Power Plants of the World: The heart of a new network

Special Features Series Sponsored By INNIO14 March 2023

Jack Burke Senior Editor, Compressor Tech2

14 March 2023

New combined heat and power plant with specially laid district heating network

Editor’s note: Each year, Diesel & Gas Turbine Worldwide invites prime-mover original equipment manufacturers to submit one specific power generation project it feels merits special attention because of advances in one or more of the following areas: efficiency increase, environmental aesthetics, operation characteristics, emissions improvements or construction principles. For the next several weeks, we will feature some of the most innovative projects on our website.

Forward-looking energy project in the Osnabrück region

A new combined heat and power plant with two MWM gas gensets has been producing electricity and heat for the residents of Alfhausen since late 2022. The heat is supplied to the connected households via a specially laid district heating network. (Image: MWM)

Since mid-November 2022, a new combined heat and power plant with two MWM gas gensets has been producing electricity and heat for the residents of Alfhausen. The heat is supplied to the connected households via a specially laid district heating network.

Two containers, just under 20 m long and weighing around 40 tons, in a hall in the new Am Waller Esch industrial estate in Alfhausen in the Osnabrück region, do not look spectacular at first glance. And yet, behind this plant lies a forward-looking heat supply concept for rural areas. Each of the two container CHP units with MWM gas gensets has an output of 2300 kW. They form the heart of the new district heating network in Alfhausen, which the local company Rasche & Weßler is building in the town of 4,000 inhabitants. It is powered by biomethane: a renewable energy source that is in demand as never before in times of skyrocketing energy costs.

The heat generated by the two MWM TCG 3020 V20 gas gensets is supplied to households via a district heating network. In addition to the new combined heat and power plant with the two large gas gensets, a hot water storage tank with a volume of almost 2,500 m3 was also built. The waste heat from the engines heats the water, which is supplied to the individual households via a district heating pipeline.

In the event of sudden cold snaps or a CHP failure, the storage unit also serves as a buffer that can continue to supply the site with heat for up to four days in winter and up to 14 days in summer. An additional gas burner also serves as a backup for emergencies. The community’s new industrial park was deliberately chosen as the site for the Alfhausen CHP plant, as it is located directly opposite the local substation. This made it easy to connect to the power grid, the electricity generated in the CHP unit can be fed into the public power grid over a short distance and also has no conversion losses due to the 10kV medium-voltage generator.

Rasche & Weßler is building the 19-km district heating network itself. The expansion began in March 2021 and is scheduled for completion by the end of 2023. “The interest, especially from private individuals, in our supply concept, was great from the start,” said Ralf Wessler, a parter in the project. But in recent months, he says, demand for connections to the district heating network has risen significantly.

Wessler and his partner Andreas Rasche have taken a unique approach to plan and building the district heating network throughout the town: they have brought Glasfaser Nordwest, a subsidiary of Telekom and EWE, on board as a partner. This means that not only will district heating connections be laid directly to customers’ homes during the construction work but the town will also be equipped with fiber optic house connections in parallel. This partnership makes the expansion more economical for everyone involved - and the same construction work is avoided. The result is a modern, climate-friendly infrastructure in Alfhausen.

The network within the town center was 65% complete in December 2022. For the final expansion, approximately 10 million kWh per year will be distributed to the respective network connections. Planning has already begun for the network installation outside the town center. In December 2022, 175 network subscribers had a house connection to the district heating network, 45 of which are already receiving heat, and additional consumers are joining daily. Currently, an average of 750 kWh of heat is being extracted. The second main line also went into operation in mid-December 2022 and an average of around 1200 kWh of heat in winter conditions, Rasche said.