In today’s electronic age, rechargeable lithium-ion batteries are ubiquitous. Compared with the lead-acid versions that have dominated the battery market for decades, lithium-ion batteries can charge faster and store more energy for the same amount of weight.

These devices make our electronic gadgets and electric cars lighter and longer-lasting – but they also have disadvantages. They contain a lot of energy, and if they catch fire, they burn until all of that stored energy is released. A sudden release of huge amounts of energy can lead to explosions that threaten lives and property.

As scientists who study energy generation, storage and conversion, and automotive engineering, we have a strong interest in the development of batteries that are energy-dense and safe. And we see encouraging signs that battery manufacturers are making progress toward solving this significant technical problem.

A new fire hazard

Urban transportation is undergoing a transformative shift toward electrification. As concerns grow in cities around the world about climate change and air quality, electric vehicles have taken center stage.

At the same time, e-bikes and electric scooters are transforming urban transit by providing convenient, low-carbon ways to navigate crowded streets and reduce traffic congestion. From 2010 through 2022, shared e-bikes and e-scooters – those owned by rental networks – accounted for more than half a billion trips in U.S. cities. Privately owned e-bikes add to that total: In 2021, more than 880,000 e-bikes were sold in the U.S., compared with 608,000 electric cars and trucks.

Battery-powered vehicles account for a small share of car fires, but controlling EV fires is difficult. Typically, an EV fire burns at roughly 5,000 degrees Fahrenheit (2,760 Celsius), while a gasoline-powered vehicle on fire burns at 1,500 F (815 C). It takes about 2,000 gallons of water to extinguish a burning gasoline-powered vehicle; putting out an EV fire can take 10 times more.

This is a major concern in large cities where electric vehicles are popular. Fire departments in New York City and San Francisco report handling more than 660 fires involving lithium-ion batteries since 2019. In New York City, these fires caused 12 deaths and more than 260 injuries from 2021 through early 2023. Clearly, there is a need for safer handling and charging practices, as well as technical improvements to batteries.

Many batteries in an EV

To understand lithium-ion battery fires, it’s important to know some basics. A battery holds chemicals that contain energy, with a separator between its positive and negative electrodes. It works by converting this energy into electricity.

The two electrodes in a battery are surrounded by an electrolyte – a substance that allows an electrical charge to flow between the two terminals. In a lithium-ion battery, for example, lithium ions carry the electric charge. When a device is connected to a battery, chemical reactions take place on the electrodes and create a flow of electrons in the external circuit that powers the device.

Cellphones and digital cameras can operate on a single battery, but an electric car needs much more energy and power. Depending on its design, an EV may contain dozens to thousands of single batteries, which are known as cells. Cells are clustered together in sets called modules, which in turn are assembled together in packs. A standard EV will contain one large battery pack with many cells inside it.

What causes battery fires

Typically, a battery fire starts in a single cell inside a larger battery pack. There are three main reasons for a battery to ignite: mechanical harm, such as crushing or penetration when vehicles collide; electrical harm from an external or internal short circuit; or overheating.

Battery short circuits may be caused by faulty external handling or unwanted chemical reactions within the battery cell. When lithium-ion batteries are charged too quickly, chemical reactions can produce very sharp lithium needles called dendrites on the battery’s anode – the electrode with a negative charge. Eventually, they penetrate the separator and reach the other electrode, short-circuiting the battery internally.

Such short circuits heat the battery cell to over 212 F (100 C). The battery’s temperature rises slowly at first and then all at once, spiking to its peak temperature in about one second.

Another factor that makes lithium-ion battery fires challenging to handle is oxygen generation. When the metal oxides in a battery’s cathode, or positively charged electrode, are heated, they decompose and release oxygen gas. Fires need oxygen to burn, so a battery that can create oxygen can sustain a fire.

Because of the electrolyte’s nature, a 20% increase in a lithium-ion battery’s temperature causes some unwanted chemical reactions to occur much faster, which releases excessive heat. This excess heat increases the battery temperature, which in turn speeds up the reactions. The increased battery temperature increases the reaction rate, creating a process called thermal runaway. When this happens, the temperature in a battery can rise from 212 F (100 C) to 1,800 F (1000 C) in a second.

Managing the thermal runaway problem

Methods to ensure battery safety can focus on conditions outside or inside of the battery. External protection typically involves using electronic devices, like temperature sensors and pressure valves, to ensure that the battery isn’t subjected to heat or force that could cause an accident.

However, these mechanisms make the battery larger and heavier, which can reduce the performance of the device it powers. And they may not be reliable under extreme temperatures or pressures, such as those produced in a car crash.

Internal protection strategies focus on using intrinsically safe materials for battery components. This approach offers an opportunity to address potential hazards at their source.

Making a thermal runaway in a battery pack less intense requires a mix of software and hardware improvements. Scientists are working to develop cathodes that release less oxygen when they break down; nonflammable electrolytes; solid-state electrolytes, which do not catch fire and also may help alleviate dendrite growth; and separators that can withstand high temperatures without melting.

Another solution is already in use: battery management systems. These are hardware and software packages built into battery packs that can monitor vital battery parameters, such as the state of charge, internal pressure and the temperature of the cells in the battery pack.

Just as a physician uses a patient’s symptoms to diagnose and treat their illness, battery management systems can diagnose conditions within the battery pack and make autonomous decisions to shut off batteries with hot spots, or to alter the load distribution so that any individual battery does not get too hot.

Battery chemistries are evolving rapidly, so new designs will require new battery management systems. Many battery producers are forming partnerships that bring together manufacturers with complementary battery expertise to tackle this challenge.

Users can also take steps to maximize safety. Use manufacturer-recommended charging equipment and outlets, and avoid overcharging or leaving an EV plugged in overnight. Inspect the battery regularly for signs of damage or overheating. Park the vehicle away from extremely hot or cold surroundings – for example, park in shade during heat waves – to prevent thermal stress on the battery.

Finally, in the event of a collision or accident involving an EV, follow the manufacturer’s safety protocols and disconnect the battery if possible to minimize the risk of fire or electrocution.

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

As wildfires burn across the Western U.S., the people in harm’s way are increasingly those least able to protect their homes from fire risks, evacuate safely or recover after a fire.

In a new study, we and a team of fellow wildfire scientists examined who lived within the perimeters of wildfires over the past two decades in Washington, Oregon and California – home to about 90% of Americans in the U.S. West exposed to wildfires over that period.

Overall, nearly half a million people in California, Oregon and Washington were exposed to wildfires at some point during the past 22 years. Alarmingly, about half the people exposed to wildfires in Washington and Oregon were considered socially vulnerable.

While the number of people exposed to fire rose overall, the number of socially vulnerable people exposed more than tripled between the first and second decades.

How social vulnerability affects fire risk

A variety of factors shape social vulnerability, including wealth, race, age, disability and fluency in the local language.

These factors can make it harder to take steps to protect homes from wildfire damage, evacuate safely and recover after a disaster. For example, low-income residents often can’t afford adequate insurance coverage that could help them rebuild their homes after a fire. And residents who don’t speak English may not hear about evacuation orders or know how to get assistance after a disaster.

Older adults face rising fire exposure

We found that older adults in particular were disproportionately exposed to wildfires in all three states.

Physical difficulties and cognitive decline can hamper older adults’ ability to keep their properties clear of flammable materials, such as dry shrubs and grasses, and can slow their ability to evacuate in an emergency. The fire that destroyed the town of Paradise, California, in 2018 was a tragic example. Of the 85 victims, 68 were 65 years of age or older.

Poverty was another important factor in the exposure of people with high vulnerability to wildfires in Oregon and Washington.

The reasons that socially vulnerable people were increasingly exposed to wildfires varied by state.

In California, the rise was in large part due to socially vulnerable people moving into wildfire-affected areas, possibly in search of more affordable housing, among other factors.

In Oregon and Washington, however, wildfires have increasingly encroached on existing vulnerable communities over the past decade, mainly in rural areas. This is predominantly due to increasing trends of intense, destructive fires.

Nearly 17,000 people living within the perimeter of wildfires in Oregon and Washington over the past decade had high social vulnerability, based on data from the Centers for Disease Control and Prevention. A smaller percentage of California’s exposed population from 2011-2021 was considered to have high social vulnerability, 11%, but that was still 26,100 people.

Secondary impacts of wildfires

Our definition of exposure to wildfire considered only those people who directly lived within a wildfire perimeter.

If you take into account secondary exposures – those living close to wildfire perimeters and likely experiencing evacuation, trauma and poor air quality – the number of people affected is many times larger.

Importantly, other hazards related to wildfires reach still more high-vulnerability communities. Wildfire smoke, for example, has frequently filled large metropolitan areas with unhealthy air in recent years, disproportionately affecting people who work outdoors and other vulnerable populations.

Policy changes that can help

To prepare and respond as wildfire risk rises in a warming world, knowledge of the local population’s social vulnerabilities is necessary, along with targeted community-based strategies.

For example, the exposure of populations with limited English-language skills highlights the need for disaster warnings and response resources in multiple languages.

While the federal government increased its investment for reducing wildfire threats to at-risk communities, including tribes, funding availability does not currently meet the demand.

Increasing exposure of certain populations, such as those living in nursing homes, requires significant investment to plan for and ensure proper and timely responses. When a wildfire in August 2023 burned more than 200 homes near Medical Lake, Washington, southwest of Spokane, it came close to a state-operated psychiatric hospital and a residential home for people with intellectual disabilities.

Finally, including social vulnerability when studying future wildfire trends is important to shape community responses and policies.

Many national disaster prevention programs skew funding toward wealthier communities because they use cost-benefit analyses to direct resources to areas with the greatest potential losses. But while wealthy residents may lose more in dollar value, low-income residents typically lose a larger percentage of their assets and have a harder time recovering. With the rising percentage of people with high social vulnerability at risk of wildfires, governments may need to rethink those methods and lower the barriers for aid.

Mojtaba Sadegh receives funding from the Joint Fire Science Program and National Science Foundation.

John Abatzoglou receives funding from the National Science Foundation, US Department of Food and Agriculture, the National Atmospheric and Oceanic Administration and the Joint Fire Science Program.

Electric vehicle sales are growing faster than expected around the world, and, sales of gas- and diesel-powered vehicles have been falling. Yet, the U.S. government still forecasts an increasing demand for oil, and the oil industry is doubling down on production plans.

Why is that, and what happens if the U.S. projections for growing oil demand are wrong?

I study sustainability and global energy system transformations. Let’s take a closer look at the changes underway.

EVs’ giant leap forward

On Sept. 12, 2023, Fatih Birol, director of the International Energy Agency, an intergovernmental organization that advises the world’s major economies, drew global attention when he wrote in the Financial Times that the IEA is now projecting a global peak in demand for oil, gas and coal by 2030.

The new date was a significant leap forward in time compared with previous estimates that the peak would not be until the 2030s for oil and even later for gas. It also stood out because the IEA has typically been quite conservative in modeling changes to the global energy system.

Birol pointed to changes in energy policies and a faster-than-expected rise in clean technologies – including electric vehicles – along with Europe’s shift away from fossil fuels amid Russia’s war in Ukraine as the primary reasons. He wrote that the IEA’s upcoming World Energy Outlook “shows the world is on the cusp of a historic turning point.”

The United Nations also released its “global stocktake” report in early September, assessing the world’s progress toward meeting the Paris climate agreement goals of limiting global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) compared with preindustrial temperatures. The report found serious gaps in efforts to reduce greenhouse gas emissions to net-zero by soon after mid-century. However, it noted two bright spots: The world is more or less on track in the growth in solar photovoltaics for renewable energy – and in the growth of electric vehicles.

The dynamics of EV expansion are important because each vehicle that uses electricity instead of gasoline or diesel fuel will depress demand for oil. Even though demand for petroleum products in other sectors, like aviation and petrochemicals, is still increasing, the IEA expects a decline in road transportation’s 50% share of oil consumption to drive an overall peak in demand within a few years.

EVs are now on pace to dominate global car sales by 2030, with fast growth in China in particular, according to analysts at the Rocky Mountain Institute. If countries continue to upgrade their electricity and charging infrastructure, “the endgame for one quarter of global oil demand will be in sight,” they wrote in a new report. As electric trucks become more common, oil demand will likely drop even faster, the analysts wrote.

Global sales of light-duty vehicles already show a decrease in internal combustion – gasoline and diesel – vehicle sales, mainly due to increasing EV sales, but also due to an overall decline in vehicle sales that started even before the pandemic.

So, why is the US projecting oil demand growth?

Based on the data, it appears that global oil demand will peak relatively soon. Yet, major oil companies say they plan to increase their production, and the U.S. Energy Information Administration still projects that global demand for oil and fossil fuels will continue to grow.

Vehicles do last longer today than they did a couple of decades ago, and they are also larger, slowing down efficiency gains. But the Energy Information Administration appears to be lowballing projections for EV growth.

The Biden administration, which pushed through large U.S. tax incentives for EV purchases, has taken steps to clear the way for increasing some oil and natural gas exploration. And large government subsidies continue flowing to fossil fuel industries in many countries. These contradictions undermine the goals of the Paris Agreement and could lead to costly stranded assets.

What do these trends mean for the oil industry?

It’s fair to assume that large industries should have a good handle on future developments expected to affect their fields. But they often have a competing priority to ensure that short-term gains are preserved.

Electric utilities are an example. Most didn’t feel threatened by renewable electricity until penetration expanded quickly in their territories. In response, some have lobbied to hold off further progress and invented spurious reasons to favor fossil fuels over renewables.

Of course, some companies have changed their business models to embrace the renewable energy transition, but these seem to still be in a minority.

Large corporations such as BP and TotalEnergies invest in renewables, but these investments are often offset by equally large investments in new fossil fuel exploration.

Both Shell and BP recently backpedaled on their previous climate commitments in spite of tacit admissions that increasing oil production is inconsistent with climate change mitigation. Exxon’s CEO said in June 2023 that his company aimed to double its U.S. shale oil production over the next five years.

What is happening in the fossil fuel industry seems to be an example of the so-called “green paradox,” in which it is rational, from a profit-maximization point of view, to extract these resources as quickly as possible when faced with the threat of future decreased market value.

That is, if a company can see that in the future its product will make less money or be threatened by environmental policies, it would be likely to sell as much as possible now. As part of that process, it may be very willing to encourage the building of fossil fuel infrastructure that clearly won’t be viable a decade or two in the future, creating what are known as stranded assets.

In the long run, countries encouraged to borrow to make these investments may be stuck with the bill, in addition to the global climate change impacts that will result.

Extractive industries have known about climate change for decades. But rather than transform themselves into broad-based energy companies, most have doubled down on oil, coal and natural gas. More than two dozen U.S. cities, counties and states are now suing fossil fuel companies over the harms caused by climate change and accusing them of misleading the public, with California filing the latest lawsuit on Sept. 15, 2023.

The question is whether these companies will be able to successfully adapt to a renewable energy world, or whether they will follow the path of U.S. coal companies and not recognize their own decline until it is too late.

Robert Brecha is also affiliated with Climate Analytics, a global non-profit climate science and policy institute. Opinions and ideas expressed in this article do not necessarily reflect those of the University of Dayton or Climate Analytics.