UniBW Study: BEV Clearly Ahead in Environmental Performance - Also Compared to Hydrogen

In your publication, 790 current car variants were compared to examine and evaluate the greenhouse gas balance over the entire lifecycle of a vehicle. How does this differ from the so-called Sweden studies from 2017 and 2019, and what is the result of your study?

The biggest difference is that in our study, we examined and compared the currently available vehicles in various performance areas and powertrains on the market, thus achieving a broad market overview. The Sweden studies state that the so-called CO2 backpack of battery production for electric cars has decreased in recent years. In our study, we highlighted that the overall emission over the lifecycle of a vehicle is decisive, and this is significantly reduced in electrically powered vehicles. Therefore, the point at which the CO2 backpack is offset is reached sooner.

What CO2 emissions occur over the lifecycle of a vehicle?

The lifecycle of a vehicle can be divided into three phases. The first is production. Here, emissions are generated during development and testing, raw material extraction, processing and assembly, as well as transportation and trade of the vehicles. The second phase describes the period when the vehicle is with the customer. Here, the well-to-wheel emissions are very well represented by the respective fuel consumption or electrical consumption. We based our study on the data from the WLTP - a scientifically recognized testing procedure - allowing the vehicles to be fairly compared. The third phase is scrapping and recycling of the vehicles. The emissions generated here can now be offset with the emissions saved when new vehicles are made from recycled materials. This applies equally to combustion engines and BEVs.

How do pure electric vehicles compare to gasoline or diesel vehicles, and what about hybrid vehicles?

Gasoline engines have the worst greenhouse gas balance because their consumption is relatively high. Diesel vehicles have slightly lower consumption, but a liter of diesel emits more CO2. Over the entire lifetime of the vehicle, diesel engines save about 20% compared to gasoline engines. Battery-electric vehicles have by far the best greenhouse gas balance, not only when operated with pure green electricity but also with Germany's standard electricity mix. In our study, we also examined and evaluated various hybrid vehicles and cars powered by LPG, natural gas, and hydrogen.

Is hydrogen the solution for the future in terms of CO2 emissions?

As of today, hydrogen vehicles have a worse CO2 balance because it is gray hydrogen produced from natural gas.

Would the balance of a hydrogen vehicle compare better with a BEV if it were refueled with green hydrogen?

In my view, no, because even green electricity has a low greenhouse gas balance, and there are significant losses in hydrogen production. It would take three times as much green electricity to power all vehicles with hydrogen compared to powering them all with green electricity.

Was the electricity mix used in battery production in the respective manufacturing countries also considered in the study?

Yes, the CO2 emissions in battery production range from 60 to 100 kilograms of CO2 equivalent per produced kilowatt-hour of lithium-ion battery. In our evaluation, we used an average value of 80. Thus, it was not specifically distinguished where the vehicle was produced, but an average value was assumed for all.

What about the sustainability of the batteries?

The CO2 footprint decreases significantly, for example, through production in gigafactories powered by green energy. Even plants in Asia are increasingly relying on sustainable energy sources. And the production processes themselves consume less energy. There is constant optimization in this area.

What usage duration was assumed in the study?

In our study, we assumed 230,000 kilometers. This value is based on the registration figures from the Federal Motor Transport Authority. This mileage is achieved assuming a vehicle is driven an average of 15,000 kilometers per annum over 15 years until it is scrapped.

BEVs could potentially run longer?

Yes, considering the warranty that the manufacturer grants on the accumulators. This is an average of 160,000 kilometers or 8 years. In comparison, a combustion engine vehicle gets a 3-year warranty, maybe 12 years for rust-through. Manufacturers like Lexus now offer a flat warranty of 1 million kilometers. A study by the Technical University of Munich showed these 160,000 kilometers can be easily achieved. Simulations with cells from the VW ID.3 revealed that after 150,000 kilometers, there was a capacity loss of less than 10%. If a manufacturer guarantees a maximum loss of 30%, this results in an extrapolated mileage of 400,000 kilometers.

You calculated 230,000 kilometers in your study. This would imply that the battery could be reused even if the car it came from no longer exists. So, the official manufacturer specifications are likely exceeded?

The discussion of warranty provision is a daily matter in many companies and needs to be well-calculated so that neither manufacturers nor companies suffer losses or appear in a negative light. Currently, the warranty is still conservatively assessed for companies.
When creating your publication, you relied on the usage data from the WLTP study.

Are these values rather optimistic or pessimistic, or do they differ depending on the vehicle?

In general, WLTP values for combustion engines are rather optimistically estimated, regardless of where the vehicle is operated. Urban traffic tends to be worse than cross-country or highway driving, but driving behavior also plays a role. This is the case for both combustion engines and electric vehicles. High speeds increase consumption for both.

In conclusion, regarding batteries and current developments: Will range anxiety eventually be a thing of the past?

For some, this will always be an issue, even if it ultimately proves unfounded. The development is heading towards a range of 500 kilometers, with the added capability of rapid charging. It's more than enough for daily commuting.

The interview is an excerpt from an episode of The smarter E Podcast. As part of this trade fair, Power2Drive Europe will also take place from June 14–16, 2023, in Munich.