Waste heat and renewable sources efficiently combined

13.05.2026

Source: E & M powernews

The new heating plant in Memmingen-Benningen shows how a supply system can efficiently integrate industrial waste heat into a heating network and thus make optimum use of all regional sources.

In the Allgäu region, parts of the town of Memmingen and the municipality of Benningen are supplied with heat via a new heating plant. It is a "lighthouse project" with several renewable sources and sophisticated technology for the district heating network. Project partners from industry, who are not only anchor customers but also feed their waste heat into the network, were a key success factor for the economic implementation.

The Memmingen-Benningen heat supply is one of the first projects in Germany to receive federal funding for efficient heating networks - and a total funding amount of 11.2 million euros. In total, "e-con AG", an energy and planning office based in the Allgäu region, invested over 30 million euros. Federal Minister for Economic Affairs Katherina Reiche (CSU) therefore officially commissioned the heating plant in mid-March together with those responsible at Econ AG as well as other project partners and the municipality of Benningen.

"The regenerative heat supply for Benningen is one of the most important infrastructure projects for the municipality in recent years," said Mayor Martin Osterrieder (CSU), who was also pleased with the great response from the local population.

"With the regenerative heat supply Memmingen-Benningen, we are impressively demonstrating what cities and municipalities can achieve with renewable energies as part of their municipal heat planning," added Econ board member Peter Waizenegger. "If we combine our two district heating networks North and South, we will achieve an annual heating volume of up to 200,000 MWh. This already corresponds to the target scenario that the city of Memmingen has determined in its municipal heating planning for the year 2040."

Heating plant supplies parts of Memmingen and Benningen

The heart of the heating network is the newly opened heating plant in Benningen, which supplies private households and industrial companies in Benningen and parts of Memmingen. A wood chip boiler with an output of 5 MW serves as the central unit for the energy supply there. According to Econ AG, the wood chips required come from the region. The fuel requirement is around 1,500 kg/h.

The plant is supplemented by a power-to-heat system and a combined heat and power plant with an electrical output of 99 kW and a thermal output of 173 kW. The CHP electricity generated is used directly in the heating plant, for example for pumps or the control system. A further 1.5 MW is to come from a large heat pump in the future.
A buffer storage tank with a volume of 280,000 liters for heating and a buffer storage tank with a capacity of 120,000 liters for cooling were installed to ensure the greatest possible flexibility of control.

The electricity required for the systems is already generated from renewable sources; it comes directly from the large solar park at Memmingen Airport. This currently has an output of around 25 MW and is to be expanded in the future and equipped with a battery storage system.

According to Econ AG, industrial anchor customers were particularly important for the economic success of the project. Rohde & Schwarz Messgerätebau in the southern industrial estate in Memmingen was an early pilot project partner. "By switching to district heating, we will become independent of gas as an energy source in Memmingen and save up to 270 tons of CO2 per year. This is a real milestone in the implementation of our 2030 climate strategy," says Michael Dill, Plant Manager at Rohde & Schwarz. Magnet-Schultz (MSM) has also committed to the climate-neutral, regional district heating connection as part of a strategic partnership and aims to save up to 500 tons of CO2 per year with this step. "This is another step towards a secure and sustainable heat supply for us," says Managing Director Albert Schultz.

4-pipe heating network for high efficiency

In this concept, the commercial customers were connected and integrated via a 4-pipe heating network in order to be able to use the industrial waste heat particularly efficiently: A pipe carries water at a temperature of around 10 degrees Celsius to the connected companies. There it is heated by the waste heat generated during production, regardless of the temperature level of the processes. In this way, energy is used that was previously released into the environment. At the same time, according to Econ, companies can reduce their cooling loads and benefit from greater energy efficiency in their production processes.

The water heated in this way then flows back to the Memmingen-Benningen heating plant via a second pipe. There it is raised to the temperature level required for the district heating network. "As the water is already preheated, this requires significantly less primary energy than heating it from the base temperature of the water," explains Enrico Lagoda, project manager at Econ AG.

Econ currently estimates the planned final expansion capacity of the heating plant at 50 MW. While the Memmingen-Benningen heating plant has now been completed after a two-year construction period, the expansion of the network infrastructure will continue to be the focus in the coming years.

Four kilometers of lines were laid in the first two construction phases. The connection of Alpenstraße and Oberbrühlstraße in Memmingen with a length of 1.8 kilometers is still to be completed by October 2026. Continuous expansion is also planned beyond that.

Author: Heidi Roider