CO2 emissions from U.S. transportation are projected to remain approximately constant over the next 30 years, according to a 2022 Outlook Report from the U.S. Energy Information Administration (EIA).
Projected CO2 emissions from U.S. transportation, according to the EIA
The seven big EV problems
Economists at the EIA do not expect CO2 from transportation to decrease due to seven big problems with electric vehicles:
- EVs cost more than gas cars over a vehicle lifetime.
- Fast-charging stations are at risk of losing money.
- Rare Earth materials are at risk of becoming rarer and more costly.
- Waiting to charge is sometimes inconvenient.
- Drivers sometimes experience anxiety over range and charging.
- CO2 is emitted when natural gas or coal is burned to make electricity.
- CO2 is emitted when one mines rare Earth materials and fabricates batteries.
The remainder of this article discusses why a standardized swappable battery could help to resolve all of these problems.
Swappable batteries to the rescue?
Currently, the world has mechanical and electrical standards that define batteries, pictured below, and these enable one to power many products at a low cost.
Examples of standardized batteries
In theory, one could have a standardized car battery that probably looks similar to the Tesla battery yet is used by multiple automobile manufacturers. The standard would define the mechanics (e.g., height, length, and width), electrical connections, and communication between battery and car.
Currently, proprietary batteries are built into EVs and are charged periodically. Alternatively, one could have a standard plug-in battery, wherein all cars use the same form, and swap with a fresh battery in less than one minute. Car owners would pay for electricity consumed and wear on the EV battery. And they would be charged less when using lower-cost batteries. Cavities would be dug out at key locations and a mechanism that charges, stores, and swaps would be dropped in. Cars would position themselves over the mechanism and swap.
Those who drive less than 100 miles a day (160 km) could swap in a low-cost, low-range battery and charge at night. Cost reduction would occur because lower-range batteries use fewer rare Earth materials (e.g., 20-kWh lithium iron phosphate [LFP] costs less than 60-kWh nickel manganese cobalt [NMC]). And on long trips, one could swap in a costly high-range battery or swap more often. Swapping could also reduce cost via commoditization, as multiple battery manufacturers would compete, and drive down price.
Homes could install swap chambers in their driveway that contain swappable batteries. These could be charged by solar during the day, power the house at night, and swap with cars as needed, as illustrated below.
EV batteries in residential swap chambers power homes at night.
Swappable batteries are not a new idea. For a video by David Borlace that discusses it, click here. For more details, see “swappable battery” in “How to Decarbonize Transportation.”
Swappable downside
Swapping might sound great; however, it has a dark side:
- Swapping would require a massive effort by automakers who design vehicles around a swappable battery and construct new factories that make those vehicles.
- The world would need to install many underground swap chambers, at a great cost.
- Swapping must battle “chicken versus egg.” Automakers might be reluctant to participate without many swap chambers, and swap companies might be reluctant to participate without many swap cars. To push forward, swap chambers might initially be placed at car dealerships, where drivers visit before a long trip to get a costly, long-range, fast-charging battery. Otherwise, they might rely on low-cost, short-range, slow-charging batteries that are charged at home.
Small money next step?
As a next step, a government or foundation could spend tens of millions of dollars to design and prototype a standardized swappable battery system to get a better sense of technical and economical feasibility.
Decrease battery costs fourfold via less range and slower fast charging
EVs typically provide 300 miles of range and fast-charge in 30 minutes. However, if range requirements were reduced twofold, and fast-charging speed was reduced fourfold (e.g., a two-hour minimum charging time), then battery-related costs might decrease by more than fourfold.
- The traditional 300-mile–range battery uses NMC chemistry. Alternatively, LFP costs approximately 3× less due to a 30% lower cost per kilowatt-hour and twice as many lifetime cycles (3 = 2 ÷ [1 – 30%]). The downside of LFP is that it provides less range for the same volume and weight (e.g., 150-mile LFP versus 300-mile NMC).
- Slower fast charging creates less heat, and this reduces the cost of thermal management systems within the battery.
- Slower fast charging increases battery longevity, which decreases costs.
- Slower fast charging requires less costly charging equipment. For example, AC-to-DC converters that charge in eight hours cost approximately 6× less than converters that charge in one hour.
- Slower fast charging requires less service from the power company (e.g., 40-kW service costs less than 160-kW service).
We will now explore why a standardized swappable battery could potentially help to resolve the seven EV problems described previously.
EVs cost more than gas cars over a lifetime
The National Renewable Energy Laboratory (NREL) reports that gas cars cost $0.30 per mile and 300-mile–range EVs cost $0.47 per mile, as shown in the below table. This includes initial car cost, gasoline cost, electricity cost, and replacement EV battery cost. Batteries are usually rated for 100,000 miles and eight years, and a car typically lasts twice as long. Subsequently, the owner is likely to buy one replacement battery during the vehicle lifetime, and these are very costly.
Cost per mile from different vehicle categories, according to NREL
Readers might have seen reports that suggest EVs cost less than gas vehicles; however, these are typically based on “studies” that “forget” to include the cost of the replacement battery. Professional economists at the EIA and the NREL are encouraged to avoid personal bias, as it decreases accuracy. Their job is to project what will happen, as opposed to what they want to happen.
For more details, see “Car Costs and CO2 Are Complicated.”
Swappable batteries reduce EV costs in the following ways:
- Most cars drive less than 45 miles a day. Subsequently, on many days, they could use low-cost, low-range batteries (e.g., 100 miles) and charge at night. And on long trips, they could use more costly, longer-range batteries or swap more often.
- Current EV owners might replace batteries after capacity has degraded 20% to 35%. However, swappable batteries could be used longer, as they could be offered as a lower-capacity battery when they get older. Drivers would not see the difference between a 150-kWh new battery and a 300-kWh old battery that had degraded 50%. Both would appear in the system as 150 kWh. Battery costs decreases twofold when they last twice as long.
Fast-charging stations are at risk of losing money
When you see a fast-charging station, what percentage of the time is it being used? In many cases, not much. This is due to charging inconvenience, high costs, easy charging at home, and not enough EVs. And low utilization often leads to station costs that exceed station revenue. When this occurs, stations might support losses with government money or investment money; however, these “remedies” are not sustainable. Station costs are high due to the high cost of fast-charging equipment and the high cost of power service. For example, one needs 150 kW of grid power to charge a 50-kWh battery in 20 minutes (150 kW × [20 ÷ 60]). This is the same amount of power that is consumed by 120 homes, and the grid equipment that supports this is costly (the average U.S. home consumes 1.2 kW).
For this reason, many fast-charging stations do not have access to significant grid power, which means they cannot charge many vehicles quickly at one time. This results in the following cascade of events: slower charging, less customer satisfaction, less station utilization, higher cost per customer, less station profit, and ultimately fewer people who want to be a station owner.
A city with many EVs and mostly on-street parking is more likely to make fast charging work economically. Alternatively, fast-charging stations in rural or suburban areas are often at risk of losing money.
For a rural station case study, see this video by Kyle Conner. He explores a station that is connected to 37 kW of power on a rural road and discusses how it contends with both technical and economic challenges.
Swappable batteries reduce fast-charging–station economic viability risk for the following reasons:
- Batteries in underground swap chambers can charge more slowly, which reduces required service power and reduces charging equipment costs.
- Batteries in swap chambers can draw power at night or when renewable sources are in saturation and electricity is less costly.
Rare Earth materials are at risk of becoming rarer and more costly
Approximately 7 million EVs were manufactured globally in 2021. If production was increased twelvefold and ran for 18 years, EVs could replace the world’s 1.5 billion gas vehicles and decarbonize transportation (7 million × 18 years × 12). However, EVs typically use rare lithium, cobalt, and nickel, and it is not clear what would happen to the price of these materials if consumption increased dramatically.
EV battery prices typically decrease from year to year. However, this did not happen in 2022 due to material shortages. Unfortunately, rare Earth materials might become rarer and lead to higher battery prices.
Swappable batteries reduce dependence on rare Earth materials, as they can more easily work with lower-range technologies that use fewer rare Earth materials (e.g., LFP batteries do not use cobalt).
Waiting to charge is sometimes inconvenient
Swappable batteries reduce refueling time, as swapping is fast.
Drivers sometimes experience anxiety over range and charging
If there were many swap chambers and many excess batteries in the system, then swapping would be easy.
CO2 is emitted when natural gas is burned to make electricity
The grid is often powered by multiple sources. For example, at any given time, a city might receive 20% of its electricity from nuclear power, 3% from solar power, 7% from wind power, and 70% from natural-gas–based power stations. Solar farms produce electricity when sunny, wind farms produce electricity when windy, and other sources tend to be less intermittent.
When one charges an EV, at least one power source on the grid increases output. Typically, only one participates due to several considerations, such as cost. Also, output from a solar farm is not likely to change, as it is set by the sun, and its electricity is typically already being consumed. Alternatively, if the solar farm is in “saturation” (i.e., discarding green electricity due to having too much), then it could increase its output instead of discarding. And one could charge an EV with no CO2 emissions at the source.
Swappable batteries reduce CO2 emissions from electricity generation, as batteries could be charged when renewables are in saturation.
CO2 is emitted when rare Earth materials are mined and batteries are fabricated
Swappable batteries reduce CO2 emissions from battery production, as one can work with smaller batteries that use fewer rare Earth materials.
Transportation is a $30 trillion problem
There are approximately 1.5 billion gas vehicles in the world, and if these were replaced with EVs, at a cost of $20,000 each, the total cost would be $30 trillion (1.5 billion × $20,000). If this was reduced by 10% via hundreds of billions of dollars of additional R&D, for example, then the cost of the R&D would be justified. We need to think about transportation as a $30 trillion problem and act accordingly — in other words, more R&D. Yet how can R&D decrease swappable battery costs? We can begin by exploring machines that automate the installation of underground infrastructure. Below are several examples. For details, see “How to Decarbonize Transportation.”
Machine that installs underground transportation infrastructure (concept only)
Machine that maintains underground transportation infrastructure (concept only)
Conclusion
To move swappable batteries forward, a government or foundation could fund the development of the following standardized systems:
- Mechanical and electrical swappable EV battery system
- Communication system between EV battery and charging mechanism
- Communication system between car and battery swap station
- Communication system between grid and car display panel
- Smart phone user interface and payment system interface
- Swap, store, and charge mechanisms of varying size
Developing a complete system to the point of prototypes might cost tens of millions of dollars; however, worldwide deployment might cost many billions of dollars.
For more information on how to reduce CO2 from vehicles, see:
Glenn Weinreb has published over 30 articles on how to tackle climate change.