Event-based upward flexibility in Spain

See analysis plan.

Between May and July 2025, Octopus Energy (OE) will run five Spain “Turn-Up” events, with exact timing determined by market conditions. For each event, participating customers will be randomly assigned to one of five groups:
1. Control – No event notifications or incentive.
2. 50% Discount – Customers receive a 50% discount on their electricity usage (€/kWh) during the event window. For example, for customers on the single-rate tariff Octopus Relax (0.118 €/kWh), the discounted rate will be 0.06 €/kWh.
3. 100% Discount (Free Electricity) – Customers pay nothing for electricity consumed during the event.
4. Free Electricity + Payment – In addition to receiving free electricity, customers are paid at their unit rate. For example, customers on the single-rate tariff Octopus Relax would be paid a further 0.118 €/kWh.
5. Prize Draw – Customers will be offered free electricity above their “baseline” – their typical electricity consumption in the hour(s) of the event. In addition to this free electricity above baseline, 10 prizes of €150 each will be awarded to randomly selected participants who participated in the event (participation defined as increasing consumption compared to baseline).

Customers will be randomized into a sequence of events such that each customer receives each of the five conditions (four treatments and one rotating control). More explanations about how these sequences are generated in the experimental design description below. In addition, we will include a separate group of customers who are never treated in any event; this pure control group will serve as a baseline for evaluating the effects of trial participation itself, independent of treatment exposure.

Those selected are automatically notified via email prior to each session, with instructions on the time window and the reward offered. They are encouraged to shift their electricity usage, such as running the washing machine, charging their electric vehicle, or heating water, into the designated session period. After each session, they receive a summary of their usage and rewards, which may include discounts, free electricity, or cash payments.

Sample: We will access a pool of 66,441 customers who are not:
Business
ATR code (in Spanish, Acceso de Terceros a la Red) different to 2.0TD
Clients who opted-out from marketing communications
Vulnerable clients
Clients with open complaints
Clients who have not received a bill in more than 60 days
Clients enrolled in the Solar Family or Sun Club campaigns
Clients who are enrolled in Intelligent Octopus Tariffs
Members of the “Comunidad Octoamigos”
Clients whose agreement with OE is to be renewed in between 30 and 60 days after the first session starts
Clients with solar panels
Clients whose main address is on the Canary Islands
Clients in distribution zones that are not able to send telemetry in less than 5 days

We will hold 5 “Turn up” events during June through September 2025. These events will not happen on predetermined days – they will run when the price of the electricity in the day ahead market is close to 0 or negative. Events will typically be 1-2 hours, but exact duration will also depend on market conditions.

2026-06-14

2026-09-14

Associated CUPS (in Spanish,Código Universal del Punto de Suministro or universal supply point number) electricity consumption (import kWh only) at the hourly level during “Turn up” events, in kWh

Consumption is measured at the customer meter point level.

Survey responses sent to all participating households (including identified pure control groups who never receive any outreach on the events). These include:
To what extent do you think that it is technically feasible to stop greenhouse gas emissions by the end of the century while [maintaining / sustaining] satisfactory standards of living in [country]?
Not at all; A little; Moderately; A lot; A great deal
If we decide to halt climate change through ambitious policies, to what extent do you think it would negatively affect your lifestyle?
Not at all; A little; Moderately; A lot; A great deal
Do you believe that Government climate policies will provide more benefits or impose more costs on you personally?
Mostly benefits; Neutral; mostly costs

These survey questions are designed to assess whether participation in the trial influences individuals' perceptions of the energy transition – specifically, whether it increases the likelihood that they view the transition as personally beneficial. The exact wording may be refined following piloting to ensure clarity, neutrality, and respondent comprehension. We will translate the questions into Spanish before sending them to customers.

See analysis plan.

See attached analysis plan for details.

Our primary research question is, how do financial incentives affect hourly electricity consumption (kWh) during “Turn-up” events? Specifically, this trial aims to quantify the causal impact of different incentives – a 50% discount, free electricity, free electricity with a payment, and a prize draw – on customers’ short-term electricity usage during targeted event windows.

The primary analysis will estimate the overall treatment effects during Turn-up events by comparing each treatment group to a pooled control group. This pooled control includes both the rotating control group (assigned during each event) and the pure control group (which is never contacted and never treated).

Computer, using R. See attached analysis plan for details.

Customer email address

Yes

66,441 clusters, where regressions are clustered at the customer email address level

For 66,441 customers, if each event is one hour (noting that events may be longer – in which case this estimate would be conservative), with a total of 5 events, this results in approximately 664,410 observations in the main analysis, clustered at the customer level (66,441 clusters).

Treatment: 51,109 (among which 20% will be a "rotating control group" at any given event; see analysis plan for details)
Pure Control: 15,332

We conducted simple simulations of our trial design using consumption data from Spanish Octopus Energy customers in 2024, assuming 10,000 customers per trial arm (ignoring the “pure control” group, which we believe makes our power calculations conservative). We created placebo treatment and control indicators, assuming five “events” between May and July 2024. Using the rule of 2.8 (wherein the MDES at 80% power and 5% alpha is 2.8 times the standard error on the treatment coefficient), we find that our MDES is 0.00519 kWh per hour (2% of hourly consumption during events).