As Great Britain transitions to a low-carbon electricity system, demand-side flexibility is becoming increasingly important for managing the grid. The Demand Flexibility Service (DFS), introduced by National Grid ESO in 2022, rewards households for reducing electricity use at specified times. This report focuses on the experiences of smart prepayment meter customers participating in the energy supplier Utilita's ‘Power Payback’ DFS offering.

Prepayment customers, who make up around 4 million British households, are more likely to be on low incomes, renting, elderly, or disabled compared to credit customers. Understanding their experiences with flexibility services is crucial for ensuring an inclusive energy transition.

We conducted nine in-depth, online interviews with Utilita customers who had varying levels of engagement with Power Payback. This was complemented by a sentiment analysis of forum posts on the topic of the DFS more generally.

The main findings were as follows:

• Financial savings were the main reason people decided to sign up, and they were generally happy even with low levels of savings (from less than a pound to nearly ten pounds overall) – there was a genuine sense that ‘every little helps’.
• Participants also valued the learning opportunities (for themselves and their families), environmental benefits, and the opportunity to disconnect from routine.
• People employed a range of actions to respond to DFS events (when they were asked to reduce consumption), with most turning off appliances, some shifting cooking times, and one turning off power for their whole home.
• The presence of children and other caring responsibilities significantly influenced the ability to respond flexibly to events, mainly out of concern for disrupting schedules and routines around school and bedtimes.
• However, due to their generally higher electricity use, larger households were able to make larger savings if they were able to shift.
• Participants generally showed low levels of awareness about the underlying reasons for the DFS.
• Views on flexibility products expected to become more common in future (like time of use tariffs) were mixed, with concerns about switching to unfamiliar products, and disruption to family routines.
• While some groups (eg, single occupants and older people) were seen as potentially better able to benefit from flexibility, this wasn't generally viewed as unfair.

Based on the findings, we present a number of provisional personas (or fictionalised consumer representations) to inform our work in this area. These draw on different aspects of people’s experiences, including educating children, exploring an interest in energy, and taking opportunities to disconnect and vary routines. We also map out customer journeys for each of these personas, with initial suggestions for how they could be enhanced.

We suggest three main areas that should be prioritised for future focus:

1. Promoting awareness: Given the low levels of flexibility that many prepayment customers can currently provide, at this stage in the low-carbon transition a greater emphasis should be placed on ways of effectively building awareness and understanding of the need for flexibility. We believe this will be important in expanding and accelerating participation in future flexibility services.
2. Recognising reliability: Where households do show the potential to provide larger responses, we need to develop mechanisms to help them increase the reliability with which they may be able to respond. Reliability increases the overall value of flexibility for both the system and, if it is appropriately recognised, households.
3. Building flexibility capital: We need to explore ways to increase the capacity to provide flexibility for a broader range of households, including through innovative business models and potential regulatory changes. Getting more flexibility, from a diverse range of sources, sooner, is likely to be key to enabling a quicker and more economical low-carbon transition.

Demand-side flexibility: why, how, and who?

In Great Britain, we are getting more of our electricity from renewable sources like solar and wind power. At the same time, we are increasingly using electricity to power our cars and heating systems. This is a necessary part of getting rid of carbon emissions from energy, but it poses challenges for energy system management. Unlike fossil fuel power stations, renewable generation can’t be turned up at will to meet high levels of electricity demand. As such, it is expected that demand-side flexibility will play a more important role in balancing the grid.

Demand-side flexibility means changing patterns (eg, the amount, time, or place) of electricity use. An example of this would be a household choosing to run a washing machine in the morning instead of at evening peak time, which occurs roughly 16:00-19:00 on weekdays. If everyone did this, the evening peak would be smaller, meaning that we could avoid the need to turn up costly, polluting fossil fuel power stations to meet that high evening demand.

Right now, the value of flexibility (and therefore the prevalence of flexibility products and services) is limited. In future, as renewable generation and electrification increases, rewards for being flexible (and potentially penalties for not flexing) could be much more significant. And in some countries, flexible tariffs are becoming either the default option (such as in Ontario, Canada), or even obligatory (such as in the regulated Spanish market).

There is growing evidence that households differ in their ability to provide and benefit from demand-side flexibility. For example, a household with a domestic battery can reduce its consumption to practically zero for a short period of time, while continuing to do the same activities as they would normally. Reducing demand at specific peak times is something that households are increasingly being offered financial incentives to do, particularly through National Grid ESO’s ‘Demand Flexibility Service’ (DFS) – see below. However, a household with children (meaning they are on a tight bedtime schedule) and which cooks with an electric stove will either have to make changes to the way they eat during a DFS event, or miss out on savings.

The costs of operating the energy system are passed on to all consumers through energy bills. So getting more flexibility is good for everyone, because it will help keep these costs as low as possible in the future. But if some customers stand to see significant direct savings from being flexible, while others either miss out or face higher costs – or have to compromise on comfort or convenience – there is a risk that the net-zero carbon transition could increase inequality.

At Nesta, one of our primary missions is to reduce carbon emissions from homes, and flexibility is expected to play a role in achieving this. Doing so in a way that benefits as broad a range of households as possible is not just fairer, but mitigates the risk of breaking the social contract underpinning support for net-zero transition. As such, we want to understand how more households – across a range of incomes, tenures, household make-ups, and so on – can be better enabled to provide and benefit from flexibility. In this study, we wanted to learn more about a specific group of households, and how they are already providing flexibility, by focusing on smart prepayment meter customers’ participation in the DFS.

The DFS and smart prepayment customers

While flexibility has long been a part of Great Britain’s electricity system management, the introduction of smart meters is opening the door to new opportunities to benefit from it. In 2022, National Grid ESO introduced the DFS. Offered by companies to their customers, it rewards households for reducing their electricity use below a calculated baseline at specified times (known as ‘events’) over the winter. Events are usually scheduled when periods of high expected demand coincide with low forecast generation.

The rationale is simple – it is cheaper to pay households to turn down demand at event times than it would be to generate the power that would otherwise be needed. This way system costs are reduced for everyone (lowering bills), while participating households see direct compensation for reducing their electricity use for a short period.

In this project, we partnered with the energy supplier Utilita, who specialise in serving prepayment meter customers. Prepayment customers – of which there are around 4 million in Great Britain – are significantly more likely than credit customers to be on low incomes, renting (private/social), without or with lower qualifications, aged 65+, disabled, or on the Priority Service Register (PSR) (CMA 2016, p455).

We believe prepayment customers may have different needs to credit customers in terms of benefiting from flexibility. They need to budget differently month-to-month, and often feel the impact of their increased or decreased energy usage more quickly and directly in their disposable income. Having a prepayment meter can be used as a way to avoid or manage energy debts – which for some customers can be linked to wider issues of energy affordability. Prepayment customers using smart meters can benefit from better real-time information about the energy they are using. This also means their energy supplier may be better able to pass on rewards from the DFS, as they can prove that they have shifted or reduced their demand to help the grid.

There has been increasing interest in the ability of different households to benefit from flexibility services. Assets that enable more flexibility, such as modern electric heating systems, electric vehicles, or home batteries, may be less likely to be accessible to prepayment customers given their higher probability of renting or being on a lower income than credit customers. But social factors, such as employment, the presence of children in a household, or living in a rural area can also play a role. Prior evaluation work by the Centre for Sustainable Energy (CSE) on the DFS has looked at prepayment customers’ experiences alongside that of credit customers, and found they actually report a slightly better experience on average, reporting slightly higher rewards and satisfaction.

Utilita’s DFS offering is called Power Payback, and it has operated for the last two winters (2022-2023, and 2023-2024). To read more about what it involves, click the dropdown.

We interviewed nine customers, recruited by Utilita, about their experience of Power Payback and their perceptions of a more flexible future for the electricity system. We wanted to delve in detail both into their DFS experience, and their perceptions of a more flexible future for energy. To provide context, we also conducted an analysis of posts on the Money Saving Expert (MSE) forum concerning DFS, identifying key themes and sentiments. For more detail, see the Methodology section at the end of this report.

We drew on this work to develop user personas, or fictionalised descriptions representing groups of users with similar characteristics. We can use these directly in future studies, informing our work to design and scale services that will help a broader range of households to provide flexibility and contribute to building an affordable low-carbon energy system. The following sections introduce our interview approach and some of our participants, our learnings on customers’ experiences of Power Payback, and perceptions of future flexibility. We then develop a range of representative personas and illustrate their different journeys attempting to provide flexibility, and how they might be improved. Finally, we suggest avenues that future work in this space could explore.

In this section, we present an overview of the people who participated in the study. We aimed to select participants with a range of levels of engagement in Power Payback, from those who opted in and responded to many events, to others who chose not to participate at all. The final sample included more highly-engaged participants, despite substantial efforts to recruit a more even spread. We should perhaps not be surprised by this outcome, and it may be informative in itself of a level of commitment to the service.

To learn more about the participants, we first asked introductory questions about their household setup, what their typical days and weeks looked like, their use of their smart meter and any low-carbon technologies (like solar power, heat pumps, and electric vehicles) if they had them.

Turning to flexibility, we were interested in their experiences of participation in Power Payback:

• What factors affected their decision to (a) opt in to the service, (b) opt in to events, and (c) participate in events? How did this change over time?
• What factors affected their perceived ability to benefit?
• What is their overall attitude towards the offering – what did they like and dislike?
• What features of future offerings would make it more likely that they would participate, respond, and have the best experience?
• How do experiences/perceptions differ with household characteristics?

We then asked about their perceptions of their potential ability to participate in, and benefit from, other flexibility offerings – what might affect this, and how would they evaluate possible trade-offs between financial savings and service quality? What is their attitude towards, and awareness of, the need for flexibility in general – and who might and might not benefit?

We also conducted an analysis of MSE forum discussions about the DFS to provide additional insight on these questions. Full details of the method, including details of recruitment, interview conduct and analysis, and forum analysis are available later in this report.

Table 1 provides an initial overview of the participants, all of whom were resident in England and Wales.

The customers we spoke to generally held positive perceptions of Utilita, and most had explicitly chosen to switch to them. There was also generally high satisfaction with their smart prepayment meters, especially compared to previous non-smart versions. Perceived benefits included the ability to top up easily via the app, schedule regular top ups, and monitor electricity and credit use.

Turning to headline participation in Power Payback, across the group, savings per event ranged from £0.19 to £0.78, while total rewards ranged from £0.47 to £8.59. Maximum participation was 11 events, with a mean opt-in rate of 84%, although some people only came onto the service later, meaning that while they responded to all calls, they participated in fewer events.

Those are the overall numbers. Click the dropdowns to see short descriptions of a few of our participants and how Power Payback worked for them.

The following section provides a synthesis of experiences of Power Payback across the participants.

This section focuses on our participants’ motivations for signing up to Power Payback, and deciding whether or not to opt in to events. Participants were initially attracted to the service by the potential to reduce their electricity bills, but further motivations were also evident, such as the interest and potential fun of taking part, environmental benefits, and reducing strain on the grid. People tended to just opt in to events when notified by SMS. Participants are referred to by their pseudonyms.

Financial savings were motivating, but often in combination with other factors

Participants remembered first hearing about Power Payback by email. You can view the email text in the dropdown.

The most common motivating factor for participants to sign up to Power Payback was the potential to save on their electricity bills. Interviewees were comfortable with the prospect of these savings being relatively small, particularly as they were viewed in the contexts of the current cost-of-living crisis, and potentially having a large family. There was a common theme of suggesting that ‘every little helps’, as described by Chris, a father of four:

Cost saving was usually mentioned alongside other motivations, including fun and interest. For example, Damon described it as, “something to do, a bit of fun. I was just intrigued by it.” Participants mentioned that the clarity of communication when they were first invited to join Power Payback was very appealing. This included an explanation as to the purpose of Power Payback as well as instructions on the structure of events. Supporting grid management or reducing fossil fuel emissions associated with peaks were very occasionally mentioned as motivating factors to opt in, such as when Gwen said, “[it] takes a strain off the grid for a little while”.

These motivations are broadly in common with those identified in previous research (see CSE, Mihalche and Hampton, 2023) on the DFS with a wider set of participants. Some motivations that featured quite prominently in work by CSE were never mentioned, such as helping reduce bills for all households and reducing reliance on gas imports.

Our interviewee Lisa, a mother of four, who did not participate in Power Payback remembered receiving the email about it, but didn’t have an opportunity to give it much thought, commenting, “I think it's just with me being busy with the children and stuff […] I don't have time to be engaging in all of that kind of email stuff”.

Generally, participants were not very clear on the central reason for the existence of the DFS. Power Payback was mainly viewed as aiming to improve customers’ knowledge about energy use and saving, and engagement with Utilita. Helping manage peaks or busy periods on the grid was rarely mentioned, despite being included in the invitation email.

People tended to opt in to events as a default

Participants were notified of specific DFS events by SMS. The opt-in SMS reads as follows: "Utilita Power Payback! Reduce your electricity usage [DAY] between [TIME_1] and [TIME_2] and we’ll pay you up to £[AMOUNT] per kWh. Normally put the washing on at this time? Try saving this job for later! Reply ‘Y’ to opt-in or ‘N’ to opt-out!" People remembered receiving the messages and most found this to be an effective method of notification. One participant noted that notification, reminder, and energy saving summary messages came from different numbers, and that consolidating these would make it easier to follow. Our forum analysis identified approval for WhatsApp-based notification, but some dissatisfaction with delayed or missed notifications in general.

Having decided to participate in Power Payback, participants tended to opt in to events almost by default; as Gwen commented, “I've just always said yes”. Again, the prospect of savings on their electricity bill by doing so was attractive. Further reasons included comparing and contrasting the savings between each event, despite the total savings for each event being relatively minimal. In multiple-person households, the decision to opt in was usually taken by one person. There was little evidence of intra-household consultation about whether to opt in, with the person who signed up taking responsibility for deciding to opt in. As Erica observed, “the financial side of things is kind of left to me because my partner's at work, [...] he just goes with what I tell him”.

There was some evidence of people considering their ability to respond before opting in. Damon, a single occupant, mentioned that he chose not to opt in to events when he was not going to be at home. This was because his approach to responding involved switching all their power off (see next section), which being out meant he would be unable to do.

Participants consistently reported that it was easy to remember when events were taking place due to email and (especially) SMS reminders sent by Utilita in advance. The reminders read: “Thank you for opting-in! Don’t forget your Power Payback event – reduce your electricity usage and earn £[AMOUNT] per kWh. The event will run between [TIME_1] and [TIME_2] today.”

Erica explained how, “I've always got my phone on me, it's in my hand or in my pocket, then that's a good reminder because the text messages are coming through [...] I'd usually just set an alarm on the phone, OK, sort of about half an hour before”. If it were the case that Power Payback customers more generally find SMS notifications to be a sufficient reminder, this suggests that inconsistency in response is less about remembering events and more about ability/willingness to respond to specific events. The way in which people responded to events is the topic of the next section.

This section focuses on what participants did to respond to Power Payback events, and what they thought about taking part in the service in general.

Responding to events – a range of actions

Interviewees undertook a wide range of types and extent of action to try and reduce their consumption. Actions taken were strongly influenced by household make-up, including the presence of children. Households with children were often on quite inflexible schedules based around school runs and bedtime. Lone occupants, on the other hand, were not constrained by the schedules and preferences of co-occupants. As Jane, who lives alone commented, “I know for some people maybe [events] might be across tea time, but I tend to eat a bit later”.

The most common actions across all household types were turning off TVs, computers and making sure that plug sockets were turned off. Often this included watching programmes or playing games on phones or tablets instead. Some participants also described how they moved the time of their usual evening activities, such as cooking and washing, in an attempt to shift their consumption, although shifting cooking was harder when younger children were present. It was common in our sample for someone in the household (usually the interviewee) to often be at home during the day, meaning doing activities like laundry at non-peak times was possible.

Despite only being able to reduce their electricity use in a small proportion of events, Erica’s household was among the highest savers overall (at £7.48). This was because it typically has higher electricity consumption, meaning that savings (when they did come) could be larger.

Some participants described how they had adopted new methods of control to try and make turning off their devices easier. This included the use of timers for thermostats as well as remote controls that enabled the turning off of lights without having to go to each room individually. For example, Kaye found that purchasing a voice-activated timer for the heating of their lizard tanks allowed them to better regulate their energy use, as “the heat is off a couple of times a day for an hour or so, and the tanks still hold the heat”.

The most extreme action that a participant took was turning their fuse box off so that they could completely remove all consumption from their property. To mitigate this loss of power, Damon would download films and TV programmes to watch on his laptop during events.

Because he lived alone, he could take this action without the risk of affecting other occupants. However, it also meant that his electricity use was generally low, meaning that his overall savings per event were the lowest of all the participants (at an average of £0.19 per event).

No-one mentioned using low-carbon technologies such as solar panels, heat pumps, domestic batteries, and electric vehicles differently to respond to Power Payback, even where (rarely) some of these were present. However, one participant with solar panels had previously changed to run their electric water heater over the middle of the day, so as to benefit from lower-cost power at this time.

In our forum analysis, discussion of responses using low-carbon technologies was infrequent but still more common. For example, people discussed how they hoped to use home batteries to export electricity and earn greater rewards.

Power Payback was popular – despite often small savings

Amongst our participants, there was generally a positive attitude towards Power Payback – although it is possible that less satisfied customers would have been less inclined to participate in this research. Interviewees mentioned that they found the events “fun” and “easy” to take part in. They appreciated the opportunity to save on their electricity bill whilst taking part in an activity that they considered as benefiting the environment. Relatively low rewards from each event were noted and a participant mentioned that it would have been nice to have saved a little more. Despite this remark, the magnitude of savings did not appear to cause any dissatisfaction or reluctance to participate in future events – again, the prevailing view was reflected by Jane, who observed that, “I know it's not a huge amount, but any little amount still helps really, doesn't it?”

Our MSE forum analysis suggests that dissatisfaction with the level of the incentive was common amongst forum posters. Almost half the times it was mentioned, it was in a negative context, compared with just over 10% being positive.

Households with children tended to appreciate the opportunity Power Payback provided to gamify energy. This took the form of participants getting their children to actively go around the home to try and find appliances or plug sockets that could be turned off. Sometimes parents even used the incentive payment to encourage their children, as in this example from Kaye:

There were also some limited reports of conflict and disagreement with children. As Gwen commented, “My son wasn’t impressed when I told him he couldn't have his computer and his Xbox on, but he managed”. The fact that events tended to happen at a similar time of day (early evening) was a frustration for some participants, especially when children were present. There was a sense that this is when the most important things are happening, not just for them but for many households. For example, Erica explained that “the most recent ones I found was all kind of at the same time period, which is really peak time. I think not just for us as a family, but for a lot of families”. Participants didn’t generally draw an explicit causal link between this kind of observation and the underlying reason for the timing of Power Payback events (managing peaks).

For households without children present, beyond financial and energy saving benefits, participants appreciated the opportunity to disconnect and do something different. As Jane observed, “it was actually quite nice in a way to turn everything off for a bit and just sit and chill out”.

There were mixed views on the quality of feedback received after events. Following an event, Utilita would send messages to customers with different wording depending on whether they saved energy or not. If they saved, the SMS read as follows: “Congrats! You’ve earned £[AMOUNT] by Power Payback! We’ve credited your electricity meter. Check out Utilita Community to see how we calculate your payment [URL].” If they didn’t save, the message read: “Thanks for taking part in Power Payback – unfortunately you didn’t manage to reduce your electricity usage enough to earn energy credit. Head to [URL] for some handy tips to reduce your energy for next time.” A confirmation SMS was also sent when credit was transferred to the meter. Some participants found the savings confirmation messages clear, while others highlighted some possible sources of confusion, relating to both information source and timing. For example, delays between the event and receiving feedback meant that participants weren’t always sure which event the feedback related to.

Our MSE forum analysis revealed that, behind only the size of the reward, most negative comments were directed towards apps/notifications, and smart meter data. The latter appears to reflect issues around customers not being able to participate due to smart meter data access problems – an issue that was not reported by any of our participants.

Having considered participants’ reflections on taking part in Power Payback, the next section turns to explore how flexibility services – both DFS and more broadly – might be evolved and taken up in the future.

Power Payback is the first exposure that many of our interviewees had to a modern flexibility offerings. Based on their experience, we were keen to learn how they thought the service might be designed to work better for them. We also explored their perceptions of a future where flexibility plays a more prominent role in the way people interact with electricity.

Customers’ suggestions for Power Payback

Participants described wanting increased warning of events alongside a calendar style notification with possible events for the month. This was to help participants plan ahead to maximise their involvement. This was especially important for certain families, such as those including children with special needs, which made pre-planning more of a necessity. For example, Kaye, whose son has special needs, told us, “You'd need to be able to let them know in advance and plan things so you can then get them ready for it”. In practice, achieving more warning would have been hard to achieve because of the limited notice period that DFS operators receive that events will be needed – and indeed, this period may be even shorter as the service evolves (potentially transitioning from day-ahead to within-day procurement.

Participants also expressed a desire for greater variation in the times and days of the week that events took place. This came from the observation that times were not always convenient and that they had differing schedules on weekdays vs weekends. There was also some appetite for events to be run more often, with Gwen reflecting that, “I think it would make people more aware of their usage”. Both of these suggestions are unlikely to be consistent with the aims of infrequent, event-based flexibility schemes like the DFS. However, they could potentially be features of alternative flexibility products like time of use tariffs.

Participants noted that real-time feedback during events would be desirable so that they could keep track of their consumption. It is worth noting that one of the participants that found this aspect desirable did remark that they actually had an in-home display, but had not been monitoring it during events. Another interviewee, Damon, remarked that they would then like to be able to compare their performance between events to see whether they had been able to reduce their consumption even more:

There was a desire from those with children for Utilita to provide some additional resources to aid participation of family members. This could come in the form of physical resources such as board games, potential competitions via an app, increased information for children to show which appliances should be turned off and even targeted help for children with special needs. As Kaye described it, “Utilita could [...] send out a little package for children to engage them a little bit more”.

Views on a flexible future

National Grid ESO recently confirmed that the DFS will continue to be developed for use in managing periods of high demand on a year-round basis. It’s likely that services like Power Payback – that incentivise occasional responses from customers at short notice – will remain a part of the flexibility landscape. But these services will increasingly be joined by a wider suite of offerings, including time of use tariffs (with fixed or variable rates). We talked with participants to get their thoughts on a more flexible future – both in general, and regarding their own perceived ability to benefit.

There was some familiarity with legacy time of use tariffs, such as Economy 7, which charge a cheaper off-peak rate overnight, and which a number of participants had experienced directly. Modern flexibility tariffs were seldom mentioned (with one mention of British Gas weekend savings tariffs). In our forum analysis there was more evidence of familiarity with flexibility products such as the Agile tariff from Octopus, including discussion of how these interact with the DFS.

In general, participants expressed mixed views on fixed flexibility products like time of use tariffs, and tended to be more negative than positive. Barriers cited included having fixed schedules with younger children, preference for a flat tariff for reasons of familiarity, and concern about operation of appliances overnight. Encapsulating this demand for stability, Erica shared that, “I would rather have to spend that little bit more to keep the structure in family life than lose that entire routine and then it creates chaos elsewhere.” However, she also reflected that if her children were older this could change, and a participant with older children thought that they would more easily be able to change their schedule.

It is worth highlighting that people may have quite different responses to products or services framed in general, rather than specific terms. This is associated with construal level, or the extent to which people are thinking about something in abstract or concrete terms. It is possible that providing specific details on prices and potential savings for a time of use tariff could have affected people’s perceptions of their willingness and ability to benefit from it.

People’s awareness of the reasons and need for flexibility was generally low. While relieving strain on the grid around peak times received occasional mention, people more commonly understood Power Payback to be aimed at helping save energy in general, improving knowledge about energy saving, and supporting engagement with Utilita:

Certain groups in the population were seen as being more likely to be able to benefit from flexibility, including singles, couples, and older people who may be more likely to be at home during the day. However, concerns were not generally expressed about the potential fairness implications of this – indeed, it was seen as reasonable that some households should pay more because of when they were using electricity. As Erica, who has children, commented:

This should be considered in the context of the earlier discussion around dissatisfaction with events coinciding with the evening peak, especially where children are present. It’s possible that as penetration of flexibility services increases, this inability of some households to respond could be felt more keenly.

As part of Nesta’s ongoing work on home decarbonisation, we’re keen to support the development of services that enable a broader range of households to benefit from providing flexibility. The next section describes the development of a number of user personas, based on this research, that we and others can use and develop when thinking about inclusive service design.

To help inform future work in the area of inclusive flexibility, we developed three provisional user personas based on the interview data we collected. Personas are fictionalised descriptions representing groups of users with similar characteristics. They are helpful in the process of designing products, services, and solutions to better address user needs – which can then be developed with the involvement of real users. The personas presented here reflect a range of attributes of our participants and their experience of engaging with Power Payback.

It is important to recognise that a persona approach can never fully capture the diversity of experiences likely to be encountered by users. However, it can help prompt creative thinking about solutions that can address a broader variety of needs than may otherwise be the case. We expect to develop these and additional personas as we learn more about people’s experiences and expectations for flexibility in the course of our work.

To develop the personas, we first identified important dimensions of difference or commonality across our participants:

• Structured schedule: This refers to how rigidly household schedules are structured by things like work, school runs, or children’s bedtimes.
• Energy curiosity: This describes a level of keenness to learn about, and experiment with, energy use.
• Self care: This describes the extent to which schedules and activities are structured by self-care requirements for issues relevant to health, such as medical equipment and appointments.
• Other care: This captures the level of general caring responsibilities for others, such as children or partners.

These factors were commonly associated with, and used by participants to explain, aspects of their experience of the Power Payback service. We sketched out backgrounds, enablers, and barriers to participation, and created generalised descriptions of these attributes informed by the interview data. We illustrated the general descriptions with examples drawn from the participants in this research, acknowledging that in reality many of our interviewees will lack some characteristics of a particular persona, or show characteristics of more than one persona.

Persona 1: Energy Educator

The Energy Educator is a parent in their 30s or 40s, living in rented accommodation in urban or suburban areas, with a younger child or children. Money is often tight but, with careful management, they are getting by. Cost-saving is the priority for them, but when it comes to saving energy, they are also keen to take opportunities to help their children learn. They may use smart meters and other energy-saving technologies to monitor and manage their household's energy consumption, sometimes involving their children in these activities to instil good habits early on – but also experiencing some conflict. Despite their busy schedules, they try to incorporate energy-saving practices into their daily routines where possible.

Goals:

• Reduce household energy bills to better manage household finances.
• Educate their children about the importance of energy saving.
• Feel they are reducing the negative environmental impact through flexibility approaches.

Dimensions:

• Structured schedule: Energy Educators tend to have more highly-structured routines due to parenting responsibilities.
• Energy curious: Energy Educators are keen to take opportunities to support their children to learn more about energy (and how to save it).
• Self-care: Energy Educators may deprioritise self-care in favour of caring for others.
• Other care: Energy Educators have significant caring responsibilities (for their children).

Persona 2: Flexible Disconnector

Flexible Disconnectors often live alone or with one other person in urban or suburban areas. They enjoy the opportunity Power Payback events provide to disconnect from their routine, take a break, and do something different, such as watching a movie from the laptop or going for a walk. While cost-saving is the main driving force, the Flexible Disconnectors are highly attracted to the invitation to relax and switch off from their usual energy use. Their flexible schedules and minimal household coordination allow them to adapt to these events.

Goals:

• Reduce energy bills even if the saving is small.
• Enjoy the break from routine offered by Power Payback events and engage in simple and relaxing activities.
• Contribute (sometimes) to environmental efforts.

Dimensions:

• Structured schedule: Flexible Disconnectors’ schedules are less structured by those of other occupants.
• Energy curious: Flexible Disconnectors may be interested in energy, but it is not a driving factor for their involvement in Power Payback.
• Self care: Some Flexible Disconnectors might have significant self-care needs, such as chronic health conditions or disabilities.
• Other care: Flexible Disconnectors may have less caring responsibilities for others if they live alone.

Persona 3: Energy Explorer

Energy Explorers are typically in their 30s to 50s, living in households that include multiple members. They approach Power Payback as an engaging challenge, experimenting through events to see what approach would have the most impact. These individuals have a high level of willingness to engage and experiment due to curiosity with Power Payback, which may or may not be accompanied by a higher level of tech literacy. Their primary goals are to reduce energy bills and explore innovative ways to optimise their household systems. Energy Explorers enjoy the process of discovering what works best, turning energy-saving efforts into a creative endeavour.

Goals:

• Reduce energy bills through experimentation.
• Have fun experimenting with energy-saving techniques.
• Optimise household systems to reduce energy consumption.

Dimensions:

• Structured schedule: Energy Explorers’ schedules might be flexible or inflexible depending on the level of their caring responsibilities.
• Energy curious: Energy Explorers are defined by their desire to learn more about their energy use (and how to reduce it), which drives them to experiment with different energy-saving techniques.
• Self care: Energy Explorers have varying levels of self-care requirements.
• Other care: Energy Explorers also have varying levels of caring responsibilities for others.

Great Britain is in the early stages of a flexibility transition. This report has described the ways that smart prepayment customers have responded to, and derived benefits from, the early iterations of the DFS, even while financial rewards were low in the context of annual energy bills.

Our findings suggest a variety of motivations for participation that go beyond bill savings – especially around learning more about energy saving (for self and others), getting enjoyment from participating in an interesting initiative, and treating the events as an opportunity to disconnect and do something different. It also shows that even small savings are welcomed, as ‘every little helps’ when things are tight. We didn’t hear concerns around the fairness of rewards – which was a more prominent theme both in our forum analysis and in previous DFS evaluation.

While our small sample of participants cannot fully represent prepayment customers, it isn’t a surprise that we saw little presence of low-carbon technologies like solar panels, domestic batteries, heat pumps, and electric vehicles. Where our participants were able to be flexible, it was mainly through manual changes in the timings of activities. Often this was against a background of already low electricity use. The irregular and infrequent nature of DFS events meant that these changes were generally acceptable, although the idea of making them more constantly was less attractive.

Participants showed variable levels of understanding of the reasons why DFS events happen, and we add our call to others to take this opportunity to raise awareness of the underlying need for flexibility as part of decarbonising the energy system. We believe there is scope to do this in ways that speak more meaningfully to the personal motivations of DFS participants.

Building awareness of flexibility

At this stage in the flexibility transition, building familiarity with flexibility should be a fundamental goal. As heating and mobility are increasingly electrified across income levels and tenures, wider societal recognition of the need for (and benefits of) flexible operation will become more critical. Policymakers and system planners should be thinking carefully now about how this can be effectively achieved. The DFS potentially provides a valuable vehicle because it is high-profile and eye-catching, but with relatively low stakes.

Given the relatively low value of flexibility and low capacity of many households to significantly reduce their electricity use for events, suppliers need to be mindful of not pushing households into changes in activities that outweigh the rewards. A balance needs to be struck that capitalises on the opportunity to provide moments for learning, fun, or relaxation, without placing a sense of financial obligation onto households to make disruptive changes in order to realise small savings. This could include approaches such as:

• learning packs and games for kids
• low energy, low stress meal suggestions (‘picnic nights’)
• chillout hours (eg, with book, music, or relaxation suggestions)
• energy tune-up events (eg, with suggestions for ways of experimenting to track and maximise savings).

Importantly, a clear thread should always be drawn between the engagement and a clear statement of why it is being done now (ie, to take pressure off the grid). Taking such an approach probably means rethinking the metrics that are used when measuring the effectiveness of schemes like DFS. While the magnitude of demand response will remain important from the perspective of system operators, policymakers and system planners should take a more strategic interest in knowledge/awareness and satisfaction.

Recognising reliability

It is clear that some prepayment customers are indeed able to deliver larger reductions that can represent both more significant financial savings, and add up to a meaningful level of demand response. The key challenge here becomes managing the predictability and reliability of the response – especially given proposals to reduce payments to DFS operators for under- or over-delivery of response.

A variety of mechanisms could be explored to increase reliability, including recognising consistency of response as well as magnitude, supporting automation of response, gamification approaches, seeking commitments or pledges to respond, along with generic approaches such as providing tips on effective energy saving. However, it is important to be mindful of the reasons why households may only be able to respond sporadically, such as interaction with children’s schedules, and take an enabling rather than a pressuring approach (eg, see low-energy meals suggestion above).

These approaches are summarised in Figure 1.

The personas we have begun to develop can be helpful in thinking about how solutions for these quadrants might be developed. For example, Energy Educators with their higher electricity use but inflexible schedules may tend to be positioned in the top left. Flexible Disconnectors, with lower electricity use but more discretion around when they use electricity, are likely in the lower right. Energy Explorers may already be providing reliable flexibility. Wherever a household is positioned, it is clear that building their underlying capacity to be flexible is likely to make it easier both to provide more flexibility, and to do it more reliably.

Building flexibility capital

Where the capacity to provide flexibility becomes valued, it can be helpful to view it as a form of capital – flexibility capital. Households that can provide more flexibility, for example by smart charging an electric vehicle or cooking at different times, have more flexibility capital. This discussion has mostly focused on how households’ existing holdings of flexibility capital are unlocked and turned into flexibility (and rewards) by services like Power Payback.

We need to recognise that the value of flexibility is very likely to increase, and with it the potential for the gap to grow between those households that are able to provide larger responses and those who can’t. So alongside building awareness, now is a time to focus on building the flexibility capital of a broader range of households. While factors such as awareness of how to provide flexibility are part of this, households with larger loads, or onsite generation or storage, are best placed to make larger and more reliable savings.

If we are to rapidly maximise the amount of flexibility we can draw on in a decarbonised electricity system, we need to explore ways of getting these technologies into the homes or communities of a broader range of households – including those of prepayment customers. While subsidy schemes such as the Social Housing Decarbonisation Fund help in this regard, a host of further opportunities and challenges present themselves. These include innovative business and funding models, identifying barriers in regulation and procurement, and tackling issues with engagement and installed performance of technologies.

We expect to conduct future work in these areas with a view to improving inclusion in the low-carbon transition – as an end itself, but perhaps more importantly as a means to success.

Interviews

This section provides details on the method used for this project following the COREQ guidelines for reporting of qualitative research. We carried out nine semi-structured interviews with Utilita customers and conducted a simplified thematic analysis of their answers based on the interview transcripts.

Research team

Interviews were led by one of three Nesta team members with experience of conducting research interviews, usually joined by another Nesta staff member to assist in note taking, and always by a Utilita staff member. Participants were not known personally to the interviewers, although they may have had a brief conversation with the Utilita staff member during recruitment (see below).

Study design

The sampling frame was Utilita customers with smart prepayment meters who were invited to participate in Power Payback. Utilita classified Power Payback participants into high, medium, and low engagement based on the proportion of events they opted in to. Further groups were identified for customers where Utilita had a record of the presence of a low-carbon technology such as solar panels or a heat pump, and for customers who did not opt to take part in Power Payback at all. Customers in all these groups were contacted by telephone to invite them to participate. We aimed to recruit 8-12 participants, spread evenly across levels of engagement. If they agreed, a time slot was booked, and they were asked to complete an online consent form. A £50 incentive voucher was offered as a thank you for taking part in the interview.

At the halfway point of the study, 18 participants had consented to be interviewed and arranged a slot, but only four had joined an interview. To improve the likelihood of ultimately recruiting enough participants, Utilita then contacted larger groups of customers by email asking them to express interest in participating. These customers were called back to arrange an interview. This resulted in a further five interviews being conducted, leading to a total of nine (see table 1). Ongoing analysis (see details below) suggested that data saturation had been reached.

Interviews were conducted online on Microsoft Teams and lasted up to 45 minutes. Prior to each interview, Utilita prepared a briefing sheet with some background information on the participant and their participation in Power Payback, as summarised in table 1. Nesta and Utilita team members joined a brief meeting in advance of each interview to become familiarised with this data. Interviews followed a topic guide, but were semi-structured and so deviated from the guide to explore points raised by participants, where appropriate. Interviews were recorded and automatically transcribed by Microsoft Teams, and notes were taken during the course of interviews to record immediate reflections.

Qualitative data analysis

Thematic analysis of the interviews was conducted using the qualitative software Quirkos. Following a general grounded theory approach to coding, transcripts were imported into the software, and an initial two interviews were blind-coded by three members of the Nesta team. There was good alignment between coders and, following discussion to maximise consistency in approach, the remaining transcripts were divided between the team. Themes emerged from the codes that were developed both deductively from the research questions and inductively from the raw data. We summarised these themes in the report, and used them to help identify illustrative quotations.

Forum topic and sentiment analysis

We also conducted a forum sentiment analysis to provide additional insight into experiences of, and attitudes towards, DFS offerings from a broader range of perspectives – such as credit customers, and households which are more likely to have low-carbon technologies such as domestic batteries or electric vehicles. This analysis was conducted using data extracted from MSE forum posts. Sampling bias resulting from factors such as who chooses to post on MSE forums, and why, means that forum data does not provide a representative view of DFS attitudes and experiences. Observations such as whether certain topics are raised at all can provide helpful context.

The earliest available post is from 2003 (although in practice the earliest post drawn on is from 2022 as that is when the DFS began), and the most recent data is from 3 June 2024. We searched for posts mentioning the following terms: ‘demand flexibility service’, ‘DFS scheme’, ‘Power Payback’, ‘Saving Sessions’. We included Saving Sessions (the DFS offered by Octopus) because it made up the largest share of demand shift in the winter of 2022/23. These terms appeared in 24 posts, which together with their total of 2,166 replies provide the corpus for this analysis. To identify themes of conversation, posts were broken into individual sentences, small sentences removed, and topic modelling (BERTopic) used to cluster sentences by topic. A sentiment analysis model was used to classify sentences by sentiment (positive, negative, neutral). By aggregating the data by theme and sentiment we were then able to draw on it in the relevant sections of this report. The analysis code is available in this GitHub repository.

We are extremely grateful to Utilita for partnering with us to explore their customers' experiences of taking part in Power Payback. In particular, we would like to thank Rebecca Clark, Dimitrios Stefanoglou, and Archie Lasseter for all their work to enable the project. Many thanks also go to the interview participants for taking the time to talk with us.

Nesta would also like to thank Camille Stengel, Head of Qualitative Research and Quality Assurance, for her assistance on this report.

Michael Fell’s work on this project was partially funded by the UKRI Energy Demand Research Centre (EP/Y010078/1).