Global potential for increasing biofuel crop yields/acre
March 16th, 2012 by Rachel Perlman,Article: Fargione, J. (2012). Boosting biofuel yield. Nature Climate Change 1: 445-446.
Background: One of the main concerns with biofuel production centers on land use change; if we convert natural ecosystems or food croplands to biofuel crops, we may be worsening other environmental and food security problems. There is debate over the extent to which biofuel production directly competes with the food market and increases food prices. In order to increase global biofuel production without the agricultural expansion, biofuel yields would have to increase.
Summary: Fargione explains that Johnston et al. have calculated that an extra 112.5 billion liters of ethanol and 8.5 liters of biodiesel could be produced if global yield for crops used to make biofuels increases (with crop area staying constant). They determined the potential yield gain by comparing current production levels with a scenario in which the half of the world’s farmers having below median yield increased yields to median levels. Separate median yield values were identified for each major crop used to produce ethanol and biodiesel in each climate zone. Thus, yields from locations that have similar numbers of growing degree-days and soil moisture/types (such as Indonesia and Brazil) and grow the same crop (like sugar-cane) were grouped together. The variation in yields of a given biofuel crop creates a “yield-gap” that would ideally be reduced by adjusting management practices, inputs, equipment, or the cultivar variety. For example, if Madagascar were to have its lower-yielding half of farmers produce at median yield levels, they could double sugar-cane yields.
Despite the great potential for energy crop yield increases, the means by which this can occur are not straightforward. Especially in developing countries, yields are often lower due to lack of capital, access to equipment, and education on farm management. Solutions require some combination of monetary aid, educational outreach, and investment in infrastructure and technology. However, closing the energy crop yield gap also has concerning realities – more fertilizers and irrigation will be needed, and with global food demand growing, policy-makers have to decide what proportion of resources should go toward biofuel versus food crops.
CATF take-away message: Boosting agricultural yields is essential to meet the growing demand for food, animal feed, and other plant-based products. However, the idea that increasing yield/acre of biofuel crops is always a “win-win” – i.e., because it would increase energy production while preventing detrimental land-use change – needs to be considered carefully. Before pouring resources into efforts to make higher yielding energy crops, we must make sure that the carbon footprint and energy balances of the biofuel production process (currently, as well as with the adjustments for higher yield) are acceptable to in the first place.
RESEARCH: Expanding the scope of traditional life cycle analyses through the inclusion of nitrogen and land use intensity to assess the environmental impacts of biofuel generation
June 14th, 2010 by CATF,Article: Miller, S.A. (2010). Minimizing Land Use and Nitrogen Intensity of Bioenergy. Environmental Science and Technology. Vol.4(10) pp.3932-3939.
Synopsis: Shelie A. Miller of Clemson University developed a system of ranking biofuel feedstocks based on land use and nitrogen intensity in order to determine which feedstocks were the most environmentally favorable with respect to these factors. Miller’s results suggest that, “current energy policies either undervalue or do not consider nitrogen and land use impacts.”
This paper explains that widely practiced lifecycle analysis methods tend to focus almost entirely on greenhouse gas emissions, despite the evidence that many environmental systems are negatively impacted by bioenergy production. In particular, most biofuels are known to be water, nutrient and land intensive. This study ranked feedstocks according to nitrogen and land use intensity as these two factors are almost entirely limited to feedstock cultivation stages, whereas water and energy are factors throughout cultivation, manufacturing and “end-of-life” stages.
In terms of the ranking system, 14 biofuel feedstocks were evaluated to determine the “minimum nitrogen and land required to produce 1000GJ of unprocessed energy.” The calculations represent ideal values for maximum energy yield (Maximum Energy Yield = harvestable yield x high heating value) and maximum nitrogen requirements (Maximum nitrogen requirements = harvestable yield x percent nitrogen composition) of each system averaged for a range of conditions and regions for each feedstock but do not account for thermodynamic losses. Land use and nitrogen intensity were weighted equally and the feedstocks were then ranked relative to one another.
The results of the Miller article indicate that sugar crops and algae are the least land intensive when accounting for nitrogen and land intensity, with sugarcane ranking as the most favorable feedstock overall. Food crops, soy and rapeseed in particular, ranked consistently low.
Environmental damages are not limited to greenhouse gas emissions; water, land and nutrient cycling are all vital ecosystem services that may be impacted by biofuel production. Going forward, this research suggests that efforts taken to determine the ecological viability of a particular fuel should include a wider scope of environmental impacts and should not be limited to greenhouse gas emissions.
The full article can be downloaded here.
CATF Applauds EPA Decision to Regulate Biofuels’ Full Effect on Climate … But Remains Deeply Concerned About Model Outcomes
February 3rd, 2010 by CATF,In a final rule revising the RFS, EPA agreed to calculate the extent to which biofuel production mandate indirectly affects land use patterns around the world by increasing demand for farmland. CATF applauds the decision to account for the impact those land use changes have on global warming. However, much work remains to be done to ensure US biofuel policy promotes fuels that truly benefit the environment.
Click here for complete press release.
RESEARCH: Bioenergy Policies Must Not Ignore Indirect Land Use Emissions
October 30th, 2009 by CATF,Article: T Searchinger et al (2009). Fixing a Critical Climate Accounting Error. Science. Vol.326. no.5972, pp.527-528
In “Fixing a Critical Climate Error,” a collection of leading energy experts found that the GHG emissions accounting method used in the Kyoto Protocol and in many national-level policies fails to consider emissions from land use when biomass for energy is harvested or grown. Instead, the policies treat all bioenergy as carbon neutral — even though there are significant differences in net emissions depending on the source of the biomass being used and its net land-use effects.
NPR coverage: Scientists: Biofuels Laws May Harm Environment
CATF: Senate Committee Must Allow EPA to Consider Land Use Change Emissions
September 21st, 2009 by CATF,In a letter submitted to the Senate Appropriations Committee, CATF and dozens of other environmental organizations called on senators to reject an amendment that would thwart EPA’s attempt to scientifically analyze the greenhouse gas emissions that result from land use changes around the world related to increased biofuel production.
RESEARCH: Modeling Uncertainty Is Not a Reasonable Basis for Ignoring ILUC Emissions
July 14th, 2009 by CATF,Article: T Searchinger (2009). Why Uncertainty in Modeling Indirect Land Use Change From Biofuels Cannot Justify Ignoring It. Princeton University & German Marshall Fund of the U.S.
An analysis by Tim Searchinger explains why modeling uncertainty does not logically or practically justify ignoring overseas emissions from the land use change associated with US biofuel production mandates.
Click here for the complete article.
RESEARCH: Environmental feasibility comparison of palm seed biodiesel, Jatropha curcas biodiesel, and oil biodiesel.
July 3rd, 2009 by CATF,Article: MH Jayed et al (2009). Environmental aspects and challenges of oilseed produced biodiesel in Southeast Asia. Renewable and Sustainable Review. Vol. 13(9), pp. 2452-2462
Southeast Asia is a major producer of biodiesel from palm seed oil and from the Jatropha curcas plant. These feedstocks have environmental advantages over conventional diesels, but they also create their own environmental damages. This study compares the life cycles of palm seed biodiesel, Jatropha curcas biodiesel, and oil biodiesel to determine which is the most environmentally feasible in terms of yield rate, land use, engine emissions, and oxidation stability. Palm seed oil is found to be the most environmentally feasible feedstock in all categories except for the production of nitrous oxide, where petrol-based diesel is actually superior.
The full article can be downloaded here.
RESEARCH: Accounting for emissions from terrestrial systems and land-use change.
May 29th, 2009 by CATF,Article: M Wise et al (2009). The Implications of Limiting C02 Concentrations for Agriculture, Land Use, Land-Use Change Emissions and Bioenergy. Science. Vol. 324. no. 5931, pp. 1183 – 1186. DOI: 10.1126/science.1168475
Synopsis: Marshall A. Wise, Katherine V. Calvin, Allison M. Thomson, Leon E. Clarke, Benjamin Bond-Lamberty, Ronald D. Sands, Steven J. Smith, Anthony C, Janetos, and James A. Edmonds of the Pacific Northwest National Laboratory’s Joint Global Change Research Institute in collaboration with the University of Maryland at College Park explain that “failing to take into account the value of terrestrial carbon storage services by unmanaged ecosystems and managed forests could have disastrous consequences for unmanaged ecosystems.”
Wise et al explore the importance of including emissions from terrestrial systems and land-use change in setting and attaining CO2 emissions targets for the future. In this study, three scenarios are analyzed including a reference case, a Fossil Fuel and Industrial Emissions Carbon Tax (FFICT) regime and a Universal Carbon Tax (UCT) regime. For each scenario carbon emission targets were set ranging from 450ppm to 550ppm.
Wise et al use the Joint Global Change Research Institute’s MiniCAM model to determine changes in crop prices, land use, land cover, energy and economy. In addition, a new ecosystem component of MiniCAM is used to determine how the system will be affected under various emissions targets, given certain assumptions on population, affluence, and technology over time. The model also addresses purpose grown biofuel versus waste fuel and combining these different biofuel options with CO2 capture and storage technologies for optimal outcomes. Wise and the coauthors explain that their methods for determining crop productivity are based on available data and projections through year 2030. Post 2030, an annual .25 percent per year productivity improvement is assumed. This value is highly speculative and also has a strong influence over model results.
The reference case assumes a consistent evolution of society (population, standard of living, etc.) and environmental quality over time while excluding any methods for limiting emissions. Under the reference scenario it is determined that forests will decline, agricultural land will increase and land use change emissions will decline. Land use emissions are found to increase under the Fossil Fuel and Industrial Emissions Carbon Tax, generally leading to higher land rental rates and prices for agricultural commodities. Lastly, under the Universal Carbon Tax scenario, cropland is found to decrease relative to the reference case, bioenergy production increases relative to the reference case but decreases relative to the FFICT and there is a reduction in the price of bioenergy.
There is considerable room for improvement with respect to the availability and reliability of the existing research and data pertinent to the MiniCAM model. Wise et al explicitly mention that including full accounting of greenhouse gas emissions, the relationship between GHG concentrations and climate variability, the effects of interactions between other GHG’s such as Nitrogen, discrete and disaggregated geographical data, as well as detailed water availability and consumption models, would improve model results. In addition to more reliable data, Wise and the coauthors explain that more research must be done in the societal aspects of the model and specifically the ability of governments to enforce carbon limits through carbon taxes or other methods.
The complete article can be downloaded here.
EPA’s RFS Proposal: One Step Forward … and Another Step Back?
May 5th, 2009 by CATF,According to its proposed rule for implementing revisions to the Renewable Fuel Standard, EPA plans to measure greenhouse gas emissions from land use changes directly and indirectly caused by biofuel production — something CATF has repeatedly called on the agency to do.
Click here for the full press release.
CATF Urges EPA to Strengthen Emissions Analysis in RFS Proposal
September 25th, 2009 by CATF,In a pair of comment letters submitted to EPA, CATF commended the agency for counting GHG emissions from indirect land use change in its proposed RFS implementation rule, and urged EPA to base it analysis on the most current data and modeling tools. CATF filed comments in conjunction with a collection of other environmental groups on a wide range of issues, while also providing EPA with separate detailed comments on issues of particular concern.
Environmental Community Comments on EPA’s RFS2 Proposal
CATF and FOE Comments on EPA’s RFS2 Proposal
Press Release on CATF’s Comments
Tags: administrative comment, EPA, ILUC, land use, policy, regulation, Renewable Fuel Standard, RFS
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