Although renewable electricity generation can provide low-carbon electricity, it relies on the wind blowing or the sun shining. At times when there is a high demand for electricity, other sources need to be used – such as fossil fuels. This intermittency results in high-carbon intensity of electricity at times when demand is high, such as in the evening when people are at home using lots of appliances.

One approach to reduce the need for high-carbon intensity electricity production is to reduce the demand for electricity at peak times. This could be by putting on dishwashers at a different time of day, or charging electric vehicles overnight.

National Grid ESO introduced the DFS scheme to explore how much electricity consumption could be reduced during peak times. The scheme offers customers who participate in discrete events a reward for reducing electricity consumption.

Through this scheme, National Grid ESO aimed to see how much consumption could be reduced by people changing their behaviour. If it proves effective, it could be implemented as one of many long-term solutions to reduce carbon emissions during peak consumption periods.

Non-financial motivators could increase participation in the National Grid ESO's Demand Flexibility Service (DFS) events, or reduce electricity consumption. We will explore whether they can increase engagement and provide evidence on how best to motivate people to reduce their energy consumption.

We wanted to explore whether we could use behavioural insights to increase engagement with the DFS events. Specifically, the DFS scheme offers a financial incentive for participation, which is the primary motivator for people to take part.

Financial incentives may be effective for some people, but money motivates some people more than others. For example, individuals who do not use much electricity would typically be paid less than those with high electricity use, as their kWh reduction would be less than those with a higher typical energy use. This means that using financial incentives alone may not act as an effective motivator for everyone.

We know from behavioural science that financial incentives (categorised as extrinsic motivators) are only one type of motivator. The other main type of motivator is intrinsic motivators, which are internally-sourced reasons to take action. Examples include pro-social motivators (such as helping others) or morals (wanting to do the right thing). Intrinsic motivators can be very powerful and can motivate us to do things even when we don’t benefit financially.

Intrinsic motivators could be used as part of the DFS scheme to increase engagement - particularly for those who aren’t motivated financially. For example, raising the importance of reducing electricity consumption to reduce carbon emissions may appeal to environmentally conscious people. These additions may have next to no cost, which could increase electricity reductions without adding to the overall cost of the scheme.

To explore whether non-financial motivators could increase engagement with DFS events, we partnered with an energy advice company. The company was involved in implementing the DFS scheme to their customers.

For each event, participants were sent an email asking if they wanted to participate. If they agreed to participate, customers were also sent reminder emails before the event (see image below).

We used behavioural insights to design two new messages, as outlined below:

• Environmental framing. The current emails only focus on the financial incentives. We believe that using an environmental framing may help to increase the motivations to opt-into and participate in events, in conjunction with the financial incentive
• Health framing. Recent evidence suggests that using a health framing can enhance household energy savings. These interventions highlight the detrimental impact of primarily anthropogenic-created air pollution on a range of health issues, such as asthma and heart disease.

Both of the framings above introduce intrinsic motivators to engage with the scheme. We also thought that remembering when an event was may be a barrier, so we also decided to test whether sending text message reminders to customers could increase electricity reductions.

We ran a field randomised controlled trial with 15,000 customers for the final three DFS events in March 2023. There were four experimental arms:

1. control group, who received the normal emails;
2. environmental framing group;
3. health framing group; and
4. environmental framing + text message reminder group.

We will compare the proportion of each group that opts into each of the three events, and electricity consumption during the events. You can read more about our trial on the Open Science Framework.