The BMW Group is now using electricity to power exhaust purification in its first paint shops. This new method allows the high temperatures needed for thermal purification of exhaust from paint booths and drying areas to be generated electrically, eliminating the need for natural gas.

Michele Melchiorre, head of production system, planning, tool shop, and plant construction at BMW Group, said, “For other energy-intensive paint shop processes, such as vehicle drying and water heating, solutions already exist for working without natural gas. Electric exhaust purification is the final steppingstone for BMW Group to run its paint shops on renewable energy.”

The first systems have been tested at Plant Regensburg and BMW Brilliance in China, while Plant Dingolfing has converted a painting line for series production. BMW’s newest plant in Debrecen, set to open in 2025, will exclusively use this method.

eRTO: The Gas-Free Alternative

eRTO (electric regenerative thermal oxidation) burns gaseous or vaporous substances at temperatures up to 1,000 °C, running entirely on electricity. This process purifies exhaust from paint booths and drying areas before it is released into the atmosphere, preventing solvents from causing environmental harm. Previously, only natural gas could provide the required energy, but the eRTO system now allows for exhaust purification using electricity from renewable sources.

Image courtesy of BMW. 

Electricity, Not Gas: How It Works

The eRTO system is installed between the painting booth, drying process, and chimney. Thermal energy is recovered by a two-meter-deep ceramic bed, where temperatures reach up to 1,000 °C. Electrical heating rods heat the ceramics, and because most heat is retained, a connected load of only a few hundred kilowatts is sufficient to run the system.

Series Production at Debrecen and Beyond

The eRTO system was initially tested in ongoing operations at BMW Group Plant Regensburg. It is now being further validated at BMW Brilliance Plant Lydia in China, where an eRTO system is used to purify exhaust from the drying system for car bonnets. In Europe, Plant Dingolfing has already converted one of its four paint lines to electric exhaust purification. More systems are planned across BMW’s production network, and the new plant in Debrecen will exclusively purify paint shop exhaust using eRTO.