Energy Systems Catapult is collaborating with Scottish and Southern Electricity Networks (SSEN) on phase two of their Demand Diversification Service (DDS) project for Load Managed Areas (LMAs).

This innovative trial aims to address the challenges posed by the 2025 switch-off of the Radio Teleswitch Service (RTS), which currently supports demand diversity in LMAs. By exploring market-based flexibility services, this project seeks to maintain or improve demand diversity while delivering consumer and network benefits.

The challenge

Northern Scotland has a significant number of LMAs established over 40 years ago to manage demand from storage heating using the RTS. The RTS was designed for a 1980s world and is due to be retired in 2025. There is a need to find a modern alternative.

Additionally, with the increasing adoption of low carbon technologies (LCTs) such as electric vehicles (EVs) and heat pumps, managing overnight demand and maintaining network diversity have become critical challenges. SSEN seeks innovative solutions to mitigate the impact of the RTS switch-off and potentially phase out LMAs where these are no longer required.

The solution

This project tests two new flexibility approaches: allocated capacity and dynamic congestion response. Using Energy Systems Catapult’s Living Lab and the WESA (Whole Energy Systems Accelerator) platform (in partnership with PNDC), the trial will:

• Signal up to 200 homes to flex the operation of EV chargers, heat pumps, and storage heaters.
• Simulate virtual networks to analyse how flexible assets can balance demand across different network conditions.
• Deliver insights into flexibility’s ability to replace RTS services while ensuring network and consumer outcomes are achieved.

The Living Lab is partnering with Connected Response to deliver storage heating control, and with Homely to deliver control of the heat pumps.

What makes this project unique?

WESA and the Living Lab enable groundbreaking new ways to test future demand management scenarios, combining real-world consumers and virtual network simulations. Unlike traditional trials, this approach allows flexibility solutions to be trialled with rapid scenario adjustments, reflecting high levels of LCT adoption that do not yet exist. Real-time feedback loops between network simulations and flexible assets ensure practical insights into network asset performance and consumer satisfaction.

Different signals will be sent to controllable appliances in homes in the Living Lab, starting with fixed signals to spread switch on times for EV chargers during cheaper, network friendly overnight periods.  The trial will progress to fully dynamic signals to EVs, storage heaters and heat pumps.

This is the first time that Distribution System Operators such as SSEN have been able to use WESA to map real world loads to simulate virtual networks in real time to investigate the potential for flexibility to limit asset loads.

Impact

The DDS project has the potential to redefine how distribution networks manage demand diversity. Outcomes include:

• Demonstrating whether market-based flexibility can mitigate RTS challenges and support LMA retirement.
• Providing scalable business models for flexibility service providers.
• Supporting a seamless transition to LCTs for consumers while maintaining energy affordability and reliability.

Next steps

The results of this trial will inform SSEN’s approach to integrating new flexibility services into their Business as Usual (BaU) operations. Lessons learned will guide future flexibility initiatives, ensuring robust, consumer-friendly solutions for demand management across UK networks.