Analyses based on Ringkøbing District Heating Our analysis will take a starting point on Ringkøbing District Heating, which lies in Western Denmark. It is, of course, a little ambitious to guide decision-makers based on only one case. However, it is an interesting case, and we will also include some of the viewpoints that came up at and after the meeting in Copenhagen. Ringkøbing DH produces around 110,000 MWh-heat/year. The plant has already invested in 30,000 m2 of solar collector and 3,000 m3 thermal storage connected to this solar collector and a tiny heat pump. However, in the analysis, we have taken the liberty of assuming that Ringkøbing DH could redo these investment decisions based on the present investment costs in Denmark. Thus, we present a counterfactual analysis of what could have been done instead. A model of Ringkøbing DH in energyPRO The analysis of the investments is made in the energy sys- tem analysis tool energyPRO2. A model for 2023 is made, as shown in Figure 1. The reference model maintains three exist- ing heat-producing units - a natural gas engine, a natural gas boiler, and an electric boiler. These units have access to the existing 4,800 m3 thermal storage made when the natural gas engine was installed, allowing the engine to primarily produce electricity and heat in hours with high Day-ahead prices. Fur- thermore, the existing thermal storage in the reference simu- lation allows the electric boiler to consume electricity in hours with low Day-ahead prices.
In the reference calculation with the assumed technical and economic assumptions, the Net Heat Production Cost (NHPC) for producing the 110,000 MWh-heat is calculated as 8.02 M EUR, which gives an average production price of 72.9 EUR/ MWh-heat. The Net calculation means that the value of the sold electricity is subtracted from the operating expenditures. The reference simulation includes no new investments in solar collectors, photovoltaic, wind power, heat pumps, or additional thermal storage. Heat pump capacity is an interesting possible new investment since it is closely related to wind power or PV investments, given heat pumps electricity demand. The price for the used electricity at the heat pump may be low in hours, where the wind turbine covers the heat pump consumption behind own meter, thus avoiding taxes and grid tariffs. Heat pumps may, of course, also simply operate on grid electricity Hourly gas and Day-ahead electricity prices in 2023 Of significant importance for choosing the optimal investment of solar collector, PV, wind turbine, heat pump, and new ther- mal storage is the assumed natural gas and Day-ahead elec- tricity prices in a lifetime of 15-20 years. For these analyses we have assumed that the prices are the same in all years as in 2023, and that natural gas and Day-ahead electricity prices in 2023 are found by multiplying the hourly natural gas and Day-ahead electricity prices in 2022 with the factor 0.4209. This factor is the ratio between the average Day-ahead electricity prices in the first eight months of 2022 and 2023. It shows that the average price was more than halved in these months from
Figure 1: Model of Ringkøbing DH implemented in the energy system analysis tool energyPRO.
2 https://doi.org/10.1016/j.energy.2022.124792
1 Live data from this plant are shown at www.emd.dk/livedata/energyweb/.
13 www.dbdh.dk
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