As UK new-builds add solar to meet the Future Homes Standard, a whole estate can export at once and overwhelm its local substation. We built the front-of-meter system that lets the substation throttle each home's inverter in real time — by the minimum needed, with a zero-export failsafe if the link ever drops.
To meet the UK's Future Homes Standard — new homes producing 31% lower carbon emissions from 2021, "zero-carbon ready" by 2025 — solar is being built into new residential estates. Full Stack Energy was approached to design and develop a front-of-meter system to control and manage the solar PV assets for a new 500-house estate with up to 2MW peak generation. The substation sends export-control limitation signals in real time to individual household PV inverters, ensuring the limitation applied is the minimum required to maintain grid stability and substation capacity.
The UK’s Future Homes Standard sets out to “radically improve” the energy performance of new homes, making them zero-carbon ready by 2025. As an interim step, from 2021 all new homes are expected to produce 31% lower carbon emissions — so energy-saving technologies, including rooftop solar, are now built into new residential estates as standard.
From a grid perspective that creates an urgent problem: multiple dispersed sources of renewable generation that all behave the same way at the same time. As domestic solar grows, the grid operator’s need to control the export of energy from it becomes increasingly important — because 500 homes exporting on a sunny afternoon can overload the local substation.
The brief was specific: a new 500-house estate, up to 2MW of peak generation, where the substation must be able to send export-control limitation signals in real time to individual household inverters — and crucially, limit export by the minimum required to maintain stability and substation capacity, so households keep as much of their own solar value as possible.
We built an end-to-end system — home hardware, load-control firmware and algorithms, a substation controller and a cloud platform — communicating over a dedicated powerline network, with a failsafe for when communication drops.
The goal isn't to switch people's solar off — it's to curtail the least amount that keeps the substation safe. Minimum-necessary control is what makes it acceptable to 500 households.
Lead Engineer, Full Stack Energy
The solution lets the substation operator intelligently control the export of power from dispersed solar PV across the estate — avoiding the substation overload that uncontrolled export of a significant amount of PV power would otherwise cause. Because the controller applies only the minimum limitation required, households keep as much of their generation as the grid can safely take.
Built end-to-end over a dedicated powerline network, with a zero-export failsafe if the link drops, the system is robust enough for a live residential estate — and scalable to fold in EV charging and heat-pump control as those loads arrive on the same network.
The politically smart part of this design is “minimum necessary”. Nobody wants to be told their solar is being throttled, so the controller is built to curtail the least it can while keeping the substation safe — households barely notice, and the grid stays up. That restraint is the whole trick.
The zero-export failsafe is the unglamorous bit we’re proudest of. Comms to 500 homes will fail sometimes; when they do, the system has to fall back to a state that can’t hurt the grid. Designing for the bad day, not the demo, is what makes something like this safe to deploy.
Under the UK's Future Homes Standard, solar is built into new estates as standard, so hundreds of homes can export at the same time on a sunny afternoon. 500 homes pushing up to 2MW back through one local substation can overload it — distributed generation that all behaves the same way at once.
A substation controller measures import and export flows in real time and sends export-limit signals to individual G100-compliant home inverters, applying only the minimum curtailment needed for stability and substation capacity. Households keep as much of their own generation as the grid can safely take.
The system falls back to a safe zero-export state, so a comms failure can never harm the grid. It runs end-to-end over a dedicated powerline network and is scalable to add EV charging and heat-pump control on the same network.
Front-of-meter control can keep dispersed solar inside a substation's limits — curtailing only the minimum needed. Let's talk.