Making Policy in the Absence of Certainty: Biofuels and Land Use Change

Biofuels are an important tool to help decarbonize our transportation system, and their role will likely grow in coming years. New tax credits authorized under the Inflation Reduction Act are being finalized; these would offer significant incentives for the biofuel alternatives to conventional jet fuel, so-called “Sustainable Aviation Fuels” or SAF. But it’s not always clear how sustainable these fuels truly are, or whether they offer a significant GHG advantage over petroleum. The proposed SAF tax credits limit eligibility to fuels that offer at least a 50% reduction in life cycle GHGs compared to petroleum and give additional incentives to those that exceed that threshold.

Biofuel technologies

Advanced fuel technologies – such as those that use inedible wastes, hydrogen, or fuels synthesized using renewable electricity – may eventually deliver very low carbon fuels, but they have yet to emerge at commercial scale. This means that current biofuel technologies that use food crops like corn or soybean oil, are likely to receive most of these tax credits for the next several years, at least. Assessing the GHG benefits of current biofuels requires a descent into the wonky world of lifecycle analysis—measuring the total emissions through farming, processing, and consumption. Much of this is fairly straightforward, by the standards of researchers and expert analysts, until one gets to the use and displacement of land.

While crop-based biofuels can reduce GHG emissions when used in place of petroleum fuels, they compete against food crops for arable land. When biofuel production increases demand for agricultural commodities like corn or vegetable oil, growers often meet this demand by expanding their planted area. Clearing land for cultivation releases much of the carbon stored in plants and soil into carbon dioxide, a greenhouse gas and the primary driver of climate change. This process of biofuel demand causing land conversion is known as Indirect Land Use Change (ILUC), and it has been a point of deep contention around biofuels over the past 20 years.

Experience has taught us that we ignore ILUC at our peril. European attempts to increase the use of biodiesel in the 2000’s overlooked the issue of emissions from land clearing. This led to widespread slashing and burning of tropical rainforest to expand palm oil plantations, much of it on sensitive high-carbon peat soil. Over 6 million hectares of tropical rainforest was lost in Indonesia and Malaysia between 2000 and 2012, demand for biofuels accounted for as much as half of this. Emissions from this conversion dramatically outweighed the benefits from additional biofuels.

Over the next few years, the key question for policy makers is: should we incentivize the consumption of more crop-based fuels, such as those made from corn or soybean oil and, if so, how much? Understanding the impacts of ILUC and getting the question right is essential to ensuring our climate policies actually reduce emissions.

All models are wrong, some models are useful

Estimates of ILUC arising from crop-based biofuel production are highly uncertain. The lowest estimates rate crop-based biofuels as up to 50% less carbon intensive than petroleum gasoline or diesel, while the highest estimates suggest that they’re several times more carbon intensive than petroleum.

Estimates of ILUC factors

Estimates of ILUC factors found in literature for a variety of fuels. Height of the gray bar represents the mean, black “x” represents the median, with uncertainty bars covering the full range of ILUC factors, and the numbers showing the number of studies contributing data points to each category. Red line shows the typical carbon intensity of petroleum. Source: Woltjer et al. (2017)

This uncertainty is due to three main factors:

  1. Complexity. Accurately modeling ILUC means accurately modeling the entire global agricultural commodity system, and the decisions of millions of individuals that make it up. Reducing this complex, dynamic system down to a single, fixed number is an impossible task, but nonetheless necessary to create a stable regulatory structure.
  2. Subjectivity. There’s no perfectly objective method for analyzing emissions from complex systems, like biofuel production or ILUC emissions. Modelers must set system boundaries and allocate impacts between products. Soybeans, for example, yield oil and high-protein meal, used as food for livestock or people. Assigning energy and pollution burdens to each of these is a subjective process. Two analyses of the same product can use equally valid assumptions and result in widely differing estimates of GHG impact.
  3. Calibration and validation. Developing ILUC models requires calibrating against real-world data about how growers make decisions about what to grow and where. These data are often incomplete, non-public, hard to interpret, or unavailable. More importantly, historical data don’t include future climate change impacts. We know that rising temperatures and changing weather patterns will make some highly productive growing areas too hot or dry to maintain yields, and other areas will become fertile. These factors will change how and where growers choose to expand cultivation – which means today’s ILUC model predictions will necessarily be calibrated with unrepresentative data.

Due to these challenges, estimates produced by any ILUC model will be rough representations of a dynamic system, based on subjective assumptions, and calibrated against data that does not reflect the world we’re trying to make policy for. In plain language: they’re going to be wrong. The thing is, there are a lot of different ways to be wrong, some of them worse than others. The question for policy makers in this case is: What’s the right way to be wrong

How to Make Decisions When Models Are Wrong

A perfect fuel policy would provide enough support to crop-based biofuels to maximize near-term decarbonization, but not so much that demand for agricultural products soars and exacerbates ILUC-driven emissions.

In a perfect world, we would use a perfect ILUC assessment to perfectly align incentives with real-world impacts, but that’s not possible in this case, so it helps to think through what happens when we’re wrong. Overestimating ILUC’s impact means biofuels will have higher carbon intensity scores on regulatory assessments, and so fewer of them will be eligible for credits and we would expect to see less of them enter the market; overestimating ILUC would therefore lead to consuming less than the theoretically optimal amount of crop-based biofuels. Underestimating ILUC’s impact means biofuels will have lower carbon intensity scores, more would be eligible for policy support and we would expect to over-consume them compared to a theoretical ideal.

Policy support for biofuel

If we get biofuel policy wrong in a way that causes us to under-consume biofuels, then we miss opportunities to reduce GHG emissions. Every billion gallons of renewable diesel made from soybean oil could offer the opportunity to reduce GHG emissions by about three million tonnes of CO2 equivalent.[1] This is not a trivial or meaningless loss. We know we must reduce emissions very quickly in coming years in order to achieve carbon neutrality by mid-century, and soybean oil based biofuels have demonstrated commercial success already.

There are significant GHG impacts of over-consuming biofuels, as well. Each billion gallons of soybean oil based renewable diesel requires about 15 million acres of land to grow – roughly the size of West Virginia. If this land were grassland in the U.S. Midwest before being converted to cultivation, the GHG emissions from land use change alone would be over two million tonnes of carbon equivalent, and much more if it were forested or land with high-carbon soil that was converted.

These direct GHG impacts are only part of the story, however. As we dig deeper into the risks associated with over- and under-estimation, critical differences arise.

  1. Timing. Carbon in land accumulates slowly but is lost quickly. Plants remove CO2 from the air over time, storing it as solid carbon and accumulating as organic matter in the soil. Converting natural land to cultivation releases that carbon in a matter of weeks to a few years. Once it’s lost, it often takes decades to recover, if it recovers at all.
  2. Diminishing returns. Higher-yielding land is likely to be converted from carbon-storing natural cover to crops first. Each additional million acres of cultivated land is likely to yield a bit less than those that were converted before it. As total demand increases, the additional land needed for every extra unit of production is expected to increase.
  3. Political momentum.  It is easier for politicians and regulators to give support to businesses than to withdraw it. Removing support can also reduce the effectiveness of future climate policy; if governments signal, via policy incentives, that investors should back biofuel projects and then quickly withdraw the incentives, those same investors would be justifiably skeptical about trusting other climate policy incentives. Starting off with lower levels of support and adding mores in the future, on the other hand, avoids sending mixed signals to the market.

These issues show that the risks entailed from under- or overshooting optimal biofuel production volume are not equal. Insufficient support for crop-based biofuels could cost us the opportunity to reduce emissions, but excessive support for them could be significantly worse. Land conversion causes a loss of stored carbon that cannot be reversed on a time scale that allows us to meet mid-century GHG targets. Once over-production of biofuels occurs, any attempt to correct it could lead to stranded assets and break financial markets’ trust that policy signals are a reliable guide when making investment decisions.

We know that ILUC analysis is difficult to get right, and we cannot count on developing a model to predict the optimum level of crop-based biofuel consumption any time soon. If we can’t be sure we’re right, we should make a decision that recognizes the profoundly asymmetric risks around biofuel consumption. The risks entailed with underestimating ILUC impacts are far worse than the risks of overestimating them, so we should err on the side of overestimation.

Developing a Risk-Aware Approach to Biofuels

In practical terms, this means the arguments over which ILUC model is best are not terribly helpful since every model is going to be inaccurate. Instead, we should look at the full range of ILUC estimates we get from the many approaches of ILUC estimation that have been put forward by researchers. We’re relatively confident that the correct answer lies somewhere within this very wide range. The risk-aware approach to biofuel policy is to select a number high enough that it’s very unlikely we underestimate the real value.

“High enough to not be an underestimate” is still not precise enough to be helpful. Other landmarks can help us get closer to a risk-aware ILUC impact estimate. We know, based on extensive scientific research, that fuels from wastes and residues generally have lower ILUC impact, and that fuels from palm oil are very likely to be worse than the petroleum they try to displace. An effective ILUC assessment should align with the ample scientific evidence on these topics.

Support for additional research and modeling can help us both narrow the range of uncertainty around this issue, as well as identify what ILUC impact value within that range should be chosen to yield the best possible result. Expert-driven consultative processes, like the National Academies committee on biofuel life cycle assessment or CORSIA workgroups developing sustainability and GHG assessment methods can serve a vital role here, not only as clearinghouses for the latest research in this space but also to allow stakeholders to engage with the process. These groups can find mutually acceptable approaches to some, though certainly not all, of the subjective decisions that are an unavoidable part of LCA.

Just as there is no perfect ILUC model, there is no simple solution to alternative fuels. We know, however, that it’s going to be virtually impossible to meet critical decarbonization targets without lower-carbon liquid fuels. Avoiding the worst impacts of climate change will require risk-aware policies that succeed without perfect modeling. In the case of crop-based biofuels, it’s quite clear that the worst risks arise when we underestimate ILUC impacts. We know that our attempts to quantify ILUC risk are likely to be wrong, but we also know that there’s a less-damaging way to be wrong in this case. Policy should reflect this reality.

Colin Murphy is the Deputy Director of the UC Davis Policy Institute for Energy, Environment, and the Economy, and the co-Director of the Low Carbon Fuel Policy Research Initiative there. Any statements or inaccuracies herein are solely the responsibility of the author and should not be taken as representing UC Davis or the Policy Institute.

The material in this blog was originally presented as part of the EPA National Center on Environmental Economics seminar series, a recorded version is available via the UC Davis Low Carbon Fuel Policy Research Initiative website. The author would like to gratefully acknowledge the assistance of Amber Manfree, Dan Sperling, and John Schmitz in helping develop and refine this material.


[1] Assuming 65 gCO2e/MJ carbon intensity (derived from approximate average CI of such fuels under California’s LCFS), and that each gallon of renewable diesel displaces 1 gallon of petroleum diesel with 91 gCO2e/MJ carbon intensity (approximate average of U.S. diesel supply).

Postdoctoral Researcher, Transportation Economics

Location: Davis, California, UNITED STATES

Keywords: Urban, Rural, Regional, and Transportation Economics; Microeconomics; Mathematical and Quantitative Methods

Position Description

The Electric Vehicle Research Center at the Institute of Transportation Studies, UC Davis is seeking a postdoctoral scholar with a PhD in Economics, Travel Behavior, or related discipline. The researcher will pursue policy-focused research on consumer vehicle purchase behaviors, vehicle use patterns, and vehicle charging/refueling issues. The researcher should demonstrate strong quantitative research skills working with discrete choice models and other advanced econometric methods as well as experience with big datasets.

The position’s responsibilities include: (1) designing, overseeing, and conducting research using quantitative methods, (2) identifying funding opportunities; leading and contributing to proposals to apply to those opportunities. (3) supervising, and mentoring students and other team members working on research projects, (4) writing articles for refereed academic journals, technical reports, and/or for conferences, (5) presenting research to a variety of audiences (academia, industry professionals, policy practitioners, etc.).

Job Requirements

  • Applicants must have a graduate degree in economics, urban planning, transportation planning/engineering, public policy or a related field. At least one of these degrees must be a Ph.D. and one a transportation-related field.
  • A record of publications in peer-reviewed journals, and some postdoctoral and mentorship experience is required.
  • The applicant must possess expertise and experience designing and conducting research; experience developing statistical models to analyze data collected by surveys or other methods.
  • The applicant should be competent in the use of at least one of the following statistical software packages: SPSS, STATA, R, or JMP.
  • The postdoctoral researcher should have a record of publications in peer-reviewed academic journals and other publication venues.
  • The postdoctoral researcher must have excellent verbal and written English language communication skills.
  • The postdoctoral researcher must be able to work collaboratively with a research team ranging from undergraduate research assistants to research faculty.

Application Requirements

Letters of Reference (2); Job Market Paper; Cover Letter; CV Please submit your application (CV and cover letter) to Zohar Tal ( )

Salary Range: $70,000

On the Governor’s Desk: What 2023 Transportation and Sustainability Bills Did California’s Legislature Pass?

At the UC Davis Policy Institute for Energy, Environment, and the Economy and the Institute of Transportation Studies, we hope to shine a light on which transportation bills might yield benefits to our communities and the environment. Of the 2,600 bills introduced to the California State Legislature in 2023, here are some of the most important for transportation and energy.

UC Day

Top Bills about Public Transit

Senate bill (SB) 434 is sitting on the governor’s desk. It was introduced by a savvy transportation lawmaker, Senator Min (a former law professor at UC Irvine). This bill would allocate funds to district public transit operators for rider safety surveys and outreach efforts. The survey would collect data regarding street harassment experienced by riders from underrepresented populations. The bill expands on San Jose State University research that found that “sexual harassment experienced by riders on buses and trains leads to reduced use of public transportation.” This bill would require transit agencies to collect and publish information on harassment reported by populations of interest including females, particularly those of color, those with low-income, and those in LGBTQ+ communities.

Another notable transit bill on the governor’s desk is Assembly Bill (AB) 971, introduced by Assemblymember Lee, which would amend the Vehicle Code to reflect the term “transit-only” instead of “for the exclusive use of public transit buses” when granting exclusive use of designated traffic lanes. ITS research supports the fact that transit-only lanes can encourage more ridership by improving bus speed and reliability. However, this bill is more procedural than substantive. It falls short of giving transit agencies what they really need, (but which local government’s hold the key) which is more control over where transit-only lanes crosscut busy roadways.

Despite many previous attempts to advance fare-free transit, this is not the year for Assemblymember Holden, a long-time transit advocate, to win on this issue. Holden’s AB 610 would have established the Youth Transit Pass Pilot Program and provided free transit service to youths attending certain qualifying educational institutions. It failed in its very last committee. Youth fare-free transit passes can increase accessibility and transit use among students, according to UC Irvine researcher Jean-Daniel Saphores. So far, the state has not found long-term sustainable funding sources for such programs.

Top Bill about Bikes

Also on the governor’s desk is SB 381, introduced by Senator Min. If signed, it will fund research on electric bicycle safety and regulation. Electric bicycles are defined as bicycles with fully operable pedals and a motor of less than 750 watts. UC Davis researcher Dillon Fitch has shown that the availability of shared e-bikes can reduce vehicle miles traveled. More research is necessary to understand safety and regulatory challenges that might inhibit scaling of e-bikes.

Bills about Emerging Technologies

The Legislature is attempting to prevent safety issues with medium and heavy-duty automated vehicles (AVs) weighing more than 10,000 lbs. These vehicles are currently not allowed to operate in the state due to a previous ban from the California Department of Motor Vehicles (DMV). AB 316 would add more limitations to the existing ban, requiring a safety driver in all automated trucks. It would also require more collision and deactivation data reporting and require the DMV to submit a performance evaluation regarding AV technology to the Legislature in five years. Researchers at UC Davis are currently studying this topic to assess whether AV safety driver requirements are the best way to increase road safety in the state. AB 316 passed the Legislature and is on its way to the governor’s desk for a signature or veto.

SB 800, authored by Senator Caballero, would require Caltrans to establish the Advanced Air Mobility and Aviation Electrification Advisory Panel. The panel would be tasked with assessing current infrastructure, developing a three year plan to advance infrastructure, and promoting pathways towards equitable access to advanced air mobility services. Members would include government and industry representatives. UC Berkeley, in partnership with NASA, is pursuing research that looks at how urban air mobility could fundamentally revolutionize regional travel.

Bills about Carbon Offsets

AB 1305, a carbon markets bill, is on the governor’s desk. This bill would add clarity to public reporting of carbon offset purchasing, which is an area that could use additional public accountability mechanisms. A sister bill, SB 390, is also on the governor’s desk. It is similarly intended to provide clearer standards for voluntary carbon offsets by defining unlawful conduct and requiring sellers and buyers to provide explicit information. Improving the transparency of carbon offset is critical to the effective functioning of the State’s carbon market. These proposed bills aim to enhance the credibility and confidence of private investors within the green energy sector.

Some Wins and Losses for Electric Vehicles

Finally, it’s worth noting a few losses and one big win for California legislative actions on EVs. The winner first, AB 126 will extend certain vehicle fees till 2035 that fund state programmatic investment in a clean transportation future. There’s a few new EV priorities added to the updated program, including a requirement that half of funding goes to disadvantaged and low-income communities, and new requirements for data reporting for EV charging reliability. The bill requires new research led by the California Energy Commission to consider alternative funding strategies for ZEV infrastructure, and consider the equity impacts of the alternatives.

Other EV bills are worth noting, even though they didn’t make it out of the Legislature. These three bills failed to make it to the governor’s desk: 

AB 591, introduced by Assemblymember Gabriel, would have forced Tesla to open charging stations to the public and require universal connectors and public accessibility at almost all new and retrofitted EV charging stations, except those located at single- or multi-family residences. This bill would also have required CHAdeMO EV service equipment be maintained in good working conditions by owners for at least five years. UC Davis researcher Gil Tal suggests that charger reliability, including the prevention of highly disruptive charging failures, is a high priority for EV drivers. The challenge is that charger owners would prefer not to bear the costs of supporting charging standards for which there are very few vehicles on the road, such as CHAdeMO. This bill didn’t make it out of its second round of committees in time, but if legislators and stakeholders can find the right solution, it could still pass in next year’s legislative session.

Another EV bill worth noting is SB 529, which would have facilitated EV sharing services at affordable housing facilities. This type of program would have been transformational and expanded access to EVs in lower-income communities. UC Davis researchers Caroline Rodier and Brian Harold have done extensive work demonstrating that low-income EV carsharing in the San Joaquin Valley has successfully expanded access to EVs with short-term vehicle rentals to people living in low-income communities. These rental programs are a game-changer for rural community members, and will be an essential part of building an equitable and clean transportation system in California. This bill didn’t get the support it needed this year, but it was authored by Senator Gonzalez, Chair of the Senate Transportation Committee and champion for equitable transportation, so we will likely see this issue raised in future legislative sessions.

Another hot topic that didn’t advance through the Legislature was SB 425, introduced by Senator Newman. This bill would have expanded rebates for new electric pickup trucks. Rebates for electric pickup trucks would be $2,500 greater than rebates provided for other electric vehicles. This bill may not have advanced because additional research is needed to understand the role of EV pickup trucks in the overall clean vehicle fleet.

Conclusions and Looking Ahead

Governor Newsom has until October 14 to act on these bills. We’ll be watching out for which bills advance this year, and which topics may need more research and deliberation.


Mollie Cohen D’Agostino is Executive Director of the Mobility Science, Automation and Inclusion Center at the Institute of Transportation Studies at UC Davis

Colin Murphy is Deputy Director of the UC Davis Policy Institute for Energy, Environment and the Economy

Emily Chiu is a law student at the UC Davis School of Law

Laedon Kang is a Graduate Student at the UC Davis Transportation, Technology, and Policy Program

Dan Sperling is Founding Director of the UC Davis Institute of Transportation Studies, and distinguished Blue Planet Prize Professor of Engineering and Environmental Policy

Postdoctoral Researcher, Consumer Adoption of Electric Vehicles & Survey Design and Implementation

About us

The Electric Vehicle (EV) Research Center launched in early 2007, with the support of the California Energy Commission. Now, the EV Research Center collaborates closely with state and federal agencies, utilities, automakers, regulators, and other research institutions to provide the rigorous research and impartial policy analysis that are needed to meet the climate, environmental, and equity goals of our society.

Moving forward our research is focused on measuring, monitoring, and understanding multiple aspects of the quickly evolving markets for zero emission vehicles, the incentives and policies needed to meet the goals nationally and internationally, the demand for infrastructure and energy, the development of new supply chains, and environmental impacts of the transition to electric transportation.

The program receives support from industry partners, planning agencies and research foundations, and works in close cooperation with the federally funded National Center for Sustainable Transportation and other research programs at UC Davis. For additional information on the EV Center and on ITS Davis, please see ( and (

Position Description

The selected candidate will join a team investigating the future of electric mobility at the University of California, Davis. The postdoctoral researcher will mainly work on survey design and implementation and modeling and analyzing the results related to transportation electrification as well as travel behavior modeling research. The postdoctoral researcher will engage in exciting projects addressing the issues of EVs and consumer behaviors, as well as develop knowledge and investigate topics relevant to the increased adoption and use of EVs.

The position’s general duties include: (1) designing, overseeing, and conducting research using both quantitative and qualitative methods, (2) identifying funding opportunities; leading and contributing to proposals to apply to those opportunities. (3) supervising, and mentoring students and other team members working on research projects, (4) writing articles for refereed academic journals, technical reports, and/or for conferences, (5) presenting research to a variety of audiences.

Qualifications & Skills

1) Candidates should have completed a doctoral degree in Civil Engineering, Transportation Engineering/Planning, Computer Science, Economics, Geography, or a related field at the time of hire. Candidates with strong multidisciplinary skills covering more than one of these areas are particularly encouraged to apply. Extremely well-qualified candidates with slightly different qualifications and/or research focus might be also considered under special circumstances.

2) The postdoctoral researcher must have a deep understanding of travel behavior, travel demand modeling, discrete choice modeling, including demonstrable experience in:

  • Transportation issues, particularly those related to zero-emission vehicle transportation.
  • Spatial analysis using tools such as ArcGIS or QGIS.
  • Quantitative methods for data analysis using statistical software such as R, Python, STATA, or equivalent.

3) Because the center’s researchers employ a range of methods to address topics relating to the purchase and use of electric vehicles, experience in the following areas is also important:

  • Market research, forecasting, and modeling the adoption of new technologies.
  • Survey design and implementation.

4) The postdoctoral researcher should have a record of publications in peer-reviewed academic journals and other publication venues.

5) The postdoctoral researcher must have excellent verbal and written English language communication skills.

6) The postdoctoral researcher must be able to work collaboratively with a research team ranging from undergraduate research assistants to research faculty.

Preferred Skills

1) Experience in working with large datasets.

2) Additional academic, industrial training or other professional experience in managing projects.

3) Ability to obtain funding to pursue their research interests and goals, or at least demonstrated proposal writing skills.

4) Ability to lead a research team of graduate students, postdoctoral scholars, and associates.

Application Procedure

Please submit your application (CV and cover letter) to Zohar Tal (

References: 3 References required (contact information only), Letters of reference will only be solicited for finalists

Salary Range: $70,000

Program Director: Sustainable Freight Research Program

Job Summary

Direct the Sustainable Freight Research Program (SF) within the STEPS+ research framework. Provide technical leadership to the SF research team and manage grant-funded and contracted research projects. Ensure high quality and timely execution of all projects under SF purview. Manage a publications program related to projects. Conduct research directly as part of the program’s work effort. Work with colleagues to expand funding, including the supporting membership of SF. Oversee the SF budget and allocate funding to researchers and students. Manage researchers and identify needs for personnel changes or new hires as needed. Interface with SF members to identify new research activities and share information and research. Work with other STEPS+ team leaders to coordinate on research and organize workshops, Symposia, and other relevant events. Function with ahigh degree of autonomy, exercising independent judgment in selecting projects, methods, techniques, and evaluation criteria for obtaining results.

Serve as an advanced technical specialist and provide leadership within the UC Davis Institute of Transportation Studies (ITS) and participate in ITS strategic planning to guide the selection of future topic areas and to engage with collaborators, clients, and funders. Develop and maintain ITS expertise in advanced environmental freight vehicles, energy storage systems, propulsion systems, and fuels, along with logistic and intermodal systems at a regional, national, and global levels. Identify and manage proposal opportunities, develop proposals, and produce briefings to funding agencies, and participate in relevant conferences, technical events, and meetings. Serve as an advisor and team leader for participating staff and for teams of students to complete funded projects within ITS.

Department Purpose

The Sustainable Freight Research Program is a growing research and policy program in the Institute of Transportation Studies of the University of California, Davis. It is part of the STEPS+ research program and focuses on truck, rail, and other freight sectors. It includes research on both technologies and fuels as well as logistic systems. It covers topics related to decarbonization, reducing air pollutant emissions, and other sustainability factors. The Center receives support from a range of government and industry partners, planning agencies and research foundations, and works in close cooperation with the federally funded National Center for Sustainable Transportation and the other research programs at UC Davis.



  • Bachelor’s degree in engineering, transportation/energy technology and policy, economics or related field or an equivalent combination of education and experience.
  • Personnel and budget management experience.
  • Excellent written, oral, and interpersonal communication skills, with skills to draft, rewrite and edit professional correspondence, reports, donor communications and other materials.
  • Strategic planning and evaluation skills to analyze, define, and assess problems, issues, and needs, and define needed actions.
  • Development (fundraising) experience, with a working knowledge of the gift-giving process and stewardship.
  • Experience using organizational, time management and event planning skills to organize and coordinate individuals and groups to develop collaborations and/or proposals/applications, and to plan large meetings, workshops, or conferences. Experience creating and/or writing presentations, informational documents, technical reports, and correspondence.
  • Computer skills including word processing, spreadsheet, database, presentations, website, electronic mail, and internet.


  • Master’s or PhD in one of those same fields
  • Experience managing and executing large, complex projects, and managing large contracts.
  • Management of and outreach to organizations that interact with own organization.
  • Proposal writing, including for large grant applications.

To apply to the position please use the following instructions:

  1. Please use the link here.
  2. Sign In to access your account or if you are not an existing user select the New User link to create one.
  3. Review the job description and select the Apply button to begin your application.

If you are an existing UC employee please use the link here.

Post-Doctoral Research in Materials Decarbonization at the University of California, Davis


The Energy and Efficiency Institute at the University of California, Davis, is seeking one post-doc to lead research in the area of low-carbon materials. The post-doc will participate in, lead, and develop new research projects in designing sustainable materials with an emphasis on assessing environmental burdens and integrating environmental impact assessment methods with material performance. The post-doc will develop means to robustly assess local, regional, and global burdens from materials consumption The research will focus on cement-based materials (e.g., concrete), bio-derived materials (e.g., wood), alloys (e.g., steel), and/or polymeric materials (e.g., plastic).

Appointment length: Maximum 24 month, 100 % time
Salary: Between $60,000 and $72,000, commensurate with experience.
Job Location: Davis, California, USA
Anticipated start date: September 2023


The successful candidate will:

(1) Oversee and conduct comprehensive data analysis including both qualitative and quantitative data.

(2) Develop and maintain online assessment tools.

(3) Identify funding opportunities; lead and contribute to proposals to apply to those opportunities.

(4) Write articles for refereed academic journals, for technical reports , and/or for conferences.

(5) Supervise, train, and mentor graduate students and other team members working on research projects.

Qualifications (at the time of application)


(1) Ph.D or equivalent International Degree in Engineering, Chemistry, Energy, or topic demonstrably related to decarbonization

(2) Research experience in techniques and policies related to low-carbon materials

(3) Record of high quality publications in academic journals and other publication venues.

(4) Demonstrated ability to work effectively as part of an interdisciplinary team, including the ability to efficiently and actively cooperate with other staff members within the organization.

(5) Strong English communication skills (oral and written).


(1) Besides the graduate study leading to the PhD, additional academic, industrial training or other

professional experience in the building sciences or closely related fields.

(2) Demonstrated ability to obtain funding to pursue their research interests and goals, or at least demonstrated proposal writing skills

(3) End-to-end experience with all aspects of research – development of initial research concept, identification of and planning for funding opportunities including forming competitive teams for funding applications, writing proposals, research design, data acquisition, occupant surveys, analysis, reporting, and stakeholder communication.

(4) Demonstrated ability to lead a research team of graduate students, postdoctoral scholars and associates.

Application Procedure

Please submit your application to Zohar Tal (

References: 3 References required (contact information only): Letters of reference will only be solicited for finalists.

Supporting California’s Move to Zero-Emission Vehicles: Creating a Viable, Large-Scale Fuel-Cell Vehicle and Hydrogen System

Hydrogen station

Photo: Adapted from Scharfsinn86 / Adobe Stock.

California is marching ahead with firm rules now in place for both light-duty and medium/heavy-duty vehicles to transition to zero emission stock by 2045. The State is requiring that all new vehicles sold from 2035 onward be “zero-emission vehicles” (ZEVs)—battery electric, plug-in hybrid, or hydrogen-powered fuel-cell vehicles. While battery electric vehicles currently dominate ZEV sales and discussions of the zero-emissions future, fuel-cell vehicles are expected to play a key role, especially in truck and bus fleets and some households. They offer a different set of strengths, such as extended driving ranges, fast refueling, and potentially greater payloads for trucks.

But creating an economically viable hydrogen system and scaling it up to meet 2035 targets will require massive investments over the next decade. While many initial investments have been made, there is no clear overarching strategy for what a full hydrogen system and supply chain infrastructure might look like in 5, 10, or 20 years. Some kind of system will be needed, given the projected needs of various sectors (transportation, industry, and buildings) and the need for low-cost renewable hydrogen to contribute to the goal of carbon neutrality by 2045 in California. Acknowledging the urgency of the moment, the state recently formed the ARCHES partnership to develop this system further.

For the past two years, a team at UC Davis has been working on the California Hydrogen Analysis Project to investigate potential future hydrogen systems and to assist in planning them through modeling. The current results of the project are described in detail in our full report. We modeled potential demands for hydrogen across sectors (with a focus on transportation), potential types and locations of hydrogen supply, and how hydrogen could be moved and stored between supply and demand locationss. We also analyzed the transportation sector, the electricity sector, and supply chains from production to end-use.

Our study has many findings across the various hydrogen sectors. Here are a few of the key findings and related policy recommendations.

Key findings

  • Transportation can lead hydrogen developments. California’s hydrogen system will need to be driven by growth in hydrogen demand from various end uses, and this growth can be led by transportation (especially by medium/heavy-duty road vehicles). By 2030 we estimate that road transportation, if properly incentivized, could create a hydrogen demand on the order of 500 metric tons per day. This should be sufficient to support development of a hydrogen production and distribution system that would be large enough to benefit from economies of scale.
  • Transportation is scalable. Rapid and incremental sales and adoption of light-duty and medium/heavy-duty fuel-cell vehicles, fostered by supply and demand-based incentives, can be supported by parallel growth of infrastructure to produce and distribute hydrogen. The decentralized nature of a transportation-focused approach can help to develop a regional hydrogen production/distribution network that can then be scaled with more stations and eventually other “offtakers”—i.e., end-users who contract to purchase hydrogen fuel when produced.
  • Strong early investment is needed. In the early years of developing hydrogen systems for transportation, many refueling stations will be needed to ensure adequate coverage so drivers can reliably find fuel as they travel. This can mean generally low utilization of stations and challenging station economics that may require policies to ensure profitability. The Low Carbon Fuel Standard (LCFS) credit systems, the Inflation Reduction Act (IRA) renewable hydrogen production cost credit, and other incentives can help. But the most important solution is to support investments in areas such as refueling stations and fleet vehicle purchases, which will quickly increase transportation demand.
  • On-going rapid scale-up should occur after 2030. Then, with lower hydrogen costs and prices available, the market should be able to further scale in a profitable manner to reach much higher fuel-cell vehicle shares and hydrogen demand. If fuel-cell vehicles succeed in growing to about 10% of light-duty vehicle shares and 25% of truck shares by 2045, hydrogen demand could be 10 times higher than in 2030, and refueling station numbers could eventually reach many hundreds or even thousands in California, depending on average station sizes.
  • Liquid hydrogen may play an important role. Currently all hydrogen is produced, stored, and moved as a compressed gas; but cryogenic liquid hydrogen may play an important role, especially for refueling large, long-haul trucks. Liquid hydrogen production/storage/station systems have significant advantages given their fuel density and potential for faster dispensing (even into gaseous storage on vehicles), particularly for vehicles, such as heavy-duty trucks, with a lot of hydrogen storage.

Policy Recommendations

The analysis has led to a wide range of findings and conclusions. Some of the most important are policy recommendations for the California Energy Commission and other agencies and stakeholders to consider. These include:

  • Set a new vision for 2030/2035. Work with other agencies and ARCHES to create a clearer vision for the fuel-cell vehicle and hydrogen market in California for the 2030-2035 timeframe, with specific targets for vehicles, fuel, and infrastructure. Align investments in all areas to grow all elements of the system in parallel.
  • Create new fuel-cell vehicle support systems. For example, the state should link incentives and rebates for fuel-cell vehicle purchases to their incremental costs over diesel vehicles, at least for the next 5 years, until market scale can be achieved. This could also be adopted for battery electric vehicles, to keep the system technology-neutral.
  • Build more and larger stations oriented to heavy-duty vehicles. The state should fund a minimum hydrogen station infrastructure to 2030 with increased emphasis on heavy-duty trucks and some stations (such as highway rest stops) that can provide for both light-duty vehicles and all types of trucks. For heavy-duty trucks, at least 50 high-volume stations (each with a capacity of around 10 tons/day) will be needed by 2030 to support a system of several thousand trucks. Larger and potentially more profitable stations are also needed. Defining these levels is key. The ARCHES partnership is developing targets and specific roll-out plans that state agencies should coordinate with and build upon.
  • Find Champion Fleets. Within the Advanced Clean Fleets policy system, find champion fleets to help support major uptake of specific numbers and types of trucks to ensure demand that aligns with a roll-out of hydrogen stations and supply growth to serve these vehicles.
  • Create a data/tracking system for fuel-cell vehicles and hydrogen systems as they develop and grow, to ensure that investments are aligned and the system is functioning as planned for all stakeholders. This system must be kept up to date with annual statistics on numbers and types of vehicles, their usage and performance, refueling infrastructure characteristics and performance, and a range of other information considered important to fleets and policy makers. This database should be publicly available and well supported by the state.

In summary, a hydrogen production and distribution system that serves the growth of fuel-cell vehicles and other end-uses in California will be key to slowing climate change. It should be both feasible and eventually cost-effective, but navigating growth over the next few years will be key. We will continue our research to support planning and informed policymaking.


For more the full report that this blog is based on and information on the ongoing hydrogen research at ITS-Davis, click here and here.

Lew Fulton is the Director of Sustainable Transportation Energy Pathways Plus.

Cutting US road sector GHG emissions by 90% or more by 2050 takes both ZEVs and low-carbon fuels

Big reductions in greenhouse gas (GHG) emissions from the transportation sector are needed to limit the magnitude of climate change impacts. Understanding what kinds of policy and market dynamics are at play can help us meet national goals. Our recent study shows that there is an interplay between policy, vehicle types, and fuel sources, and that early investment in zero-emission vehicles (ZEVs) could yield big savings and big reductions in GHG emissions, by 2050. Low-carbon fuels for non-electric vehicles will also need to play an important role.

While the United States has not formally adopted long term targets for the sales of ZEVs, including battery electric, plug-in hybrid, and fuel cell vehicles, the Biden administration is a 50% sales share of light-duty ZEVs by 2030 and the US EPA has issued a proposed rule intended to slightly exceed this target.

California is leading the transition with nearly 20% ZEV market share in 2023, and with the most ambitious rules requiring a full transition of LDV sales to ZEV by 2035 and trucks to ZEV by 2040. Many states are following. So far, 16 states have committed to adopting the California LDV ZEV program, and at least 16 have signed the Multi-State Medium- and Heavy-Duty Zero Emission Vehicle MOU. If the Biden administration adopts the CO2 rules as currently drafted all 50 state vehicle markets will be required to move in the same direction. It then seems likely that most states will achieve 100% ZEV sales by 2045, 10 years after California’s target.

We recently published a major report on transitioning the US to ZEVs, along with other steps to achieve a very low carbon road-transport sector in the US by 2050. Our report considers a range of scenarios based on vehicle market and policy trends, extending trajectories to 2050. In each case, overall GHG emissions reductions are achieved sooner with the adoption of low-carbon fuels such as advanced biofuels. Our results show that it is possible to reach a 90% or greater reduction in road GHG emissions by 2050 compared to 2015, even in our slowest ZEV transition scenario.

Major findings include:

  • Fast ZEV uptake works but is challenging. Our Low Carbon California (LC CA) scenario is the most ambitious, reaching 100% ZEV sales nationwide by 2035, and 90% ZEV stock by 2050. It involves achieving 68% and 51% of ZEV sales by 2030 for LDVs and trucks, respectively, which will be challenging over the coming seven years.
  • Very high uptake of low-carbon fuels is another, complementary option. Our Low Carbon 10-to-15-year (LC 10-15) scenario is the least ambitious for ZEV uptake and therefore requires the most liquid fuels to reach a 90% GHG reduction. It does not reach 100% ZEV sales nationwide until 2050, resulting in about 54% ZEV stock in that year. These, along with a high uptake of low-carbon fuels in remaining ICE vehicles, achieves an overall GHG reduction of 90% in 2050.
  • Low GHG electricity and hydrogen are critical for both types of scenarios. All ZEVs must eventually be powered from these energy sources, with the electricity and hydrogen providing net zero carbon energy hopefully well before 2050.
  • The slower the ZEV uptake, the more challenging the biofuels component. The result of slower ZEV uptake is a build-up to very high—possibly infeasible or unsustainable—levels of advanced, very low-carbon biofuel use to ensure ongoing GHG reductions in the transportation energy sector. A transition will be needed from today’s dominant grain and oil-based biofuels to predominantly cellulosic biomass-based fuels to maximize their GHG benefits.
  • All scenarios save money, but ZEVs are likely to be cheaper than low-carbon fuels. Cumulative costs of the alternative scenarios from 2020 to 2050, aggregated across LDVs and trucks, are much lower than the business-as-usual (BAU) scenario. The faster the ZEV transition, the greater the net savings between now and 2050. This is mainly due to the lower need for maintenance and higher fuel efficiency of ZEVs. As ZEV prices fall over time, savings on vehicle costs of the alternative scenarios also contribute to overall savings. However, for some specific vehicle types, such as long-haul (LH) trucks that are dominated by fuel cell vehicles (FCV) with only a modest increase in fuel economy over diesel trucks, there are no fuel cost savings, so overall costs are higher than the BAU scenario.

Our analysis also evaluates battery electric energy vs. hydrogen fuel cells for 10 different vehicle types, including LDVs, trucks and buses of different sizes and types. The general results are shown here, with sales shares varying by vehicle type and year for our BAU and two fastest transition scenarios. Our background technology analysis shows that electric vehicles dominate LDV and most truck sales by 2035. However, for long haul trucks, we find hydrogen fuel cell trucks eventually could dominate. In any case, the ZEV sales share is 100% by 2050 in all our scenarios except the BAU.

Bar chart showing vehicle sales shares across vehicle types, scenarios, technologies, and years.

Comparing the fastest transition (LC CA) to BAU for costs, including purchase, fuels, and maintenance costs of all vehicles, we find that this scenario is more expensive than BAU until around 2030, then has lower net costs, becoming much lower very quickly. These higher “investment” costs pay off with around 54 times the savings after 2028 in a non-cost discounted scenario. Slower ZEV transition scenarios save less money, since it’s the ZEVs—particularly battery electric vehicles—that save money, while biofuels costs are generally higher than fossil fuels.

Plot graph showing total vehicle and operation and maintenance cost differences from 2015 to 2050 for light-duty vehicles and trucks combined for the LC CA scenario and BAU.

As our report describes, there are many details that are uncertain. Continuing research will be needed to better predict outcomes. For example, costs may change over time in unpredictable ways, and will depend to a large degree on scaling and learning. The level of policy support that may be needed to help manage the costs of transition are uncertain. The net societal costs of various types of policies and/or regulatory strategies are important, though often difficult to estimate. Our research over the coming one to two years will focus on better understanding fleet behavior, non-cost decision factors, electricity costs, and the potential role, sourcing, and costs of advanced biofuels as well as e-fuels.


Addressing the Impact of Lithium-ion Batteries on Low- and Middle-income Countries

The impacts of lithium-ion batteries on low- and middle-income countries are increasing as the global electric vehicle (EV) market continues to grow. The environmental and health burdens of production mainly affect countries that supply raw materials for EV batteries, while increasing exports of used EVs are going to poorer countries.

In the absence of strategic policies, the positive impacts of new EVs—such as decreased pollution and greenhouse gas emissions—could disproportionately benefit higher-income countries, while the negative impacts of second-hand EVs—such as battery disposal—could fall more on lower-income countries. 

To shed light on this problem and outline possible policy solutions, researchers at ITS-Davis collaborated with the United Nations Environment Programme (UNEP) and produced a March 2023 report entitled Electric Vehicle Lithium-ion Batteries in Lower- and Middle-income Countries: Life Cycle Impacts and Issues. Alissa Kendall, lead author and UC Davis professor of Civil and Environmental Engineering highlighted the aims of the study:

“The exponential growth of new EV sales in regions like Europe and the US is exciting to see given the key role that vehicle electrification will play in decarbonizing the transport sector. Second-hand or used vehicles from high-income regions are important sources of lower-cost vehicles in many lower- and middle-income countries, so the rapidly changing fleets have implications for the vehicles available in these regions. Unlike engines and other powertrain components in gasoline and diesel vehicles, which can be repaired, EV batteries aren’t as repairable, and as they age, their capacity and power inevitably fade. We undertook this research to make a first estimate of the magnitude of internationally traded second-hand EVs in the coming decades, and then explored the potential impacts, risks, and benefits to lower- and middle-income countries.”

The report and Figure 1 describe the life-cycle of lithium-ion batteries (LIBs)—from mineral extraction, to use in original vehicles, to secondary use in 2- and 3-wheel vehicles and microgrids, and finally disposal and recycling of components.

Life cycle of lithium-ion batteries in second-hand electric vehicle exports.

Figure1. Life cycle of lithium-ion batteries in second-hand electric vehicle exports.

The impact of second-hand EVs and batteries in lower- and middle-income countries, and whether they provide a net benefit or impact, is a function of the EV battery state-of-health at the time of import, the potential for repairing or replacing the battery, the availability of charging infrastructure, and the energy resources (fossil-fuel or renewable) used to charge batteries.

The authors of the report conducted an extensive literature review, consulted with an expert in a major used-EV importing country (Sri Lanka), and analyzed data from multiple sources on EV sales, imports, and exports. This last endeavor revealed major discrepancies in vehicle numbers reported by paired exporting and importing countries, such as the US and Mexico shown below.

Chart showing second-hand vehicle export and import estimates, with discrepancies in data from paired countries. The number of vehicles going from the US to Mexico surged when the North American Free Trade Agreement began, then fell when policies limiting imports went into effect.

Figure 2. Second-hand vehicle export and import estimates, showing discrepancies in data from paired countries. The number of vehicles going from the US to Mexico surged when the North American Free Trade Agreement began, then fell when policies limiting imports went into effect.

Policy suggestions stemming from this research, include:

  • Upon export, provide information on battery condition, technical information for safe repair and repurposing of batteries, and data on the movement of second-hand vehicles.
  • Ensure that secondary parties other than battery and vehicle manufacturers have the right to repair batteries and EVs and have access to real-time information on battery condition.
  • Create a harmonized reporting system for collecting data at the point of export and import.
  • Institute export and import controls, such as minimal requirements for the state-of-health of batteries.

Such measures can help prevent second-hand EV and battery exports from becoming a least-cost disposal option for exporting markets, burdening rather than benefiting importing markets.


Seth Karten is a science writer at ITS-Davis.

UC Davis Secures $20 Million Federal Grant Renewal to Lead the National Center for Sustainable Transportation

National Center for Sustainable Transportation

This week, the U.S. Department of Transportation announced that the National Center for Sustainable Transportation (NCST), housed at the UC Davis Institute of Transportation Studies (ITS-Davis), would receive $20 million to lead a group of seven universities studying transportation effects on the environment. The award reinforces UC Davis’ standing as the nation’s leading university center on sustainable transportation.

The funding was granted as part of the Department of Transportation’s University Transportation Center (UTC) program. This year’s grant competition included a total of 230 applications, representing the largest number of applications ever submitted in the 35-year history of the UTC Program. The NCST is one of only five national transportation centers awarded under the UTC program, and the only one focused on the DOT research priority of Preserving the Environment.

The NCST’s $20 million grant ($4 million per year over 5 years) will allow researchers at UC Davis and other consortium member universities to focus on accelerating equitable decarbonization that benefits both the transportation system and the well-being of people in overburdened and historically disadvantaged communities. Research activities will concentrate in three critical domains: vehicle technology, infrastructure provision, and reshaping travel demand to accelerate reductions in greenhouse gas emissions.

“Finding a way to decarbonize transportation that does not exacerbate existing inequities is one of the most significant societal challenges we face,” said UC Davis Professor Susan Handy, Director of the NCST. “I am thrilled that we will have the opportunity to work with the U.S. Department of Transportation on this challenge and continue the important work we’ve been doing for the last nine years. With the new grant, we will expand our focus on equity and justice and launch new initiatives on rural mobility, vehicle electrification, and sustainable freight.”

The new grant also enables the NCST to expand its consortium. Professor Handy continued, “We are delighted to welcome Texas Southern University to our partnership.” TSU joins the original members of the NCST consortium: California State University Long Beach, Georgia Institute of Technology, University of California Riverside, University of Southern California, and University of Vermont.

“TSU is honored to join the highly prestigious team of NCST and is truly excited for the opportunity to make contributions to research and education that promote a sustainable and equitable transportation development,” said Lei Yu, Professor of Transportation Studies and Director of TSU’s Innovative Transportation Research Institute (ITRI).

This round of funding marks the second time UC Davis has been able to renew its status as the host of the National Center for Sustainable Transportation. Since its establishment in 2013, the NCST has helped to organize and fund research addressing urgent and critical transportation challenges, and its researchers have partnered with thought leaders and stakeholder groups to provide national leadership for advancing an environmentally sustainable transportation system.

“ITS-Davis is proud and honored to receive this award, recognizing our decades-long commitment to sustainable transportation,” said UC Davis Professor Dan Sperling, Founding Director of ITS-Davis. “Kudos to Susan Handy, our fearless leader of the Center since the first award from the DOT in 2013. We are on a mission to transition our transportation system to a more equitable, environmental, and economically sustainable future—in the U.S. and globally.”

The NCST provides national leadership in advancing environmentally sustainable transportation through cutting-edge research, direct policy engagement, and education of our future leaders. For more information on the center, visit:

For more information on the announcement by the U.S. Department of Transportation, visit: