Firm demand access capacity at network nodes

In compliance with RD 1183/2020 of 29 December on access and connection to the electricity transmission and distribution networks, Article 5, and CNMC Circular 1/2024 of 27 September, which establishes the methodology and conditions for access and connection to transmission and distribution networks for electricity demand facilities, Article 16, the firm access capacities are published for each busbar with a voltage above 1 kV in the substations operated by EDistribución Redes Digitales SLU and Energías de Aragón I SLU. These capacities are reported and calculated as defined in the CNMC Resolution of 8 June 2025, which sets out the Detailed Specifications for determining firm demand access capacity to the distribution networks, as well as in the CNMC Resolution of 30 April 2025, which establishes the formats for publishing demand and generation capacities by distribution network operators.

The available access capacity for each node has been determined as the maximum additional active power that can be demanded at that node, taking into account the occupied capacity reported at all network nodes and the planned installation scenario without considering additional reinforcements, in accordance with the criteria set out in CNMC Circular 1/2024 and the Detailed Specifications for determining firm demand access capacity. The published access capacities are for information purposes only and do not remove the need for a specific study for each individual request, which will take into account any variations in the scenario, such as pending requests with higher priority, both at the node under study and at other nodes in the network that may influence it.

Limitations that may exist in other distributors’ networks, in the transmission network, or in the substation itself, due to configuration or operational aspects, and those relating to connection feasibility, are not taken into account. Such limitations would, where applicable, be identified in the corresponding acceptability and access, and connection feasibility reports that must be carried out for each request.

The reported “Available Access Capacity” values must not be interpreted as simultaneous or cumulative capacity values. The connection of a demand at one node not only reduces the available access capacity at that node but also at nodes within its adjacent network.

The reported values for occupied capacity and for admitted but not evaluated capacity refer exclusively to demands connected or with access and connection permits granted or requested at these nodes or within their underlying network at the same voltage level.

As publications are issued monthly using data from the previous month, they may reflect available capacity at a node that has already been fully allocated due to requests accepted before the publication date, both at the node itself and at other nodes in the network that may influence it or its underlying networks.

Except in duly justified exceptional cases, access and connection requests that do not comply with the maximum and minimum power ranges per voltage level established in the “Detailed Specifications” will be rejected.

Requests specifically targeting nodes where the published capacity is 0 MW will be inadmissible, in accordance with Article 8.1(d) of RD 1183/2020.

However, in accordance with the provisions of Article 10.1 of RD 1183/2020 of 29 December, on access and connection to the electricity transmission and distribution networks, only generating facilities of more than 100 kW are required to submit a request for a specific node or line section of the network. In other words, demand requests are not required to indicate the network element to which they intend to connect.

Only demand requests that indicate the network node to which they intend to connect may be rejected, in accordance with the provisions of Article 8.1.d) of the aforementioned Royal Decree.

NOTE FOR STORAGE REQUESTS

Regarding the entry into force of the CNMC Resolution of 27 June 2024, which establishes and amends the Detailed Specifications for determining access capacity for demand and generation to distribution networks, specific operating patterns for storage shall not be taken into account until they are approved by a CNMC resolution and published on this platform. In accordance with the First Transitional Provision of CNMC Circular 1/2024, and until such resolution is approved, storage facilities shall continue to be assessed based on the existing firm capacity of the network, considering their operation both as generation and as demand.

According to RD 1183/2020 and CNMC Circular 1/2024, demand requests in the distribution network may require an acceptability report from the System Operator to evaluate the impact on the transmission network of the connection to the distribution network, in accordance with the criteria set out in the Detailed Specifications for determining access capacity to the transmission network.

Additional information on grid access and connection

1. Short-circuit power at distribution-to-distribution interconnection points

   Download file Short-circuit power at distribution-to-distribution interconnection points

2. Power connection thresholds by voltage level

   According to the CNMC Resolution of 3 June 2025, which establishes the detailed specifications for determining the firm access capacity of demand to electricity distribution networks:

   

   

3. Indicative and non-binding information on electrical connections and other actions necessary to provide the supply until connection and commissioning.

   Download file Indicative and non-binding information on electrical connections