We humans don’t really like the cold. After all, our blood flow decreases, heat loss increases, and we suffer from reduced manual dexterity.
But what about the machines, especially our electric vehicles (EVs)? Well, it turns out they don’t like the cold weather either.
A new study1 has found that the total energy consumed and regenerated by electric buses increases by an average of 48% when the temperature is in the range of -4 °C to 0 °C compared to the Optimal Temperature Zone (OTZ). Meanwhile, the average increase in the range of -12 °C to 10 °C is 28.6%.
Why Electrification Is Reshaping Transit and Energy Worldwide
Electric buses are part of the electrification trend, which is rapidly shaping the global energy landscape. This marks a shift towards electric vehicles and energy storage solutions, replacing the use of fossil fuels. These replacements are more efficient, reduce energy demand, and decarbonize the power and transportation sectors.
This transition not only lowers greenhouse gas (GHG) emissions but also enhances energy security, promotes sustainable economic growth, and supports the development of cleaner, more resilient energy systems worldwide.
As part of this trend, electric vehicles (EVs) are gaining a lot of traction, with more than 4 million electric cars sold in the first quarter of 2025, which is over a million more EVs sold in the first three months of this year than in the same period the previous year.
Light-duty vehicles (LDVs) like cars and vans account for most of these EV sales. According to the International Energy Agency (IEA) report, while electric buses and electric LDVs had about the same stock share in 2024, the sales share of the former is growing more slowly.
The share is projected to reach less than 20% globally by the end of this decade in the Stated Policies Scenario (STEPS), which provides a sector-by-sector evaluation of policies implemented to achieve stated energy-related goals. As a result, electric buses are expected to account for slightly more than 10% of the global bus stock by 2030.
Still, the global electric bus market is projected to grow from $17 billion in 2024 to $37.5 billion by 2030, representing a compound annual growth rate (CAGR) of 14.2%.
In alignment with this trend, Tompkins Consolidated Area Transit (TCAT), a public transportation operator in Ithaca, New York, obtained the funding to get seven all-electric buses for a trial run, but the experience didn’t turn out to be as good as expected. The buses actually struggled in the region’s hilly terrain and were unreliable with reduced range in cold weather. So, TCAT connected with Cornell researchers to gain insights from their pilot program.
Cornell researchers undertook this task and carefully assessed the underperformance of buses in cold weather, as well as its implications for manufacturers, operators, policymakers, schools, cities, and other groups considering the electrification of their fleets.
Why Electric Buses Struggle in Cold Weather: Key Challenges
While battery-electric buses (BEBs) have shown great potential in reducing GHG emissions and are expected to play a key role in transforming public transportation toward clean energy alternatives, they are facing challenges that are restricting their widespread implementation.
Among these technical challenges, the limited operational range of BEBs, especially in cold weather conditions, is a major issue.
The thing is, much like any other EV equipped with high-voltage battery packs, battery-electric buses also suffer a significant decline in energy efficiency when operating below the optimal temperature. This particularly applies to subzero conditions, which then leads to increased total operational cost and range anxiety.
With urban transit buses averaging 42,940 miles annually, which is four times more than a typical car, and running on fixed routes and schedules, cold weather variability in electric bus performance creates serious challenges in meeting transportation demands.
Besides complications in scheduling charging and dispatching vehicles, challenges included difficulty with selecting battery size and planning charging infrastructures. All of these factors can adversely affect the economic feasibility of BEBs compared to diesel buses.
When it comes to the reduced operational range of BEBs in cold weather, it is due to a number of interrelated elements.
Most importantly, the chemical properties of the battery cells, which are sensitive to temperature, lead to reduced capacity and lower discharge rates. In order to keep battery cells at optimal temperature, battery thermal management systems (BTMS) have been developed, but even they can be energy-intensive depending on the operating conditions.
Then there is the increased energy loading from the ventilation, heating, and air conditioning (HVAC) system, which significantly contributes to a reduced operational range.
The effectiveness of regenerative braking systems, which capture energy during braking, is compromised under cold conditions due to various technical and environmental factors. On top of it, the behaviors of drivers and operators, which are influenced by adverse weather conditions and route characteristics, significantly impact BEBs’ energy efficiency.
So, understanding all these human and mechanical factors in detail is essential to develop effective strategies to mitigate the cold weather’s adverse effects on BEBs. This, in turn, reduces operating costs for fleet operators and enables manufacturers to improve their vehicle design for better cold-weather performance.
Several studies have tried to quantify the impact of cold weather on the performance of BEBs by simulating their energy consumption and investigating the impact of ambient air temperature on the real world.
However, significant gaps remain in understanding how that impact is influenced under different, more complex scenarios, such as idling and driving instances on rural and urban routes, which is crucial for targeted regional operation strategies.
Not only have the contributions of battery heating, regenerative braking, and other key components to energy performance not been adequately discussed in complex route scheduling, but there is also a lack of real-world studies that cover significant distances at freezing temperatures. Furthermore, information is limited regarding the feasibility of BEBs in cold weather, and guidance is insufficient for cold-weather operation strategies.
So, researchers from Cornell University undertook the task of analyzing the impact of cold weather on energy consumption and regeneration, breaking down BEBs using real data spanning two years from the seven battery-electric buses operated by TCAT. More than 40% of the trips of these BEBs occurred below 12 degrees Celsius.
To quantify the impact, the team developed Optimal Temperature Zone (OTZ) models to predict the energy consumption during idling, driving, and regeneration for each trip, assuming ideal temperatures.
Having identified the operational factors responsible for the increased consumption, the researchers also offer recommendations for improving the buses’ functioning.
Quantifying Cold Weather Impact on Electric Bus Efficiency
As we described earlier, the Cornell University study found that batteries in electric buses consumed up to 48% more energy in cold weather, with temperatures ranging from 25°F to 32°F. These batteries also consumed almost 27% more energy in a broader temperature range, from 10 to 50°F.
This drastic increase in energy consumption, senior author Max Zhang, the Irving Porter Church Professor of Engineering in Cornell Engineering, said, was unexpected, but added that “any lessons are good lessons. This helps us learn as a society and do better.”
The quantification of the pilot fleet’s increased energy consumption is based on two years of data collected from TCAT, making it the first to assess and analyze the performance of electric buses in the northeastern U.S.
This way, TCAT and Cornell researchers share their insights with each other and learn from one another through data and collaboration. Zhang’s team met with TCAT officials repeatedly as the research progressed.
Notably, the dataset from TCAT covered a significant distance, with a total mileage of 225,837 kilometers in Tompkins County, New York, operating under diverse conditions, thereby providing a more comprehensive dataset than previous BEB studies.
4.7% of this total distance was recorded under average ambient temperatures, i.e., subzero, while about 50,000 miles or over 80,000 kilometers was logged in cold temperatures, i.e., 0 °C to 12 °C range.
According to Zhang, who is a provost’s fellow for public engagement:
“We’re benefiting from TCAT being a leader in this region, and it’s a real privilege to have access to this data, so we can see the performance in real-time. One of the lessons we’ve learned is that these buses should be designed for the whole country, including states with colder climates. We’ve also found that they’re different from conventional diesel buses, with different behaviors, which require different strategies to take advantage of this.”
The researchers first modeled how the vehicles would perform at ideal temperatures to account for factors not related to temperature alone, such as variations in traffic conditions.
For this, they developed an innovative OTZ baseline model that simulates BEB performance under optimal temperatures, while maintaining the non-temperature-sensitive conditions as those at the time of the real cold weather operation.
Then they compared it to their actual performance across over 40 complex routes and schedules.
Researchers found that battery self-heating accounts for half of the increased energy use in cold weather. EV batteries perform best around 75°F, so the colder they are at startup, the more energy is needed to warm them.
The heating of the bus’s cabin is the other main reason. Frequent stops, which especially happen in urban routes, involve the opening and closing of doors every few minutes, and that means batteries have to work harder to heat the cabins.
“With an all-electric vehicle, the battery is the only onboard energy source. Everything has to come from it.”
– Zhang, who’s also a senior faculty fellow at the Cornell Atkinson Center for Sustainability
Regenerative braking is also found to be less efficient at low temperatures by researchers. This energy recovery mechanism slows down a moving vehicle by converting its kinetic energy into electric energy that can be used right away or stored for future use.
This mechanism is found in most hybrid and fully electric vehicles. Unlike in a conventional braking system, where the vehicle slows down due to friction between the brake pads and rotors, resulting in the loss of almost all the kinetic energy that’s propelling the vehicle forward, regenerative braking recaptures over 70% of the energy.
Now, this system gets less efficient in cold weather, likely due to the battery struggling to maintain an even temperature across its cells. The battery of electric buses, after all, is about eight times the size of a standard EV battery, in order to accommodate longer routes and larger passenger capacities.
Now, the question is, what can be done to improve the performance of battery electric buses in cold weather? For this, the researchers recommend storing the buses indoors when they’re not in use to improve the batteries’ performance. Besides keeping the ambient temperature warmer during extended idling periods, other short-term strategies recommended for operators include charging the battery when it’s still warm, installing side coverings to reduce air convection into the cabin, and limiting the duration of door openings at stops.
For manufacturers, the researchers recommended optimized designs for battery heating and HVAC systems. The study can also help policymakers create incentive guidelines, evaluate viability, and establish route priorities of electrified public transportation.
On a larger scale, doctoral student Jintao Gu, the first study author, stated that this research highlights the need for assessment and greater adjustments in the infrastructure to support electric buses.
“You have to try to optimize the schedule of all of the buses and to consider the capability of your infrastructure – how many charging stations you have, and if you have your own garage. You have to train the drivers, the dispatchers, and the service workers. I think from an operational and infrastructure perspective, there are a lot of messages here for future transit system planning.”
– Gu
The rural and urban routes of Ithaca, along with its hilly terrain, enabled the researchers to obtain far more insights about the performance of buses.
This helped them find that electric buses showed a smaller increase in energy utilization on rural routes compared to the urban ones in cold weather. According to him, such information could help fleet planners make informed strategic decisions when assigning routes to electric buses.
Investing in the Electrification Trend
REV Group is likely to benefit the most from the growing trend of converting traditional fuel-powered vehicles into electric vehicles. It is a designer and manufacturer of specialty and recreational vehicles and primarily serves the North American market with the following products:
- Fire apparatus equipment under the KME, E-ONE, Ferrara, and Spartan ER
- Ambulances under the Leader, Horton, Road Rescue, AEV, and Wheeled Coach brands
- Terminal trucks under the Laymor and Capacity brands
- Recreational vehicles through American Coach, Lance Camper, Holiday Rambler, Renegade RV, Fleetwood RV, and Midwest Automotive Designs
REV Group (REVG -2.56%)
In 2021, REV Fire Group introduced a fully electric fire truck called the Vector, featuring 316 kWh of automotive-grade batteries. Additionally, REV Ambulance Group announced the first U.S. all-electric ambulance, offering up to 105 kWh of battery capacity. REB Group’s subsidiary, Capacity Trucks, meanwhile, has produced the hydrogen fuel cell and a battery electric terminal truck using Lithium-Ion (NMC) batteries.
The company was also involved in the bus manufacturing business but decided to exit the market last year by selling its Collins school bus brand to Forest River in 1Q24 for $303 million and its El Dorado National (ENC) transit bus division to Rivaz in 4Q25 for $52 million as part of its initiative to streamline operations and enhance profitability.
REV Group, Inc. (REVG -2.56%)
When it comes to the market performance of REV Group, the $1.9 billion market cap company has been enjoying a strong uptrend. As of writing, REVG shares are trading at $37.49, up 17.63% this year so far. The stock price is trading around its all-time high (ATH) of $38.50, which was hit just a couple of weeks ago.
It has an EPS (TTM) of 1.76, a P/E (TTM) of 21.26, and an ROE (TTM) of 20.13% while offering a dividend yield of 0.64%.
As for company financials, REV Group reported net sales of $525.1 million, net income of $18.2 million or $0.35 per diluted share, and a record adjusted EBITDA of $36.8 million for the first quarter of 2025. Capital expenditures also declined substantially from $10.5 million in 1Q24 to $4.9 million in 1Q25.
This record starts in 2025, CEO Mark Skonieczny said, demonstrates the “strength of our operational execution and disciplined approach. This performance reinforces our confidence in the momentum we are building and positions us well for the year ahead.”
Using its strong financial position, the company recommenced share repurchases, which Skonieczny said, “we view as an attractive use of capital at the current valuation.”
In Q1 of 2025, REV Group repurchased about 0.6 million of its common shares for $19.2 million at an average purchase price of $33.09 per share. As of Jan. 31, 2025, it reported $290.2 million in trade working capital, $108.4 million in net debt, and $31.6 million in cash on hand.
Latest REV Group (REVG) Stock News and Developments
Conclusion: Overcoming Cold Climate Barriers in EV Public Transit
As the world transitions to electric vehicles, battery electric buses offer a promising path toward achieving sustainable mass transit. However, their performance in colder climates presents critical challenges hindering their broader adoption.
Addressing these challenges is essential to decarbonizing the transportation sector, which requires understanding the complexity of energy use, operational conditions, and climate impacts. The latest comprehensive research from Cornell provides the much-needed insight into these factors, helping operators, manufacturers, and policymakers navigate the promises and pitfalls of electrification with a better and more informed understanding, thereby paving the way for a smoother and more resilient transition to a cleaner public transportation system.
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Studies Referenced:
1. Gu, J., Liao, Q., & Zhang, K. M. (2025). Assessing the cold weather impact on battery electric transit buses. Transportation Research Part D: Transport and Environment, 127, 104809. https://doi.org/10.1016/j.trd.2025.104809