When utility costs for consuming grid electricity began to rise early last year from circa 14p/kWh to 45p/kWh (and even higher), the economics of using all the energy generated from a PV array through utilising energy storage systems began to make sense.   

Previously, exporting some of the energy to the grid for payments under the Smart Export Guarantee was not ideal as it did not significantly affect the payback of a system. In today’s economic climate, if a building exports 14,000kWh of electricity, this would equate to approximately £6,300? of lost revenue per year. 

Sizing energy storage systems has always been a question here at KJ Tait; however, we now use software that can give us an accurate idea of whether an energy storage system would make economic sense and what size it would need to be in terms of capacity and storage. 

For existing buildings, our analysis requires a year's half hourly electrical data for a building’s main meter and PV installation area.  Our software is then capable of informing us just how much energy would be exported to the grid, particularly on those peak summer days when the energy demand in the building is lower than the electricity generated.  We then size the battery to mitigate this export and analyse the potential payback and return on investment.  For new buildings, we can complete a CIBSE TM54 assessment using IES Apache HVAC to produce an expected half hourly load for a building.  This can give us confidence to maximise the PV array, often a requirement of Local Planning Authorities, and size any potential storage properly to deliver the best solution for our Clients.