Energy

Leading the change towards a more sustainable future.

Líneas de Negocio - Energía

Telecommunications

Advanced solutions for a constantly evolving market.

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Special Projects

Transforming major challenges into unique solutions.

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Energy

Líneas de Negocio - Energía

Telecommunications

Special Projects

Welcome to SEMI

Tradition, experience, and future.

Over 100 years driving the electrical and industrial sectors through innovation, excellence, and quality in all our services.

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Key Figures 2025

0M€

Annual Production

Professional Employees

Our Clients

Clients with whom we have shared successes and goals.

Business Lines

Líneas de Negocio - Energía

Energy

The energy sector faces increasingly pressing challenges, such as the need to address growing energy demand driven by consumption in the most prosperous countries and the emerging needs of developing nations.

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Telecommunications

SEMI began its Telecommunications activity in the 1950s, participating in the construction of Television, Telephone, and Radio networks. Today, we have extensive experience in deploying Fiber Optic Networks and Mobile Telephony Networks.

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Líneas de Negocio - Telecomunicaciones
Líneas de Negocio - Telecomunicaciones

Special Projects

Over time, SEMI has excelled in the execution of specialized civil works, with a particular focus on projects for the Armed Forces, industrial facilities, and demolition and dismantling works, among others.

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Featured Projects

Explore our most outstanding projects

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Telecommunications in the Railway and Metro Sector

Fiber Optic Networks

Telecommunications in the Railway and Metro Sector

The synergies between our Railways and Communications business lines enable us to provide clear added value in telecommunications solutions for railway environments. As a result of these synergies, we have successfully undertaken various projects: We have certified Pilots and Supervisors, allowing us to execute these projects autonomously and on a turnkey basis. Key Projects:

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AIRCRAFT PARKING EXPANSION

Specialized Civil Works

AIRCRAFT PARKING EXPANSION

The primary objective of this project is to protect aircraft from Foreign Object Damage (FOD). To achieve this, a Design and Construction project was carried out at the Rota Naval Base Airport, involving improvements to the shoulders of the runway and taxiway, as well as a new Drainage System based on the modification and expansion […]

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Demolish NSGA Facility

Demolish NSGA Facility

Demolición de 8 Edificios y sus Vías de Acceso, incluso desmantelamiento de las instalaciones y equipos con recuperación de materiales. Posteriormente el reacondicionamiento paisajístico de toda la zona tratada.

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Rehabilitation of Distribution Networks

Rehabilitation of Distribution Networks

Replacement and extension of the Medium Voltage (MV) network, installation of transformers, expansion of the Low Voltage (LV) network, and installation of prepaid and postpaid meters.

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Digitalization Plan EN 61850

Digitalization Plan EN 61850

Implementation of IEC 61850 as the main communication protocol in the new telecontrol systems of ENEL’s High Voltage Substations, using IDACS+ technology.

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PE Andella

PE Andella

A 50 MW wind farm, with works consisting of civil construction, as well as electrical infrastructure and power evacuation systems.

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Commissary & Navy Exchange

Commissary & Navy Exchange

Construction of a building designated for a shopping center and warehouses with a total built area of 19,000 m², including public roads and parking facilities.The building features a metallic structure with trusses and a full perimeter of reinforced concrete walls. The project included all standard installations as well as industrial refrigeration chambers.

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SEMI Around the World

México

Alemania

Francia

República Dominicana

Rumania

El Salvador

España

Panamá

Grecia

Perú

Emiratos Árabes Unidos

Chile

Uruguay

Arabia Saudita


21 April 2026

News

Safety Awareness and Reflection Sessions

On March 25 and 26, SEMI suspended its activity in Galicia and León to hold awareness and reflection sessions on safety, with a strong focus on prevention and raising awareness. These sessions, held in Ourense and León, were attended by our CEO, Maikel García, as well as Berta Domínguez, HSQ Director, and Julián de Bustos, […]


21 April 2026

News

In line with its commitment to young talent

SEMI is once again taking part in Leoni4, a meeting forum that brings together university students from the Schools of Engineering and companies from the province of León, allowing them to learn first-hand about the companies where they can develop their professional careers.


18 February 2026

News

SEMI participates in the recovery of the electrical grid in Portugal after storm Kristin

From SEMI, we have traveled to our neighboring Portugal to collaborate in the recovery work of the E-REDES distribution network, affected by storm Kristin. The Northwest Electricity Delegation team has been in charge of carrying out this deployment, thus reinforcing our presence and operational capacity at a particularly complex time. Our commitment and vocation for […]