Swiss researchers have investigated whether storage could be cheaper than curtailment in medium-voltage distribution networks with significant amounts of solar power capacity. They looked at storage costs, operating costs, grid constraints, electricity costs, solar generation models and loads.
A linearized power flow model was used instead of traditional non-linear alternating current optimal power flow models.
“We use a linearized power flow model because it can be applied to distribution networks with both radial and network structures, unlike the second-order cone relaxations typically valid for radial systems,” they explained.
They looked at storage costs, operating costs, grid constraints, electricity costs, solar generation models and loads. They also hypothesized that energy storage provides active and reactive power compensation if solar power produces excess production.
They found that the profitability of storage systems and their sizing are strictly dependent on electricity prices, which can be affected by higher or lower levels of solar electricity production. The researchers concluded that restriction is cheaper than installing batteries.
“Sensitivity analysis showed that a reduction in the cost of energy storage technologies could make the installation of energy storage competitive compared to limiting solar production,” they said.
They presented their findings “Optimum dimensioning and placement of energy storage systems considering the limited production of solar electricity in electricity distribution networks”, published recently Applied energy. The research group includes researchers from e.g École polytechnique fédérale de Lausanne (EPFL) and the Swiss Institute for Sustainable Energy.
“Investigating the sizing and placement of energy storage systems together with limiting solar PV production to meet grid constraints is the main contribution of this paper,” they concluded.