Micro steam turbine generates electricity and saves energy

Many years of research work on the conversion of waste heat into electricity laid the foundations for the development of a new micro steam turbine for steam as part of an EXIST project. The use of this innovative turbine makes it possible for the first time for small steam generators to generate their own electricity cost-effectively and efficiently in terms of energy and resources. The spin-off TURBONIK GmbH, which was founded after successful development work in the Fraunhofer project, has been producing and selling the micro steam turbine since 2017. Since then, the prototype of the turbine has been used in the combined heat and power plant of Oberhausen-based energy supplier evo in order to use the steam required for degassing the district heating water to produce electricity and thus save costs and resources.

With the micro steam turbine, smaller steam quantities or low pressure differences are sufficient for the first time to generate one’s own electricity.

An optimized blade design and the direct coupling of the turbine and generator ensure that the micro steam turbine is not only significantly more compact than conventional steam turbines, it also has significantly higher efficiency, is completely oil-free due to the absence of a gear, and can be easily integrated into existing systems and plants.

Small and medium-sized companies operating steam systems in the lower output range can be found, for example, in the food, pharmaceutical, chemical, and textile industries, as well as among furniture manufacturers and energy suppliers. The new turbine offers them high energy-saving potential. The small steam turbine generates up to 40 percent more electricity with the same fuel input than conventional steam turbines in the output range up to 300 kW. Due to the high efficiency and low life-cycle costs of the turbine, for example, electricity costs can be halved, even in single-shift operation.

When installed in the evo combined heat and power plant, the micro steam turbine replaces a pressure relief valve in the steam system for district heating degassing. In order to degas the district heating water, the steam required for this was previously generated in a steam boiler at elevated pressure and mechanically reduced to the required working pressure by a pressure relief valve. Located between the steam boiler and the district heating water degassing tank, the new turbine now permanently generates up to 75 kW of electricity instead. Within one year, the micro steam turbine in Oberhausen can produce up to 300,000 kW of electricity and, at the same time, save up to 10 percent of primary energy. The sophisticated use of the energy means that evo avoids around 90 tonnes of carbon dioxide annually and can thus make a considerable contribution to climate protection and reduce its own energy costs.

The cold and warm start-ups have been completed. Following optimization of the turbine control system and integration of the plant into the control technology for the district heating water degassing system, the handover and further operation by evo is scheduled for summer 2018 after completion of the trial operation and final CE certification.

• TURBONIK GmbH, Dortmund
• Energieversorgung Oberhausen AG, Oberhausen