E-fleets benefit twice from used batteries

Out of the electric vehicle into the battery storage

A new study from July 2025 by The International Council on Clean Transportation (ICCT) shows: Battery electric vehicles in e-fleets have a clear advantage in terms of climate protection. Over their lifetime, electric cars emit around 73 percent less CO₂ than comparable petrol cars. The ecological advantage is clear and it grows with every percentage point more renewable energy in the grid.
But what happens to the batteries after the vehicle’s life? The Chair of Production Engineering of E-Mobility Components (PEM) at RWTH Aachen University has now published its latest findings, also in July 2025, in the journal ScienceDirect, stating that the recycling of electric vehicle batteries in Europe is currently not profitable. According to the analysis, particularly high investments are made in transportation, which accounts for up to 70 percent of the total recycling costs, depending on the classification of the batteries. Another challenge is that most of the recovered black mass has to be sold abroad due to a lack of European demand.

What if, instead of recycling, we could make a second use of used car batteries not only more sustainable, but also economically attractive? The second life of vehicle batteries offers potential that has hardly been exploited to date. Although many batteries are no longer ideal for vehicle operation, they still have sufficient capacity to continue working as stationary battery storage solutions. And they can do so economically, resource-efficiently and directly on site where they are needed: for example in the charging hub or depot of e-fleets.

Double challenge for operators of e-fleets

The electrification of vehicle fleets is a key lever in the mobility transition. However, many fleet operators face a double challenge , such as achieving climate targets, keeping costs under control:

• Expensive battery investments quickly lose value
• There is a lack of strategies for old batteries
• Rising energy costs due to charging infrastructure and peak loads
• Limited grid connections meet increasing charging requirements
• Sustainability must be economically viable

As a result, valuable batteries are being disposed of far too early, while electricity costs are rising, despite PV systems on the roof or wind farms nearby.

Our answer to the challenge: The Battery Hotel

With the Battery Hotel, STABL Energy offers a solution that starts right here: Used batteries from your own e-fleet are collected, tested, processed and reused directly on site as electricity storage in our 20-foot container. Instead of generating costs, they now provide further added value:

• Cushioning peak loads (peak shaving)
• Increase self-consumption of PV systems or wind farms
• Relieve the grid connection
• Blackout resilience through backup function
• Measurably meet sustainability and ESG requirements

The Battery Hotel turns used batteries into an energy resource and makes the company premises a little more independent.

Second life with a double effect for sustainable profitability

At the heart of the solution is STABL inverter technology, which makes second-life batteries safe, efficient and flexible to integrate. Each battery module is monitored and controlled individually, as this increases the service life and simplifies maintenance. This turns the often unsolved and expensive problem of old batteries into a real location advantage for charging hubs and e-fleet depots.

E-mobility is not limited to the purchase of an e-vehicle. It is the smart use of the battery over the entire life cycle of the vehicle that brings the decisive advantage. It is precisely this added value that the Battery Hotel creates, putting the concept of the circular economy into practice.