Cellulosic ethanol's highly subsidized failure

Actual U.S. production of cellulosic ethanol and other cellulosic liquids compared to the targets for cellulosic biofuels specified in the Renewable Fuel Standard

Cellulosic ethanol, once a great green hope for cutting petroleum use and CO2 emissions, has been a bust. The chart above compares the volume of cellulose-based liquid biofuels (largely ethanol) actually used in the United States to the targets for such fuels set by Congress when it expanded the Renewable Fuel Standard (RFS) in 2007. Note the logarithmic scale on the vertical axis; the gap between promise and reality is so large that actual production would be barely visible on a linear scale. 

The fuel has been delivered at levels of no more than about 0.1% of (three orders of magnitude less than) the volumes on which the RFS was premised [1]. This chart does not include cellulosic biogas, which EPA re-classified to qualify for RFS compliance purposes and has seen recent production of around 500 million ethanol-equivalent gallons. However, such "renewable natural gas" is not in the spirit of the law, which envisioned liquid biofuels that could be readily used in motor vehicles. The 2019 RFS target for cellulosic biofuels was 8.5 billion gallons, set to reach 16 billion gallons by 2022. But in 2019, before the pandemic-related drop-off in 2020 for nearly all forms of energy, only 9.8 million gallons of cellulosic ethanol were tallied by EPA.  

Carbon balance effects of biofuel expansion

The 4th biennial America's Grasslands Conference organized by the National Wildlife Federation was held in Fort Worth, Texas, on 14-16 November 2017. What follows is the narrative with key slides from my presentation in the session on "The Ethanol Mandate as a Driver of Land Conversion and Carbon Emissions." 

I imagine that you have often heard that ethanol and other biofuels are "clean and green" compared to ordinary gasoline. Even if not perfect, aren't biofuels better than petroleum because they recycle carbon from the atmosphere instead of getting it from under the ground? That makes them inherently carbon neutral, many people believe.

Unfortunately, that belief is quite misleading. Take, for instance, the claim that corn ethanol reduces greenhouse gas emissions by 43% compared to gasoline, as given by a recent USDA study (which is critiqued here). That value is based on computer modeling and the assumption that biofuels fully recycle carbon is hard-coded into the model. However, when using field data to evaluate how much CO2 is actually recycled, it turns out that such modeling is off base, and not by just a small amount. In fact, biofuels fall so far short of being truly carbon neutral that they cause higher rather than lower CO2 emissions than petroleum fuels.

Biofuel Research vs. Mandates: House Science Committee Hearing

John DeCicco speaking before the U.S. House of Representatives Committee on Science, Space and Technology, where the Subcommittees on the Environment and on Energy held a joint hearing entitled "Examining Advancements in Biofuels: Balancing Federal Research and Market Innovation" on Tuesday, July 25, 2017. What follows is the statement 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. 

Separating fact from fiction in the newest U.S. federal ethanol study

Debates about the merits of biofuels have been going on for at least a generation. My favorite clip from the early, oil-crisis era ethanol push was Nicholas Wade’s article, "Oil pinch stirs dreams of moonshine travel," published by Science in June 1979. Save for one topic, the terms of the debate — the costs of producing biofuels, whether ethanol took more energy to make than it delivered, the extent to which it really helps energy security, the hope for cellulosic biofuels and the food-versus-fuel dilemma — were the same nearly forty years ago as they are today.

Global warming is the topic not on the table then that is so important now. The effect of biofuels on greenhouse gas (GHG) emissions is the focus of many recent studies. To compare fuels according to their GHG impact, policymakers have adopted a form of computer modeling known as lifecycle analysis (LCA). A new report from the U.S. Department of Agriculture (USDA) is the latest LCA study to claim significant GHG reductions from the use of corn-based ethanol, concluding that it has net GHG emissions 43 percent lower than those of petroleum gasoline. Those results are similar to the findings of lifecycle modeling from Argonne National Laboratory (ANL), on which this latest USDA study heavily relies.

My own work has long come to an opposite conclusion. It shows that the use of biofuels (both ethanol and biodiesel) makes GHG emissions worse that they would otherwise be. This finding is not based on computer modeling, but relies instead on field data to assess the real-world CO2 flows involved when substituting biofuel for fossil fuel.

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.

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.

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: https://goo.gl/rM5EpM. 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.

A-\R-\Corn+soy+biofuel_stats

Latest tweak to U.S. biofuel mandate is politically correct and ecologically cruel

EPA's new Renewable Fuel Standard (RFS) proposal modestly increases the amount of biofuel that America's cars and trucks have to consume next year but still keeps the total renewable fuel mandate below the Congressionally scripted target.

In the plan released on May 18, ordinary corn ethanol gets a 300 million gallon boost, biodiesel is bumped up by 100 million gallons and other so-called advanced biofuels see a 200 million gallon increase compared to last year's regulation. Nevertheless, the proposed 18.8 billion gallon total remains significantly lower than the 24 billion gallon goal for renewable fuel in 2017 that Congress wrote into law back in 2007.

EPA's approach reflects a compromise worked out last year after several tortuous years of regulatory delay. This "politically correct" strategy has the agency taking a middle road that balances the money-making interests of the biofuel industry and the corn and soybean lobbies against the engineering and economic realities that render ethanol and biodiesel such inferior motor fuels. Reactions to the proposal were predictable. The renewable fuel lobby and its allies complain "that's not enough" while the oil industry and other critics say "that's too much" biofuel.

House Oversight Testimony on the RFS

This post is a transcript of my oral testimony at the U.S. House of Representatives as delivered on March 16, 2016. 

I wish to thank the Chairs, Ranking Members and other members of the committee and subcommittees for inviting me to today’s hearing.

My name is John DeCicco and I am a research professor at the University of Michigan Energy Institute. My main focus is transportation fuel use and its environmental impact. I hold a doctorate in engineering from Princeton University and have worked on America's energy challenges for nearly 40 years, including 21 years at environmental organizations before returning to academia in 2009.

My recent research has included scientifically rigorous evaluations of the Renewable Fuel Standard (RFS) and other policies that promote biofuels such as ethanol and biodiesel. RFS proponents claim that the policy reduces CO2 emissions. I have found that it does not. In fact, from its inception, the RFS has increased rather than decreased the amount of CO2 entering the atmosphere compared to petroleum fuels such as gasoline.

Questions and responses on RFS testimony

House Science Committee Hearing on the RFS, November 3, 2015
(photo credit: Michael A. Waring) 

Following the recent hearing on the Renewable Fuel Standard (RFS) held by the House Science Committee, the subcommittee chairs asked me to respond to some questions for the record, following up on my testimony at the hearing. Here are the questions and an abbreviated version of the answers, summarizing my full written response. 

In his testimony, Mr. Coleman referenced cellulosic ethanol that is "129 times better than gasoline on carbon emissions." Based on your research, is this a reasonable claim?

No, that is not a reasonable claim. Such assertions are based on paper studies of hypothetical ethanol production methods. There is indeed a literature on the subject that applies lifecycle analysis (LCA) to proposed cellulosic ethanol production methods and projects that the resulting systems would not only fully offset tailpipe CO₂ emissions but also offset other CO₂ emissions such as those from fossil-based electricity generation.

However, as pointed out in my testimony (and in papers explained elsewhere on this blog), the LCA methods used to justify such claims are scientifically incorrect. Moreover, the cellulosic processing methods involved remain speculative as far as any meaningful commercial-scale operation is concerned. In short, claims of biofuels that achieve a more than 100% reduction in carbon emissions are rooted in flawed analysis of fantasy fuels. 

Testimony on the RFS

Here's my statement at today's House hearing on the RFS; see links at the end to access the written testimony and related videos. 

My research shows that the Renewable Fuel Standard, or RFS, has been harmful to the environment from its inception. Now, ten years after the 2005 Energy Policy Act, the program has resulted in higher CO2 emissions than would have occurred otherwise. It also harms the environment in other ways. Sadly, the adverse impacts of the RFS have grown worse since it was expanded by Energy Independence and Security Act (EISA) of 2007.

The notion that renewable fuels readily reduce CO2 is based on a scientifically incorrect understanding of carbon neutrality. Only under certain conditions does substituting a biofuel for a fossil fuel neutralize the CO2 leaving the tailpipe. For that to occur, harvesting the feedstock must significantly increase how rapidly cropland absorbs CO2 from the atmosphere on a net basis. That condition is not met for the corn ethanol mandated by the RFS. It might be satisfied for cellulosic feedstocks, but once properly evaluated, the gains may not be as great as advocates assume.

The mistaken modeling behind biofuel boosters' emissions claims

Arguments about the pros and cons of biofuels such as ethanol have gone on for many years. The latest debates pertain to whether proposals to limit the ramp-up of the Renewable Fuel Standard (RFS) would result in higher or lower emissions of carbon dioxide (CO2) and other climate-disrupting greenhouse gases.

This week Environmental Protective Agency (EPA ) Administrator Gina McCarthy tweeted the benefits of biofuels: 

and signaled the agency's intent to further raise the RFS volumetric mandate: 

At the crux of the issue is the ability to determine the “carbon footprint” of biofuels using computer models. These models, such as the GREET model developed by Argonne National Laboratory in Illinois, use what are known as lifecycle assessment techniques that claim to account for all of the emissions associated with producing and using a fuel. GREET modeling is the basis for assertions by BIO (the Biotechnology Industry Organization) that the RFS has reduced carbon emissions since it was passed in 2005. It is also the basis for the recent University of Illinois statement that the proposed RFS limits would increase CO2 emissions as much as putting nearly one million more cars on the road. 

Bringing biofuels back to earth

After all that's been written about the pros and cons of biofuels over the years, it's fair to ask whether there's anything left to say. It turns out that there is, and a new insight comes from evaluating what actually happens on the earth, that is, on the land where the plants used to make biofuels are grown.

When do biofuels really balance carbon?

The belief that biofuels are inherently carbon neutral rests on an assumption that the CO₂ absorbed when their feedstocks are grown balances out the CO₂ emitted when the fuel is burned. That's why it's said that biofuels recycle carbon, in contrast to fossil fuels' one-way flow of carbon into the atmosphere.

However, the extent to which CO₂ emissions actually get balanced needs to be verified, not just assumed, even as obvious as it may seem. A careful analysis shows that biofuel carbon flows balance out only under certain conditions. Moreover, those conditions are at best only partly met for the biofuels now being used. To see why, it is necessary to understand some fundamental concepts about CO₂ flows between the biosphere and atmosphere.

Scrutinizing the logic on biofuels

This post picks up a thread based on comments that Prof. Robert Brown and Prof. Bruce Dale made on my "Don't pitch low-carbon fuel ..." post. Both Robert and Bruce take strong exception to my analysis. They invoke the commonly made assumption that substituting a biofuel for a fossil fuel reduces net CO₂ emissions because biofuel use recycles carbon while fossil fuel use does not.

This widely used view of the biofuel lifecycle does not tell
the whole story.  [Image credit: www.EthanolRFA.org] 

Their argument is based on the following logic:

(1) Fossil fuels send old carbon on a one-way trip to the atmosphere, thereby increasing the amount of CO₂ in the atmosphere.

(2) Biofuels use carbon recently taken from the air that is then released back to the air, resulting in no net change in the amount of CO₂ in the atmosphere.

(3) Therefore, substituting a biofuel for a fossil fuel reduces the rate of CO₂ buildup in the atmosphere.

Although this basic analysis neglects processing emissions, we can leave those aside for the purpose of this discussion. They are not what's at the heart of the disagreement, and in any case processing emissions do get tracked by lifecycle models, e.g., as used in the RFS and LCFS. 

Why bad bookkeeping undermines fuel policies

There's a problem with the policies now imposed on transportation fuels in an attempt to control CO2 emissions. The issue has to do with how carbon is counted when the policies are defined.

Good accounting needs to reflect the fact that motor fuels are liquids that contain carbon as their molecular backbone. By nature, liquids flow. That's one main reason why they are so valuable for fueling cars, trucks, ships and planes. Carbon flows with the fuels, and it's the rate at which the carbon flows to and from the atmosphere in the form of CO2 that matters for global warming.

Note the "to and from" in the previous sentence. A big focus of climate policy is reducing CO2 emissions, e.g., reducing the rate at which carbon flows into the air due to energy use. But the from part is also important, and in fact, the CO2 problem is best described as an imbalance in the global carbon cycle due to human activities that cause carbon to flow into the atmosphere faster than natural processes can remove it.

The Global Carbon Cycle
(Source: www.esrl.noaa.gov Carbon Cycle Toolkit)

The adjoining figure illustrates the global carbon cycle. As suggested by the relative thickness of the arrows depicting the flows, the overall cycle is much larger than the excess from fossil fuel use. In round numbers, the natural CO2 flow amounts to circulation of about 200 PgC/yr (petagrams, i.e., 1015 grams, or billion of metric tons, of elemental carbon per year) between the atmosphere and the earth's surface (both land and sea). The total flow into the atmosphere from fossil fuel consumption has been steadily climbing and is now about 10 PgC/yr. Roughly another 1 PgC/yr of emissions are due to deforestation. (The latest data can be found at the Global Carbon Project.)  

The carbon cycle matters a lot when biofuels enter the picture. To protect the climate, biofuels must increase the from part of the carbon cycle; that is to say, they have to increase the net rate at which CO2 is removed from the atmosphere. After all, they don't decrease the to part of the cycle because simple chemistry tells us that a given biofuel emits essentially the same amount of CO2 as the fossil fuel it replaces. As I've put it elsewhere, if biofuels have a benefit, it's not when they're burned.

Flawed studies underpin low-carbon fuel policies

Nearly all of the studies used to promote biofuels as climate-friendly alternatives to petroleum fuels are flawed and need to be redone. This conclusion is just one of the findings of my advanced review paper, "The Liquid Carbon Challenge: Evolving Views on Transportation Fuels and Climate," recently published online by Wiley Interdisciplinary Reviews: Energy and Environment. The unhappy assessment is based on an in-depth review of the literature published on the topic over the past two decades.

Once the erroneous carbon accounting methods are corrected, the results will show that policies used to promote biofuels -- such as the U.S. Renewable Fuel Standard (RFS) and California's Low-Carbon Fuel Standard (LCFS) -- actually worsen the buildup of CO₂ in the atmosphere rather than reducing emissions as promised. 

The Liquid Carbon Challenge

In addition to reducing how much fuel gets burned, cutting the climate risk from gasoline and other liquid fuels requires balancing their CO₂ emissions by removing additional CO₂ from the air in locations other than the transportation sector. 

Options for addressing carbon dioxide emissions from liquid transportation fuels

It's easy to take for granted just how important liquid fuels are in everyday life. Gasoline, diesel and jet fuel remain crucial for transportation. Petroleum fuels are the world's most widely used form of energy and rank second to coal as a source of global CO₂ emissions, a situation unlikely to change for at least two decades. Although some worry about peak oil, in reality the world is not about to run out of fossil hydrocarbons that can be turned into convenient liquid fuels at an affordable price.

Time for realism on renewable fuels

This month, the Environmental Protection Agency upheld its requirement for blending ethanol into gasoline. Though not unexpected given the strength of renewable fuel interests, this decision ignored the pleas of 10 governors, almost 200 members of Congress and many Michigan businesses. With drought destroying much of America's corn crop this summer and Thanksgiving dinners costing significantly more since 2005, the downsides of renewable fuels became all too clear. Responsibility now falls to Congress to roll back the unrealistic renewable fuel goals set in the Energy Independence and Security Act (EISA) of 2007.

To understand how we got to this unhappy place, a bit of history is needed. Renewable fuels such as ethanol and biodiesel have long been hailed as alternatives to America's reliance on petroleum. The fuels bolster crop farmers' incomes and claim to protect the planet by recycling carbon from the air. As prices at the pump climbed over the last decade, biofuel proponents rallied support for a mandate to replace petroleum with home-grown biofuels.

An unheeded warning on ethanol

As concerns about the adverse impacts of expanding biofuel use continue to mount, I can't help but note that a number of policy analysts raised red flags about the issue a decade ago, when proposals to mandate biofuel use began to get legs in Washington. Such was the case for a short position statement opposing an ethanol mandate that I co-wrote while on staff at the Environmental Defense Fund (EDF).

The 9/11 attacks in 2001 shocked U.S. public sentiment in many ways, including a re-awakened concern about energy security and the risks of dependence on foreign oil, as many put it. Policymakers suddenly became much more willing to seriously back petroleum alternatives. Biofuels had long enjoyed a basic level of support, including subsidies established following the 1970's oil crises. Ethanol advocates now saw an opportunity to boost biofuel production in a political climate that made policymakers from both parties happy to intervene in the market as a way to show the public that they were taking action on energy security.

Bills to mandate ethanol in gasoline were introduced early in 2002. The policy immediately found support, especially in the Senate where heartland votes easily overcame the skepticism of members from the left and right coasts.

A number of environmental organizations viewed biofuels as a crucial renewable alternative to petroleum-based gasoline. Although the net benefits of corn ethanol were always questioned, some green campaigners thought it had at least modest benefits. Just as importantly, they believed that mandating ethanol would build a market that would eventually shift away from corn to hoped-for cellulosic feedstocks that were considered much more beneficial.

Along with fellow EDF staffer Tim Searchinger, I was then quite skeptical of ethanol. The position statement we wrote opposing the ethanol mandate argued that its greenhouse gas reduction benefits were small at best while the expansion of corn growing that it would induce would be harmful to wildlife and water quality.

Needless to say, cautious voices like ours were drowned out by the rising chorus of those who were promoting biofuels for one reason or another, from the understandable self-interest of corn growers and processors to energy security hawks and green advocates of renewable energy.

Although other policy disagreements prevented an energy bill from passing in 2002, the ethanol mandate was one of the most widely supported provisions. It was re-introduced in successive Congresses, passing as part of the 2005 Energy Policy Act and then being greatly expanded by the 2007 Energy Independence and Security Act (EISA).

In retrospect, our reasons for skepticism were even better founded than we knew at the time, and the ethanol mandate has turned out to be even more of an environmental disaster than we imagined.