NISO Attributes Recent Power Allocation Cuts to Transmission Line Outages, Not Generation Shortfall
The Nigerian Independent System Operator, NISO, has attributed the recent changes in power allocations to Distribution Companies in Lagos, Abuja and the Northern corridor to multiple transmission line outages and constrained network capacity, not to a shortage of generation.
In a statement issued by the Management on August 30, 2026, NISO said adjustments were made in the course of normal system operations to keep the interconnected grid within secure operating limits following the loss of critical 330kV lines.
NISO clarified that the availability of generation does not, by itself, guarantee that power can be delivered to a particular load centre. Power transfer depends on the availability and capacity of transmission infrastructure and the prevailing configuration of the network.
The Lagos complex was affected by successive outages of the Olorunsogo–Ayede 330kV Line 1, Benin–Egbin 330kV Line 1 and Benin–Omotosho 330kV Line 1, in addition to the prolonged outage of the Osogbo–Ikeja West circuit. The cumulative loss reduced transmission transfer capability into Lagos. Consequently, NISO curtailed load allocations to Eko Electricity Distribution Company, EKEDC, Ikeja Electric, IE, and the Sakete international supply.
In the Northern corridor, the Shiroro–Mararaba 330kV Line 1 tripped between August 24 and 26, 2026, affecting supply to Abuja and the North. More critically, at 06:47hrs on August 27, 2026, Shiroro–Mando 330kV Line 2 and Mando–Jos 330kV Line 1 tripped simultaneously. With Mando–Jos 330kV Line 1 being the only available circuit serving Jos and the North-East, and Apir–Lafia 330kV Lines 1 and 2 already out due to faults, the outage led to a significant loss of supply to Jos and North-East areas. This necessitated the revision and curtailment of allocations to Kano, Kaduna, Jos, Yola and other affected areas to operate the remaining network within secure limits.
For the Abuja axis, at 03:55hrs on August 29, 2026, Shiroro–Katampe 330kV Line 1 and Gwagwalada–Katampe 330kV Line 1 tripped simultaneously, temporarily constraining supply to Abuja. Both circuits were restored at 07:25hrs and 07:20hrs respectively, after which transmission capacity was recovered.
NISO, as the operator responsible for real-time monitoring, coordination, control and dispatch of the Nigerian Electricity Supply Industry, said where transmission constraints or changes in network configuration affect the ability to safely transfer available power, it must temporarily redispatch generation, curtail load or revise DisCo allocations to maintain system security and prevent wider disturbances.
The organisation said the recent changes in allocations resulted from transmission line outages, constrained transmission capacity and prevailing system configuration, rather than generation availability. The clarification is intended to provide the public with a clear understanding of the circumstances surrounding the recent changes in power allocations.
