In recent years, Spain has seen a high penetration of renewables in its energy mix, which has reduced electricity prices, especially during daytime hours. This has made energy storage an essential tool to provide flexibility and security to the electricity system, as well as to ensure the economic viability of renewable generation projects. At the same time, this context is favouring the development of data centres and energy-intensive industries, attracted by competitive electricity prices. Both storage facilities and data centres and new electricity consumers require access capacity in order to consume electricity, which has made access and connection permits for demand as sought-after as generation access permits were — and still are — in earlier years.
As a general rule, the granting of grid access and connection permits is governed by the principle of chronological priority. However, faced with the growing scarcity of available access capacity and in order to avoid speculative behaviour in relation to such permits, the Spanish Government has introduced a new exceptional mechanism applicable at certain transmission-grid nodes.
In this regard, Royal Decree-law 8/2023, of 27 December, amended Royal Decree 1183/2020, of 29 December, on access to and connection with the electricity transmission and distribution grids (hereinafter, “RD 1183/2020”), to incorporate a new competitive-concurrence procedure, articulated through public access-capacity auctions for demand installations. The following sections describe the procedure and the criteria applicable to these capacity auctions.
The applicable legal framework
Capacity auctions for demand are governed by Articles 20 bis, 20 ter and 20 quater of RD 1183/2020. In this respect, Article 20 bis of RD 1183/2020 provides that access-capacity auctions for demand installations must be called, by resolution of the Secretariat of State for Energy, at a specific transmission-grid node with a voltage level equal to or above 220 kV, provided that the circumstances set out in Article 20 quater.1.c of Royal Decree 1183/2020 are met.
Procedure of the access-capacity auctions for demand
Under Article 20 quater of RD 1183/2020, once a demand access request has been submitted, the transmission system operator must publish on its website, for a period of one month, a notice stating that a request has been received at the relevant node for a given capacity. From that point, the following situations may arise:
- If no new requests are received within the stated period, the transmission system operator will grant the access capacity to the initial request in accordance with the general principle of chronological priority.
- Likewise, if new demand access requests are received within the same period and all of them can be served simultaneously in accordance with the applicable criteria, the access permits will also be granted in accordance with the chronological-priority principle.
- By contrast, if, within the established period, new access requests are submitted whose total capacity cannot be served in full, the transmission system operator must notify this to the Secretariat of State for Energy and suspend the access procedures based on the chronological-priority principle.
The situation described in point (c) triggers the start of a future demand capacity auction. In that case, the transmission system operator must notify the affected parties of the suspension of their access and connection procedures.
The transmission system operator must also provide the Secretariat of State for Energy with all the information it requests for holding the auctions, in particular that relating to the total capacity reserved at each node.
The capacity reserved for a future auction will be maintained until the resolution calling that auction is approved. That resolution must be issued by the Secretariat of State for Energy.
Criteria applicable to the access-capacity auctions for demand
As regards the criteria applicable to demand auctions, Article 20 ter of RD 1183/2020 provides that these auctions must have the following features:
- The right to be awarded will consist of access capacity for consumption, expressed in MW.
- They will cover the entirety of the access capacity available at the node.
In addition, the conditions for participation — including, where applicable, any additional guarantees required — and the details of the procedure applicable to demand auctions must be regulated by an Order of the MITERD. That regulation must establish, as a minimum, time-related criteria regarding the start date of the demand installation’s consumption, commitments on consumption flexibility and demand management, energy-efficiency improvements, socio-economic, environmental and territorial impacts, productive links, the technical and financial solvency of the project and its promoters, criteria relating to the volume of investment and criteria relating to the greenhouse-gas emissions avoided by the project for which access capacity is requested.
It should be noted, however, that under the second paragraph of the Sixth Transitional Provision of Royal Decree-law 8/2023, of 27 December, demand auctions may be held even where the MITERD Order has not been approved. In such cases, the auctions may be processed and decided by resolution of the Secretariat of State for Energy, applying the general framework provided for in RD 1183/2020. The only exception concerns the set of criteria to be considered for awarding access, which must be limited to the project’s consumption start date, the volume of investment and the greenhouse-gas emissions avoided.
As at the date of this article, the aforementioned MITERD Order has not yet been approved. Consequently, for the time being, demand auctions are expected to be conducted in accordance with the framework described above. This is precisely the case of the first capacity auctions called by Resolution of 11 July 2025 of the Secretariat of State for Energy.
Conclusions
In a context in which grid access capacity for demand installations is increasingly scarce and in which additional investment in grid infrastructure is required, access-capacity auctions for demand are configured as a key tool to prioritise access for the most advanced projects and those best able to provide security and flexibility to the system, as well as to generate positive socio-economic and environmental impacts.
Unlike what happens with generation access-capacity auctions, the Government has shown a greater commitment to holding demand access-capacity auctions. Proof of this is that in July 2025 the MITERD called the first auctions for eight transmission-grid nodes. These auctions are expected to be decided in February, since the MITERD has a legal period of six months from the date of the call to decide each auction.
Likewise, in the short term a greater number of transmission-grid nodes are expected to be reserved for demand access-capacity auctions. This expectation is linked to the CNMC Resolution of 1 December 2025, which sets out the detailed specifications for determining demand access capacity on the electricity transmission grid and requires the transmission system operator to publish, from 2 February 2026, for the first time, the access capacity available at the transmission-grid nodes. This publication will allow demand-project developers to identify precisely the capacity available at each node and, therefore, is expected to encourage the submission of access requests, which will foreseeably give rise to a greater number of demand access-capacity auctions.
