
Tony Dickson

Mike, while I was converting another couple of tonnes of firewood this afternoon, I was reflecting on the graph. Do you have any metadata to support the conclusions re the EROEI of firewood? There was nothing in the article by Gulland. There are so many variables applicable to firewood production, I cannot help being sceptical about the graph.
For example, Adelaide and surrounds, imports over 30,000 tonnes of red gum industrially processed from remnant forests in NSW each year. That is a 600 klm road trip. My plantation firewood market is twelve to fifteen klm from where it was grown. Much of the work is done by manual labour. I sell about 100tonnes pa. Australia’s firewood consumption is estimated at about 5 million tonnes pa, almost all of it wild harvest.
I would certainly like to believe it, but I have never been very good at cognitive dissonance, which is why I do not subscribe to any ideologies or religions. This is an affliction that can be very inconvenient at times, as I am sure you are aware.
By the way, are you familiar with the good Dr. Dorothy Robinson that I mentioned previously? She is an anti firewood zealot. I fully acknowledge the validity of her concerns in places like Armidale and Launceston etc., but she wants wood fires banned nationally for reasons of CO2e emissions.

4 04 2014

Hi Tony……. of course, not all firewood is created equal. Calculating ERoEI of ANYTHING is mired with complications. In the case of firewood, even whether it’s been dried properly or not is an issue!

I know what you mean about cognitive dissonance…. I constantly struggle with this. Especially over at The Conversation!

Transporting anything long distances is an obviously bad idea, however, I have seen figures showing mass transportation by cargo ship/containers is so efficient, it becomes virtually meaningless as an added cost in embodied energy. I can’t find it right now, but I’m pretty sure I saw somewhere that it costs 11 cents to ship a pair of jeans from China (as part of a large container shipment obviously), and if that 11c is entirely fuel (and it wouldn’t be), then it represents perhaps 250 grams of CO2 emissions.. You’d probably emit that by just burning the kindling to start your fire….

Zealots are a pain in the arse, whether they are anti firewood or pro renewables..!

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