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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PFV Nöhra Sud

Operation and Maintenance

PFV Nöhra Sud

Construction of a photovoltaic plant with a capacity of 5.5 MW, featuring a fixed structure, delivered under a turnkey contract, including operation and maintenance services.

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“Cruce de Cabral” Project

Electrical Substations

“Cruce de Cabral” Project

The Cruce de Cabral project involves the construction and expansion of 3 Electrical Substations located in the southern region of the Dominican Republic:

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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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ADD Approach Light System Runway 20

ADD Approach Light System Runway 20

Ampliación del Sistema de Aproximación de la Cabecera de Pista nº20, realizándose una carretera de servicio de mantenimiento, para la instalación de las nuevas luces de aproximación para la pista de vuelo. Incluye el desmontaje de parte de la valla de seguridad de la base y la ampliación de la misma.

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FTTH and FTTN Network Deployment

FTTH and FTTN Network Deployment

SEMI has been involved in the deployment of FTTH networks, with over 100,000 homes passed, and FTTN links, with more than 3,000 connected nodes. These projects add to SEMI’s extensive experience in the deployment and maintenance of fixed networks, both for operators and carriers, as well as utilities, in aerial and underground environments.

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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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400 kV León Substation

400 kV León Substation

Electromechanical assembly of the new 400 kV substation.

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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 […]