Figure 2: Daily average gas and Day-ahead prices in Denmark in 2022.
2022 to 2023. Figure 2 shows a clear relation between daily average natural gas and Day-ahead prices in 2022. Thus, the same factor is used for natural gas and electricity prices. Investment costs in Denmark today The specific investment costs used in this analysis are shown in the Fact Box. The investment costs are estimated in collab- oration with the manager of Ringkøbing District Heating, who has the general task of tracking potential investment options and costs. The reason for also including cable cost is that it may be rel- evant to invest in a direct line between the plant and, e.g., a wind turbine, to allow the benefits of operating behind the same meter in private wire operation.
the upper graph is shown the Day-ahead electricity prices. The following two graphs show the heat and electricity production and consumption. At the bottom are shown the contents of the existing thermal storage. Notice that the electric boilers are operated in the first three days due to low prices in the Day-ahead market. However, the prices are higher on Sunday, June 28, yet the electrical boilers are still operating up to the PV production level during these hours. This is because the PV is operated behind own meter, thus providing cheap electricity to the electrical boilers.
In the last three days, there have been hours with high Day- ahead electricity prices; thus, the natural gas engine is operated.
Yearly benefit of an investment of 8.9 MEUR in Ringkøbing
Investment costs in Denmark of today Solar collector 0,3 MEUR/1000 m2 Heat pump 0,9 MEUR/MW-heat Wind turbine 1,3 MEUR/MW-el Photo voltaic 0,7 MEUR/MW-el Thermal Storage 0,3 MEUR/1000 m3 Cable 0,2 MEUR/km
In the previous section, we demonstrated some system effects of devoting the 8.9 MEUR investment sum to PV. It is, however, a multi-dimensional challenge to choose the right investment among the several possibilities, investments that typically live for at least 15 to 20 years. Table 1 shows the yearly benefits of extreme investments, where all 8.9 MEUR is used on solar collectors, PV, wind tur- bines, or heat pumps (with appropriate investments in addi- tional new thermal storage). The yearly benefit is calculated as the reduced NHPC sub- tracted from the annual annuity of the investment. For exam- ple, no new investment has a yearly NHPC of 8.02 MEUR. When investing exclusively in solar collectors and storage, this NHPC is reduced to 6.46 MEUR, giving a surplus of 1.55 MEUR. The
Optimising an investment of 8.9 MEUR For the analyses, we will optimize the benefit of a total invest- ment of 8.9 M EUR. This corresponds to what the present 30,000 m2 solar collector and 3,000 m3 additional thermal stor- age would cost today.
For example, Figure 3 shows the optimized operation in seven days in May, where the 8.9 MEUR is used exclusively on PV. In
14 HOTCOOL no.7 2023
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