The gas-fired and hydropower Generation Companies (GenCos) have called on the Transmission Company of Nigeria (TCN) to improve the transmission networks to save their generating machines from recurring frequency oscillations.
Its umbrella body, the Association of Power Generation Companies (APGC) told the Daily Trust at the weekend that the “Frequency oscillations which is due to weak transmission network have adverse effects on the generators, units and station auxiliaries in both the thermal and hydro power plants.”
APGC said one of the effects is the increase in both the machines’ fixed maintenance cost and variable maintenance costs. It added that the Grid Code of the Nigerian Electricity Regulatory Commission (NERC) provides for how the risks should be shared amongst the market participants.
The Executive Secretary of APGC, Dr. Joy Ogaji said the about 24 operational GenCos are designed to operate optimally and efficiently at base loads but operating less than these causes reduction in efficiency and a hike in gas consumption by 15 to 20 per cent that is not captured in the tariff – Multi Year Tariff Order (MYTO).
She told our reporter that when system collapse occur as it was last week, the number of Start and Stops of those machines increases the machines and turbines’ Equivalent Operating Hours (EOH) triggering more maintenance cost.
APGC said the generating firms have been operating under high frequency which it described as ‘System Stress Zone’ in the Grid Code ranging from 48.75 Hertz (Hz) to 51.25Hz which is against the normal 49.75 – 50.25 Hz band.
“This high frequency is damaging the generators and it also induces high temperature and overheating in the rotor,” Ogaji lamented.
The GenCos therefore demanded the immediate installation of regulatory spinning reserve on the network, implementation of the reviewed ancillary services and utilisation/payment for spinning reserve procurement.
They also urged NERC to immediately intervene by ensuring strict adherence to the Grid Code by the National Control Centre (NCC), a technical section of TCN in Osogbo that controls electricity transmission frequency.
They noted that with the introduction of a free governor control system last year, their plants are now being run as regulating power reserves by TCN to stabilise the national grid at the detriment of the machines.
