Renewable energy generation solutions are, by their very nature, either intermittent (wind) or they produce power only during a portion of the day (photovoltaic or PV). This often means that when you need it most, renewable energy is just not available. The only way to make the investment in renewable energy generation available when it is most needed, is to invest in an energy storage system that allows for the following:
- Load shifting – shifting energy from times when there is surplus energy to times when there is an energy deficit (i.e., during periods of peak consumption).
- Peak shaving – to reduce the peak demand by despatching energy from the battery rather than drawing energy from the grid.
- Energy arbitrage – to draw and store power from the grid when it is least expensive and despatch it from the battery when the grid power is most expensive. This is only applicable with Time of Use (ToU) tariffs.
- Load shedding – despatch energy from the battery when grid power is not available.
Energy Storage Systems also provide other benefits. For safety reasons, many PV systems are set up in a way that when the grid power is not available, power from the PV system is curtailed (disconnected). However, when a battery is integrated with the energy system, the PV array will not be curtailed and instead the energy that it generates will be feed directly into the facility with any surplus energy used to recharge the batteries. Further, batteries can improve the quality of the power by maintaining frequency and managing inrush currents, etc. This can protect sensitive electrical equipment.
Long Duration Batteries
There are several long duration storage technologies that are commercially viable. This includes:
- Iron Flow Batteries (IFB) – these new solutions are now competitively priced and will last as long as the PV system to which they may be “attached” with very little degradation over that period of time.
- Sodium Sulphur Batteries (NAS) – these solutions have been widely deployed globally and have a smaller foot-print than the IFB due to the higher energy density and so may be more easily deployed in urban environments.