CrowdFlex publishes latest results and insights from large-scale domestic flexibility trials

CrowdFlex, is a NESO led innovation project, funded by Ofgem’s Strategic Innovation Fund (SIF), which is investigating the potential of domestic flexibility, where consumers adapt their electricity usage, or make their electric vehicle available for automated control. The reliability of domestic flexibility is being explored to help support the balancing of electricity supply and demand on Great Britain’s national electricity network. 

Following on from the success of this project’s summer trials in 2024, CrowdFlex has delivered a new series of trials, this time over the more energy intensive winter months. 

From October 2024 to April 2025 participating households and consumers were incentivised to adjust their electricity usage in utilisation trials or to make assets like electrical vehicles (EVs) available for automated control (where flexibility service providers managed how they charged or discharged on behalf of the consumer) in availability trials.

As part of the utilisation trials, OVO Energy recruited approximately 55,000 customers to take part, across a series of 76 events where consumers turned up their electricity use, turned down their electricity use or a mixture of the two, over a set time period. Customers were encouraged to shift their electricity usage into or out of event time windows, depending on the required need, typically using or delaying their use of energy intensive devices such as washing machines and dishwashers.

For the availability trials, over 8,000 Ohme EV and 5,900 OVO customers were recruited to take part across 375 events. The trials explored the extent to which customers changed their EV plug-in behaviour and their willingness to allow their EV charger to be remotely managed, to optimally balance the network and to charge their EV. 

CrowdFlex is using these randomised control trials to test recruitment messaging, incentive levels, fatigue and other event parameters, and how they could affect participation. Trial data is being used to build domestic flexibility forecasting models and to help establish whether domestic flexibility is a reliable resource to support the balancing and operation of electricity networks.

Following the winter trials, nearly 31,000 of the participants took part in customer surveys and interviews, sharing valuable feedback on their experience. Six customer surveys are being conducted over the duration of CrowdFlex, with some participants taking part in a number of the surveys to give feedback on their experiences over an 18-month period.

The results and analysis of the trials and surveys have revealed some interesting insights (please see the full results in the reports linked below):

• Financial incentives are proven to be effective in stimulating flexibility, with turn-up events (where consumers increase their electricity usage) eliciting over twice the response of turn-down events (where consumers reduce their electricity use). Lower incentives were more cost-efficient per unit of flexibility, though higher incentives delivered slightly greater absolute response but with diminishing returns in terms of overall value.
• During the winter season the CrowdFlex trials dispatched a total of more than 400 events which provided data that demonstrated automation tools helped users shift 30% more electricity and earn more rewards, suggesting automation is key to scaling domestic flexibility.
• Beyond the purely financial incentives, most customers reported positive experiences, with two-thirds expressing they felt they were making a difference, and across the board the majority enjoyed participating.
• One-third of participants cited habit as a reason for continued participation, even when financial interest declined. 12% of repeat participants reported waning interest, but those who developed habits were 8% less likely to disengage.
• The inclusive nature of the trials ensured that vulnerable customers and renters were included, although due to typical lower energy use, they contributed smaller or less consistent volumes of flexibility.

The final phase of trials, over summer 2025, has recently started, with the number of customers recruited increasing to 30,000 for availability trials and 80,000 for utilisation trials. 

The summer 2025 trials are conducting even deeper research, testing different messaging, event timings and with a focus on low income and vulnerable customers, different archetypes, and gathering more data to further train and refine the forecasting models.

Sanna Atherton, CrowdFlex Project Lead, NESO: “This pioneering innovation project is playing a major role in achieving the smart and flexible energy grid that is essential to reach clean power. It’s exciting to be part of this industry collaboration that is gathering this valuable data to build forecasting models that will give control room operators the real-time visibility they need. CrowdFlex is also enabling consumers to contribute to achieving a greener energy system while also helping reduce their energy costs.”

Marzia Zafar, Deputy Director of Governance for Data & Digitalisation, Ofgem: “CrowdFlex is more than a trial, it’s a blueprint for the future of domestic flexibility. By developing real life data driven models that demonstrate how households can reliably support the grid, we’re laying the foundation for a smarter, more decentralised energy system. This work is critical to delivering the ambitions of Clean Power by 2030 (CP2030) and ensuring that consumers are at the heart of the energy transition. Projects like CrowdFlex are essential to realising the ambitions of the CP2030 framework and ensuring our energy future is affordable, sustainable and customer driven.”

Elizabeth Allkins, Future Energy Director, OVO: “The winter trial reports land at a pivotal moment, providing strong, timely evidence to underpin the government’s recent Clean Flexibility Roadmap. By engaging tens of thousands of OVO customers and seeing consistent demand shifts, we’re helping system operators build the confidence needed to embed consumer-led flexibility into core system planning. Learnings from CrowdFlex help create the market design that enable market-leading propositions like OVO’s Power Move, Charge Anytime and Battery Boost, to reach and benefit even more consumers. The fact that habits formed, and customer enthusiasm persisted into the winter season shows that with the right market design and incentive structures, consumers will not only understand the role they can play in balancing the grid but begin to build lasting behaviours that make more flexible energy use the norm.”

David Watson, CEO, Ohme: “Grid flexibility services are estimated to save consumers £10bn per year in energy costs by 2050 and this research shows that customer engagement is essential in generating more flexibility and helping the system meet peak demand, reducing costs and carbon emissions for everyone. Through Ohme's participation in this trial we have seen engagement extend beyond those customers that were already engaged. If we are to achieve the increase in domestic flexibility needed to deliver the Government’s CP2030 ambitions, then attracting this wider core of customers will be vital for the future. Energy suppliers cannot engage all customers so there is clearly a role for companies like Ohme to extend the benefits of flexibility to all.”

Chloe McLaren Webb, Fair Transition Research lead, CSE: “One of the factors setting CrowdFlex apart is the scale and depth of the research with participating households. We’ve heard from over 20,000 households and are running longitudinal studies to understand how household experiences change over time. This gives incredibly rich insights into the different ways households take part in flexibility services. Importantly, we’ve been able to bring people’s experiences and feedback right into the heart of the project, influencing trial design and ensuring that the SIF vision of empowering people is achieved. As a result, the consumer research delivered through CrowdFlex is providing a strong evidence base that can be used to support effective demand shifting for different types of households, including those in more vulnerable circumstances.”

CrowdFlex was awarded funding through Ofgem’s Strategic Innovation Fund (SIF), which is managed in partnership with Innovate UK. The project is being delivered for NESO by a consortium of partners: OVO, Ohme, Centre for Net Zero, ERM, AWS, National Grid Electricity Distribution and Scottish and Southern Electricity Networks. NESO is also being supported by Smart Grid Consultancy Ltd, CGI, Smith Institute and Centre for Sustainable Energy.

CrowdFlex