11 Storage technologies at district-scale
Results are based on a district-scale (= decomposed) optimisation with stochasticity using a standard deviation of 1 for the time-shift and considering the transformer constraint equals to two times the maximum domestic electricity power.
In this chapter, the objective is to analyse the performance of the scenario if a battery storage system is introduced. We have focused solely on the Vessy district because of its characteristics, because we haven chosen to test a scenario where each individual within the district possesses an electric car that can function as a mobile battery.
An analysis of Table 11.2 reveals that the installed capacity remains similar between the two scenarios, with the exception of the battery component, which is expected. In Table 11.1, with PVC of 0 in the scenario with storage, we see that curtailment disappears. Consequently, self-consumption and self-sufficiency increase. The disparity in PVC between the two scenarios is further evident when comparing Figures 11.1 and 11.2. Figure 11.1, representing the case without storage, depicts curtailment, particularly during summer when energy consumption is lower. Conversely, in Figure 11.2, the presence of storage eliminates this effect.
| Storage technology | SC | SS | PVC | GUs | GUd | PVP | LCoE1 |
|---|---|---|---|---|---|---|---|
| Without | 0.499 | 0.566 | 0.100 | 1.87 | 2.17 | 1.135 | -0.116 |
| With EV | 0.689 | 0.779 | 0 | 2.02 | 2.18 | 1.131 | -0.104 |
| Storage technology | PV | Electrical Heater SH | Heat pump Air | Heat pump Geothermal | Water Tank SH | Electrical Heater DHW | Water Tank DHW | EV |
|---|---|---|---|---|---|---|---|---|
| Without | 309.65 | 93.54 | 59.99 | 3.24 | 8.04 | 4.59 | 2.35 | 0 |
| With EV | 311.65 | 87.47 | 64.02 | 0 | 7.84 | 4.47 | 2.35 | 1610 |
Figure 11.1: Energy profiles with hourly moving average of Vessy without storage technologies
Figure 11.2: Energy profiles with hourly moving average of Vessy with EV as storage technology
A comparison of the two Sankey diagrams on Figures 11.3 and 11.4 reveals several observations. Firstly, the inclusion of the battery does not impact space heating, domestic hot water and electrical appliances. However, the addition of storage through the electric vehicle leads to a reduction in electricity imports for several reasons. Firstly, because there is no longer any curtailment, but also because the presence of a battery allows for energy supply during periods without sunlight. Moreover, the ability to store energy reduces the need for electricity export.
Figure 11.3: Sankey diagram of Vessy without storage technologies
Figure 11.4: Sankey diagram of Vessy with EV as storage technology
As previously mentioned, the installed capacity, excluding the battery, remains nearly unchanged, which explains the constant CAPEX observed in Figure 11.5 across both scenarios. The decrease in electricity imports results in a reduction in OPEX. Consequently, TOTEX decreases thanks to the introduction of storage. This reduction is 11.5%.
Figure 11.5: TOTEX comparison between some storage technologies Vessy
Figure 11.6: GWP comparison between some storage technologies Vessy