Under the influence of the European Union's Energy Efficiency Directive, Spain has established one of the most innovative and rapidly growing markets for energy efficiency in Europe. Central to this transition is the system of Certificados de Ahorro Energético, known as CAEs, which was introduced in Spain under Royal Decree 36/2023. Coordinated by the Ministry for the Ecological Transition and the Demographic Challenge, the CAE system translates verified energy savings into tradable economic assets. The publication of Order TED/133/2026 on 25 February 2026 established the energy saving obligations for 2026, marking a significant milestone for energy companies and project developers alike.

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The Mechanics of the Spanish CAE System

A CAE is an official electronic document that certifies that a verified energy efficiency measure has achieved a final energy saving equivalent to one kilowatt-hour. For example, a project that successfully reduces final energy consumption by 400 kilowatt-hours per year will generate 400 CAEs. These certificates are utilised within a regulated market where energy supply companies, categorised as required parties or sujetos obligados, must meet annual energy saving targets. The required parties include gas and electricity suppliers, wholesale petroleum product operators, and liquefied petroleum gas distributors.

For the year 2026, Order TED/133/2026 has established a total national energy saving target of 801.822 kilotonnes of oil equivalent, which is equivalent to 9,325.189 GWh. Each obligated company is allocated a specific quota of this target based on its annual sales volume. To satisfy their legal targets, these required parties have two primary options, they can either make a financial contribution to the National Energy Efficiency Fund, known as the FNEE, or they can submit verified CAEs to demonstrate equivalent physical savings.

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Financial Equivalence and Cost Optimisation

The financial equivalence for 2026 has been set at 2.31 million euros per kilotonne of oil equivalent saved, which translates to exactly 198,624.25 euros per GWh of final energy savings. Under the current rules, obligated energy companies can meet their targets by making a minimum contribution to the FNEE of 8 per cent of their total liability, while offsetting the remaining 92 per cent of their obligation through the surrender of CAEs.

Because the market cost of procuring CAEs is typically lower than the equivalent financial contribution rate to the FNEE, this structure provides required parties with a strong commercial incentive to purchase certificates on the secondary market. Sourcing CAEs from third-party energy efficiency projects allows obligated utilities to reduce their compliance costs significantly while still fulfilling their statutory obligations. This compliance-driven demand has created a highly liquid and predictable certificate market, backed by creditworthy corporate buyers.

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From Saving Energy to Liquid Capital

The CAE system is not only a compliance tool for large energy retailers, it is also a powerful financing mechanism for project owners, including industrial facilities, SMEs, public administrations, and residential associations. Any physical intervention that reduces final energy consumption, such as upgrading building insulation, replacing old combustion boilers with heat pumps, or installing highly efficient LED lighting systems, is eligible to generate CAEs.

To monetise these savings, the project owner signs a CAE agreement with a required party or an accredited delegated party. Once the efficiency measures are physically implemented, the actual energy savings must be calculated using standardised methodologies or via a singular project file. An independent, accredited Verifying Entity must then technically and legally validate the declared savings to ensure compliance with Spanish regulations. Following this verification, the regional authority issues the certificates, and the National Coordinator registers the CAEs in the official national registry, allowing them to be traded or surrendered for compliance.

The growth of the Spanish CAE market has been remarkable. By January 2026, official data from the ministry showed that over 4,830 applications had been submitted, requesting more than 7,810 GWh of energy savings. This represents a tenfold year-on-year increase in certificate requests compared to the previous year. Notably, the industrial sector has emerged as the primary driver of this growth, accounting for more than 65 per cent of all requested savings. Additionally, these certificates are highly compatible with public aid programmes, provided that the public grants are not funded directly through the FNEE, enabling project developers to combine subsidies with certificate revenues to improve the overall return on investment.

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For corporate sustainability and facility management teams operating in Spain, the CAE system represents an essential tool to improve the financial viability of energy-saving projects. By turning avoided energy consumption into tradeable capital, Spain has successfully bridged the gap between environmental performance and corporate profitability.