Figure 4 shows the energy saving effect of energy storage on different train types. However, these figures have to be treated with some care. They are a result from theoretical calculations by manufacturers and are quite optimistic. Even so, the figures indicate the huge saving potential offered by energy storage in DC systems. As can be seen in Figure 4, the energy saving potential comes from two effects: - recovery and reuse of brake energy ("vehicle only" in the figure)
- reduction of losses in the distribution network due to reduced peak currents (Losses are proportional to the square of the current!).
Figure 4: Energy savings by energy storage for different trains (% of total energy consumption) Source: IZT, data from: Hentschel, Müller 2000 |