Are biofuels a core climate solution?

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"Are biofuels a core climate solution?"

algae.jpgAs part of my ongoing series on core climate solutions (see links below), let’s examine biofuels.

If we are going to avoid catastrophic climate outcomes, we need some 11 “stabilization wedges” from 2015 to 2040 (see here). So if you want to be a core climate solution, you need to be able to generate a large fraction of a wedge in a climate-constrained world. And that is a staggering amount of low-carbon energy (see “Is 450 ppm politically possible? Part 1“).

Princeton’s Socolow and Pacala describe one wedge of biofuel in their original August 2004 Science article on the wedges:

Option 13: Biofuels. Fossil-carbon fuels can also be replaced by biofuels such as ethanol. A wedge of biofuel would be achieved by the production of about 34 million barrels per day of ethanol in 2054 that could displace gasoline, provided the ethanol itself were fossil-carbon free. This ethanol production rate would be about 50 times larger than today’s global production rate [actually, now more like 60 times current U.S. biofuels production], almost all of which can be attributed to Brazilian sugarcane and United States corn. An ethanol wedge would require 250 million hectares committed to high-yield (15 dry tons/hectare) plantations by 2054, an area equal to about one-sixth of the world’s cropland. An even larger area would be required to the extent that the biofuels require fossil-carbon inputs. Because land suitable for annually harvested biofuels crops is also often suitable for conventional agriculture, biofuels production could compromise agricultural productivity.

Biofuels thus have several problems as a large-scale medium-term climate solution:

First, virtually all crop-based biofuels are worthless from a climate perspective (see “About those two studies dissing biofuels“) and probably a bad idea from most other perspectives (see “Let them eat biofuels!“). Second, there is not a single commercial cellulosic ethanol plant in United States yet. Third, I’m not sure there is an agreement in the scientific community about how to do lifecycle analysis needed to determine the net carbon benefit from cellulosic fuels.

Fourth, in a post-2050 world with 3 billion more people who are losing water from melting glaciers and desertification, arable land and water will be very dear commodities. That means the only biofuels that would make sense to fight global warming would be ones that do not require arable land or much fresh water.

So I think the jury is very much out on whether a wedge-scale contribution from cellulosic biofuels is practical and affordable and a climate-constrained world. It should probably be considered a half-wedge solution until we see major advances in large-scale microalgae-to-biofuels.

If you want to see the entire Princeton discussion on the biofuels wedge with all of their assumptions detailed, go here.

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21 Responses to Are biofuels a core climate solution?

  1. Peter Krantz says:

    Many calculations of the future required quantities of ethanol are based on a) productivity is constant (it is rapidly increasing, see e.g. the Economist article on biofuels in Brazil), b) a constant mpg (which also is imrpoving rapidly).

    Although everyone agrees that electric cars is the future (mainly because the energy source decision is moved from the car owner to the electricity company) it will take some time. It is simply not possible to buy an electric car in most parts of the world today. Ethanol is maybe the best current solution as it is easy to convert current cars and utilise the current fuel distribution infrastructure. It will not be suitable for the medium to long term unless someone has a breakthrough in cellulosic ethanol.

  2. David B. Benson says:

    I suggest Jatropha for biodiesel production. It grows with little or no fertilization on poor soils under almost all percipitation condtions so does not have to compete with traditional agriculture. Being poisonous, it is often used by the poorest peasants as borders for their fields, keeping pests out. These poeple would be happy to be able to sell the oily bulbs.

    There is ample degraded lands in Africa which could be, and to some extent are being, used for just this purpose.

    Of course, the diesel (hence biodiesel) market is quite large. The ocean vessel fleet alone accounts for about 3% of the CO2 emissions; there are also trains and large trucks.

    Others who have looked into biofuels suggest that, realistically, it can account for 25% up to maybe 50% of the expected world energy needs in 2050 CE of about 800 exajoules. I doubt these calcualtions are that seriously in error.

  3. Earl Killian says:

    Peter Krantz said, “Many calculations of the future required quantities of ethanol are based on a) productivity is constant (it is rapidly increasing, see e.g. the Economist article on biofuels in Brazil), b) a constant mpg (which also is imrpoving rapidly).

    I’ve done the calculations for 2050 at high MPG, and the numbers still don’t look good to me.

    Peter Krantz said, “Although everyone agrees that electric cars is the future (mainly because the energy source decision is moved from the car owner to the electricity company) it will take some time.

    And low-carbon ethanol won’t take time too? Be fair.

    Peter Krantz said, “It is simply not possible to buy an electric car in most parts of the world today.

    In most parts of the world, E85 is similarly not available.

    Peter Krantz said, “Ethanol is maybe the best current solution as it is easy to convert current cars and utilise the current fuel distribution infrastructure.

    Only to about the E10 level.

    Peter Krantz said, “It will not be suitable for the medium to long term unless someone has a breakthrough in cellulosic ethanol.

    A breakthru in cellulosic ethanol will not solve the feedstock problem (the issue being that plants turn much less than 1% of sunlight into stored chemical energy). Algae have higher potential efficiency here, but we’re probably talking a couple of percent. In contrast, solar electricity is approximately 30% efficient. The end result is that biofuels take a lot of land area compared to mirrors in the desert and PV on rooftops that would otherwise be wasted area.

    E85 makes a decent liquid backup fuel for PHEVs. Imagine a fleet of PHEV-40s that get 80% of their miles from the grid, and only 20% from E85. Let’s say they get 50 MPG instead of 20.43 we get today. Only 15% of the fuel is gasoline. That works out to 20%*41%*15% = 1.2% of the gasoline consumption per vehicle. The ethanol consumption is 7%. This might be doable with cellulosic ethanol.

    Algae biodiesel unfortunately as the Black Carbon problem that Joe has blogged on before.

  4. Earl Killian says:

    The one US biofuel that might make sense is using corn stover to make cellulosic ethanol. Stover doesn’t compete with food, and doesn’t use additional land. I am unsure about the consequences for soil health, however.

    How much fuel can be made from agricultural residue (which doesn’t compete with food)? ORNL suggests 170 million tons (154 million tonnes) of corn stover is possible. If one assumes 0.38 L ethanol per kg for cellulosic conversion, then you get 58 billion liters or 15 billion gallons, which would make 18 billion gallons of E85. Using 86.4 MJ/gal for the LHV of E85, and 121.3 MJ/gal for the LHV of gasoline, this means the E85 is the equivalent of 13 billion gallons of gasoline.

    In 2030, a US population of 364M driving 9300 VMT per capita gives 3.4 trillion miles. If 20% are E85, that is 676 billion miles. Dividing this by 13 billion gallons of gasoline equivalent gives 52 MPG. I.e. if we had 52 MPG in hybrid mode, we can fuel our post-electricity PHEV travel with cellulosic ethanol made from corn stover.

  5. I can’t believe this website is still discussing the potential viability of using food crops for biofuel.

    Isn’t there enough starvation in the world already?
    Aren’t food prices high enough already?
    Isn’t it apparent by now that using food crops is a very inefficient way of making biofuel, both energetically and financially?

    No food crop is viable! The only crop that makes sense is algae.

  6. David B. Benson says:

    Kevin Schmidt — Actually, in some parts of the world, food crops for biofuel make good sense. Tubers such a sweet potatoes and casava are not the most desirable of foods; people prefer better ones if available. But these will grow on poorer soils and with less irrigation, if any. So peasants can grow their food crops on their better land and tubers on poorer. This provides an important form of food security ‘insurance’ if the main food crops partially fail; if a successful harvest, then sell the tubers to the biofuel producer.

  7. John Mashey says:

    While I generally agree that ethanol is not some magic solution, don’t think much of corn ethanol, and I wish a lot of the weird farm subsidies would go away.

    Removing too much corn stover has its own problems:
    Google: corn stover carbon replenishment

    a) Politically, it would be way better to convince (for example) Iowa that there is a better path forward that involves little or no biofuels over the long-term. The Iowa Office of Energy Independence strangely thinks that biofuels might be important to their future, especially given that Iowa has little fossil fuels of its own. Their plans are worth reading, if only to get a viewpoint from the middle of the country.

    b) There will be some timeframe before all farm machinery is electrified, in which petroleum fuel will be very expensive. Are people prepared to tell farmers to go out of business rather than selling crops for biofuel? Do people prefer that corn go to HFCS and beef feedlots rather than ethanol?

    Like it or not, those big mid-West farms do not yet run on electricity alone.

    c) Are people prepared to make it *illegal* for a farmer to raise whatever crops they think make them the most money? Should it be illegal for corn to be diverted to ethanol away from beef feedlots? Away from HFCS?

    d) There has *got* to be a positive model for the mid-West [windmills, electrified machinery, better railroads (see recent article in The Oil Drum), and probably encouragement to grow a modest amount of the best fuel crops possible (not corn) for whatever fuel is still needed. Personally, I’d be ecstatic if the acreage devoted to HFCS turned into switchgrass/miscanthus or something else good for fuel.

    BEVs and PHEVs will help, but not as much as it is likely to help us in areas of higher density. At least some people have pickup trucks that get used as such. Grain trucks matter. So do schoolbusses, for which, in some areas, there are few good alternatives.

    The US doesn’t need to be subsidizing silly things, but:

    “farmers: raise food, not fuel … and we’re sorry that petroleum is so expensive you must go out of business as a result” not only doesn’t make sense (how does that grow more food?),

    but is also not a good plan for getting mid-West farm state support for anything, and there are bunch of them, and they have a lot of Senators.

  8. red says:

    Methanol as well as ethanol should be considered in the biofuels assessment. It can be derived from natural gas, coal, and various renewable biomass sources. Similar to ethanol and E85, M85 would require a relatively minor conversion of existing vehicles and vehicle manufacturing. In the short run this makes it an interesting option to help achieve some degree of energy independence. In the longer run PHEVs should be able to work their way into the marketplace and M85 and E85 combined with PHEVs would be, as Earl demonstrated, be able to achieve even greater energy independence.

    Not every methanol option is attractive from a climate progress point of view, but many are. The market should be able to sort out that kind of thing as long as appropriate incentives are in place to encourage the more climate-friendly variants.

    Methanol and ethanol have a lot to contribute to both energy independence and climate progress, but right now there’s little reason for a customer to buy a flex-fuel vehicle (there aren’t many M85/E85 gas stations), there isn’t much reason to build FFVs (customers won’t pay the small extra price for a car using fuel that can’t be found), and the gas stations don’t have an incentive to support the pumps with such a small percentage of M85/E85 vehicles on the road. It reminds me of the computer operating system market.

  9. CoRev says:

    D Benson said: “Of course, the diesel (hence biodiesel) market is quite large. The ocean vessel fleet alone accounts for about 3% of the CO2 emissions; there are also trains and large trucks.”

    Does anyone know the difference in CO2 output from biodiesel versus oil-based diesel? Will conversion to Bio-diesel make any difference in this percentage?

    CoRev, editor
    http://globalwarmingclearinghouse.blogspot.com

  10. Bob Wallace says:

    “Does anyone know the difference in CO2 output from biodiesel versus oil-based diesel? ”

    There’s a fairly simple answer to this one.

    Biodiesel releases CO2, but it is CO2 recently captured from the atmosphere by the growing plants. It doesn’t add new CO2 to the system, simply recycles it.

    Oil-based diesel releases CO2 that was sequestered. Burning fossil fuels takes CO2 safely stored underground and pumps into the atmosphere.

    Biofuels would be a wonderful thing. Except they just aren’t practical for large scale use. We don’t have enough land or water to make them happen.

  11. David B. Benson says:

    Bob Wallace wrote “We don’t have enough land or water to make them happen.” If by ‘we’ you mean in the United States, that is true. However, there is plenty of both in the global South, especailly Africa.

  12. John Mashey says:

    red:

    According to E85 map, there are 1200 stations in the US, most of them in the upper mid-West.

    Iowa has 85 stations spread around the state. [See my earlier comments about Iowa.]

    list of flex-fuel vehicles. Unsurprisingly, these include vehicles popular in mid-West.

    Now 85 isn’t huge, but it’s enough that a FFV might actually be useful there.

  13. Jonas says:

    Biofuels are the single biggest wedge

    Strange how opinions can differ.

    Let’s look at two rather authoritative sources:

    1. James Hansen.

    2. For those who know the debate in Europe, let’s look at the wedges presented in the Bellona Foundation’s most recent report on mitigating climate change.

    =======

    James Hansen says: we need to aim for 350ppm. The only feasible way to do this is via biofuels:

    -biomass coupled to CCS
    -bioenergy coupled to biochar.

    James Hansen, Makiko Sato, Pushker Kharecha, David Beerling, Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer, James C. Zachos, “Target Atmospheric CO2: Where Should Humanity Aim?”, March 2008.

    http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf
    ========

    Now let’s look at the Bellona Foundation, which aims for an 80% reduction of carbon emissions by 2050.

    The Bellona Foundation, so far, is the only organisation taking bio-CCS and bio-CCCS into account. Thus it can be easily considered to be the most up to date on the technologies.

    These are its wedges (roughly sketched, more details in the link):

    1. Carbon-negative biofuels: 22%
    2. All other renewables combined: 10%
    3. CCS: 10%
    4. Land use change: 8%

    In short, biofuels alone represent twice as large a potential than wind, solar, geothermal, wave, etc… combined.

    Graph.
    http://i234.photobucket.com/albums/ee274/biopact3/biopact_carbon-negative_bellona.jpg?t=1212759388

    Bellona Foundation: It is fully possible to reduce emissions by 85 percent – June 5, 2008.
    http://www.bellona.org/articles/articles_2008/cc8_conference

    The logic is quite straightforward: old school renewables like wind or solar remain carbon-neutral forever. They can never take CO2 out of the atmosphere.

    Carbon-negative biofuels, on the contrary, can take huge amounts of CO2 away.

    Let’s look at the numbers. How much CO2 can each technology reduce or remove? Or, put differently, how much CO2 does the technology yield per Gigawatthour of electricity generated?

    Here are the numbers:

    -solar PV: +100 ton CO2/GWh
    -wind: +30 to 50 ton CO2/GWh
    -large hydro: +10 to 20 ton CO2/GWh
    -biomass+CCCS: -500 to -800 tons CO2/GWh [that is: minus]
    -biomass+CCS: -800 to -1000 tons CO2/GWh [that is: minus]

    In short: for each GWh of electricity generated, carbon-negative bioenergy can reduce emissions by up to 10 times compared with wind and solar.

    ========

    Obviously, biofuels are “the” most important technology to mitigate climate change.

    There is basically no discussion about this, is there? The numbers speak for themselves: biofuels are the single biggest wedge of the future. (+100tonCO2/GWh versus -1000tonCO2/GWh… add Hansen…).

    But apparently, the news still has to cross the pond. If there’s anything else we can help our American friends with, let us know!

    [Jonas: You are not talking about biofuels -- biomass to liquid fuels - but rather biomass power. I tend to throw that in with the PV/renewables wedge. In fact, if coal with carbon capture and storage proves practical on a large scale (and the jury is out on that) then yes throwing in some biomass is probably the best use of that biomass. But we are two steps removed from that being practical. I think there is only one commercial coal/biomass power plant in the world. Some of us on this side of the pond try to stay ahead of the curve, but we appreciate all the help we can get from the old World.]

  14. David B. Benson says:

    Joe — There is a coal reactor near St. Louis using nut shells from a nearby processing plant to co-fire about 10% of the power generated.

    There is a torrified wood reactor making about 75,000 tonnes of ‘biocoal’ per year in The Netherlands; the torrified wood is co-fired in German coal reactors.

    There are at least two more similar torrified wood reactors being built in The Netherlands; might be operational by now.

    Anyway, there is more than one commercial coal/biomass power plant in the world.

  15. Ronald says:

    Jonas,

    It’s great to hear there is something that works well in decreasing carbon dioxide in the atmosphere. I do have a question about it. You decribe the most important measurement of an carbon reducing energy source as CO2/GWh of which I’m not familiar with, but I would say that two other measures are more important.

    One of these measures is cost of electricity per KWH or for us across the pond as dollars per KWH.

    The second measure is cost per ton of Carbon Dioxide sequestration.

    Your measure of tons CO2/GWh doesn’t mean that much to me if my electricity costs are high and the cost per ton of Carbon Dioxide is high also.

    If I’m wrong about that let me know. I just don’t think that tons per CO2/GWh is the best measure.

  16. Robert says:

    To talk about ‘core climate solutions’ is misleading.

    The market decides how energy will be generated and consumed. The ‘core climate problem’ is therefore political, in that we would need to wrest control away from the 6.7 billion individuals who cumulatively decide these things (i.e. the market) and place it in the hands of a global political force that puts climate change at the top of its agenda.

    Unless this happens your ‘core climate solutions’ will only see the light of day if there is some technoloical breakthrough that makes it the cheapest way of generating energy – unlikely as things stand.

  17. John Hollenberg says:

    > The market decides how energy will be generated and consumed.

    The exact reason that government intervention/regulation/subsidy is needed in some areas. You are describing the failure of free markets to adequately address problems that when the cost to society is not included in the cost of doing business.

  18. Robert says:

    John – Exactly. And if we exclude technological breakthroughs that might make low carbon energy the free market choice by being cheaper then the only thing left to talk about is the preferred mix of government intervention/regulation/subsidy and how to achieve it politically at a global level.

    So why does this blog talk endlessly about ‘core climate solutions’ but ignore the real question of the political route to achieving it – globally? For a start, Joe seems to forget that the world continues beyond the borders of the US. Very odd.

  19. Cyril R. says:

    800 Exajoules of bio-energy?

    The IPCC has summarized the literature as 22 EJ – 400 EJ if I recall correctly. So that shows the large uncertainty; depending on assumptions on learning rates, tech breakthroughs, what type of impacts are acceptable etc etc.

    But even on the low end scale, tens of EJ is rather large niche solution!

  20. msn nickleri says:

    But even on the low end scale, tens of EJ is rather large niche solution!

  21. vivek says:

    Biofuels have been considered as a serious alternative around the world but as far as my knowledge goes the cost of production and the subsidies provided by the government . But then this model has been implemented in a couple of places effectively . I guess this should interest you .