Lower temperatures, lower CO 2 emissions and higher profitability
By: Kristina Lygnerud, Energy department manager, Swedish Environment, Research Institute (IVL) and Associate Professor in Industrial and Financial Economics at Halmstad University.
With lower system temperatures, it is cost-efficient to use renewable heat sources and waste heat. The slow takeoff can be seen as a chicken or egg dilemma. What should come first? Investments to lower temperatures -allowing efficient use of renewable heat sources and waste heat- or renewables or waste heat- rendering low system temperatures cost-efficient?
technology is a family of many different network configurations for heat distribution. Notably, cold and warm networks are siblings in this family of configurations. Returning to the book, finalized this Spring, it covers several things: what to do in the building and in the district heating system to allow the low temperatures. Early installations have been identified and analyzed in-depth, generating hands- on experiences. Last, but not least, we have dedicated two chapters of the book to the economics and competitiveness of low-temperature district solutions. At lower distribution temperatures, the economic benefits of renewables and recycled heat are based on efficiency gains stretching from heat supply to the buildings, illustrated below.
Since 2018, a team has built a guidebook on implementing low-temperature district heating (LTDH) (work of Annex TS2, IEA-DHC). Together, we have tossed and turned existing knowledge around to condense all relevant information into a guidebook to facilitate implementation. When we started the writing process, we defined Fourth Generation District Heating (4GDH). Now, three years later, our definition of 4GDH applies to all new technological features and concepts using low temperatures, which are considered best available from 2020 onward. As experienced in previous technology generations, a wide diversity of technology choices in 4GDH is expected. Hence, cold district heating systems are also included in our definition of 4GDH. The corresponding technology comprises all heat distribution technologies that will utilize supply temperatures below 70°C as the annual average. 4GDH
Figure 1. Economics of LTDH
Heat supply
Cash flow from reduced annual supply costs from lower temperatures
Network
Cash flow for proper maintenance and some minor additional investments for obtaining lower temeratures
Substations
Buildings
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