Monday, July 13, 2009

The Renewables Hump 8: Concluding Thoughts on EROEI and Carbon

Time to wrap up my "Renewables Hump" series with a few concluding thoughts. Below are links to each of the prior 7 posts. My current plan is to synthesize this series into a shorter set of posts for The Oil Drum--I'll post those links here when they're up.

Renewables Hump 1: Introduction
Renewables Hump 2: Digging Out of a Hole
Renewables Hump 3: The Target
Renewables Hump 4: EROEI Issues
Renewables Hump 5: Proxy EROEI Calculations
Renewables Hump 6: EROEI of Solar and Wind
Renewables Hump 7: Can We Transision?

In wrapping up my thoughts on EROEI and the potential for our civilization to transition to renewable sources of energy, there remains at least one loose end I'd like to address:

Climate change. One of the most frequently-cited arguments in favor of transitioning to renewable sources of energy is that these technologies tend to be zero-carbon soruces of energy. What seems to go unsaid, however, whether we're talking about solar, wind, geothermal, or even (not really renewable) nuclear, is the up-front carbon footprint required to build this infrastructure. Simply put, the vast majority of the energy required to build a renewable energy generation infrastructure will be carbon-heavy fossil fuels. That means, in order to affect a transition, we need to spike carbon emissions in the build-up phase in order to reap lowered carbon emissions at some point in the future.

This necessarily cycles back to the EROEI questions that I have raised in this series. If the EROEI of renewable technology X is 40:1 over a 20-year lifespan, then only a very small amount of fossil fuels must be burned to produce long-lasting clean energy, and after a very short time the remainder of this transition can be financed with clean energy from the renewables build at the outset of the project (here, as fast as 6 months with a maximal investment at startup). Of course, if the EROEI is actually 4:1 over that same 20-year lifespan, for every 4 tons of carbon saved over that lifespan, one ton must be emitted in production, and that carbon emission must be up-front. Additionally, it won't be possible to bootstrap this clean energy to produce more clean energy for years, and likely far longer because it would create an impracticable energy price spike to build enough generation at the very outset of such a transition to allow for complete bootrapping of the next waves of production.

All this boils down to some of the most poorly understood aspects of climate science: are we better off raising carbon levels now in order to better reduce them in the future, or is it more important (from the perspective of various feedback loops, etc.) to keep levels from ever going over a certain threshold, even if that means more overall emission down the road? We simply don't have an answer to this question, but it suggests that the climate/carbon argument for a renewables transition is, at a minimum, built on a shaky and uncertain foundation. The real problem is that--much like broader discussions of the renewables transition--the uncertainty in the carbon-reduction argument for renewable energy flies under the radar because nearly all involved in the discussion use very high EROEI figures for renewables. If these figures, as I have argued, could actually be 10x lower than current estimates, then much of the current debate is off track.

None of this is to suggest that we should use uncertainty to abandon action, to stop efforts to transition to a sustainable society. However, we must accept this uncertainty in deciding HOW to best make that transition. More centralized wind and solar and a better grid might be the answer. It might not. Maybe the answer is decentralization and radical reduction in energy consumption? As I'll address in the future, structurally self-interested participants tend to argue for the former solution--you don't hear GE raising the uncertainties and potential socio-political pitfalls of centralized wind or solar. Unfortunately, we'll only find out if their confidence in our ability to transition was misplaced after such efforts have conclusively failed...


Rice Farmer said...

Thanks much for this series, and I look forward to seeing you post this on TOD.

You have made a good point with regard to carbon emissions and climate change, but interestingly, this same approach raises, as a corollary, the very question of how much we can depend on fossil-fuel bootstrapping. In bootstrapping the first wave, there is not just the problem of spiking carbon emissions, but also the more vital question of whether fossil fuels will be cheap enough. If, for example, developed countries decided to pull out the stops and build all the renewable infrastructure they can ASAP, the attendant rise in industrial activity would be expected to spike oil prices again. And we would also, as you pointed out previously, be dependent on the legacy industrial infrastructure to to this. Assuming we successfully build and deploy the first wave, what about the second or third? Will we still have affordable fossil fuels? Will the legacy infrastructure still be usable?

These questions need to be addressed, but we never even see them asked, let alone answered. Today I saw a follow-up post on Kitegen on TOD: Europe. In sum, they make it sound great. But no one seems to wonder where all the steel is coming from. All that is just taken for granted.

Jeff Vail said...

Rice Farmer:

I think the key issue is time. If we're in no rush to transition, then I think it's certainly realistic to build a small renewable build-out utilizing fossil fuels and legacy infrastructure (and a similarly small carbon footprint), and then to gradually use the carbon-neutral energy from this phase 1 renewable buildout to build phase 2, etc., gradually ramping up the rate of production. In fact, I'd argue that's essentially what we're currently doing. The question is--and here EROEI becomes key--how long will this process take to reach a given level of renewables generation? Can this process ramp up renewable generation fast enough to mitigate peak oil (the target I've suggested)? What about fast enough to further reduce carbon levels to some target level/date? Again, this is a matter of EROEI--if the "true" EROEI of the technology in use is 70:1, then I would be very confident that the answer is yes. If it's 3:1, then I'm equally confident the answer is no. Which, alas, brings us right back to the issue of uncertainty...

On KiteGen--I, too, saw the second installment on TOD. I agree, it looks very interesting, and, to push aside my tendency toward skepticism for a moment, it also looks very promising. Assuming you can control cable weight through high-tech materials, and assuming you can have a sufficiently sophisticated set of kite controls, it might work. It really needs to be an advanced, ultra-light-weight, variable-geometry flying wing with fly-by-wire controls (in part to capitalize on the enhanced maneuverability, but mainly because flying-wing configurations are notoriously unstable). That's a lot of high tech--the manufacuring for these advance materials, the design, maintenance, and operation of this flight system, etc. My guess is that the hidden, unaccounted for energy input here will be less the steel (as I previouly guessed) and more the number of people and facilities that will need to operate to put together something this fast. Look at a $2 billion B-2 bomber: the energy embodied in the steel isn't that great, but the energy required in the manufacture and engineering of the advance materials, the massive numbers of people required to design and build the system, etc. are where the real eneryg is embodied (as represented by the $2 billion price tag. I think KiteGen is more of like the B-2 than a windmill...

Also, I wonder about scalability. Unlike windfarms, where you can put up one op dozens or hundreds of turbines in a square mile, this kite system looks like you'd need much more spacing, especially for optimal flight routing...

bryant said...

This has been a great series of articles, Thank you.

In your response to Rice Farmer you said:

the energy required in the manufacture and engineering of the advance materials, the massive numbers of people required to design and build the system, etc. are where the real energy is embodied

So true! Odum strikes again. The decline in per capita energy in the US is visible in the scientific professions...we know and understand less than our fathers.

Anonymous said...

Jeff: Thanks for a very interesting series – I'll be looking at EROEI numbers much more critically in the future!

To some extent the discussion of transitioning to renewables is academic, at least as far as climate change is concerned. When you consider both who holds power, and human nature (who's going to give up their SUV – or their chance to own a Tata – voluntarily), the chance for a shift to renewables, or what's really needed, a massive conservation effort, are pretty slim.

Some interesting numbers from the latest BP Statistical Review: 2008 world energy consumption up 1.4%, China up 7.2%, US down 2.8%; for the 3rd year in a row coal accounted for the majority of energy consumption growth. Not good news for climate. Realistically, if Hansen's 350ppm CO2 max is anywhere close to right, the critical problem becomes dealing with massive climate change.

Al Eggen said...

sorry - I hit the wrong button anonymous is me....

Rice Farmer said...

Thanks for the thoughtful response. The point about the energy embodied in technology is well taken. We don't even need to look at something as big as a B-2 bomber. Jet fighters are much smaller but also very expensive. The energy embodied in their high technology far outweighs that in their steel.

There is one other nagging question to be addressed here. Kitegen and the like will generate electricity. In fact, renewables will give us mostly electricity, while producing relatively small amounts of liquid and solid fuels. Clearly, there will not be enough high-density solid fuels to keep blast furnaces and steel mills running, and I dare say electricity cannot be expected to take up the slack. Here again, proponents seem to assume this will take care of itself.

The bottom line is, keeping high-tech industrial civilization running is going to be a far greater challenge than most people imagine.

ryan said...

great series, jeff.

"Simply put, the vast majority of the energy required to build a renewable energy generation infrastructure will be carbon-heavy fossil fuels. That means, in order to affect a transition, we need to spike carbon emissions in the build-up phase in order to reap lowered carbon emissions at some point in the future."

yikes! spiking carbon heavy fossil fuels to build "renewable" energy infrastructure to power a culture that still seeks "growth." not a good idea.

"Realistically, if Hansen's 350ppm CO2 max is anywhere close to right, the critical problem becomes dealing with massive climate change."

it turns out 350 is probably too high to avoid climate change events with the potential to end civilization. see "350 is the wrong target" at

"So 350 ppm is the wrong target because 350 ppm CO2 cannot restore the Arctic ice to its full extent. The people who run probably now recognise that, because their language is changing. One of their slides used to say: “We need to be here: 350”, it now says “we need to be lower than: 350ppm”. McKibben now talks about 350 ppm as being “the upper limit”, and in a recent radio interview said pre-industrial levels might be the only safe zone. But it’s too late to advocate targets that are only a signpost towards the target we really need to get to."

a global movement to shut down coal plants and radically reduce fossil fuel use combined with reforestation of the tropics (oh, we have to end deforestation, too), and creation of decentralized "carbon negative" communities linked through emerging online networks might give us a chance. Biochar seems to be the most effective and easy to implement carbon negative technique. i estimate we have maybe 5 - 10 years to get this going before social upheaval from failing states, resource conflict, enviro collapse make the effort virtually impossible.

if McKibben's 350 movement pushed for global networks of carbon neg communities it would take very little time for the trend to catch on. the idea would be to get groups going dedicated to living "beyond sustainable" - after they achieve their own self-sufficency they would endeavor to stabize civilized regions - especially poor areas (the beneficiaries of civilization are typically not interested in living differently).

"The bottom line is, keeping high-tech industrial civilization running is going to be a far greater challenge than most people imagine."

agreed. civilization is brittle and unprepared for rapid change.

check it out: American Renewable Energy Day in Aspen
the slogan is "The Problem is the Solution."

whew! we're saved! it turns out the problem is not actually the problem... its the solution... according to the industry responsible for and profiting from the problem.


industrial civilization requires slaves. it represents the latest attempt in the history human societies to maintain hierarchy and repression. slavery as a human institution has always failed.

civilization is a hypertrophy of innate structures - basic primate biological impulses manifested into culture.

if we are able to push cultural evolution consciously into adaptive modes more in tune with both human nature as well as the circumstances of the 21st centruy world something may emerge.

esme said...

Ahh, so many intelligent opinions and analysis. It makes me glad to see that there are very involved discussions/questioning going on at this site.

I agree with so many of the previous comments, and i am in no way a technology person, but i appreciate a smart, simple, effective tool when i see one. Too bad our society runs on so many inefficient, redundant, absolutely uneccessary, overly-complex machines. The only thing they power, is this obsessive, mass social and nature control experiment that we have embarked on.

In many ways, industrialized people are very much primitive, for our societies are built on top of fiercely held ideologies and "beliefs" about how the world works and what may come to pass. Our whole commercial culture is based on fantasies and fabricated, mass-dispersed dreams.

Whatever happens, all we can do is take charge of our own lives, help our families, friends and neighbors take charge of theirs and in doing so, change our lifes into something we cannot fathom, just as someone from 200 years ago couldn't fathom life as we know it today.

Robert Martini said...


I've always wondered about a fundamental basic charateristic of centralized and decentralized systems. My theory is that centralized systems leverage power and decentralized systems leverage raw efficiency. The idea is that Centralized system can organize a process and streamline it to produce things fast, but tend to sacrifice efficiency and produce waste because of the energy required to concentrate energy, materials and the associated transportation and infastructure cost. Decentralized systems because of there nature of having the production process at the location of the resource node and therefore having little or no transportation cost tend to maximize full uses of resources and efficiency. They lack the centralized capital to be able to streamline and increase the the resource can be utilized. The reason centralized systems are so prevalent are their resistance to isolated shocks or competition, whereas in times of resource scarcity, decentralized systems tend to prevail.

Even in biology the body size of creatures is a good indicator of the resistance to extinction. One could argue body size is an indicator of the centralized nature of a certain amount of biomass, and that an extinction period is due o relative resource scarcity? The larger a creature though, the more resistant is it to isolated shocks such as a predator or threat of competition. Good analogy or no??

DaveK9999999 said...

I have written an article called "The energy dynamics of energy production" that deals with this very subject.

It is not so wordy and descriptive as your article, but gets down to the calculations more quickly (contrast the lawyer with the mathematician :-)

The key is to use a spreadsheet to lay out the history of a single year's worth of production - its EIUF (Energy Input Up Front) and the following ER, and then to repeat that for each year with a growth factor representing the increase in production. These histories can then be totalled for each year, and the results plotted in a chart.

The results will be counter-intuitive for some, but you are right that the green vision of PV, which I once championed myself, is a myth. We will get half way there and then the remaining fossil fuels will be too precious to spend on anything other than keeping the lights on.

Obviously there is a different history for each technology, and PV is simple because all the EI is EIUF, whereas with nuclear, a lot of EI is spent on making fuel rods and in the decommissioning phase.

For PV with an ERoEI of 3 and a lifetime of 25 years, a panel is only able to produce enough energy in a year to build 12% of a panel. Thus if the growth of the PV industry is to be more than 12%, the panels' output will never be sufficient to power the industry and it will always need a fossil energy subsidy.

The article includes a spreadsheet in which you can try different values out.


Joy said...

You need to factor in energy efficiency, doing more with less, which has $ payback often in 1, 2, or 3 years for the low-hanging fruit.

Conservation, doing less, has infinite EROEI.

We need enough efficiency plus conservation to counter fossil fuel spikes necessary to build renewables.

Once the investment has been made, the marginal cost of solar will be close to zero. We will live in a world of free (but limited) energy, as I do today (solar paid off, no electric bill).

Thin film PV has a much lower $ and energy cost than crystalline silicon. Not only are costs dropping rapidly, installation and other BoS costs are being rationalized and meeting economies of scale.