The Transmission Company of Nigeria (TCN): What It Does and Why It Matters

by Elsan Editorial Team Power Infrastructure 8 min read
Aerial view of a high-voltage electricity transmission substation in Nigeria at dusk, showing power transformers and steel lattice towers

The Transmission Company of Nigeria (TCN) is the federally owned utility responsible for transmitting bulk electricity across Nigeria’s national grid. Operating at 330kV and 132kV voltage levels, TCN moves power from generating companies (GenCos) to distribution companies (DisCos) using a network of high-voltage transmission lines, substations, and power transformers. As of 2025, TCN has a wheeling capacity of 8,700 MW — making it the single most critical link in Nigeria’s electricity supply chain.

Engineers monitoring Nigeria's national electricity grid in a modern SCADA control room with real-time transmission data on screens

What Is the Transmission Company of Nigeria (TCN)?

The Transmission Company of Nigeria (TCN) is a federal government-owned electric utility company established in 2005 as part of the landmark unbundling of the National Electric Power Authority (NEPA). When President Olusegun Obasanjo signed the Electric Power Sector Reform Act (EPSR Act) into law, NEPA was restructured into 18 successor companies — six generation companies (GenCos), eleven distribution companies (DisCos), and one transmission company: TCN.

Incorporated in November 2005 and granted its transmission licence by the Nigerian Electricity Regulatory Commission (NERC) on 1 July 2006, TCN is headquartered in Abuja, in Nigeria’s Federal Capital Territory. Unlike the DisCos, which were privatised in 2013, TCN retained government ownership to allow for centralised, policy-driven management of the national grid — a strategically deliberate choice given the grid’s role as critical national infrastructure.

TCN is also a member of the West African Power Pool (WAPP), an ECOWAS agency committed to improving cross-border energy flow across the region. In this capacity, TCN supplies bulk power to the Republic of Niger, Republic of Benin, and Togo, positioning Nigeria as a regional energy hub.

What TCN Does: Core Functions Explained

TCN’s licensed activities have historically covered three interconnected functions: electricity transmission, system operation, and electricity trading. However, a landmark structural reform under the Electricity Act 2023 has changed this picture significantly.

2025 Structural Update: Through NERC Order No. NERCC/2024/45, TCN was formally unbundled into two separate entities. TCN retains the Transmission Service Provider (TSP) licence — the “wires” side — while a newly established body, the Nigerian Independent System Operator (NISO), now holds responsibility for the “brain” side: system operations, market operations, and grid code enforcement. NISO’s board was inaugurated in April 2025, with Engr. Abdu Mohammed as Managing Director, marking the start of TCN’s formal separation into two distinct institutions.

1. Transmission Service Provider (TSP) — TCN’s Retained Role

The TSP is responsible for building, maintaining, upgrading, and operating Nigeria’s high-voltage transmission network. This includes:

The TSP evaluates new grid connections and only admits users who meet the requirements laid out in the Market Rules issued by NERC. This ensures the integrity and stability of the national grid.

2. Nigerian Independent System Operator (NISO) — The New System Brain

Previously performed by TCN, system and market operations now sit with NISO. Operating in compliance with the Grid Code, NISO manages real-time load dispatch from GenCos to DisCos, ensures grid security, oversees SCADA/EMS management, and coordinates all electricity market participants for transparent, rule-based operations. NISO was also formally admitted into the West African Power Pool (WAPP) in January 2026, positioning it as Nigeria’s representative for regional grid coordination.

TCN continues to operate its physical infrastructure across 10 transmission regions — Lagos, Osogbo, Kaduna, Kano, Bauchi, Shiroro, Enugu, Port Harcourt, Benin, and Abuja — supported by a National Control Centre (NCC) in Osogbo, three Supplementary National Control Centres, and 10 Regional Control Centers.

Grid Voltage Levels and the Role of the TCN Nigeria Transformer

Understanding how the national grid operates requires a clear picture of Nigeria’s transmission voltage hierarchy. This is where the TCN Nigeria transformer becomes indispensable.

Nigeria’s Transmission Voltage Hierarchy

LevelVoltageFunction
Primary Transmission330kVLong-distance bulk power movement from GenCos
Secondary Transmission132kVSub-regional distribution to load centres
Sub-Transmission33kVHandoff to DisCo injection substations
Distribution11kV / 0.415kVFinal delivery to end users

When electricity leaves a power plant, it is stepped up to 330kV by a generator step-up transformer to reduce current and minimise losses over long distances. At TCN’s 330/132kV receiving substations, large power transformers step the voltage down to 132kV. A second transformation at 132/33kV substations further reduces voltage before power is handed to distribution companies.

Technical cutaway diagram of an oil-filled power transformer showing internal windings, core, bushings and cooling system used in Nigeria's transmission grid

The voltage control policy for TCN’s transmission network is 330kV (±5%/-15%) and 132kV (±10%/-15%), with a system frequency of 50Hz (±4%). Maintaining these parameters is critical — voltage deviations can cause equipment damage, load shedding, and, in extreme cases, total grid collapse.

The grid transformer (or power transformer) is therefore at the heart of every node in this system. A single failed transformer at a major TCN substation can deprive an entire region of bulk power. This explains why transformer procurement, quality, and maintenance are not merely technical concerns — they are economic and social ones.

As a specialist transformer company serving Nigeria’s power sector, Elsan Transformer supplies locally available power transformers that meet the specifications required for integration with TCN’s transmission infrastructure. Having a reliable transformer supplier within Nigeria significantly reduces lead times and procurement risk for utilities, contractors, and industrial customers.

TCN vs DisCos: Understanding the Difference

One of the most common sources of confusion in Nigeria’s power sector is the distinction between TCN and the eleven Distribution Companies (DisCos). The table below clarifies their separate roles:

AttributeTCNDisCos (e.g. EKEDC, IBEDC, IKEDC)
OwnershipFederal GovernmentMajority private (post-2013)
Voltage Level330kV and 132kV33kV, 11kV, 0.415kV
CustomerDisCos (wholesale)Homes, businesses, industries (retail)
Regulatory BodyNERCNERC
Primary RoleBulk power transmissionLast-mile electricity distribution
InfrastructureTowers, HV lines, power transformersDistribution lines, injection substations

In simple terms: TCN moves electricity in bulk across the country; DisCos distribute it to your premises. When there is a power outage caused by a fault on a 132kV or 330kV line, TCN is the entity responsible for fixing it. When there is a fault on the low-voltage distribution network near your home or business, your DisCo is responsible.

This distinction matters enormously for businesses sourcing grid transformers in Nigeria. Injection substations — where 33kV is stepped down to 11kV for distribution — sit at the interface between DisCos and end users. Industrial facilities connected at 33kV or 11kV typically procure their own transformers through vetted transformers dealers who supply equipment compatible with both TCN’s transmission standards and DisCo requirements.

Why Grid Reliability Matters for Businesses and Homes

Nigeria’s grid has experienced well over 230 partial and total collapses since 2010 — NERC’s own data documents at least 222 between 2010 and 2022 alone, with a further 12+ recorded across 2024 and 2025. Each collapse results in total blackouts across entire regions, costing businesses millions in lost productivity and damaged equipment. The World Bank estimates grid outages cost Nigeria approximately $29 billion annually, equivalent to around 10% of 2025 GDP estimates.

The picture is improving, but unevenly. TCN officially recorded a 76.47% reduction in grid disturbances when comparing the five-year period 2020–2024 (20 disturbances) against 2015–2019 (85 disturbances) — a real and significant improvement driven by infrastructure investment and, critically, the deployment of the Generation Dip/Loss Detection System (GLDS) and IoT monitoring tools. However, the grid still collapsed in September 2025, December 2025, and twice in January 2026, a reminder that the structural causes — gas supply debt, ageing infrastructure, and limited redundancy — remain unresolved. A core part of the long-term solution is real-time grid visibility: without SCADA (Supervisory Control and Data Acquisition) systems monitoring voltage, frequency, and load across every substation node, operators cannot detect cascading faults fast enough to isolate them before a full collapse. This is precisely why the Presidential Power Initiative (PPI) with Siemens — covered in the [Expansion section below](Expansion section below) — prioritises SCADA/EMS deployment alongside physical substation upgrades as a paired modernisation strategy.

Nigerian street during a power outage at night showing a business relying on a generator while surrounding buildings remain in darkness

The Transmission Bottleneck

Despite Nigeria having an installed generation capacity exceeding 13,000 MW, the grid regularly transmits far less. Historically, Nigeria’s actual peak transmission has hovered below 5,500 MW — far short of what generation capacity could support. This mismatch is a transmission problem as much as a generation problem: without adequate TCN infrastructure to wheel power, generated electricity simply cannot reach consumers.

In 2025, TCN reported a current wheeling capacity of 8,700 MW — a significant improvement driven by ongoing substation upgrades, reconductoring of ageing lines, and the installation of higher-capacity transformers. For context, in the second half of 2025, TCN installed 15 units of 300MVA power transformers across major substations including Akangba, Lekki, Osogbo, Jos, Kumbotso, and Benin — the first time transformers of that capacity had been deployed in Nigeria’s national grid.

Why This Matters for Transformer Procurement

For industrial facilities, real estate developers, telecom operators, and manufacturers, understanding TCN’s infrastructure constraints helps inform smarter energy planning decisions. When grid supply is unreliable, businesses turn to embedded generation and private distribution networks — both of which require distribution and power transformers sourced from a credible transformer dealer in Nigeria.

Working with reputable transformer suppliers who understand local grid conditions — voltage levels, impedance requirements, and the relevant standards set by NEMSA (Nigerian Electricity Management Services Agency) and NERC — is essential for ensuring that equipment purchased today is compatible with a grid that is rapidly being upgraded.

For guidance on selecting the right transformer for your facility or project, visit Elsan Transformer’s Power Transformers resource page or contact their team directly.

TCN’s Ongoing Expansion and Modernisation Projects

TCN is currently implementing a number of major projects designed to address the historic infrastructure gaps that have constrained Nigeria’s power supply.

World Bank and AfDB-Funded Projects

TCN is implementing several donor-funded projects worth a combined $1.16 billion, supported by development partners including the World Bank and the African Development Bank. These projects fund substation construction, transformer procurement, and grid digitalisation.

Presidential Power Initiative (PPI) with Siemens

The PPI — a tripartite agreement between Nigeria, Germany, and Siemens — targets the modernisation of Nigeria’s transmission and distribution infrastructure. The initiative aims to upgrade substations, deploy Supervisory Control and Data Acquisition (SCADA) systems, and expand grid capacity incrementally.

WAPP Synchronisation and Regional Power Trade (June 2026 Target)

One of the most consequential milestones in Nigeria’s power sector history is now imminent. On 8 November 2025, Nigeria successfully conducted a landmark 4-hour grid synchronisation trial with all 15 West African countries through the West African Power Pool — the first time in history that Nigeria’s grid operated in a unified, fully harmonised configuration with the rest of the region. NISO was formally admitted into WAPP in January 2026.

NERC has confirmed a target of June 2026 for full permanent synchronisation, which would allow Nigeria to trade electricity seamlessly across the region. The Federal Government projects up to $1 billion in annual revenue from electricity exports at the prevailing regional tariff of approximately $0.19/kWh — far above domestic Nigerian tariff levels. For context, this would position NISO and TCN’s transmission infrastructure as the backbone of a literal regional energy market.

The Nigerian component of the North Core Transmission Project (NETAP) further supports this vision, connecting Nigeria, Niger, Benin, and Burkina Faso on a 330kV line to deepen cross-border power trade.

Recent Substation Upgrades (2025–2026)

Electrical engineers installing a large power transformer at a Nigerian TCN transmission substation as part of the 2025 grid expansion programme

These upgrades demonstrate that the grid transformer in Nigeria is not just a passive component — it is the primary instrument through which TCN expands the grid’s capacity to meet Nigeria’s growing power needs. For businesses, contractors, and utilities tracking these developments, sourcing transformers from a local transformer company with deep knowledge of Nigeria’s grid standards significantly reduces procurement risk compared to sourcing from foreign suppliers with longer lead times.

For more on transformer specifications relevant to Nigeria’s grid environment, see Elsan Transformer’s full product range.

Frequently Asked Questions

What does TCN stand for in Nigeria? TCN stands for the Transmission Company of Nigeria. It is the federally owned company responsible for transmitting bulk electricity across Nigeria’s national grid, operating at 330kV and 132kV voltage levels.

Who owns the Transmission Company of Nigeria? TCN is wholly owned by the Federal Government of Nigeria. Unlike the DisCos, which were privatised in 2013, TCN retained government ownership to allow for centralised management of the national grid as critical public infrastructure.

What is TCN’s current wheeling capacity? As of 2025, TCN has a reported wheeling capacity of 8,700 MW across its 330kV and 132kV transmission network.

What is the difference between TCN and DisCos? TCN transmits bulk electricity at high voltage (330kV and 132kV) from power plants to distribution load centres. Distribution Companies (DisCos) then take this bulk power and distribute it at lower voltages (33kV, 11kV, 0.415kV) to homes, businesses, and industries.

What voltage levels does TCN operate? TCN operates primarily at 330kV (primary transmission) and 132kV (secondary transmission). Power is stepped down through large power transformers at TCN substations before being handed to DisCos at 33kV.

How many substations does TCN operate? TCN’s historical network includes over 23 substations at 330/132kV and over 91 substations at 132/33kV rating, spread across 10 transmission regions nationwide.

Why does the national grid collapse so often in Nigeria? Grid collapses are caused by a combination of infrastructure deficits, vandalism, gas supply shortfalls to thermal GenCos, inadequate redundancy, and cascading voltage or frequency instability at key nodes. NERC data documents at least 222 partial and total collapses between 2010 and 2022, with further collapses in 2024, 2025, and early 2026. TCN has recorded a 76.47% reduction in disturbances comparing 2020–2024 against 2015–2019, aided by the GLDS and IoT monitoring tools — though structural challenges remain.

How can a business procure a transformer compatible with TCN’s grid? Businesses should work with a NEMSA-recognised transformer supplier who understands TCN’s voltage specifications and NERC standards. Elsan Transformer offers locally available transformers suited to Nigeria’s grid environment. Always engage a qualified electrical engineer and NEMSA-licensed contractor for installation and commissioning.

Is TCN part of the West African Power Pool? Yes. TCN is a member of the West African Power Pool (WAPP) and currently provides bulk power supplies to Niger, Benin, and Togo.

What is SCADA and does TCN use it? SCADA (Supervisory Control and Data Acquisition) is a real-time monitoring and control system for power grids. TCN’s SCADA/EMS project — funded by the World Bank and contracted to NR Electric — was reported at 69% completion as of early 2025, with control centres in Osogbo and Gwagwalada nearing readiness. In the interim, TCN deployed its in-house GLDS (Generation Dip/Loss Detection System) and IoT monitoring tools to improve grid visibility, expanding monitored generator stations from 6 to 27. SCADA remains one of the most consequential infrastructure projects in Nigeria’s power sector.

What is NISO and how does it relate to TCN? NISO (the Nigerian Independent System Operator) was established under the Electricity Act 2023 through NERC Order No. NERCC/2024/45. It took over TCN’s system and market operations role, becoming the “brain” of the grid while TCN’s TSP unit retains the physical “wires.” NISO’s board was inaugurated in April 2025. It is now Nigeria’s representative in the West African Power Pool (WAPP) and oversees real-time grid dispatch, Grid Code enforcement, and electricity market operations.

Summary

The Transmission Company of Nigeria (TCN) is the backbone of Nigeria’s electricity supply chain. Established in 2005 from the unbundling of NEPA, it is responsible for wheeling bulk power across the national grid using a network of high-voltage transmission lines, substations, and power transformers operating at 330kV and 132kV. Under the Electricity Act 2023, TCN has itself been further unbundled: it now operates solely as the Transmission Service Provider (TSP), maintaining the physical grid infrastructure, while the newly established NISO handles system and market operations.

With a current wheeling capacity of 8,700 MW (targeting 10,000 MW), ongoing substation upgrades backed by over $1 billion in donor funding, a WAPP full synchronisation target of June 2026, and a clear mandate to integrate renewable energy into the national grid, TCN is undergoing the most significant structural and operational transformation in its history. For businesses, contractors, and utilities operating in Nigeria’s power sector, understanding this evolving landscape — and sourcing transformers from credible, locally present suppliers — is essential for making informed decisions about grid connectivity and energy planning.

External References

Disclaimer: This article is intended for educational and procurement guidance purposes. Always consult a qualified electrical engineer and engage NEMSA-licensed contractors for transformer installation and commissioning in Nigeria. Transformer specifications, prices, and regulatory requirements may change — verify current information with your supplier and NEMSA before finalising any purchase.