One opportunity to think creatively occurred at Orchard Fields School, Banbury, where the grid application identified a thermal constraint - meaning that whilst we wanted to install 100 kWp of solar PV - installing over 50 kWp had the potential to overheat the electrical cables between the school building and the local substation.
Our installer Joju Solar engaged with Macklin Controls, a company who design export limitation equipment - and this specification was reviewed and approved by local grid operator Western Power.
This is our first solar PV installation with bespoke export limitation technology installed – a system that automatically switches off parts of the system (by shutting down inverters one at a time) to ensure no more than 50 kWp is being exported into the cables at anyone time.
We had to model how much energy would be lost if we took this action, and whether the project was viable at this larger scale at still despite losing some generation as the export limitation system was activated - and limitation losses are expected to be below 5% and therefore the project works well at this scale.
As a pioneering and bespoke solution, the implementation has been more complex and required more testing and tweaking to implement. The school has been very patient and flexible whilst our specialists have implemented this solution, and we are very grateful for this.
We have now just agreed our first export limitation solution with SSE in South Oxfordshire - using a new method devised by German inverter company SMA.