• Under current legislation, industrial companies can “build” their own electricity substations, but the procedures are complex and the decision on access lies, in the first instance, with the grid operator.

  • The company must bear the costs and, in the case of transferred infrastructure, the transfer does not grant reserved capacity or priority access.

  • Building it does not buy the permit. Access remains essential and is granted by the grid operator.

2 October 2026.

Two weeks ago, the update to our substation map showed that 86.5% of Spain’s substations are saturated and that only 826 of the 6,127 still have available access capacity. While the proposed transmission-grid plan through 2030 remains under consideration, companies that need to connect today cannot wait that long. In this context, agility has become a competitive asset.

This has given rise to a strategic alternative: for industry itself to build part of the infrastructure required for its connection. It is not a new idea on paper, but it is still largely unknown. This option has existed in Spain for years, and it appears that the United Kingdom is also considering applying it. For this reason, at Foro Industria y Energia we have launched an investigation to learn more about this possibility and analyse the advantages and disadvantages that its application could entail for industrial companies, while answering specific questions such as: What exactly can a company build? Which assets does it retain and which does it transfer to the distribution system operator? What does it obtain in return, beyond saving time?

In any event, this is a complex and little-known issue that can be summarised as follows: industrial companies can indeed build their own substations using two different models: either by creating a private substation or by financing infrastructure that they subsequently transfer to the grid. In both cases, however, the initial decision lies with the grid operator: it grants or denies the access permit and determines the connection point and technical conditions, without prejudice to the administrative authorisation of the facilities or the possibility of bringing an access dispute before the CNMC. In today’s article, we examine the finer details.

Two models: the private substation and transferred infrastructure

The private substation. It belongs to the company: it remains under the company’s ownership and responsibility, although its operation and maintenance may be contracted out to third parties (Article 4 of Royal Decree 1048/2013 and Article 38.2 of Royal Decree 1955/2000). It requires administrative authorisation and must comply with the access and connection conditions (Articles 31 and 32 of Royal Decree 1955/2000).

Transferred infrastructure. This is infrastructure that becomes part of the grid. The connection bay at the distribution system operator’s substation is always financed by the consumer and transferred to the grid. Facilities intended to serve more than one company are also transferred. The distribution system operator operates them, but the system only recognises its maintenance costs, not the investment (Articles 12.3 and 25.5 of Royal Decree 1048/2013).

The rules of the game

  • Who pays. Small connections on developed land—up to 100 kW at low voltage and 250 kW at high voltage—are carried out by the distribution system operator in exchange for connection rights. In all other cases, the applicant bears the cost of new-extension facilities, without prejudice to any works on the existing grid that fall to the distribution system operator.
  • Who decides. The distribution system operator sets the connection point, voltage and technical solution, and reserves the right to carry out any intervention on the live grid.
  • Who builds. New-extension facilities, from the existing grid to the first element owned by the applicant, may be built either by the distribution system operator or by an authorised installer selected by the customer. The distribution system operator must provide a separate technical specification and an itemised budget.
  • How long is there to decide? The regulations allow six months to notify who will carry out the work; if this is not done, the application expires.

Building is not enough: in the end, everything depends on technical factors

Building does not guarantee access. It depends on why the grid connection point is saturated, and our latest analysis of the substation map already distinguished between two situations.

The first is a physical problem. We identified 234 substations where there is no room to expand or connect a new bay, affecting 530.8 MW of available capacity. This is capacity that exists but has nowhere to connect, like a power strip with no free sockets. Here, a new bay or substation could make it usable. This is a hypothesis that will have to be confirmed on a case-by-case basis.

The second is an electrical problem. A further 243.3 MW depends on transmission-grid nodes located upstream. If the limitation lies in the grid supplying the substation, building another facility connected to it does not create additional capacity—just as opening a new tap on a pipe without pressure does not provide more water.

Neither transferring the infrastructure nor building one’s own substation guarantees capacity. In the case of transferred infrastructure, the CNMC has held that transferring a facility does not grant the developer reserved capacity or priority access. The reasoning is the same for a private substation: the access permit is a separate procedure from the construction works and is granted by the grid operator according to the capacity available at the node, not according to what is built.

The main advantages: cruising speed versus administrative sluggishness

In both models

  • Control over the timetable. The company can better align the works with the pace of its own industrial project instead of depending on the distribution system operator’s schedule.
  • Price competition. It can compare bids from several authorised installers instead of accepting a single offer.
  • Transparency from the outset. It knows the technical specifications and itemised budget before committing.
  • A possible route to capacity blocked by a lack of space, according to our hypothesis, which must be confirmed.

With a private substation

  • Ownership and control. The company has control over the design, equipment and timetable within its own premises.
  • No obligation to open it to third parties. Since it is for exclusive use, the company does not have to transfer or share it (although the connection bay on the grid is transferred).

With transferred infrastructure

  • No need to operate it. Maintenance, security and quality of supply pass to the distribution system operator.
  • Partial recovery of the investment. The company may require a compensation agreement lasting at least ten years, under which companies connecting later pay their share.
  • Exemption from the reservation fee. Royal Decree-Law 7/2026 exempts transferred infrastructure because it connects several companies—industrial estates and similar developments—and also exempts it from the obligation to maintain the activity for three years.
  • It facilitates the collective development of shared infrastructure.

The finer details: the risks of taking the wheel

In both models

  • The works are costly and paid for by the company.
  • Building it does not buy the permit. Access remains essential and is granted by the grid operator.
  • The applicant bears the construction risk. The applicant assumes a substantial part of the risks associated with execution: processing, coordination, construction costs and possible delays in a project it is carrying out directly.
  • The distribution system operator remains in charge. It retains technical control over the connection: it determines the conditions of the solution, supervises the project and its execution, verifies the facilities and retains exclusive control over works on the existing live grid.
  • Tight decision-making deadlines, with the application expiring if they are missed.
  • Regulatory uncertainty. The regulatory framework envisaged for industrial estates is still pending development, and these permits expire after five years if there is no operating authorisation or transfer.
  • A barrier for SMEs. The model requires capital, technical capacity and construction-project management.

With a private substation

  • The company assumes responsibility for operation, maintenance, security and breakdowns, requiring specialised equipment and personnel.
  • There is no compensation agreement, because nobody else uses the facility and there is no one with whom to share the cost.

With transferred infrastructure

  • The company loses ownership, and the investment is not incorporated into the distribution system operator’s regulated asset base: for the purposes of the system, these facilities generate remuneration only for operation and maintenance. For the developer, recovery of the investment will depend on any compensation agreement and on the subsequent connection of third parties.
  • Compensation is not guaranteed. It depends on other companies connecting during the term of the agreement.
  • Coordination is complex when the project is collective: several companies, cost-sharing arrangements and joint decisions.

What is being debated elsewhere

The United Kingdom is considering something similar. The regulator, Ofgem, is preparing measures to allow large consumers to build and own high-voltage infrastructure, with a consultation scheduled for autumn 2026. Independent operators already existed in distribution. What is now being considered is extending these construction and ownership arrangements to high-voltage assets.

An option worth examining, but no false panaceas

Allowing industry to undertake part of the construction—either privately or through transferred infrastructure—will not solve the system’s structural saturation. Each case will have to be analysed to determine when each model makes sense. But the fact that companies are considering building their own infrastructure in order to connect confirms what our map had already shown: access to energy has a decisive impact on competitiveness.

Reference legislation

  • Law 24/2013 on the Electricity Sector. This is the framework law. It defines distribution activity and distribution grids (Article 38) and establishes the basis for access and connection (Article 33).
  • Royal Decree 1955/2000. Historical regulation. It establishes that consumer connection facilities do not form part of the grid but require authorisation (Articles 31 and 32), and that consumer facilities for exclusive use are outside the distribution grid (Article 38.2). Twenty-five years ago, it already provided that whoever requested a large supply should pay for the extension and transfer it. Part of its provisions on service connections was subsequently repealed by Royal Decree 1048/2013.
  • Royal Decree 1048/2013. Article 21 defines a new grid extension and reserves the setting of the connection point and voltage to the distribution system operator. Article 24 regulates payments, including supervision of transferred assets. Article 25 establishes who pays, who may carry out the works, the six-month deadline, the mandatory transfer when more than one consumer is served, the transfer of the connection bay and the compensation agreement lasting at least ten years. Article 12.3 clarifies that transferred assets are remunerated only for operation and maintenance.
  • Order IET/2660/2015. Defines when grid reinforcement qualifies as a new extension and is therefore borne by the applicant. One of the requirements is that the application exceeds 20% of the previous capacity of the element to be reinforced.
  • Royal Decree 1183/2020. Requires access and connection permits to be obtained before connecting. If the new extension is carried out by an installer, the developer submits the project and execution schedule to the distribution system operator.
  • CNMC Circular 1/2024. Establishes the method for demand access. The grid operator’s preliminary proposal includes the connection point, technical specifications and budget, and states that the connection bay is financed and transferred, as well as the possibility of a compensation agreement.
  • Royal Decree-Law 7/2026 (analysis by Gómez-Acebo & Pombo). Creates a capacity-reservation charge for demand permits with a connection point equal to or greater than 1 kV (Article 11); establishes an exception for transferred infrastructure intended for several consumers; regulates the linking of the permit to the CNAE classification and, pending specific regulatory development, establishes a transitional five-year expiry regime for certain urban-development projects and industrial estates.
  • CNMC Resolution CFT/DE/002/18. This is the criterion establishing that transferring a facility does not grant reserved capacity or priority access.