Dynamic electricity pricing vs. bidirectional charging – the key factors driving low-voltage grid expansion
The electrification of the mobility and district heating sectors is expected to contribute significantly to their decarbonization. As a result, an ever-increasing amount of heat pumps, battery-operated electric vehicles and the associated charging infrastructure is expected in the upcoming years. This represents a significant shift in the load on low-voltage grids. Compared to other low-voltage consumers, electric vehicles offer great flexibility potential due to their storage capacity. Depending on the charging management system, this can be utilized in various ways, e.g. to use renewable electricity directly or to contribute to systemic stability by feeding it back into the grid.
Variable and dynamic electricity pricing, which incentivizes the immediate consumption of energy as a proportion of energy generation, is a key factor contributing to this. From 2025, energy suppliers will be obliged to offer their customers products of this kind, which will particularly benefit flexibilities that can adapt their consumption, such as charging an electric vehicle, to a favorable electricity price. In the optimized case, the electric vehicle is then operated bidirectionally in order to supply the previously cheaper charged electricity back into the grid as an energy sources in times of high electricity prices, thereby generating additional revenue (use case: arbitrage trading).
From the distribution grid perspective, dynamic electricity pricing is considered positive to a limited extent as relevant studies indicate that the market and systemic incentive, due to the simultaneities initiated by high price spreads, will result in a significant additional local load and additional grid expansion. As a consequence, arbitrage trading in particular is viewed critically, as, in contrast to unidirectional price-optimized vehicles, this also impacts the grid during the associated reverse power supply.
In a simulative case study with 1,206 low-voltage grids, both dynamic electricity pricing and bidirectional charging were analyzed in the context of the grid load in eight scenarios (see Figure 1) to obtain an indication of the resulting additional grid expansion.
The following research questions were addressed:
- What effects do different degrees of electric vehicle penetration, which follow dynamic electricity prices uni-/bidirectionally, have on the grid load?
- What grid expansion requirements are expected in this context?
- To which extent does the interaction of bidirectional charging and dynamic electricity pricing (arbitrage trading) increase the load on the grid compared to the optimization of unidirectional vehicles?
More Information
- unIT-e² – living lab for integrated e-mobility – FfE
- GridSim – Electric Grid and Energy System Model for Distribution Grids – FfE
- Household flexibility: the key to a sustainable energy transition – FfE
- One cable, two directions: Bidirectional charging of electric vehicles as game changer! – FfE
- Analyzing the Potential of grid-serving Flexibility – A novel approach to the synthesis of low-voltage grids – FfE
- Is charging electric vehicles with variable tariffs worthwhile? Attractiveness for electric vehicle drivers and business model potential for electricity providers and aggregators – FfE
