CAE system guide
What are Energy Saving Certificates?
Definition, legal framework and operation of the CAE system in Spain, explained for delegated parties, intermediaries and verifiers.
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Definition and legal framework
Energy Saving Certificates (CAE) are instruments that attest, in a documentary and verifiable way, to an energy saving achieved through a specific energy efficiency action. Each certificate represents a set amount of final energy saved, expressed in kWh.
The CAE System was created by Real Decreto 36/2023, which transposes the saving obligations derived from the European energy efficiency directive. Its aim is to mobilise private investment toward actions that reduce energy consumption in homes, industry, transport and services.
Unlike traditional subsidies, CAEs create a market in which energy saving has a tradable economic value. Whoever carries out an efficiency action can generate certificates and transfer them to obligated parties, who must meet an annual saving quota set by the Administration.
The system rests on a simple principle: each year, obligated parties (mainly energy retailers) must demonstrate to MITECO a set volume of energy saving. They can achieve this by carrying out actions directly or by acquiring certificates generated by third parties.
This mechanism turns energy saving into an asset: a company that renovates the lighting of an industrial building, replaces a boiler or improves a building's insulation can translate that saving into certificates with a market value.
The catalogue of eligible actions is defined by the standardised data sheets published by MITECO, which set the saving calculation formula for each type of intervention.
4 942GWh
Annual saving obligation
114sheets
Actions in the MITECO catalogue
50-150€/MWh
CAE price range
66
Accredited delegated parties
Regulatory basis
All CAE regulation in one place
Real Decreto 36/2023, Orden TED/815/2023, MITECO data sheets and CNMC resolutions, compiled and explained in plain language.
The system's actors
The CAE System brings together several actors with clearly distinct roles, from the Administration that oversees it to the professionals who carry out the actions.
MITECO
Ministry for the Ecological Transition and the Demographic Challenge
Defines the regulatory framework, publishes the standardised action data sheets and oversees compliance with the annual saving obligations.
Obligated parties
Gas, electricity and fuel retailers
They must demonstrate a volume of energy saving each year. They meet it by carrying out actions or by acquiring certificates generated by third parties.
Delegated parties
Companies authorised to manage CAE actions
Currently 66 accredited entities that carry out the actions, prepare the files and submit them to the system on behalf of the obligated parties.
Verifiers
Verification bodies accredited by ENAC
They independently check that each file complies with the applicable data sheet and that the declared saving is real and duly documented.
CNMC
National Commission for Markets and Competition
It manages the certificate register, oversees transactions and guarantees the integrity and traceability of the CAE market.
The relationship between these actors defines the life cycle of each certificate. The obligated party needs to demonstrate saving; the delegated party carries out and documents the action; the verifier validates the file independently; and the CNMC registers the issued certificate so it can be transferred and settled.
This separation of roles is deliberate: it ensures that the certified saving is real and not a mere self-serving declaration. That is why independent verification by an ENAC-accredited body is the credibility cornerstone of the entire system.
For the delegated party, mastering this chain of responsibilities is key. A well-prepared file, consistent with the data sheet and with complete documentation, clears verification without incident and speeds up the issuance of the certificate.
Simplified system flow
How a CAE file works
Each action moves through a sequence of states, from the initial data capture to the final settlement of the certificate. CertificAhorro faithfully reproduces this flow.
Draft
The file is created and the action's data is entered: location, equipment, applicable MITECO data sheet and technical parameters of the intervention.
Calculated
The regulatory formula of the corresponding data sheet is applied and the energy saving in kWh, the basis for the certificate's value, is obtained.
File ready
The complete documentation is gathered and checked (technical report, invoices, photographs, sworn declaration) and the file is ready to be submitted.
Sent to verifier
The file is sent to the ENAC-accredited verification body for its independent review.
Verified
The verifier confirms that the action complies with the applicable data sheet and that the declared saving is correctly documented.
Application submitted
The certificate issuance request is submitted to the system, with the file already verified.
Processing
The Administration reviews the request within the corresponding administrative procedure.
Favorable decision
A favourable resolution is obtained: the action is accepted and the issuance of the certificate is authorised.
CAE issued
The certificate is issued and registered in the register managed by the CNMC, becoming available for transfer.
Settled
The certificate is transferred to the obligated party and financially settled, closing the file's cycle.
Why the CAE market is an opportunity
The CAE System has created, practically from nothing, a market worth several hundred million euros a year. The annual saving obligations are substantial and growing, which sustains a structural demand for certificates from obligated parties.
For energy efficiency professionals (installers, engineering firms, ESCOs and intermediaries) this means that every action carried out can generate additional income at no cost to the end customer, simply by monetising the saving that is already produced.
The delegated parties that know how to operate at scale, managing many actions efficiently and with documentary rigour, are the ones that best capture the value of this market. The ability to process volume without multiplying the operating cost is the competitive differentiator.
The bottleneck is usually not demand, but the capacity to prepare correct and verifiable files quickly and at scale. That is where a specialised tool multiplies profitability.
The challenges for delegated parties
Operating profitably in the CAE market requires overcoming three types of challenges that multiply as the volume of actions grows.
Regulatory complexity
- More than a hundred MITECO data sheets with distinct formulas and parameters.
- Frequent regulatory updates that require revising the criteria.
- Coefficients and calculation factors specific to each type of action.
- Documentary requirements that vary by sector and intervention.
Operational workload
- Manual preparation of each file, slow and prone to errors.
- Simultaneous management of dozens or hundreds of actions in parallel.
- Tracking the status of each file throughout the flow.
- Coordination with customers, installers and verification bodies.
Risk of rejection
- Inconsistencies between the technical report and the supporting documentation.
- Calculation errors that invalidate the declared saving.
- Incomplete documentation that delays or stalls verification.
- Repeated corrections that increase the cost and the issuance time.
The solution
How CertificAhorro helps you
CertificAhorro is the platform designed specifically for delegated parties and intermediaries to manage CAE files with regulatory rigour and at scale.
Complete catalogue of MITECO data sheets
All data sheets integrated with their formulas and parameters, always kept up to date in line with current regulation.
Automatic saving calculation
The correct regulatory formula is applied systematically, eliminating manual calculation errors.
Documentation generation
The technical report and the file's other documents are generated from the data entered, with no manual rewriting.
Consistency validation
The system detects inconsistencies and missing data before submission for verification, reducing rejections.
File tracking
View the status of each action throughout the flow, from draft to final settlement.
Multi-user, scalable management
Teams, roles and a high volume of files managed from a single organised workspace.
What documentation does each CAE file require?
The main reason CAE files are rejected by ENAC verifiers is incomplete or inconsistent documentation. Each file must include five types of documents, designated D1 to D5 in industry practice. The technical report (D1) describes the action carried out, the equipment replaced and the new equipment installed, with reference to the manufacturer's technical specifications. The installation certificate (D2) confirms that the action was carried out by a qualified professional. The invoices and delivery notes (D3) justify the acquisition of the equipment and the provision of the services. The photographs (D4) document the before and after state of the installation. The sworn declaration (D5) commits the holder of the action to the truthfulness of the information provided.
Preparing this documentation manually for each file consumes considerable time, especially when the delegated party manages dozens or hundreds of simultaneous actions across different sectors and with different MITECO data sheets. The most frequent errors include technical parameters that do not match between the technical report and the invoice, calculation formulas applied with incorrect coefficients, insufficient photographs or incomplete end-customer data. Each correction requested by the verifier delays the issuance of the certificate and increases the file's operating cost.
In this context, having a tool that automates the generation of documentation from the file's data, that systematically applies the correct regulatory formula and that flags any inconsistency before submission for verification makes a decisive operational difference. This is exactly the kind of problem CertificAhorro was designed to solve: eliminating avoidable errors, reducing the preparation time of each file and increasing the first-time verification approval rate.
Have more questions about CAEs?
All the frequently asked questions about the CAE system, the regulation, the MITECO data sheets and CertificAhorro are gathered in one place.