Seasonal storage is a key component in the transformation of today’s energy industry. Besides storing energy in summer for heating in winter, it can also be used to save waste heat from the industry and to increase the electricity production from biomass CHP plants. Experiences gathered with the technology during case studies were summarised as part of the study Seasonal thermal energy storage – Report on state of the art and necessary further R+D, which was published by Task 45, Large Scale Solar Heating and Cooling Systems, of the IEA SHC programme. Together with the Guidelines for Materials & Construction on the two most common storage types, borehole (see the chart) and water pit, it provides a good overview of the current advancements in this field (all three documents attached). Additional research into the design of seasonal storage will be carried out in follow-up Task 55, Towards the Integration of Large SHC Systems into District Heating and Cooling (DHC) Network. Interested stakeholders have been invited to join the kick-off meeting of Task 55 in Graz, Austria, between 19 and 21 October (see contact details below).
Dronninglund, Vojens and Gram are three Danish solar district heating plants whose underground heat storage has been lined with a new type of improved polymeric geomembrane. This membrane, which was developed and is produced in Germany by GSE Environmental, can withstand peak temperatures of up to 95°C and has an expected lifetime of at least 20 years. Headquartered in Houston, Texas, GSE Environmental is a manufacturer of geosynthetics –materials that ensure the durability of state-of-the-art lining solutions for various applications, such as in landfills, mining, water and waste water treatment, as well as in the oil, gas and energy sector. The photo shows the Vojens installation, a 203,000 m³ storage system which should come into operation next year.