Wednesday, August 16, 2017

A new and deeper wrinkle in the biofuel debate

Two short articles just published by the journal Climatic Change highlight the divide in scientific thinking about the effect of biofuels on CO2 emissions. A commentary by Robb De Kleine and colleagues at Ford Motor Company criticizes a paper on the topic published last year by myself and colleagues at the University of Michigan. My response to their commentary explains why I believe that our approach is correct, in contrast to the established lifecycle analysis method that our critics say is the best way to address the question. 

Cropland adjoining patches of forest. All arable land
carbon from the atmosphere at varying rates. 
This quarrel reflects a new stage in the long-running debate because it does not involve disputes about net energy use or even the food-versus-fuel and land-use change issues raised over the past decade. It is instead a disagreement about the core assumptions to use when examining the question, particularly whether or not biofuels should be treated as inherently carbon neutral. That's the assumption that the CO2 emitted when biofuels are burned does not count because it is biogenic, i.e., newly removed from the atmosphere when feedstocks are grown. My work challenges this assumption, showing that it only holds under certain conditions. De Kleine and colleagues defend the assumption, arguing that it is true unconditionally.

The disagreement is not merely academic. Because new oil production technologies have expanded the supply of economically attractive fossil-based liquid fuels, the business case for biofuels rests increasingly on their value for mitigating CO2 emissions. The stakes are high for both the biofuels industry and for policies to address global warming.  

To dig into the details, start with our paper from last year, "Carbon balance effects of U.S. biofuel production and use." Using field data, we found that the rate at which CO2 was removed from the air was enough to offset only 37% of the CO2 emitted from biofuel use, rather than 100% as commonly assumed. Once production-related emissions are considered, we concluded that biofuels (corn ethanol and soy biodiesel) worsened CO2 emissions rather than reduced them over the 2005-2013 period examined.

The commentary by De Kleine and colleagues walks readers through reasoning that defends the proposition that biofuels are, by definition, fully carbon neutral based on how carbon cycles through the global ecosystem. They say that our carbon balance analysis has inconsistencies and fails to consider economic effects. They also state that our method is not robust because it uses a term that is not pertinent for measuring the direct CO2 impact of biofuels and depends on the time period chosen for analysis. De Kleine and colleagues conclude that our results are unfounded and that their examination of our data and assumptions falsifies the approach we used.

In response, I explain the mistakes in the logic used by De Kleine and colleagues, as well as by the majority of biofuel researchers and government officials who apply lifecycle analysis for policy. They assume that biogenic carbon flows are always in balance over a biomass product's lifecycle; in other words, that flows of CO2 between the atmosphere and biosphere (which includes crop and forest lands as well as all other ecosystems) always even out. They therefore believe that lifecycle analysis, which treats carbon flows as being steady (not varying over time) is suitable for evaluating biofuels. 

In reality, however, carbon flows are dynamic (vary over time). The atmosphere and biosphere are not in balance because mankind is consuming ever more biogenic carbon for food and other economic uses. It is therefore necessary to examine the dynamics of biofuel use and determine the extent to which biogenic CO2 emissions are balanced by CO2 uptake on a case-by-case basis.

My response invites readers to visualize how the rate at which CO2 is removed from the atmosphere by farmland changed as U.S. biofuel production ramped up over the years. One can compare that change in biomass carbon uptake to the fact that biofuel use does not appreciably change the rate at which CO2 is emitted from motor vehicles. This thought experiment underscores the need to look at how carbon flows change through time, i.e., to analyze the dynamics of the situation, as we did in our 2016 paper.

To put the debate in perspective, I explain why it is so appealing to idealize biofuels as part of a circular economy in which inputs always balance outputs. But the world is far from that ideal state and so cannot be analyzed correctly using methods which assume that carbon flows are already in balance. Moreover, transitioning from today's unsteady (and unsustainable) state to one where CO2 levels are no longer rising is itself a dynamic process. Lifecycle logic breaks down in the real world and so does the assumption that biofuels are inherently carbon neutral.

Readers are invited to judge for themselves which view they find to be more convincing.

DeCicco, J.M., D.Y. Liu, J. Heo, R. Krishnan, A. Kurthen and L. Wang. 2016. Carbon balance effects of U.S. biofuel production and use. Climatic Change 138(3): 667-80.  
De Kleine R., T.J. Wallington, J.E. Anderson and H.C. Kim. 2017. Commentary on "Carbon balance effects of U.S. biofuel production and use" by DeCicco et al. (2016). Climatic Change, published online 16 Aug 2017. 
DeCicco, J.M. 2017. Author's response to commentary on "Carbon balance effects of U.S. biofuel production and use." Climatic Change, published online 16 Aug 2017. 

Thursday, July 27, 2017

Biofuel Research vs. Mandates: House Science Committee Hearing

On Tuesday, July 25, 2017, the Environment and Energy Subcommittees of the U.S. House of Representatives Committee on Science, Space and Technology held a joint hearing entitled, "Examining Advancements in Biofuels: Balancing Federal Research and Market Innovation." This post is the statement I delivered at the hearing. 

I wish to thank the chairs, ranking members and other members of the Committee and Subcommittees for the opportunity to testify.
The question being addressed today, that of the right balance between fundamental scientific research and government intervention in the marketplace, is crucially important. The focus on biofuels is telling because it involves so many aspects of the question. Indeed, federal biofuels policy provides a morality tale of how things go wrong when the right balance is not maintained.
Before delving into the problems, however, I want to emphasize the importance of maintaining a robust federal investment in research across all fields of study. Funding for science is crucial to maintain American leadership and foster the innovation that leads to high-quality job growth. Federal support for university research is especially crucial for training a new generation of Americans who can fill those jobs.
To summarize my written testimony, here are the key points:
1.   Protecting the climate from a worsening disruption due to excess CO2 in the atmosphere is now a top challenge for energy research and policy.
2.   But, the choice of what technologies to deploy must be left to the marketplace, to industries and entrepreneurs who take risks with private money rather than rely on public funds. Policies to address non-market concerns such as CO2 should therefore be technology neutral and well informed by independent science.
3.   Moreover, the climate challenge should not be an excuse to pick winners through demonstration and deployment programs, subsidies and technology mandates. Federal resources are best leveraged through fundamental R&D and technology-neutral regulation.
4.   Unfortunately, federal biofuels policy has overstepped these bounds. The result is not only wasted tax dollars, but excess costs for consumers and harm to the environment. Biofuels are making CO2 emissions worse and the Renewable Fuel Standard has been damaging in that regard.
5.   Finally, it is time to face up to the fact that the federal push for advanced biofuels has failed. DOE and other agencies have supported bioenergy research, demonstration and deployment for many decades and with billions of dollars. None of the promised cellulosic fuels have become commercially viable, even with subsidies amplified by mandates.
In short, it's time to go back to basics on these issues, to revisit biofuel policies that the science and economics now show to have been ill premised.
I realize that my work contradicts longstanding assumptions about biofuels. Twenty years ago, I accepted the notion that biofuels such as ethanol and biodiesel were inherently carbon neutral, meaning that the CO2 emitted when they are burned does not count because it is taken from the air when crops grow. In reality, however, all CO2 emissions increase the amount of CO2 in the atmosphere regardless of where the carbon came from. The correct question is whether feedstock production speeds up how quickly CO2 is removed from the air. That doesn't happen when productive land is used for biofuels instead of food or forests that sequester carbon.
Last year we published research to evaluate what actually happened as the RFS ramped up. We found that ethanol and biodiesel are not carbon neutral and their use provided no significant direct CO2 reduction. Once indirect impacts are considered, it turns out that biofuels have caused higher CO2 emissions than petroleum fuels.
We do need to address emissions from motor fuel use along with those from the power plants and other sources. The best ways to do that are improving vehicle efficiency, controlling emissions during oil production and offsetting tailpipe CO2 through reforestation.
If biofuels policy were restricted to basic R&D, we would learn some things and help students build science and technology skills. Those are worthwhile outcomes even if the research does not yield successful products. Research is risky by nature; not all of it bears fruit and that's why the portfolio should be diverse. University research is broadly beneficial in that regard. In contrast to when federal funds are used for subsidies and demonstrations, they go a long way when shared with many schools to support students and young scientists.
Thank you again, and I'll look forward to your questions.

For the written testimony, see: 

DeCicco, J.M. 2017. Testimony on Advancements in Biofuels: Balancing Federal Research and Market Innovation. Washington, DC: U.S. House of Representatives, Committee on Science, Space and Technology, Subcommittee on Environment and Subcommittee on Energy. July 25. [PDF]

Link to a video of the hearing.

Tuesday, March 21, 2017

Deceptive jobs rhetoric and auto regulation

Last week, President Trump worked long-time big-business lobbying scripts about "job-killing regulations" into his populist speech here in Michigan. The setting was the Willow Run facility in Ypsilanti and the props included a crowd of Chrysler, Ford and General Motors auto workers bussed in by the former Big Three to cheer for the Donald.

In reality, environmental regulations do not kill jobs. Read a rebuttal to the speech in my article on the "The ‘Job-Killing’ Fiction Behind Trump’s Retreat on Fuel Economy Standards" at Yale's e360 online magazine.

Friday, March 3, 2017

Clean fuels and climate leadership.

The past few days found me at this year's Climate Leadership Conference in Chicago, where I moderated a panel session entitled "Employing The Next Generation of Clean Fuels." This annual event brings together a diverse set of private companies who are pursuing strategies to reduce greenhouse gas (GHG) emissions with partners in nonprofit and government sectors.

The clean fuels panel was framed around the fact that transportation is now the nation's highest emitting sector in terms of greenhouse gases. It addressed how adopting alternative fuels or expanded electrification can reduce the GHG emissions stemming from personal and business travel. The other panelists were Rebecca Boudreaux of Oberon Fuels, a company that produces dimethyl ether (DME); Jon Coleman of Ford Motor Company; Angela Foster-Rice of United Airlines; and Ed Harte of Southern California Gas.

Most panelists focused on the opportunities and challenges associated with the particular fuel options they are pursuing. Both natural gas and DME are being targeted to replace petroleum-based diesel fuel in commercial vehicles. Airlines such as United have been testing biofuels, which have a significant role in the industry's international plan to avoid further growth in GHG emissions from air travel after the year 2020. As a manufacturer of vehicles for utilizing all of the major alternative fuels, Ford highlighted the need to carefully analyze the many factors that influence whether and to what extent a given alternative fuel might be adopted.

Not surprisingly, I sounded a note of caution about clean fuels and climate.

Thursday, February 2, 2017

A to-the-point radio interview on biofuels and climate

As a guest yesterday on the WEMU (89.1 FM from Eastern Michigan University) "Issues of the Environment" segment, I answered host David Fair's questions about how our recent work differed from the established lifecycle analysis methods used to analyze the greenhouse gas emissions impacts of biofuels.

The resulting interview has great questions from David and clear explanations from myself about why the results of government modeling of the issue are misleading and why, as far as climate is concerned, it's better to repeal biofuel policies and focus on reforestation and other ways to remove carbon from the air and sequester it on land.

Morning Edition: Issues of the Environment 
U-M Researcher Calls For End To Current Biofuel Policy In The U.S.


In August of 2016,  University of Michigan Energy Institute scientists, led by John DeCicco, released an 8-year study.  It estimated powering an American vehicle with ethanol made from corn increased carbon pollution more than using gasoline.  In this week's "Issues of the Environment,” David Fair talks with Professor DeCicco about the findings and what it means to future policy. 


Listen Here [10:09 mp3 link] 

Sunday, December 18, 2016

The need to speed up carbon uptake

Last week I gave a talk, entitled "Net Ecosystem Production and Actionable Negative Emissions Strategies," at the American Geophysical Union (AGU) fall meeting in San Francisco. It was presented in a session on negative emissions strategies, which refers to the topic of removing CO2 from the air in order to slow -- and hopefully one day reverse -- the buildup of carbon in the atmosphere.

Net ecosystem production (NEP) is the net rate at which carbon is taken up by a terrestrial ecosystem. It determines the amount of carbon that becomes available for some use (e.g., crop or timber harvest) or for sequestration on the land. Scientifically speaking, any parcel of land with living organisms on it is an "ecosystem," including farm land or managed forests as well as natural lands and parts of the built environment that aren't totally paved with sterile concrete.

Plants and other organisms that carry out photosynthesis in the terrestrial biosphere actively remove CO2 from the air. Thus, they provide a fundamental mechanism for pursuing negative emissions. However, to be meaningful for climate mitigation -- which is the sense in which the term negative emissions is used -- carbon must be removed from the air more quickly than it is already being removed. That's what "the need to speed up carbon uptake" means and for the terrestrial biosphere, that means increasing NEP.

The fact that terrestrial carbon management is an actionable ("here-and-now") strategy and that using it for negative emissions requires increasing NEP are the main points of my talk. It can be download here in PDF format including both the narrative and slide images.

Friday, November 11, 2016

A simple comparison of ABC to LCA results for corn ethanol

Our recent paper [1] provides an example that compares annual basis carbon (ABC) accounting results to typical lifecycle analysis (LCA) results for corn ethanol. As noted in the paper's discussion section, we used the same process GHG emissions as used in a standard LCA but then adjusted for the fact that biofuel combustion is not fully carbon neutral, as LCA assumes. The implication is then that corn ethanol is 27% more carbon intensive than gasoline instead of 44% less carbon intensive as was claimed by the LCA previously published by Wang et al [2]. This post describes how we made that comparison.

Monday, October 24, 2016

Carbon balance effects of real-world biofuel use

Most of the debate about the environmental merits of biofuel use has been based on lifecycle analysis (LCA). Also known as life-cycle assessment, carbon footprint analysis, "cradle-to-grave" analysis, or (in the case of motor fuels) "well-to-wheels" analysis, LCA is a method for adding up all of the impacts of interest associated with a product. It includes the effects of producing a product and its component materials, associated shipping and packaging effects (as relevant), the use of the product and any related disposal effects. For assessing climatic impacts, LCA tallies the greenhouse gas (GHG) emissions associated with the production, use and disposal of the product. When the product is a motor fuel, the numerical result of such LCA modeling is called the fuel's "carbon intensity," as calculated for California's Low-Carbon Fuel Standard (LCFS), for example.

A cornfield does not absorb CO2 from the atmosphere
any more quickly 
when it is used to make ethanol than
when it is grown for food or feed. 
This basic fact of 
carbon mass balance is ignored by the 
lifecycle studies
that claim climate benefits for biofuels. 
The question, "how does the overall emissions impact of using a biofuel such as ethanol compare to that of a fossil fuel such as gasoline?" seems straightforward, and sounds like something that LCA can answer. However, that question is actually ill-posed scientifically speaking. In other words, when one looks carefully at what actually happens when a given biofuel substitutes for a fossil fuel, it turns out that LCA cannot give a straightforward, unambiguous answer. Properly qualified, the answer will always be, "it depends." And it doesn't just depend on the particular fuel and how it is produced; it also depends on the design of the LCA model and the assumptions it invokes.

Thursday, September 29, 2016

U.S. biofuel consumption chart through 2015

Just to provide an updated picture of the rise in U.S. biofuel consumption, here's a chart based on the latest annual data from EIA's Monthly Energy Review (MER). 

As of calendar year 2015, U.S. ethanol consumption was 13.9 billion gallons per year, up from 1.7 billion gallons in 2000. In 2000, biodiesel consumption was below the level of significance for EIA reporting (i.e., statistically zero relative to overall U.S. motor fuel use). Biodiesel consumption reached 1.5 billion gallons in 2015, and so total biofuel consumption amounted to 15.4 billion gallons that year.

For context, U.S. motor gasoline consumption was 140 billion gallons and distillate fuel oil (which is mostly but not all highway diesel) was 61 billion gallons last year.

In terms of carbon, biofuels accounted for 4.7% of total direct CO2 emissions from the U.S. transportation sector in 2015.

A short URL for embedding this chart is: If you use it, please credit this blog. The source data can be downloaded as Tables 10.3 (for ethanol) and 10.4 (for biodiesel) from the Renewable Energy section of EIA's MER webpage.