The Bonn municipal utilities have retrofitted their northern combined heat and power plant (CHP) for hydrogen use. Two gas turbines can now be operated with this energy carrier. Starting from 2025, hydrogen will gradually replace natural gas.
The inauguration and commissioning of the hydrogen-compatible technology took place last Friday (September 27) in Bonn, attended by representatives from business, politics, and energy supply sectors. According to a statement from Bonn's municipal utilities (SWB), the modernization of the CHP plant cost around 90 million euros. It now has two hydrogen-capable gas turbines as well as a refurbished and new heat recovery steam generator. Additionally, there is a new workshop and office building, as well as a new machine house.
"Thanks to the hydrogen-capable turbines, we are increasing the potential for environmentally friendly district heating and electricity production in Bonn," emphasized SWB Managing Director Olaf Hermes. At the CHP North, "the course has been set for a sustainable energy economy."
First Hydrogen in Bonn from 2025
By the end of 2025, SWB could use up to 15 percent hydrogen by volume in the CHP North, according to Helge Wilhelm, Head of Energy Generation at the municipal utilities. This proportion will be gradually increased until 2035.
In the future, district heating will also be generated using green hydrogen with the new and refurbished gas turbines. The use of the previous fuel, natural gas, will be gradually minimized. The plan is to initially deliver hydrogen by truck from 2025 until a technical supply infrastructure is available at the power plant itself.
Combined Heat and Power for Efficiency Gains
The modernization of the facilities also makes electricity and district heating supply more reliable and efficient. By combining district heating and electricity production in the expanded CHP, up to 295,000 tons of CO₂ per year can be saved compared to separate electricity and heat production with natural gas.
This is made possible by the so-called combined heat and power generation with which the CHP works. As in a car, a fuel is used, in this case natural gas or hydrogen, to generate mechanical power from thermal energy, which is converted into electricity. The residual heat remaining in the process is not lost but is used for heating. Thanks to combined heat and power generation, the fuels used produce both electricity and district heating.
For production, SWB additionally uses the steam generated during the thermal utilization of unavoidable residual waste in the waste incineration plant. The energetic use of the "renewable raw material" household waste contributes significantly to the fact that Bonn's district heating has an "outstandingly good primary energy factor."
CHP Plant Achieves 130 MW Output
Thanks to the new technology, the municipal utilities can generate up to 70 percent of Bonn's electricity demand in the CHP plant itself, according to their own information. With an additional 40 megawatts (MW) of electrical power, the Siemens turbine significantly increases the plant's capacity. In combination with the existing gas turbine and the steam turbines, the power plant now produces an electrical output of around 130 MW.
In addition, the plant produces up to 180 MW of peak load for district heating. SWB also wants to double its district heating network: So far, around 2,800 customer systems are connected to the 130-kilometer-long pipeline network.
In February of this year, the German federal government decided on its power plant strategy. This envisages putting hydrogen-capable gas power plants with a total capacity of 10 gigawatts (GW) into operation by 2040.
