A economic assessment of the residential PV self consumption support under cost-reflective grid tariffs

摘要

By generating their own electricity, households are less dependant from the grid. PV self-consumption received a lot of attention due to its potential of decreasing the dependency on fossil fuels. However, because there is a mismatch between PV generation and consumption, the economic benefits from self-consumption rely on the economic compensation of the excess electricity fed into the grid (Bertsch et al., 2017; Dietrich and Weber, 2018). The economic benefits may drop by the implementation of cost-reflective grid tariffs such as Time-of-Use tariffs or capacity tariffs. Indeed, a capacity-based tariff decreases the variable part of the retail rate as well as the economic benefit from self-consumption. With a dynamic tariff, the prices are higher during the night when PV generation does not occur. In France, Time-of-Use network tariffs will be extended in a few years for most electric customers. Thereby, the development of prosumers (producer and consumer) would probably decrease without an increase in self-consumption (Kaschub et al., 2016). To do so, the storage of electricity could be necessary to store PV generation in excess, to consume it at another period when needed. Battery is a promising technology for reaching this goal. In fact, batteries can also provide grid benefits by decreasing the peak load during high demand and the peak generation during sunny days. In this paper, we investigate how public supports can trigger grid benefit by the development of PV self-consumption. First, we perform an economic assessment of the PV self-consumption with the current Frenc policy support. We show that it is profitable without any subsidies but only for a self-consumption ratio from 88%. Then we propose an alternative policy support which guaranteed an upfront purchase subsidy for battery investment and the excess generation is sold at the market price. Based on this alternative policy, we simulate economic benefits from various PV panels and battery capacities with a Time-of-Use network tariff. Finally, we compare the current support with the alternative one. The profitability of a PV-battery investment is not profitable even with the implementation of an upfront purchase subsidy which represents 77% of the battery costs. The pricing structure has a significant impact. The profitability increases with a peak / off-peak rate but decreases if there is a seasonal differentiation.