If more PV electricity is being produced than consumed, excess electricity can be fed into the public grid and the utility provider offers remuneration.However, funded PV installations are not allowed to feed their full output into the grid; instead, feed-in must be curtailed to 40%, 60% or 70% of their maximum potential output. Excess solar energy goes unused during the curtailment phase.Forecast-based charging helps avoid this uneconomical consequence as much as possible.
Every day, the TESVOLT Energy Manager controls the optimum charging and consumption strategy. It bases this on weather forecast data, battery capacity and the battery charging level, combined with statistics about typical energy consumption patterns in the system – meaning that it recognises how much power is typically consumed at particular times of day.
Tomorrow’s weather forecast is sunshine for the first half of the day and cloud from the afternoon.The TESVOLT Energy Manager has learnt that peak loads always happen in the afternoons and late evening. It will therefore start the day with an empty battery storage system so that it can absorb as much photovoltaic energy as possible.
While the PV installation provides its maximum output in the first half of the day, the TESVOLT Energy Manager will distribute the generated electricity between consumers and batteries so that the storage system is fully charged before the start of the second half of the day. If the amount of energy collected first drops and then dries up completely in the evening, the battery storage system kicks in and, at times of peak load, supplies the consumers with the solar power generated beforehand.
As well as avoiding curtailment losses, the TESVOLT Energy Manager can support efficiency-based charging, which ensures that the storage system is charged at the optimum operating point with maximised efficiency.
Another option is grid-assisted charging, which enables additional grid backup measures to be taken.