Earth Notes: On the UK SSES 1st Phase ESA Regs (2026)

Some abbreviations:

16WW

16 Willingham Way

A2A

Air-to-Air heat-pump

A2W

Air-to-Water heat-pump

ASHP

Air-Source Heat Pump

BESS

Battery Energy Storage System

DNO

Distribution Network Operator

EHA

Electric Heating Applicance

ESA

Energy Smart Appliance

EVSCP

Electric Vehicle Smart Charge Point

GB

Great Britain

SSES

Smart Secure Electricity Systems

High-Level Points

1. A2A is currently out of scope for SSES, but as GB demand for cooling grows maybe this will prove to contribute to an evening duck-curve / ramping issue (as the sun goes down so PV generation drops away but homes are still hot), so maybe allow scope for larger A2A units to be brought in to scope easily. Also encourage those larger units to provide the functionality ASAP eg to save users money.
2. A2W ASHP is in scope (as an EHA) but is it still in scope if it can do cooling (as allowed under recent BUS grant changes) or when it is doing cooling if it does both? To avoid the duck-curve / ramping issue above from cooling demand, that mandated grid-friendly operation should also apply to the cooling aspects.
3. The proposed evening SSES peak time from 4pm to 10pm is very broad, and likely too long for many homes to coast through thermally if their EHA is throttled back for the full peak, which might encourage householders to turn off all such default limits, so I suggest defining a high-peak or 4pm to 7pm in line with eg common GB DNO practice, within which such grid-friendly aspects are heightened / concentrated. This observation is relevant to such EHAs (Electric Heating Appliances) as heat pumps, heat batteries, storage heaters and standalone direct electric hot water cylinders. Also to EVSCPs.
4. I suggest that all EHAs of a particular type, eg A2W, should be obliged to have a common element to their installer and end-user UI/UX for the aspects around energy saving and grid-friendly behaviour, so that installer set-up expertise and user familiarity is easily transferred across products, to give users agency in particular.
5. I suggest that for the benefit of homes with domestic batteries (BESS), larger heat pumps such as A2W ASHP should be configurable to operate far as possible within a constrained power limit that is within the power limit of the batteries, to minimise draw from the grid. But such limits might be ignored for critical events such as A2W defrosting, and if target temperatures (eg target DHW and radiator flow) temperatures are not being met within a reasonable time. This soft limit feature does not require any real-time control interaction between the heat pump and the battery.

Notes

I have tried applying possible SSES demand moderation to my own retrofit home A2W ASHP to help get a better feel for practicability, albeit for an EPC A structure:

• 16WW heat pump control current configuration.
• 16WW heat pump electricity demand load profile.

These adjustments include by-time-of-day power limits and WC (weather compensation) curve deltas.