Information regarding the procurement notice titled DB.ATT.35 400/154/33 kV DEVEKIRAN Air Insulated Substation (AIS) can be accessed through the EKAP Public Procurement Bulletin and at the following link: <a target="_blank" rel="noopener noreferrer" href="https://www.teias.gov.tr/en-US/bids">https://www.teias.gov.tr/en-US/bids&nbsp;</a>

DB.ATT.35- Invitation For Bids

Request for Proposals (RFP) for the “Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications” submission date has been postponed from 23.03.2026 at 11.00 to 25.03.2026 at 14.00 as a result of the issued addendum.

ADDENDUM- REQUEST FOR PROPOSAL-Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications

Request for Proposals (RFP) for the “Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications” submission date has been postponed from 18.03.2026 at 10.30 to 23.03.2026 at 11.00 as a result of the issued addendum.

Request for Proposals (RFP) for the “Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications” submission date has been postponed to 18.03.2026 at 10:30 as a result of the issued addendum.

ADDENDUM - REQUEST FOR PROPOSAL - Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications

As a result of the evaluation of the firms that submitted an Expression of Interest under the Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications, the shortlist has been established as shown below.<figure class="table"><table><tbody><tr><td style="border:1.0pt solid windowtext;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">Leader(Name and Nationality)</td><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:none;border-right-style:solid;border-top-style:solid;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:156.05pt;">Members of the JV (if any) (Name and Nationality)</td><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:none;border-right-style:solid;border-top-style:solid;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.9pt;">Sub-Consultant (if any) (Name and Nationality)</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">AtkinsRealis Inc. (Canada)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:148.9pt;">-</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">CESI S.p.A. (Italy)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;vertical-align:top;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:148.9pt;">Eltem-tek Elektrik Tesisleri Muhendislik Muteahhitlik Danismanlik ve Ticaret A.S. (Türkiye)</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">Elia Grid International (EGI) (Belgium)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;vertical-align:top;width:148.9pt;">MRC (Türkiye)</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">Manitoba Hydro International Ltd. (MHI) (Canada)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:148.9pt;">-</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">RTE International (France)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:148.9pt;">EPRI (The Electric Power Research Institute) (United States) &amp; MRC (Türkiye)</td></tr><tr><td style="border-bottom-style:solid;border-color:windowtext;border-left-style:solid;border-right-style:solid;border-top-style:none;border-width:1.0pt;padding:0cm 5.4pt;vertical-align:top;width:148.65pt;">Siemens Energy Global GmbH &amp; Co. (Germany)</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:156.05pt;">-</td><td style="border-bottom:1.0pt solid windowtext;border-left-style:none;border-right:1.0pt solid windowtext;border-top-style:none;padding:0cm 5.4pt;width:148.9pt;">-</td></tr></tbody></table></figure>Request for Proposal documents have been sent to the shortlisted firms, and the proposals will be opened on 04 March 2026 at 10:30 a.m. at the Meeting Hall of the Trade Department.

REQUEST FOR PROPOSAL-Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications

Terms of Reference for Consultancy Services for HVDC Transmission Facility are provided below.&nbsp;

Terms of Reference for Consultancy Services for HVDC Transmission Facility

Environmental and Social Management Framework Document for the Additional Finance for the Renewable Energy Integration Project (REIP) Supported by the World Bank in Türkiye

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Integrated Management Policy

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As Turkish Electricity Transmission Corporation (TEİAŞ), we have a long history based on the Turkish Electricity Authority, which was founded in 1970 and we're moving towards bigger goals more decisively, proud of leaving behind the years full of achievements since 2001 that we started our journey under the name of TEİAŞ.&nbsp;With our strong heritage that we received from the past, we operate the electricity transmission system and network of Türkiye at international standards, in a good quality and economical and reliable manner.&nbsp;While expanding our electricity transmission infrastructure each day in parallel with the developments in the energy need, we cross the mountains and deep straits that are difficult to overcome with our electricity transmission lines and we 24/7 transmit Türkiye’s energy all over the country with our 18.000 employees, 22 regional directorates and 10 load dispatch centers.&nbsp;Today, while taking firm steps with the vision of being a leading system and network operator compatible with our country's national energy policies and integrated into international energy markets, we are continuously making contributions to the economy of our country with our strong financial structure and qualified expert staff.&nbsp;We have great goals for the coming period. Within the framework of our agreement with the first nuclear power plant of our country, we will connect the produced energy to our electricity transmission system. In this context, we started the construction works of 6 high voltage lines.&nbsp;As TEİAŞ, with my colleagues, we will continue our services for the bright future of our country and continue being the “Power of Energy”.&nbsp;Best regards,&nbsp;Orhan KALDIRIM Chairman of the Board General Manager

Message from our General Manager

A meeting was held between our Corporation and the ENTSO-E delegation.&nbsp;Meeting Held Between Our Corporation and the ENTSO-E Delegation&nbsp;On 14 July 2026, our Corporation hosted an ENTSO-E delegation to discuss opportunities for further strengthening the existing cooperation between our Corporation and ENTSO-E, as well as the next steps regarding the continuation of our Observer Membership process.&nbsp;The meeting was chaired by Mr. Mustafa PUSTU, General Manager and Chairman of the Board of our Corporation. The ENTSO-E delegation was represented by Mr. Zbynek BOLDIS, President of the ENTSO-E General Assembly, and Mr. Damian CORTINAS, Chair of the ENTSO-E Board.&nbsp;During the meeting, the parties exchanged views on enhancing the existing cooperation between our Corporation and ENTSO-E and reaffirmed their shared commitment to maintaining close collaboration and advancing the Observer Membership process in the period ahead.&nbsp;

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Meeting Between TEİAŞ and ENTSO-E

TEİAŞ had the pleasure of hosting the OPC/STA Summer Summit 2026 in Istanbul from 16–18 June, welcoming representatives from Transmission System Operators (TSOs), Regional Coordination Centres (RCCs), and ENTSO-E to strengthen cooperation and exchange expertise on Outage Planning Coordination (OPC) and Short-Term Adequacy (STA) assessments. The summit provided a valuable forum to review the progress achieved during the first half of 2026, align on upcoming milestones, and discuss key priorities for the months ahead. The discussions reinforced the importance of close collaboration and coordinated operational planning in maintaining a secure, reliable, and resilient interconnected European electricity system, particularly as the energy transition continues to reshape power system operations. We thank all participants for their valuable contributions, insightful discussions, and collaborative spirit. Through continued collaboration, we strengthen regional cooperation and contribute to the secure and efficient operation of Europe's interconnected electricity network.

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OPC/STA Summer Summit 2026 - Istanbul

An agreement for a 750 million dollar loan was signed between our corporation and the World Bank for the "Transmission System Transformation" project.&nbsp;&nbsp;This significant step, which will make our country's energy future more reliable and efficient, was taken in the presence of the Honorable Minister at the 11th Energy Efficiency Forum and Exhibition held on October 6-7 at the Istanbul Congress Center.

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750 Million Dollar Agreement Signed Between Our Corporation and the World Bank

On the second day of the 11th Energy Efficiency Forum and Exhibition, held on October 6-7 at the Istanbul Congress Center, our Deputy General Manager, Mr. Deniz Coşkun, was among the speakers on the highly-attended panel titled "Redesigning the Energy System: Energy 2.0." Mr. Deniz Coşkun evaluated critical topics such as the transition to renewable energy sources, the digitalization of energy grids, and our corporation's role in this process.

Our Deputy General Manager, Mr. Deniz Coşkun, Spoke at the Panel within the 11th Energy Efficiency Exhibition

Under the auspices of our Ministry, we participated in the 11th Energy Efficiency Forum and Exhibition, held on October 6-7 at the Istanbul Congress Center.&nbsp;&nbsp;At this event, which is of critical importance for Turkey's energy future, we shared our role in national energy transmission and our efforts in the field of energy efficiency. We met with industry stakeholders to evaluate the steps to be taken for an efficient and sustainable energy system.

Our Corporation Participated in the 11th Energy Efficiency Forum and Exhibition

A workshop titled “Towards an Integrated Euro-Mediterranean Electricity Market: Overcoming Technical and Policy Barriers” was held on May 27, 2025, in Antalya, hosted by the Energy Market Regulatory Authority (EMRA) and Turkish Electricity Transmission Corporation (TEİAŞ), in collaboration with the Association of Mediterranean Energy Regulators (MEDREG) and the Mediterranean Transmission System Operators (Med-TSO).The event brought together key stakeholders including representatives from MEDREG, Med-TSO, the European Commission, General Secretariat of the Arab League, and other major sectoral institutions. Topics discussed included cross-border interconnections, the integration of renewable energy, and the development of a harmonized regulatory framework.Co-financed by the European Union, the workshop reaffirmed MEDREG and Med-TSO's shared commitment to building a compatible and sustainable Mediterranean energy system. Emphasis was placed on strengthening regional electricity connections to enhance grid stability, integrate renewables, and improve energy security across the Mediterranean.The opening speech was delivered by TEİAŞ Chairman and General Manager Mr. Orhan KALDIRIM. Among the prominent attendees were EMRA President Mr. Mustafa YILMAZ, European Commission Director General for the MENA region Mr. Stefano SANNINO, Med-TSO President Mr. Sabah MASHALY, and MEDREG Director Mr. Hasan ÖZKOÇ.

Strengthening Energy Cooperation in the Mediterranean

During the 11th Southern Gas Corridor Advisory Council and the 3rd Green Energy Advisory Council Ministerial Meeting, held on April 4, 2025, in Baku, Azerbaijan, an Operational Agreement was signed between TEİAŞ and AZERENERJI, Azerbaijan's electricity generation and transmission company.With this agreement, electricity trade opportunities between Türkiye and Nakhchivan have begun.

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Operational Agreement Signed Between TEİAŞ and AZERENERJI

Within the scope of the visit of the Uzbekistan Delegation to our Corporation, an experience sharing meeting was held at the General Directorate of our Corporation under the chairmanship of our Deputy General Manager, Mr. Deniz COŞKUN, on 15 October 2024, with the participation of our Ministry, EÜAŞ and TEMSAN officials.&nbsp;In addition to the delegations of the Ministry of Energy of the Republic of Uzbekistan and the Ministry of Economy and Finance, officials of the O'zbekgidroenergo company also attended the meeting. Following the opening speech of our Deputy General Manager, Mr. Deniz COŞKUN, a presentation was made about EÜAŞ by an EÜAŞ official, and a presentation was made by an official of our Corporation on the integration of renewable energies into the transmission system, and the questions of the Uzbekistan side on the subject were answered. Following the meeting, a visit to the National Load Dispatch Center was made.

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The Republic of Uzbekistan Ministry Delegation and O'zbekgidroenergo Company Officials Visited Our Corporation

The delegation consisting of Ambassador of the Republic of Sudan Mr. Nadir Yousif ELTAYEP, Sudan's Ministry of Energy and Petroleum and Sudanese private company officials visited our Corporation on 14 October 2024 to evaluate cooperation in the field of electrical energy transmission.&nbsp;&nbsp;Following the opening speech made by Deputy General Manager Mr. Deniz COŞKUN, Sudanese officials provided information regarding Sudan's electricity transmission network and projects, pointed out the importance of our Corporation's experiences, especially in the field of electricity transmission, and requested our support in sharing experience.&nbsp;A contact point has been determined by our Corporation to take steps in this context, and it has been communicated that the necessary work can be initiated in close coordination with Sudan.

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A Cooperation Meeting Was Held Between The Delegation of The Republic of Sudan and Our Corporation

The 63rd Board Meeting of the Coordinated Auction Office in South East Europe (SEE CAO), of which our organization is among the partners, was held in Ankara on 10 October 2024.&nbsp;In addition to TEİAŞ, representatives of transmission system operators from Albania (OST), Bosnia and Herzegovina (NOSBİH), Montenegro (CGES), Kosovo (KOSTT), Croatia (HOPS), Macedonia (MEPSO), Greece (IPTO) and officials from the SEE CAO office attended the meeting.&nbsp;Within the scope of the meeting, the chairman and deputy of the SEE CAO board of directors, who will serve for the next 2 years, were determined. Serhat METİN, Head of Planning and Investment Management Department, was elected as the new president of SEE CAO by receiving the majority of the votes. In addition, at the same meeting, Foreign Relations Manager H. Mehmet KARA was appointed as the 9th member of the Board of Directors of SEE CAO. H. Mehmet KARA will hold this position for 1 year.

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Serhat Metin, Our Head of Planning and Investment Management Department, Was Elected As The Chairman of The Board of Directors of SEE CAO

We work continuously with our live maintenance teams in our energy transmission lines and Substations to ensure uninterrupted and quality electrical energy, minimize interruptions and reduce energy and production losses.We perform these live maintenance applications in two ways: The first one is the distance working method. Here, our operators carry out maintenance work with isolated rods (an insulating apparatus with a hook end used for safety during maneuver) and equipment connected to these rods, taking into account the distances calculated and to be complied with before the operation. The second one is the method of working on potential.In this method, our operators perform the work depending on certain rules and distances, by entering into the same potential with the system potential in three different ways. Vehicles such as positioning chair, ladder and insulated tower, isolated crane are used to provide the operator the same potential with the system potential. With our investments in Research &amp; Development and innovation, we provide saving of both source and time, transmit Türkiye's energy 24/7 all over our country.

Canlı Bakım | TEİAŞ

We continue our live maintenance activities, which we started to implement in 2014, by expanding all over our country.

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Live Maintenance

We have been providing energy security of supply of the region by connecting Europe and Asia under the sea at the Dardanelles Strait since we launched first high-voltage submarine cabling project of Türkiye in 2015.The first project put into service, is 3.9 km long Lapseki 1 - Sütlüce 1 submarine cable and it is the first jointless project in the world at 400 kV at this length. After this project, we implemented the second submarine cable project with 4.1 km long Lapseki 2 - Sütlüce 2 line in 1 km south.The connection consists of a 4-circuit double-circuit alternating current (AC) energy transmission system, each with a capacity of 1000 MW between Lapseki substation on the Asian side and Sütlüce substation on the European side.

Deniz Altı Kablolama  | TEİAŞ

We deliver the electricity produced in South Marmara with submarine cable projects under the Dardanelles Strait to all Thrace, particularly to Istanbul.

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Submarine Power Transmission Cable

Live maintenance operations with helicopter are carried out in high-voltage lines without interrupting the power by using a method that is applied for the first time in Türkiye in 2019. First of all, energy transmission lines are aerial surveyed by helicopter. At the specified points, each of the insulators, which are polluted over time due to dust, sand, chemical wastes, pesticides, sea salt, and which may cause malfunctions, are cleaned with purified water sprayed from the helicopter in about two minutes.On the other hand, in live maintenance activities with helicopters, energy transmission lines, which are difficult to access from the ground, are provided by aerial access and malfunctions are eliminated or periodic maintenance works are carried out. The works are carried out by our technicians in the basket with isolated ropes hanging from the helicopter, with live maintenance method without de-energizing the line.

Helikopterli Bakım Site

Thanks to live maintenance with helicopter, we carry out maintenance activities in the areas that are difficult to reach, meters above the ground without switching off the energy of the system.

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Live Maintenance with Helicopter

Mobile Substations are of great importance for Türkiye's energy supply security. It can quickly meet the energy requirement in the region in case of a natural disaster or maintenance-failure of the SubStations in the operation. There are 12 mobile Substations in our company.Long processes are required to establish fixed Substations in the energy sector. In addition, with the migration waves, rapid increases can occur in energy requirement. Mobile Substations are portable substations with 154 / 33.6 kV 50 MVA power and capable of meeting the energy requirement of a medium-sized city. The mobile SubStations that are put into service weigh 150 tons and are 27 meters long. They are transported by a special trailer with high maneuverability.These Substations become ready for service in a few days where additional power is needed.

Mobil Trafo  | TEİAŞ

With the Mobile Substations, we meet the energy requirement quickly when additional power requirements arise in the energy transmission system.

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Mobile Substations

The National Load Dispatch Center has the most important function in ensuring the real-time generation-consumption balance by maintaining the security and supply quality of the national energy generation and transmission system and operating the 400 kV transmission system that forms the main backbone of the network and operating the balancing power market and real-time ancillary services market.Regional Load Dispatch Centers mainly carry out 154 kV transmission system operation, maneuver, data collection and evaluation activities.Within the scope of load dispatch operation, electricity supply and demand is balanced in real time, the Balancing Power Market and Ancillary Services Market are operated, operational planning is carried out, international interconnection lines are operated, faulty situations and planned work maneuvers are carried out, short-term energy planning is made, daily operation programs and load frequency control are performed, N-1 analyzes are carried out to establish system security.

Yük Tevzi Merkezi | TEİAŞ

We 24/7 operate the electricity transmission system of our country with the National Load Dispatch Center and 9 Regional Load Dispatch Centers.

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Load Dispatch Control Centers

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Energy Transmission Line (by the end of June 2026)

77.188 KM

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Installed Capacity (by the end of July 16, 2026)

126.138,66 MW

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Annual Electric Energy Generation (by the end of March 2026)

90,8 TWh

Annual Electric Energy Consumption (by the end of March 2026)

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90,0 TWh

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0,3 TWh

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1,1 TWh

High-Voltage Substations (by the end of June 2026)

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The requirement for Research & Development and innovation emerging due to the international competition and globalization process in the world is gaining importance for companies. We are closely following these requirements emerging worldwide nowadays and we are renewing and improving our current activities every day in this direction. Thus, we save time and reduce our costs. While continuously maintaining our technology investments, we 24/7 transmit Türkiye's energy all over our country.

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Integrated Management Policy

Announcements

18 Haziran 2026DB.ATT.35- Invitation For Bids

23 Mart 2026ADDENDUM- REQUEST FOR PROPOSAL-Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications

10 Mart 2026ADDENDUM- REQUEST FOR PROPOSAL-Consultancy Services for Preparation of HVDC and Owner’s Engineer Technical Specifications

Meeting Between TEİAŞ and ENTSO-E

Technology

Research-Development and Innovation

Live Maintenance

Submarine Power Transmission Cable

Live Maintenance with Helicopter

Mobile Substations

Load Dispatch Control Centers

Statistic Data (Values are live, gross and temporary)

Electrical Transmission in Türkiye

Production Share of Renewable Energy

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Hydro

Wind

Thermal

Sun

Others