If you can't measure it, you can't bill it: flexibility still has no baseline to settle against

Cristina Corchero, technical director and founder of Bamboo Energy, set out the definition in full on the energy management panel at RENMAD UsefulAI 2026 on 3 June: "Flexibility is nothing more than the ability to change the way you consume or generate energy. That's how it's defined." Then she added what the definition leaves out: "The definition is very nice, but if you now start thinking about how you measure it, it can't be measured."

A meter measures what a building consumes or what a solar PV plant generates. Nobody measures your ability to change either of them. Corchero calls it "a non-measurable variable": "I can only measure it if I use it, I mean, if I activate it." And if you do activate it, you have measured it exactly once: "then I'll have measured the flex, but I'll have measured it at that precise moment. I won't have a data series that I can feed into a model and tell it: learn from this." The only data you could train an estimator on come from the moments somebody chose to activate.

You sell a difference, measured against consumption that never happened

A flexibility contract pays out on a difference, and one side of that difference never happened. Corchero framed it from the system operator's side: "if we have this installation and we say we're going to offer them one megawatt", Red Eléctrica, Spain's transmission system operator, "wants to be able to see that that megawatt has happened". In generation, physical models and a meter answer that. On the demand side you have to reconstruct what you would have consumed if you had not been activated. That figure is a hypothesis.

What she asks of the method is what you would ask of a standard: "In the end the difficulty is having a method that is explainable, transparent, replicable, so that any player in the sector or any player involved in that business model can validate that that consumption was really the one that was expected, the one that was going to happen in the next quarter of an hour." Whoever calculates the baseline has an interest in it coming out generous. Whoever checks it does not know the industrial process behind it. The method has to satisfy both.

Outside Spain the gap is the same. "Calculating the baseline is an open problem at European level," she said. She pointed to the groups inside Data for Energy that, by her account, work on nothing else. Data for Energy is a standing group of the Smart Energy Expert Group that the European Commission set up in 2023, with flexibility for markets and the grid among its workstreams. The week before, they had been at the CNMC, Spain's competition and energy regulator, discussing baseline methodologies.

The decree recognises the aggregator and parks the payment method

Royal Decree (Real Decreto) 88/2026 of 11 February was published in the BOE on the 12th and came into force the same day. It recognises the independent aggregator and defines it as a "market participant that provides aggregation services and is not related to the consumer's supplier". Under that definition, a third party will be able to pool flexibility from several consumers and sell it without their supplier's permission.

The decree parks the hard part in its third transitional provision, which states that "the methodology for determining the base reference programme of the demand facility shall be established by resolution of the State Secretariat for Energy". That base reference programme is the baseline under another name, and it decides how much you get paid. The decree gave the CNMC three months, until 12 May, to adapt the rules on market participation.

On 14 August MITECO, Spain's Ministry for the Ecological Transition and the Demographic Challenge, put out to public consultation the draft resolution covering that methodology, the price and the compensation scheme for the supplier, and the operating procedures. The consultation closed on 3 September, and the draft is still a draft. The decree also provides that what it defines for the independent aggregator will not take effect until that CNMC adaptation arrives, together with the adapted data exchange files. The role is in the BOE, but it still lacks the two instruments that make it operational: one to switch it on and one to say how much you are paid for it.

A demand market filled to 76%

What is already being settled on the demand side gives a sense of scale. For the second half of 2026, Red Eléctrica allocated 1,775 MW under its active demand response service against the 2,339 MW the specifications called for, or 76%. The marginal availability price came in at €42.62 per allocated MW per hour, with a 1 MW threshold that you can reach on your own or through aggregation.

Activations are a different matter. The service's first deployment of the year came on 28 January, and since July it has been activated again several times, according to industry counts based on data from ESIOS, Red Eléctrica's system information platform.

This service settles cleanly because it pays for availability against contracted capacity and is activated with advance notice. That is the easy case. The money Corchero talks about is in the 15-minute markets, where activation is continuous and expected consumption is recalculated every period. "You can't have an Energy Manager checking the price of ten quarter-hour markets and deciding: now I stop this wastewater treatment process, now I start charging the battery […]. That orchestration has to be run by an automated agent." In Belgium, where Bamboo operates, the system operator publishes a price every minute, so what you are chasing is a forecast of how far you will be able to shift consumption.

Since 1 September, flexible access requires being able to cut consumption

On 31 July the CNMC approved the types of flexible access permit for demand on the transmission and distribution networks, implementing its Circular 1/2024. They were published in the BOE on 11 August and have applied since 1 September, with exceptions by permit type. Type 3 facilities, those connected directly to the transmission network, are obliged to "reduce the consumption capacity held under a flexible access permit" on justified grounds, where a failure to meet the security criteria for system operation is identified. Consumption under a firm access permit is not affected. New demand now pays for its connection partly in flexibility. And accepting a real-time setpoint means knowing what you can touch without breaking anything, what Corchero calls the boundary constraints.

Before the baseline, know what each meter measures

A replicable method cannot rest on data nobody has labelled. Guillermo Matas, head of research and development at Edison Next, described the starting point: "very often we find mislabelled data, misaligned data, data that is simply completely outside the permitted ranges." His answer is the semantic model, "a map of the data", a phrase he credited to Corchero. It records what each signal refers to and what it means physically. That map is the chain of custody for a baseline a third party can check.

Matas puts the OPEX reduction they have quantified in modelling at around 70%. For fault pre-diagnosis he gave a range of 70% to 80%, presenting it as an estimate. Corchero warned that in flexibility forecasting "there are very few numbers". Hers is 93% to 95% accuracy across ten large office buildings in Málaga, from a project a year and a half ago with Endesa, the Parque Tecnológico de Andalucía and other partners. It is her own figure and has not been published.

Who signs off the activation

"I think it's becoming clearer and clearer to us that the limit isn't going to be technological," said Matas. What matters, he added, is critical infrastructure, worker safety, contracts and "when there's a decision, whether it's good or bad, who is responsible and who guarantees that that decision, who signs that decision". Corchero agreed, with a different emphasis: "Yes, honestly, I think regulation is something we're going to have to tackle, because in the end you can't fence it in." She does not expect regulation to hold it back, because "we've already found the shortcut to be able to use that tool".

The baseline is where those two points meet. To sign off an activation you need a document stating what was activated and against what consumption. That document comes from a method that someone accountable owns and a settlement body checks. Without that method, the shortcut works and you don't get paid.

Whoever can prove the method will write the rule

The rule is being drafted now, and the method that ends up in the BOE will look like whichever one somebody managed to demonstrate on a real site, in front of a third party from outside the process. Corchero's three adjectives already work as a specification: explainable, transparent, replicable. Turn up with that and you write the rule you will be paid under, rather than waiting for someone else to write it for you. And the line she uses to sum up the business of shifting demand will have a meter behind it: "consumption stops being a cost and becomes income".

Cristina Corchero (Bamboo Energy, technical director and founder) and Guillermo Matas (Edison Next, head of research and development) spoke on the energy management panel at RENMAD UsefulAI 2026, Madrid, 3 June 2026.