New deals, old bottles

I’ve just come across an interesting article on skewering the old ecomodernist fable that the discovery of oil saved the whales from extinction. Funnily enough I wrote a blog post making much the same argument four years ago, which I think I’m right in saying is the only post I’ve written that received precisely zero comments. The perils of being ahead of one’s time… Well, no matter, let us press boldly on with a new post…which I fear may be my second one to attract no comments, since pressure of work on the farm and in the study has led me to grievous neglect of this website.

So, New Left Review has recently been running a series of articles on the environment and left politics, and I thought I’d comment briefly on a few points arising from them – not least in relation to Troy Vettese’s article ‘To Freeze the Thames’, which follows on neatly from my previous ‘half-earth’ post1.

Let me begin by saying that we leftists do often struggle with the issue of the environment. One member of our tribe recently told me proudly on Twitter that the left was ‘against nature’ (yes, really), and it’s true that historically we’ve had a bit of a thing about trying to keep the messy world of the natural, the organic and the rural at arm’s length through various ruses like economic growth, industrial development, tractor production and occasionally even the odd bout of peasant-slaying. So as you can imagine, I had to submit myself to several years of therapy before feeling able to commit to writing a blog called ‘Small Farm Future’. And I still own a tractor. Hell, some things are sacred.

Anyway, the point of all this is to start off with a thumbs-up for Vettese – while the neo-Bolshevik wing of left-green writing drifts towards self-parody in its demands for air conditioning as a human right, Vettese’s program of organic vegan eco-austerity and ‘natural geo-engineering’ strikes a more authentic note for me. Nevertheless, I have some problems with it…though also with Robert Pollin’s ‘green new deal’ and anti-degrowth response to Vettese (and others) in the latest issue of the journal2. So here’s a brief precis of the issues as I see them.

Vettese thinks we should plant trees to mitigate climate change. A lot of them. On the basis of a paper by Sonntag and colleagues in Geophysical Research Letters3, he suggests that if 800 million hectares of land were reforested globally, the carbon thus sequestered would reduce atmospheric CO2 to the low 300s ppm, a feat of ‘natural geoengineering’ far wiser than the various madcap high-tech schemes currently mooted, putting CO2 concentration into a “safer range”. The 800 million hectares would mostly be carved out of current agricultural land. For Vettese, “agriculture is by far the most profligate sector of the economy in its greenhouse gas emissions and land-take” (p.82) – particularly in terms of livestock production. So he proposes to find his forest land by ‘euthanizing the carnivore’ (a paraphrase of Keynes on landlords). No more ruminant meat or milk, and no more arable crops for livestock fodder. But Vettese also has roads and urban sprawl in his sights – not so much because of their emissions (“energy efficiency means that carbon pollution from cars is not as great as one might have expected”) but because of land scarcity. Land scarcity is Vettese’s big thing: “It is land scarcity, rather than rare natural resources, that is the ultimate limit to economic growth” (p.66).

Scarcity, schmarcity says Robert Pollin in the succeeding issue. Invoking the authority of Harvard physics professor Mara Prentiss’s ‘rigorous account’, he argues that the US could meet its entire energy consumption needs through solar energy alone while utilizing no more than – and possibly much less than – 0.8% of its total land area for photovoltaics. Other countries like Germany and the UK with higher population densities and lower insolation face somewhat more challenging tasks, having to ramp up their energy efficiency and devote a bit more land, but still only about 3%, to photovoltaics. And that’s pretty much the alpha and omega of Pollin’s intervention. In his view, if we quickly decarbonize the world’s energy supply, then we can continue growing GDP and global incomes – whereas degrowth scenarios would slash incomes, prompting an economic depression that would make social welfare and environmental protection improbable.

Working through these analyses, starting with Vettese, to my inexpert eye his inferences from the Sonntag paper seem sound. But even assuming the political will I’d question how easy it would be to forest large swathes of the world currently used for rangeland, which weren’t necessarily forested in the first place (there’s a side issue here about premodern human forest clearance which, again, Vettese disposes in favor of his scheme rather questionably, essentially via a single reference). Moreover, the Sonntag paper suggests that, in the absence of other mitigation efforts, the temperature reduction caused by the forestation would only be about 0.27K – so yes, “safer” in terms of climate change, but not necessarily “safe” (incidentally Sonntag says that only a minor fraction of the carbon sequestration would occur in the soil, which further makes me question the soil sequestration claims of the regenerative agriculture brigade I’ve previously discussed).

There are also problems with nutrient limitation to forestation that Sonntag explicitly omits from his analysis, but others have raised as an issue4. I can’t claim to be able to model forestation effects with the sophistication of Sonntag, but I do wonder about it. FAO data suggest that the mitigation provided by the world’s existing forest cover of about 4 billion hectares amounts to only about 5% of current emissions, so on the basis of those figures if forest cover doubled (a much greater forestation than proposed by Vettese) and all direct agricultural GHG emissions ceased but emissions otherwise remained the same, then global emissions would still be occurring at about 80% of current levels.

In fact, this is the biggest problem I have with Vettese’s analysis. Cars and other fossil fuel-burning technology may emit “less than one might have expected” but it depends on what “one expected” – this is an extraordinarily weak claim on which to build a whole mitigation approach. FAO data suggest that about 50% of global emissions come from the energy sector, 14% from transport and 7% from industry, with only about 11% coming from agriculture and another 11% from land use change (though some of the energy, transport and industry emissions are agriculture and food system related). Agricultural methane emissions largely associated with livestock only account for 6% of total emissions (leaving aside methane-GHG equivalence issues) and agricultural nitrous oxide emissions only partly associated with livestock account for 5% of total emissions. I get the sense that Vettese’s veganism may be the tail that’s wagging his climate mitigation dog – maybe another example of what Simon Fairlie calls the “mendacious rhetoric about cows causing more global warming than cars”5.

Still, I’m not fundamentally opposed to Vettese’s vision of an organic, vegetable-oriented agriculture. He says almost nothing about the geography of his proposals but I’m guessing that an eco-austere world of minimal fossil fuels and mostly vegan organic agriculture would also have to be a mostly rural world of distributed human populations. I don’t have too much of a problem with that, but in such a world organic smallholders would have to build fallows and leys into their cropping for fertility reasons and efficiency would be enhanced if they included some livestock to graze them and perhaps some pigs or poultry too to clean up wastes and do a little work around the holding (ground preparation, manuring, pest control etc.) In temperate climes particularly, their fat as well as their meat would certainly be a welcome and possibly a necessary addition to the diet.

But if Pollin is right this is all a huge overreaction. Just decarbonize the power supply, mostly through photovoltaics, then we can get back to economic growth as usual, and leftists can get back to the safe territory of their long-running battle with rightists about the just distribution of the spoils. I’d like to believe him, and I agree that switching away from fossil fuels towards photovoltaics as rapidly as we can right now is a good idea. But in the face of the world’s numerous intersecting social, political, economic and biophysical crises which have been voluminously discussed on this site over the years, I don’t think a rapidly decarbonized energy system, or even a wider ‘green new deal’ associated with it, is adequate to the task of renewal.

I took a look at the Prentiss book referenced by Pollin6. Table 11 on p.153 seems to be the critical one on which Pollin bases his claims. I can’t claim Prentiss’s exalted credentials as a physicist, but I was surprised at how un-“rigorous” the table seemed – no dates, no sources and somewhat slapdash in its use of units. But anyway, assuming the data she presents are sound, the basic claim seems to be that PV panels in the USA can on average capture 40 watts per square meter – ‘on average’ presumably meaning that this figure adjusts for summer and winter, night and day. That’s a lot more than the panels on my roof capture, though to be fair I live on a (usually) rain-soaked island at a more northerly latitude than the great majority of the US population. I do wonder a little about where Alaska fits into this picture, since it constitutes about 18% of US land area and is even more northerly than my location, but anyway taking Prentiss’s data as given suggests by my calculations that each of the USA’s 300 plus million residents would require something like 150 square meters of PV panels to furnish current energy consumption (and here we’re just talking about domestic energy consumption, not energy embodied in imported artifacts).

Pollin’s point is that, contra Vettese, this 150m2 when it’s aggregated up isn’t a large proportion of the USA’s land, and he’s right about that. But when you pace it out – 12.2 meters by 12.2 meters for every single resident in the world’s third most populous country – it does seem to me a large amount of material and engineering infrastructure, not to mention a huge social transition towards a completely electrified energy system. Pollin’s notion that it’s achievable worldwide without major perturbation in the global economy seems optimistic at best. For sure, anything humanity does to tackle the issues it currently faces is going to have to be huge. Pollin’s critique of the degrowthers for ducking current energy and carbon imperatives in favor of a more generalized approach to economic downscaling is perhaps well taken, but I can’t help thinking his analysis involves a complacency of its own.

Pollin says that a good ethical case can be made for high-income people and high-income countries to reduce their emissions to the same level as low-income people and countries, but that there’s no chance this will happen and “we do not have the luxury to waste time on huge global efforts fighting for unattainable goals” (p.21). The problem as I see it is that the same applies to his own prescription. While the world’s political structuring hinges on nation-states with vastly different levels of economic and military power jockeying with each other out of short-term economic self-interest with only the most reluctant (and dwindling) concessions to multilateral concord, then the idea of a rapid decarbonization in the USA – one of the most powerful of such nation-states – out of some wider ecological perspective seems remote. Likewise, the idea that other countries will prioritize decarbonization in meek acceptance of the fact that the US and other wealthy countries won’t play ball with their per capita emissions. Frankly, the idea of a rapid switch out of fossil fuels in a country enjoying a second fossil fuel bonanza in fracked natural gas – a country in which so many chafed under a center-right president widely regarded as some kind of communist, and then elected a successor who doesn’t think climate change is happening and wishes to invest in coal – seems highly unattainable to me. Mind you, politics has become so capricious and unpredictable these days that I wouldn’t entirely bet against some green new dealer making it to the White House in 2020. But if I had to put up some money, I’d still bet against it. Meanwhile, for his part Vettese also has a penchant for unattainable goals, in this case a venerable leftist one: “A solution to global environmental crises requires the humbling of the global bourgeoisie, the richest several hundred million” (pp.85-6). No doubt, but I’m not seeing how that will take shape in the present global political landscape.

Of course, it’s easy to pull down other people’s castles in the air without suggesting more plausible alternatives. Sadly all I have to offer is this: the time for climate change mitigation that will prevent major future climate perturbations is probably more or less over, and what we’re faced with is climate change adaptation. I think that process will be grim, but I also think that ultimately it will probably spell the end of the contemporary nation-state, the world system of states, and the global capitalist economy, and for some people at least that may prompt some more positive outcomes – perhaps along the lines of the world imagined by Vettese. I’m aware that some commenters on this site find such views repulsively negative, but I don’t see it that way. I’m looking for the most positive outcomes I can find out of the most realistic socio-political trajectories I perceive. More on that soon, I hope.


  1. Vettese, T. 2018. To freeze the Thames: Natural geo-engineering and biodiversity. New Left Review 111: 63-86.
  2. Pollin, R. 2018.De-growth vs a green new deal. New Left Review 112: 5-25.
  3. Sonntag, S. et al. 2016. Reforestation in a high-CO2 world—Higher mitigation potential than expected, lower adaptation potential than hoped for. Geophysical Research Letters 43: 6546-6553.
  4. Kracher, D. 2017. Nitrogen-Related Constraints of Carbon Uptake by Large-Scale Forest Expansion: Simulation Study for Climate Change and Management Scenarios. Earth’s Future 5: 1102-1118.
  5. Fairlie, S. 2010. Meat. Permanent Publications, p.184.
  6. Prentiss, M. 2015. Energy Revolution: The Physics and the Promise of Efficient Technology. Harvard Univ Press.

24 thoughts on “New deals, old bottles

  1. Left a message on Resilience. But I want to add that the prescription to plant trees/bushes/regrassify (depending on local conditions) is doable one person, one small organization at a time. It is not subject to Jevons Paradox. So I would not knock it. (I know you don’t, having done it yourself, just sayin’.)

  2. Don’t confuse the carbon sequestration from existing, mature forests with the sequestration possible from new plantings. If existing forests are absorbing 5% of current emissions, that’s 5% more than I would have expected. At some point a forest reaches carbon saturation, it loses carbon as fast as it’s absorbed and becomes carbon neutral.

    I think the best way to expand forests is in areas that are warming rapidly and are able to grow trees that wouldn’t have survived that long ago. Massive expansion of boreal forests toward the poles and alpine forests up mountain ranges will happen naturally, but the process could be greatly accelerated with human help. This is a lot of acreage that would not be deducted from food production. It would also help to harvest as much wood as possible from mature trees everywhere and use it in long-lived structures instead of steel and concrete.

    In more southern latitudes planting nitrogen fixing trees would greatly mitigate the nutrient issue. There is a wide range of nitrogen fixers from red alder to albezia that covers a variety of temperature zones.

    Of course the best thing would be to stop emitting carbon right now and let natural vegetative growth absorb the excess carbon in the atmosphere, but that has some undesirable side effects, like losing most of the human population.

    Even so, of all the possibilities, it seems to me that a civilizational collapse resulting in a halt to emissions is more likely than an energy transition or a giant sequestration project. That’s what I would recommend as the primary focus of any adaptive strategy, but I’m not one who finds “such views repulsively negative”, just realistic. Sometimes there just aren’t any good solutions and we have to make the best of a bad situation.

    • Lucid.

      And. We don’t need a giant project, just lots of people jumping on the bandwagon. Would be a nice thing for Gaia no matter what happens to humans.

  3. If we focus on land-use I believe the superiority of vegan diets are grossly exaggerated. if you look at the food and agriculture system as a system and not as fragmented LCA results, you will see that livestock and crops are complementary and that you can produce more food by having both. Which is what all agricultures of the world have had. The proportions will vary depending on local factors. Even in a more limited perspective, if we take nutritional values into account, the superiority of crops are exaggerated when it comes to supply of essential amino acids. In the linked research, the researchers studied GHG emissions and land use from animal and vegetal foods and related that to the supply of essential amino acid. Not surprisingly, soy beans is the winner of the game also when protein quality is taken into account (they didn’t discuss antinutrients etc), But many animal protein sources were more efficient in land use than many vegetal sources and even for GHG emissions there was no clear advantage of many vegetable crops.
    For some crops, while their footprint is small, there is a need to eat unrealistic quantities to satisfy needs of the limiting amino acid (e.g. 2,8 kg of potatoes or more than a kg of peas), which also means that people HAVE to overconsume protein and calories to get enough of the limiting ones. The researchers even tested a few combinations of grain-pulses which are know for complementarity in protein and while that improved the equation a bit, it was not that much.

    Their conclusion is:
    “In this study we estimated the environmental footprint, expressed both as land use and as GHGE, associated to production of standard amounts of selected, reference foods, in respect to the requirements of essential amino acids for humans. The main conclusion of the study is that, under this perspective, the theoretical advantage of producing vegetal rather than animal proteins, is either markedly blunted, abolished or even reverted, with the notable exceptions of soybeans ”
    And this is not the only study showing similar kinds of results.
    As for reforestation, that is all cool and it is already happening, Global forest cover is on the increase since approximately year 2000. But the question of how much carbon you can actually bind in forests is still an open question. People tend to see the trees, but the longer term sequestration of carbon is the build up in the soils as above ground carbon will be recirculated in the biosphere at a much quicker rate. It is likely more efficient to restore many of the wetlands and peat bogs that have been drained for agriculture or forest purpose. Those lands are constantly losing carbon, in Sweden the carbon loss from drained soils corresponds to somewhere between 1/3 and 1/2 of all our emissions, and carbon loss from agriculture soils is bigger than total GHG emissions from all arable farming. On the flop side, if you re-wet those wetlands (I am sure there is a better English term to use, but forgive me) methane emissions will increase giving a one off spike in temperature. So yes, there are many issues to consider, but there are also many pitfalls and we don’t know enough to embark on those kinds of grand schemes that are suggested. The equation that 1 atom of carbon burned in fossil fuels will add one molecule of carbondioxide, is a lot more straight-forward and clear, and we know the effects of curbing the emissions.
    As for the grand solar power schemes, they tend to forget a lot of devilish details. I am all in favour of a continued expansion of pv, but we should have realistic expectations, and the suggestion that it will be easy to just switch from fossil to solar is still unsubstantiated.
    I also note that in Sweden (which of course is as bad or worse as your neck of the world when it comes to solar) no private energy company invest in solar energy, despite the fact that many claim that solar is now economically viable. But the same companies invest in solar farms in India or elsewhere. Perhaps the solar revolution will shift some advantages to the tropics, which would only be fair in the large play of human civilization.
    And as so many times before, I find that I am in agreement with Joe: “it seems to me that a civilizational collapse resulting in a halt to emissions is more likely than an energy transition or a giant sequestration project.”

    • Excellent points Gunnar. Thanks for the Tessari et al. link. I’ll not go off on my usual soy as savior rant. Rather, I’d like to point to some other plant species being enhanced for nutritional composition. [but even under these plant improvement scenarios I agree there is still a place for animal ag in our food systems]

      In 2016 Howarth Bouis was awarded the World Food Prize. Howarth has a Google Scholar page where one can find all sorts of information. Rather than use a link to that I’ll provide a link to one of his frequent co-author’s works:

      Table 2 of this article (Saltzman et al. 2017) lists numbers of new varieties of maize, cassava, beans, pearl millet, rice, wheat, and orange sweet potato that have been conventionally bred to have better levels of nutrients like Provitamin A, ZInc, and or Iron. No GMO needed.

      These are not futuristic technologies. The germplasm exists, is being deployed, and people are benefiting (particularly – small holders).

      To return to an element of Gunnar’s thought – animals as contributors in the overall system: biofortified staple crops like maize, beans, millets, etc are also more valuable to our domesticate animals. Wastes from these crops can be fed to animals with better results.

      Ecosystem services provided by those pesky hominids.

    • “The researchers even tested a few combinations of grain-pulses which are know for complementarity in protein and while that improved the equation a bit, it was not that much.”

      That study seem to be twisting the results a bit, putting some ‘spin’ into the conclusions that are based on some unrealistic assumptions and omissions.

      When looking at the “Footprint of food combinations to provide the RDA of all EAAs” (Fig. 3 from that study), it’s clear that getting that complete daily dose of amino acids from Beef would result in about 8 times the GHG emissions and would require about 5 times the land use, when compared to ‘Rice and Soybeans’. This is quite a significant disadvantage to eating beef.

      Figure 3:

      By that same measure (RDA of all EAAs), Figure 3 shows ‘Pasta and Beans’ as having a clear advantage over Beef, since Beef results in over 3 times the GHG emissions and still requires more land.

      If one’s diet is limited to only ‘Peas and Rice’ to achieve the recommended daily amounts of all the Essential Amino Acids, then Figure 3 shows that the resulting GHG emissions are still better than eating Beef (which would have about 50% more GHGE). For reduction of GHG emissions, Fig. 3 shows that any of these plant-based diets are better than eating beef.

      However, if ‘Rice and Peas’ are the only sources of protein that a person eats, then more land use would be required to supply at least 100% RDA of all EAAs. This tells me that peas are not a good single source of essential amino acids, no surprise there. Food combinations are typically done with multiple sources of protein over a number of days, with less common EAAs in one food being supplied by another food, and so on. The study’s underlying assumptions of strict diet limitations, with overeating (instead of more food combinations) being a means to achieve the daily RDA of EAAs, is pretty unrealistic.

      And such a comparison seems incomplete without looking at the other nutrients, besides EAAs, in that 1732 g of ‘Rice and Peas’, which is 10 times the mass of food, and still grown with less GHG emissions, than that 171 g of Beef (as shown in Figure 3).

      • Well Steve, as they said: nothing beats soy beans. Beef is by far the least GHG efficient animal food stuff (at least if you believe in the not so scientific use of CO2e as a measure), so it is no surprise the beef emits more than veg combos. I think it was good that the researchers showed that graph, but it doesn’t take away the value of their main conclusion, that the simplistic notion that “plants” are always superior of livestock, when it comes to supply us humans with necessary nutrients, in this particular case, essential amino acids. Obviously, this new research doesn’t now mean that animal food are superior or always cause less harm. I believe that plants and animal foods are complementary and play vital roles in our production system (I have been a veggie farmer for 40 years…)

        It seems to me that overeating as a way to get the needed nutrients is not that uneralistic, I would venture that this is one of the drivers of obesity…..

        • Gunnar and Steve L –
          There is another paper out tracking along these lines:

          This one (Berners-Lee et al. 2018) cites the Poore and Nemecek paper Chris refers to below (which is how I found it). These authors look at current (actually 2013) food production levels and forecast that this level of production can feed the projected 9.7 billion human pop of 2050. I’ve not finished going over it, but a significant part of their plan requires “radical societal adaptation” which translates into our eating things we currently feed to animals.

          They don’t appear to track EAAs, but do track protein, vitamin A, iron and zinc. I find their methods interesting – relying on FAO stats and demographic data to inform their modeling. They bring up iodine and then choose to avoid it in their analysis as it is fortified in salt all over the world… so their transparency in how they put their analysis together is impressive.

          One immediately wonders whether 2013 levels of production can be maintained into a future with changing power supplies… and I don’t know yet if they address this at all… but to their thesis that we can help ourselves by looking at what we choose to eat – makes sense to me.

  4. Good debunking. The 150m2 of PV panels per capita figure you deduce is 50 per cent more than the land used to furnish one lacto-vegetarian with their yearly veg, according to a book I’m reading about the Krishna ecovillage in Hungary, which started in 1992 on 120 hectares and today sustains around 150 devotees.

    More figures from the book for the hell of it: Hungary is 70% cultivable; in 1933-34, 80% of the population derived their livelihoods from agriculture; in 1949, this figure had dropped to 53%; at the time of the book’s publication in 2012, 6.5% worked in (big) agriculture for a living (unfortunately I don’t have pop. figures, though today it’s pretty stagnant at around 10 million).

    The Krishna community is another example of a fairly fossil-fuel lite way to live, certainly by European standards. They don’t use mains water or electricity but do use some PV-powered tools. Make their own fertilisers and sprays. Cows for milk (and some essential amino acids), oxen for ploughing, bees for honey; beeswax candles for lighting an early to bed lifestyle. Like many they believe a collapse is inevitable but wish to develop essential skills in the meantime. I mention it here as one positive way to go about things. No doubt the faith they ascribe to helps more than it hinders.

    • Maybe my lack of metric system use is going to show here, but I thought a hectare measures 1,000m2. If the Hungarian Krishnas are sustaining themselves on just under one hectare per person (which fits with other estimates I’ve seen) then the comparison to PV is different isn’t it?

        • I was pointing out the space given over for vegetables on the farm, per person (100m2), having a smaller ‘footprint’ than Chris’ PV estimation. Grains, oilseeds, fodder and so on is grown elsewhere on the farm. Still, for a lacto-veggie diet I thought the space needed was modest, unlike the 150m2 PV figure.

  5. I haven’t read the linked articles (and most likely won’t) but it sounds like Prentiss’s PV analysis and 150 square meters only covers operating capacity, and not, as you say the manufacture, installation and replacement of such generating capacity.

    I have yet to hear of anyone manufacturing PV panels using power from PV panels, and if I were putting money on it, I’d be inclined to bet that you’d need more panels to run the factory than the factory would produce – even through its full lifecycle. I would be happy to see someone prove me wrong with an actual operating factory rather than with numbers on a napkin. Those napkins always seem to leave off all the details and devils.

    • Or here is a simpler test, using money as a proxy for energy:

      Take out a loan to purchase some PV panels. Using only the revenue from sale of electricity generated by those PV panels, pay back your original loan, and see how many more PV panels you can purchase with the money left over after paying off the loan.

      I am guessing that if such a strategy worked, at least a few people would be using it rather than the usual funding regime of stock options and government subsidies.

        • I thought I recognised the name. From Mr Shellenberger’s organisation WWW site:

          “As Founder and President of Environmental Progress, Michael is one of the world’s leading pro-nuclear environmentalists. His efforts to date have helped save 14 nuclear reactors around the world, from Illinois and New York to South Korea, which prevented an increase in emissions equivalent to adding 14 million cars to the road.”

          I wasn’t aware there was a ‘Save the Nukes” foundation. And interesting to see coverage of what might be described as polemic regarding PV’s from this source on Small Farm Futures. Here’s some other material from the WWW about Mr Shellenberger:

          However, ecomodernist rants aside, there’s no doubt that PV’s will need recycling in a safe and effective manner. I’d be interested to know what the situation is in Europe which has had cradle-to-grave recycling mandates for many products for some time. Do they cover PV’s?

          • I get the impression a lot of recyclable material gets sent overseas. It might be worth keeping your eye on this news site for a feature on recycling within the battery sector due out very soon. Here’s a news story which sketches out the state of recycling within the battery industry within the EU (see ‘Pragmatism needed’ headline, second story down on the home page:

      • This was one of the sillier arguments against PV promulgated amongst the apocalypterati ten years ago. The financial return on PV’s – ignoring all the economic externality benefits like cleaner air, reduced mining impact and not trashing the atmosphere – is sensitive to local energy costs, site demand curve shape for behind the meter installations, installation costs, insolation, feedin tariffs, local Power Purchase Agreement (PPA) availability, local cost of battery storage and a number of other factors. I do this analysis for a wide range of sites from smallish rooftop to MW solar farm installations. Other factors include local infrastructure support for demand management programs/smart grid/Internet of Things/prosumer exchange etc

        3 year simple payback is possible at some sites but more commonly 5-7 years.

        Generally speaking, if you’re within 40 degrees of the equator PV is likely to stack up from a technical and cost perspective. Outside 40 degrees it will be a lot more situational.

        And while I’m up on the soapbox before I settle into a day of renewable energy, smart grid and so on, people working in renewables in my experience don’t think that it will all be PV. There’s some IMO very silly WWW pages and studies that hold out nonsense along these lines but I question their relevance. A blend of intermittents takes you further along. Adding some thermal and battery storage helps. Always start with energy efficiency and mandated energy efficient appliances. A generous dollop of smart grid/IoT is very useful.

        But you still end up with the need for some despatchable. This can be a small amount of total energy demand but is still essential in my experience. Some biomass/bioenergy can help but limited sustainable feedstocks. Hydro and geothermal are useful but large-scale river based hydro schemes have pretty much had their day with respect to substantial new projects. Turkey-nest pumped hydro at a range of scales has great potential IMO.

        • Do any PV manufacturers recycle their own products at the end of their useful life? Or in your experience, do photovoltaic panels get recycled or are they more likely to become toxic waste?

    • EROI on PV’s has been flogged to death in the literature. Depends on where the panels are installed and some other factors such as whether they’re roof-mounted (simple racks) or ground mounts (more embodied energy mounts) and where the LCA boundaries are drawn but around 12-18 months EROI is a reasonable current figure.

  6. I was going to comment only to ensure you knew the lights were on.

    Instead, you have a raft of excellent comments responding to a very clear post.

  7. Thanks for the comments. Only time for a few brief responses I’m afraid…

    Trees & sequestration: Yes, I’m persuaded that increasing tree cover on scales large or small is a good thing and can play a role in short-term climate change mitigation. But, as with veganism, I think it’s dodging the main issue, which is fossil fuel combustion, and unless we face that front-on I don’t think reforestation is going to make much of a difference. Good point from Joe on new vs mature forests…on the basis of my own tree-planting exploits and a quick whizz over some research papers my feeling is that large-scale human tree-planting efforts would be a short-term carbon source rather than a sink, then a short-term sink which might help a little alongside a massive energy decarbonization push (but not in its absence) and then carbon neutral. Perhaps much the same could be said of soil carbon sequestration? On boreal forest cover, what I’ve read suggests it’s balanced on a knife-edge – warmer temperatures may permit northwards spread, but also greater fire risk, slower summer growth and then melting permafrost creates water limitations that may reduce forest cover. I wouldn’t want to bet the farm on it…

    Livestock: thanks for those commentaries Gunnar & Steve. Much to ponder. I’ll look at the Tessari paper. I’ve been looking at Poore & Nemecek’s paper , which comes out strongly against the environmental performance of livestock farming. But these studies never look at livestock in the context of mixed farming in circumstances of energy and fertilizer constraint – so while it may be true that meat consumption in the current global food system has large negative effects, it doesn’t follow that vegan agriculture is optimal. However, it does seem to me that a sustainable food system at anything like current human population levels would have to produce a lot less meat than we currently do.

    PV panels – I largely share the skepticism others have expressed here about PV, certainly if it’s promoted as a complete solution to environmental problems in the way that Pollin does. My understanding is that lifecycle EROEIs of PV generally come out as positive, but that’s not the same as saying that we can sustain the global economy in its present form on the basis of it.

  8. Re: Chris’ last paragraph; Yes, I agree that realistically we should now be focussing a good bit of our planning on adaptation.

    All the more reason to plant trees. Yes, they are a short term carbon sink, but they provide food, fuel and building materials in an energy declining world. Perennial agriculture will wax as fossil fuel enabled annual agriculture wanes. Toss in a bit of prudent biochar production for longer term carbon sequestering, and that is about all I think we’ll be able to manage. The other advantage to tree planting is that it is quite compatible with local, bottom up deployment. Massive, government initiated programs might be quicker, but are not necessary, and quite unlikely to happen.

    To debate whether to reduce fossil fuel use or to work on carbon sink increases is a false dichotomy. Both are needed, but again, I don’t think political will at the nation state level will result in anything happening.

    And finally, PV is only possible within the technical/financial ecosystem enabled by fossil fuels, so they will only extend the fossil fuel era a bit. It should still be done ( I’m not sure of how much is the best use of our resources), but only to ease the transition to the low energy future. Training wheels, if you will.

    • All sounds persuasive to me. I’d agree that debating fossil fuel reduction vs carbon sink increase is a false dichotomy, but in so many analyses I’m encountering at the moment it seems to me that the importance of the first is systematically downplayed.

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