Category: Transportation and Climate Blog

Releasing the Pressure: Cultivating Graphite Value Chains in an Expanding Market


Graphite is carbon in its crystalline form. With its distinctive electrochemical properties, it forms anodes in lithium-ion batteries (LIBs), ensuring that they have stable charge and discharge cycles. Globally, as countries rely increasingly on electric power, the demand for LIBs—and therefore graphite—will be driven by both in-vehicle batteries and stationary energy storage. As nations choose where to invest, care must be taken to ensure that negative social and environmental impacts are avoided and that geopolitical concerns are carefully managed.


Graphite demand will soar in the decade ahead. We expect a compound annual growth rate (CAGR) of 11.6% between 2022 and 2035, with global demand of around 7,334 kt in 2035—4.2 times higher than in 2022. We estimate that the proportion of demand related to LIBs will grow from 36% in 2022 to 78% in 2035.

Demand for both natural and synthetic graphite has risen in recent years as end-user markets for LIBs have expanded, putting significant pressure on supply and value chains. Global reserves and ore quality of natural graphite are high, but mining operations are not well-developed in all locations with mineral deposits. Most natural graphite is sourced from mines in the Global South—especially Mozambique and Madagascar—while synthetic graphite is primarily produced in China.

Major world economies such as the United States (US), the European Union, China, and India have listed natural graphite as a critical mineral. In October 2023, China restricted exports of graphite suited for electric vehicle battery production. As China exports more graphite than any other country, graphite has quickly become a focal point in global supply chain conversations.

Our recent report on graphite discusses value chains, anticipated increases in demand, and highlights the need for equity considerations while expanding mineral availability.

Our Key Findings are:

  1. China dominates graphite production and exports. As of 2022, China holds the largest market share of graphite production at 62%, followed by Mozambique at 12%, Madagascar at 8%, Brazil at 6%, and India at 4%. Between 2019 and 2022, there was a significant increase in natural graphite production in Mozambique, Madagascar, and Tanzania in Africa, as well as in India in South Asia.

    China is now the dominant exporter of natural and synthetic graphite. However, its share of global natural graphite exports declined from 50% in 2019 to 44% in 2022, while its share of synthetic graphite increased from 60% in 2019 to 77% in 2022.

  2. Mineral Security Partnership (MSP) countries are net importers. Although Germany, the US, and Canada are the top graphite exporters amongst MSP countries, each are net importers—and each relies on China (Figure 1). These MSP countries don’t have natural reserves, so exports include material that is first imported from other countries and then re-exported. Graphite originating in China may appear as coming from elsewhere if it passes through other countries. Germany is an exception as a net exporter of synthetic graphite. Australia, Canada, and India could become exporters of natural graphite, given their estimated reserves. In the US, the use of synthetic graphite may emerge as a solution to attain compliance with the Inflation Reduction Act and reduce import dependence.

    Share of natural graphite imports directly from China, by country.

    Figure 1: Share of natural graphite imports directly from China, by country. South Korea and Japan exhibit the highest dependence on China followed by Australia, the US, and Finland.

  3. Trade value of natural and synthetic graphite has increased significantly. Price per tonne for both natural and synthetic graphite varied from $90 to $9,113 (US dollars) between 2019 and 2022. China has seen a 12% CAGR in export value over that period. Natural graphite import cost in the US has risen at 22% CAGR, reaching $2,180/tonne, while Canada saw synthetic graphite import cost increase by 15% CAGR, reaching about $2,200/tonne in 2022. India, France, Sweden, and Finland saw increases of up to 7% CAGR.
  4. Geographical concentration of mine ownership is the primary factor limiting graphite supply, raising concerns of availability and criticality. The ore quality of most of the 68 mines we evaluated met the criticality threshold. These mines are in Europe, America, Asia, and Africa. Despite broad geographical distribution, ownership of graphite production is concentrated in a handful of countries.

    We assessed 60 mines operated in Africa, America, Asia, and Europe. They are controlled by 41 privately owned companies, primarily headquartered in Australia (22 mines), the UK (12 mines), Canada (7 mines), and Brazil (5 mines).

  5. Modelled graphite demand scenarios point to opportunity for MSP countries. Graphite export restrictions were recently adopted by China. To explore potential impacts, we modelled a 50% reduction in China’s global graphite production, shifting from a 62% market share (as in 2022) to 31%. The result is an opportunity for diversification among MSP network countries. In this scenario, Mozambique, Madagascar, Tanzania, Brazil, and India emerge with market shares of 23%, 15%, 12%, and 8%, respectively (Figure 2).

    Potential for natural graphite global supply diversification from 2022 to 2035.

    Figure 2. Potential for natural graphite global supply diversification from 2022 to 2035.

  6. India can be a major price-competitive global supplier of natural graphite. While India is ranked ninth in graphite reserves, it is among the top five global suppliers. Some countries with large reserves, like Brazil and Turkey, have not scaled production, and Ukraine and Russia have constrained outputs. Compared to other major natural graphite producers, India’s exports are priced competitively at around $650-700/tonne compared to the global average of $1,400/tonne.
  7. The Global South can leverage market share by complying with mining regulations. Many graphite-producing countries have a history of economically, socially, and environmentally exploitative resource extraction. The MSP has established Principles for Responsible Critical Mineral Supply Chains to ensure that projects meet environmental, social, and governance standards. Thus, MSP countries can be expected to favor exports that comply with these standards (Figure 3).

    An assessment of Worldwide Governance Indicators in 21 graphite-endowed countries suggests that some Global South countries, including India, have emerged with relatively high rankings.

    Figure 3. An assessment of Worldwide Governance Indicators in 21 graphite-endowed countries suggests that some Global South countries, including India, have emerged with relatively high rankings.

In summary, there is a growing need to develop a cohesive strategy on international trade of critical minerals and to de-risk the supply chain through diversification. There is also a rare opportunity to cultivate emerging market dynamics in a way that improves conditions in graphite-endowed countries in the Global South. Growing demand, new regulations, trade limitations and quotas, geopolitical interests, and other factors are changing the market, creating potential partnerships for graphite-endowed countries. However, to reap benefits from these changes, a commitment to improved regulatory compliance in mining from mine-owners and oversight agencies is essential.

Electrifying Transportation and Shifting Travel Patterns can Cut CO2 while Saving the US Trillions of Dollars

Widespread adoption of electric vehicles—combined with a shift in travel modes towards more walking, cycling, and transit use—can help ease the climate crisis, improve quality of life, and save Americans money. A key to shifting travel modes to less automobile use is making biking, walking, and transit safer and more convenient by redirecting infrastructure investments and making urban areas more compact. When compared to the trajectory we are currently on, faster vehicle electrification and a shift in travel modes could save the US economy a cumulative $13 trillion, save the average urban resident $2,000 per year, reduce transportation inequities, and make cities more livable.

A recent study, from ITS-Davis and the Institute for Transportation & Development Policy, explores four scenarios and identifies steps that can move us in the direction of cost savings and lower emissions of greenhouse gasses and pollutants:  

  • In the Business as Usual scenario, vehicle electrification and a shift in travel modes occur gradually, according to current trends and policies.  
  • In the Electrification scenario, the transition to electric vehicles is faster – as fast as experts consider possible.  
  • In the Mode Shift scenario, people use non-automobile travel modes at a “maximum feasible” level as these modes become more feasible and appealing. 
  • In the fourth Electrification + Shift scenario, these last two scenarios are combined.  


The Electrification scenario has sales of new light-duty vehicles (cars and light trucks) reaching 60% electric nationwide by 2030 and 100% by 2050. The US reached about a 7.6% electric (and plug-in hybrid) vehicle market share in 2023, which is a good start, but there is a ways to go.

Achieving the Electrification scenario will probably require that eventually: 1) electric vehicles provide significant ownership savings compared to gasoline vehicles; 2) electric vehicle ranges are sufficient to meet all driving situation needs, and 3) public charging becomes widely available at or close to most homes and in public roadside locations convenient for long trips. If these conditions can be met, then the main challenge will be a marketing one: convincing Americans that EVs are desirable and meet their needs.

Mode Shift

Getting Americans to reduce their dependence on cars and use other modes of transportation may seem harder than going electric, though the changes envisioned in our Mode Shift scenario are not massive. In this and the combined Electrification + Shift scenario, urban car, SUV, and personal pick-up truck (light-duty vehicle) travel in 2050 would be about 25% less than in the Business as Usual scenario. This reduction goes along with much better infrastructure to increase travel by transit, biking, and walking. And even with the increases in infrastructure and operations for these modes, the shift will save governments and individuals considerable funds and provide an important range of health benefits, which are described in the report.

Chart showing how many miles traveled by different traveling modes

Miles traveled using each mode according to year and scenario; “Bike” includes electric bikes.

But what changes are needed to make such a mode shift possible? It will require increasing density and mixed-use development in cities and suburbs, coupled with more sidewalks, protected bike lanes, and safer streets with slower traffic. All of this will encourage people to choose to walk or ride a traditional or electric bike or an e-scooter. Electric bikes could play a growing role for trips under 5 miles if roadways are designed to make this safe. On the transit side, there is a critical need for more frequent service, which could be made possible by increased population density and would make using transit more appealing and logical. People will need to consider these modes convenient and safe and at least give them a try. Having the right infrastructure and shorter trips is a prerequisite. 

American cities are already getting denser, but the trend is gradual. The average neighborhood has about 12,500 people per square mile today, and we’re on track to increase to 13,500 by 2050. But achieving the Mode Shift and combined scenario will require reaching an average density of nearly 17,000 people per square mile by 2050. This doesn’t mean that everywhere will look like New York City—it just means that the average American city will look more like Los Angeles than Atlanta, the average neighborhood more like Arlington, Virginia than Arlington, Texas.  

Small and large cities will have a density and layout more resembling a walkable town than spread out areas of housing, miles from shopping plazas. Such moderate densities can be achieved through public policy that is already being adopted in some states. Examples include missing middle policies to legalize multi-family housing up to six or eight units on all lots and removal of requirements for a minimum of off-street parking. The densified cities in the mode shift scenarios will not require anyone to leave or redevelop their home against their wishes—it will only create a supply of walkable neighborhoods that are currently in high demand. 

The expansion of public transit and protected bike and pedestrian ways will require investment, but the funds required are less than what is currently spent on building and maintaining road infrastructure. The estimated cumulative savings for national, state, and local governments between 2024 and 2050 would be $2 trillion. Similarly, much of the annual savings of $2000 for urban residents would come from the reduction in car ownership.  

Action Plan

The most important point is that we need citizens and governments committed to making this happen, voting for it, and re-allocating sufficient funds. The report on our study provides a list of policy strategies at federal, state, and local levels that would enable these changes. Some examples include:  

  • Modestly increase the tax on internal combustion engine cars to help fund incentives to lower the costs of electric vehicles and to fund transit and infrastructure for cycling and walking. 
  • Support equitable placement of public charging points and charging in multi-unit dwellings. 
  • Reallocate federal and state transportation budgets and road space to walking, cycling, and public transport. 
  • Entirely stop building new roads or expanding existing ones. Use the funding to maintain and improve the capacity of existing roads by reallocating space to more efficient modes, like cycling and public transport. 
  • Along major roads, build a connected, integrated network of bus rapid transit lines—buses that operate like light rail: have a dedicated center-running lane, take priority at intersections, and are boarded from stations. 
  • Redirect existing subsidies for fossil fuels to the expansion and decarbonization of the nation’s electricity system to support clean transportation and other uses. 

This transformation is possible. Cities around the country have already proven that it can be done. In only two years, Seattle transformed its bus network such that 64% of residents live near a bus line with ten-minute service or better, up from only 25% before the change, leading to increased ridership. Arlington, Virginia demonstrated the importance of rapid transit: by routing a Metro line through commercial neighborhoods and building density around the stations. Arlington was able to dramatically increase population and tax revenue without any increase in traffic. In the future, cities around the country could replicate this success using affordable bus rapid transit instead of rail. The state of Minnesota is debating an act that could remove parking minimums all across the state, cutting required parking lot construction, and thus making additional space available for housing, shops, and walking.  

In 30 years, our cities could be greener, more walkable, more efficient, less congested, quieter, and more affordable. We could save money for the public and private sectors. We could reduce air pollution, social segregation, and the cost of living. All that’s needed is the collective willingness to act.  


Lewis Fulton is Director of the Energy Futures Program at ITS-Davis. 

As Countries Set Ambitious Targets for Electric Vehicle Sales, More International Trade and Domestic Investment Is Needed

EV assembly line

In an effort to curb emissions, governments in major vehicle markets are proposing and adopting requirements that electric vehicles (EVs) make up a certain percentage of new vehicle sales in coming years. This week the Government of Canada announced EV sales targets of 60% by 2030 and 100% by 2035 for light-duty vehicles, similar to the goals the United States announced last year of 50% by 2030 and 67% by 2032. Other countries and regions such as China, Japan, and Europe have also made commitments to specific targets.

These targets raise a key question: Can enough electric vehicles be produced in time across the range of countries making these commitments?

Answer: Maybe. There is a great deal of uncertainty, but this is clear: keeping trade open will help, and investing in domestic EV production is critical.

In a recent study, we modeled scenarios in which governments in six electric vehicle markets—the US, Europe, Canada, Mexico, Japan, and South Korea—adopt sales targets requiring EVs to make up a certain percentage of their new vehicle sales by 2030. Depending upon whether these governments adopt higher or lower proposed targets, the markets will need 12 to 25 million new EVs per year by 2030.

The chart below shows the comparisons between higher and lower national EV sales targets, on one hand, and higher and lower company planned EV production capacity, on the other hand. The higher and lower planned production capacities represent “tentative” and “firm” plans and investments, based on our review of related announcements by automakers beginning in 2020.

Comparison of low and high proposed EV sales targets (yellow dots and triangles) with firm and tentative planned production capacity (solid and hatched bars) for 2030.

Comparison of low and high proposed EV sales targets (yellow dots and triangles) with firm and tentative planned production capacity (solid and hatched bars) for 2030.

As shown by the right-hand bar in the chart, if these six governments were to adopt the lower proposed targets, their combined EV production capacity, according to “firm” plans, would be just enough for the required 12 million EV mark. But, if they adopt higher targets (here assumed to be 50% EV sales shares by 2030), their combined production capacity could have a shortfall of 9 to 13 million EVs in that year—which is a third to half of the total number of EVs needed across the countries.

If national shortfalls are relatively small and limited to few of these individual markets, then trade among them could make the combined goals achievable. For example, the US and Europe—the two largest EV markets examined—can achieve their lower sales targets if their planned capacities are pooled. So transatlantic trade may serve as an important approach for reaching combined targets.

On the other hand, with the higher targets, especially combined with lower “firm” production capacities, the shortfalls are too great to be made up only through trade among these countries. In the US-Europe example, their combined annual production shortfall would reach 10.6 million EVs in 2030. This may be addressed with additional automaker investment in each region; if done in line with each region’s needs, the total investment would be $108 billion, which would require an additional $66 billion above the current firm commitment of $42 billion. In this case trade—between these countries and also including additional countries such as China and India—can still play a key role, since it would provide more flexibility regarding where these needed investments can be made.

However, while trade of EVs and their parts can help, trade dynamics are complicated and subject to limitations by regional and national policies and geopolitical matters. These limitations reinforce the need to boost investments in production capacity within each market, though it is unclear that each market will be able to meet 100% of its own demand in the high target scenarios. We believe it is very important to keep trade options as flexible as possible.

Another factor affecting supply is that manufacturers are understandably wary of making large EV production investments in the short-term, because producing the required number of EVs to meet a sales target does not guarantee that consumer demand will follow and protect the companies from financial loss. So attracting the large investments needed is complicated, and policies and incentives that support demand are key. One hopeful example is California, which has an EV sales target of 100% by 2035 and policies supporting demand. In that state, EV sales have skyrocketed from about 7% of new vehicles in 2020 to nearly 27% in 2023.

We do not know yet how targets, demand, or supply growth will play out. Other unknowns not examined or modeled in our study, such as availability of raw materials for batteries and batteries themselves, may also affect production capacity. Right now, the situation looks challenging in the 2030 timeframe. The US and other countries may need to encourage greater investments in EV assembly capacity so this can ramp-up more quickly. More trade may also help, but comes with its own limits and risks.

Hong Yang is a PhD candidate in the UC Davis Energy Systems Program.

Lewis Fulton is the director of the Energy Futures Program at ITS-Davis and the former director of the Sustainable Transportation Energy Pathways Program at ITS-Davis.

Putting the Brakes on Global Growth in SUVs Would Curb Emissions, Improve Safety, Reduce Critical Mineral Use, and Address Inequities

Trends in the global vehicle fleet - 2023On the path to global transportation sustainability, electric vehicles (EVs) are making inroads, but larger cars with bigger carbon footprints are hampering climate progress. The right policies can correct our course.

A recent report by the ITS-Davis European Transport and Energy Research Centre, the FIA Foundation, and the Global Fuel Economy Initiative identifies trends in the global car market from 2010 to 2022 and their impacts on energy consumption and CO2 emissions. The report highlights increasing light-duty EV sales that have substantially reduced energy consumption and CO2 emissions alongside rising SUV sales that have counteracted these reductions.

Two Steps Forward, One Step Back

Energy and direct CO2 emissions intensities for new vehicles declined globally at a rate close to 2% per year between 2005 and 2022. From 2020 to 2022, average energy consumed per mile for new light-duty vehicles decreased faster, by 4.2% annually, on average. CO2 emissions per mile declined almost 6% annually in the same period. These accelerations are mainly due to an increase in EV sales.

Emissions could have fallen farther, however.

A persistent shift to larger and heavier SUVs is offsetting benefits from EVs. Global sales of SUVs increased from 22% of all light-duty vehicles in 2005 to 51% in 2022. The case of the US is extreme, by global standards, with SUVs and pick-up trucks now accounting for 75% of all vehicles sold.

Global light-duty vehicle sales by segment (LCV = light commercial vehicle)

Global light-duty vehicle sales by segment (LCV = light commercial vehicle)

If the global average weight of vehicles had stayed constant since 2010, energy and CO2 emission intensities of combustion engine vehicles would have declined about 30% faster. The shift to SUVs also exacerbated equity and road safety challenges, due to their higher prices and danger to other road users.

This trend toward bigger and heavier vehicles is not limited to combustion engine vehicles. EVs are also getting larger, creating more demand for critical materials, such as lithium and cobalt, that are subject to supply risk—adding to possible bottlenecks for EV production in the absence of policy action. The report on vehicle trends offers policy suggestions to steer markets toward cleaner vehicles and away from large and heavy vehicles.

Quick stats

  • The global average weight of a “light-duty vehicle” reached an all-time maximum of 3,370 lbs (1,530 kg) in 2022
  • Batteries increased globally from 40 kWh/vehicle in 2017 to 60 kWh/vehicle in 2022 on average, resulting in heavier vehicles and greater demand for critical materials
  • In the US, SUVs and pickup trucks increased from 43% of sales in 2010 to 75% in 2022, of which 38% were large SUVs

Better policy needed to meet emissions goals

Policies encouraging the downsizing of vehicles and boosting of the EV market are needed to reduce climate change and meet net-zero greenhouse gas emissions goals.

Downsizing (and down-weighting) vehicles would also increase road safety and reduce inequities, especially in countries that have limited alternatives to car travel. Downsizing would make EVs more affordable and reduce the amount of critical minerals needed for batteries, thereby reducing the social, environmental, and geopolitical security risks from mining and mineral processing.

Policy recommendations

  • Reduce the sales-weighted average footprint and weight of vehicles over time.
  • Reduce battery weight and capacity (kilowatt-hours per vehicle) using a corporate average approach, as is done with fuel economy standards. These limits would restrict the growing demand for critical materials and the negative human and environmental impacts from mining, including in low-income and underserved communities.
  • Regulations on the size and weight of vehicles (including EVs) should reward innovation (and reduce costs) by allowing the trading of credits across vehicle categories and companies, as is now done in Europe and the US with emissions and fuel economy standards.
  • Eliminate regulatory carve-outs for SUVs and pickup trucks—which have been used in the US and are a primary factor in the rapid transition from cars to SUVs.
  • Introduce more stringent environmental regulatory requirements and require more stringent safety standards for heavily-used vehicles, such as those used by ride-hailing and taxi drivers since the EV transition is more cost-effective in these cases, and road safety benefits are higher for vehicles that travel more.
  • Regulations and incentives should be expanded to allow universal and equitable access to EV charging infrastructure—including requiring or funding charger installations in or near multi-unit dwellings.
  • Vehicle taxes should be differentiated on the basis of energy efficiency and environmental impacts. They should also be modulated based on size, weight, and price to respond to challenges for equity, road safety, and material demand. Taxes and charges adopted at the local level can also be tailored to respond to these effects. Key examples already exist in Paris and other French cities, which will start applying in 2024 parking fees differentiated based on size and weight and engine type.

A shift away from SUVs, paired with tailored and continuous support for EVs, will be crucial to reducing CO2 emissions, enhancing energy savings, improving road safety, and addressing social inequities within and across countries. The task is complex, but we know what can be done, and we can build on and learn from policy and technological innovations from around the world.

Pierpaolo Cazzola is Director of the European Transport and Energy Research Centre at ITS-Davis.

Getting Over Our Highway Habit

Shifting Gears book cover by Susan HandyDriving between the Bay Area and Sacramento has long been a challenge. For the past several months, it has been a construction nightmare. Heading east from Davis, drivers face seventeen continuous miles of construction zones, first for the Yolo I-80 Pavement Rehab Project , then for the on-going “Fix50” project through the core of Sacramento. Heading west, the construction zone for the Solano I-80 Managed Lanes Project  starts before Vacaville and continues through Fairfield. I dread the day that construction starts between Davis and Vacaville, not just because construction makes for a miserable driving experience but also because it means the last remaining remnants of the iconic oleander median will be gone.

What does all this construction get us – and is it worth it?

The official rationale for these roads projects is the need to modernize old freeways (especially Highway 50) and accommodate the growing flow of traffic between Sacramento and the Bay Area driven by differentials in housing costs, the post-COVID ability to work remotely, and other economic forces. Congestion “relief” is cited as a goal of the projects in both official documents and statements by public officials. To relieve congestion, Caltrans is adding “managed lanes” to freeways, usable for free by carpools and electric vehicles with clean air vehicle decals and, in some cases, by other drivers for a fee.

This rationale does not entirely square with the state’s Climate Action Plan for Transportation Infrastructure (CAPTI). One principle of this plan is “promoting projects that do not significantly increase passenger vehicle travel.” As ITS-Davis researcher Jamey Volker and I have documented, a growing number of rigorous studies provide robust evidence that adding highway capacity generally leads to an increase in vehicle miles of travel (VMT), a phenomenon known as “induced travel.” Although the evidence on the effects of managed lanes is slim, there are good reasons to believe that these lanes may generate as much of an increase in VMT as the old-fashioned “general purpose” lanes. In short: adding lanes, even if they are managed lanes, is not consistent with state goals for reducing vehicle travel.

This can be a challenging idea to accept. For the past several years, Jamey and I have participated in countless Zoom meetings in which state, regional, and local officials have argued that highway widening projects within their jurisdictions would not lead to an increase in VMT or, at most, would result in a much smaller increase than studies suggest. After Caltrans official Jeannie Ward-Waller raised questions about the Yolo I-80 Pavement Rehab Project, which appears to be laying the groundwork, literally, for an additional lane, she was fired by the agency, as reported by the Los Angeles Times. Her concerns centered around potential abuses of the environmental review process, the purpose of which is to fully vet the likely impacts of proposed projects, including impacts on VMT.

Our own work has demonstrated how induced VMT has traditionally been underestimated or even ignored in the environmental review process. Agency forecasts of the VMT impacts of proposed highway projects are not especially good at capturing the various adjustments that drivers make when a new freeway lane opens. For example, deciding to drive to a more distant store, or making a trip that previously would have been too much of a hassle. By failing to account for these adjustments, forecasts tend to understate induced VMT which means that they understate environmental impacts and overstate congestion reduction. These biases undermine good decision making. Highway projects around the country are being challenged on this basis.

All of this controversy reflects something deeper and even more difficult to address than forecasting practices: an entrenched way of thinking that perpetuates the highway-widening treadmill that has dominated transportation planning for the last century, as I discuss in my new book, Shifting Gears: Toward a New Way of Thinking About Transportation.

One idea at the core of the traditional way of thinking about transportation is that congestion is bad, that it should be reduced, and that it can be reduced. No one likes congestion, but you’d think that, after a century of failed efforts to reduce it, we would have learned better by now. Congestion did abate temporarily during the COVID-19 pandemic, but not for reasons we would ever want to repeat. Rather than focusing on reducing congestion, we might be better off focusing on ways to make congestion less relevant to our lives. One way to do this is by providing good alternatives to driving, such as high-quality transit service. Another way to do this is by bringing the places we need to go closer to where we live. Rather than pouring billions into reducing congestion for workers who can’t afford to live near their jobs, why not pour billions into providing affordable housing for them near those jobs?

Another core idea that needs rethinking is that speed is good. Speed is psychologically complicated, in that it both thrills us and terrifies us. And terrify us it should: the faster that cars go, the more likely that their occupants—and bystanders—will die when cars crash. This trade-off is well documented and widely known but, too often in practice, speed takes precedence over safety. The transportation profession defines efficiency in terms of speed, and efficiency is something to be maximized. But just how much speed do we need? Isn’t this obsession with congestion really about our expectations about how fast we should be able to get places? Is it reasonable to measure traffic “delay” with respect to traffic-less “free flow” conditions? It would be a whole lot cheaper—and safer—to reset our expectations than to widen our freeways.

The power of these ideas might explain why the cost/benefit analyses that inform decisions about highway projects also fail to account for the costs that drivers incur during the construction itself. This failure suggests that such costs are accepted as a necessary part of providing congestion relief. But as a recent Sacramento Bee story poignantly documented, the human toll of highway construction can be intolerably high. Following the publication of the article, in which I was quoted, I received a heart-breaking email from a mother who her lost her daughter last year to a crash in the Fix50 construction zone.

We owe it to ourselves to reject a way of thinking that prioritizes congestion reduction and puts speed ahead of safety. It is high time for a new way of thinking about transportation.


Susan Handy is  the Director of the National Center for Sustainable Transportation at UC Davis. Her research focuses on the relationships between transportation and land use, particularly the impact of land use on travel behavior, and on strategies for reducing automobile dependence.

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).

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

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.