Emmerthal (OKa). This year’s university colloquium of the energy supplier EWE was held on 6 March 2017 in Emmerthal together with the Institute for Solar Energy Research (ISFH) of Lower Saxony. 17 scientists, university professors and engineers spent a day discussing aspects of the topic of “regenerative heat supply for quarters”.
“The heating sector contributes more than 50% to the final energy demand in Germany. Today, only about 13% of this comes from renewable energy sources,” says Dr. Oliver Ruch from EWE VERTRIEB GmbH, describing the situation on the heating market. “What ways of decarbonising the heating sector can be pursued in the balancing act between environmental protection, social acceptance and corporate goals?”
With the expansion of renewable generation capacities for wind and solar power, there is an increasing disparity between times of electricity production and energy demand. This relationship already plays a major role in regions with intensive wind power generation, such as the Weser/Ems region. “In 2015, 10.5 TWh of EEG electricity were fed into EWE’s grid area, which corresponds to 85% of the transmitted energy,” explains Thomas Götze of EWE NETZ GmbH. Any capacities that cannot be accommodated must be cut down. Thus, the local utilisation by means of electricity to fuel or electricity to heat concepts becomes interesting. EWE is working with other partners on a number of sector coupling projects as part of the “enera” SINTEG funding project.
The energy transition in the heating sector must meet local requirements. Jürgen Knies from the Jade University of Applied Sciences Oldenburg shows how methods of geoinformatics can be used to develop energy-efficient neighbourhood models that will support long-term, renewable energy planning in the future. The models provide spatial supply/requirement analyses that are required, for example, for the integration of industrial waste heat for heat supply. Many examples from Scandinavia show what role heat networks can play. Georg K. Schuchardt, Head of R&D at the Fernwärme-Forschungsinstitut Hannover, describes the development of district heating technology from the steam networks of the Gründerzeit to the modern fourth generation local heating networks, in which low-temperature heat from different regenerative sources – geothermal, solar thermal, environmental and waste heat – can be optimally and flexibly combined. Dr. Orozaliev from the University of Kassel shows how such concepts are currently being implemented in concrete plans using the example of the new district Kassel-Feldlager.
District heating-based supply solutions also provide an efficient basis for the introduction of regenerative resources in the area of existing districts. Using the example of the municipality of Eberswalde in Brandenburg as an example, EWE, together with ISFH and the German Geo-Research Centre in Potsdam, investigated ways of integrating solar energy into an existing district heating network. “If areas are available, solar thermal energy can also easily contribute to covering the basic summer load of large districts in existing second-generation networks,” explains Prof. Oliver Kastner of ISFH. Solar energy supply solutions for the winter period, on the other hand, require solutions for long-term heat storage.
At ISFH, it is shown on a smaller scale how solar thermal and geothermal methods can complement each other: “We regenerate geothermal systems with the help of simple solar collectors. This enables us to achieve high coverage rates and minimise the investment costs,” explains Dr. Giovannetti from ISFH. Cost-efficient collector systems can be used, which are elegantly integrated into the building envelope, as Mrs. Vargas from GeoClimaDesign AG shows.
Finally, the heat pump is also an important coupling technology between the heating and electricity sectors. With their help, low-temperature heat potentials can be raised to a required useful temperature. The energy required for this comes from the electricity sector – ideally from surplus energy from regenerative production. The successful Danish heat supply concepts also provide examples of domestic supply solutions,”explains Prof. Kastner. Their success is based on the great flexibility of the supply systems, which efficiently combine conventional CHP with innovative heat pump-based storage technology and solar thermal energy. “This enables us to react optimally to the fluctuations in production of a renewable-based electricity industry.”
Information on EWE and ISFH
EWE
With annual sales of over 8 billion euros, EWE AG is one of the largest municipal companies in Germany. The Group’s portfolio includes energy products, telecommunications, especially in Northwestern Germany, Brandenburg and Rügen. The group, headquartered in Oldenburg, Germany, has its own generation capacity from renewable and conventional energy sources. In addition, EWE companies also operate networks for electricity, natural gas, district heating and communications.
ISFH
ISFH is a non-university research institute of the state of Lower Saxony and an independent associated institute of the “Gottfried Wilhelm Leibniz Universität Hannover”. It carries out applied research and development for solar energy in the departments “Photovoltaics” and “Solar Systems”. ISFH thus contributes to the cost reduction of solar energy and makes an important contribution to the energy transition. The current managing director of ISFH is the physicist Prof. Rolf Brendel.