Red Eléctrica (RE)
TSO - Spain
Publication info
| Status of publication | Published |
| Link to website | Generation: https://www.ree.es/es/clientes/generador/acceso-conexion/conoce-la-capacidad-de-acceso Demand: https://www.ree.es/es/clientes/consumidor/acceso-conexion/conoce-la-capacidad-de-acceso |
| Accessibility | Open |
| Regional Scope | Country |
| Spatial granularity | Nodal (substation) |
| Operator voltage level scope | 220 kV-400 kV |
| Timeline for which HC is provided | Y+6 (NDP horizon) |
| Information format | Table |
| Categories of grid users considered | Generation demand and storage |
| Type of grid connection capacity information | Available, requested, connected and reserved capacity |
| Availability of API | Not provided |
| Update Cycles | Monthly |
| Available language | National language(s) only |
| Additional information | The published hosting capacity values are for informational purposes only and do not constitute a binding commitment by RE. They do not imply any guarantee of actual grid availability, nor do they entitle any party to reserve capacity or claim priority for grid connection. All connection requests remain subject to individual technical assessments and regulatory procedures. |
Hosting capacity assessment
| Capacity type considered for hosting capacity information |
Firm and flexible |
| Description of what firm capacity means and the aspects that structure the definition |
Firm access capacity is the maximum active power that can be supplied with a guarantee of supply at all times of the year. It only applies for demand as generators and storage do not have guarantee of injection of power. |
| Description of the methodology that leads to firm capacity results |
In demand, static, dynamic and short circuit power studies, in a nodal and zone basis, lead to a value for firm capacity. From the static perspective, it is the maximum value that can be guaranteed in the 100% of scenarios analyzed (when technical restrictions can solve the problems, 98% is used for the calculation of capacity) |
| Description of what flexible capacity means and the aspects that structure the definition |
Flexible access capacity refers to a situation in which the requirements for firm power are not fully met, because supply is not guaranteed at all times of the year. |
| Description of the methodology that leads to flexible capacity results |
Static, dynamic and short circuit power studies, in a nodal and zone basis, lead to a value for flexible capacity. From the static perspective, it is the maximum value that can be guaranteed in the 90% of scenarios analyzed for generation and demand, or in the 70% of scenarios for the storage. |
| Description for the criteria and methodologies used that lead to the published information |
The criteria used to calculate generation capacity take into account the following:
The total capacity of a bus/zone corresponds to the minimum value of the three criteria. The methodology used for the calculation is explicitly stated in the regulation, i.e. the Resolution of 27 Jun 2024, of the NRA, which establishes the detailed specifications for the determination of generation access capacity in the transmission and distribution grids and the Resolution of 1 December 2025, of the NRA which establishes the detailed specifications for the determination of demand access capacity in the transmission grid. |
| Main assumptions/disclaimers behind calculations |
Network Development Plan (NDP) scenarios and time horizons are considered, as well as full network availability. The same methodology is used for storage plants (except for a different acceptance ratio within the static criterion). The calculation also takes into consideration the capacity reserved for access and connection auctions by the ministry. |
| Additional information |
The TSO considers the generation, storage and demand facilities with permits issued by the DSOs in their grids. Permits granted on the distribution grid above a power threshold occupy capacity on the transmission grid. In addition, the DSO must request acceptability from the TSO for certain installations that exceed a power threshold. |
Additional information for connection request and hosting capacity information
| Connection request procedure |
Requests for access and connection to the transmission grid must be made for existing substations or substations included in the national NDP in force and, within these, for existing or planned positions (https://www.planificacionelectrica.es/). Before applying for access and connection permits, promoters must:
The TSO verifies the completeness of the information and issues a request for information for any missing information. A maximum of two requests for information can be made. Once the application is complete, it can be accepted for processing. At this point the TSO verifies the existence of access capacity and the feasibility of connection. The TSO issues a pre-proposal for access and connection, including economic and operational conditions and limitations. If the applicant agrees to the content and accepts the pre-proposal, the TSO issues the access and connection permits allowing connection to the transmission network. . Regarding payment of costs, the applicant is responsible for the connection position/bay and all connection infrastructure between the bay and its project. The electricity system bears the costs associated with reinforcing the substation and the grid itself, including new lines, upgrading of existing lines, etc. |
| Options available for the investors if the map shows 'no capacity available' in their interested area |
If the hosting capacity table indicates that no capacity is currently available at a specific substation, investors cannot request connections in this specific substation, and capacity within other substations will be investigated. If a facility must be connected in a specific location, then investors shall participate in the public process prior to the next national NDP. |
| Connection request rules |
First-come-first-serve |
| Information published for volumes of connection requests/waiting lines |
Yes |
| Granularity of published connection requests/waiting lines |
Per node and switch bay, per technology |
| Additional information |
The main principles of the access and connection request rules are the same for generation, demand, and storage. It is regulated by Royal Decree 1183/2020, of 29 December, on access and connection to electricity transmission and distribution grids. There are two mechanisms for allocating access capacity, applicable to both generation and demand. As storage in Spain requires both generation and demand capacity, it must fulfill both generation and demand criteria (although some specificities apply in the calculation that lead to wider capacity values): 1) General procedure according to the order of application (first come, first served principle): The first complete access and connection application received has the right to obtain grid access capacity. 2) Auctions for access capacity: Held to allocate generation, storage, or demand connected to transmission network nodes where requests are high and/or capacity is scarce. These auctions are conducted when established by the ministry, with evaluation criteria potentially including commissioning deadlines, as well as technological, socioeconomic, and environmental factors. In the meantime, the capacity is reserved and cannot be allocated by the TSO. In addition, several other regulations apply to the access and connection procedure, including reserved capacity, specific auctions for fair transition substations (NTJ, substations where thermal generators were connected and subsequently shut down), and specific capacity for self-consumption generation 3) Recently in march 2026 regulation for demand changed, and there is a need for a monthly payment as a access capacity reservation (aiming to move towards first ready, first served). |