Power: Kainji, Jebba Cut Output Constraints with Water Forecast System

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Chineme Okafor in Abuja
Two of Nigeria’s three hydro power plants – 760 megawatts (MW) Kainji and 578.4MW Jebba plants, would be able to maintain optimum efficiency in the amount of electricity they generate following the installation of a state-of-the-art water management system at their operational site, the Chief Operating Officer (COO), of Mainstream Energy Solutions Limited (MESL), Mr. Jose Villegas, has disclosed.

Villegas, told journalists during a recent tour of the plants in Niger state that the innovative water management system – Inflow Forecasting System and Operational Planning Tool (IFS-OPT) had been installed at the plants’ water basin by Austrian firm Pöyry Energy, and would enable them maximise their generations during periods of high and low rainfalls.

Speaking alongside MESL’s Operations Supervisor for Jebba, Mr. John Onimisi, Villegas, explained that efficient water management using the IFS-OPT would also keep the plants turbines in good condition, in addition to helping them manage their water discharge to avoid instances of flooding of communities on their downstream.

According to Villegas and Onimisi, water inflow into Kainji and Jebba reservoirs which is usually from Guinea, Niamey in Niger Republic, and of course rainfalls from communities in northern Nigeria are usually subject to strong seasonal variability, with a distinct low flow period and two distinctive seasons of high flows that are categorised as white and black flood.

These periods, they noted are also usually categorised by strong short-term changes in water inflow, and as such required good water management to keep electricity generation from the plants optimal, thus the decision of MESL to implement the IFS-OPT.

“We have black flood which takes off from Guinea, and white flood which comes from Niamey and northern Nigeria, and we need to manage these inflows into our reservoir. In order to improve the operation of the hydropower cascade we have implemented an Inflow Forecasting System (IFS) and Operational Planning Tool (OPT).

“The system will provide us a long-term and short-term water inflow forecasts to support our seasonal, monthly and daily generation plans. The objective is to improve flood safety while maximising the energy output under given constraints,” said Onimis, in his explanation of the workings of the IFS-OPT.

The duo stated that the main components included a hydrological model that covers the whole Niger basin, a river and reservoir routing module, as well as a reliable database and graphical user interface operated on a central server at the hydropower plant.

They noted that the application provides seasonal water inflow forecasts at monthly resolution as well as short-term forecasts at daily resolution using satellite-based rainfall observations and numerical weather and climate forecasts as input.

Jebba and Kainji, they added are about the only two hydro plants in the country with the IFS-OPT system.
Similarly, Villagas, stated that the plants were not allowed to operate at their optimal capacities because of frequent requests from the National Control Centre (NCC) Osogbo, on it to cut down its output on account of distribution companies’ inabilities to take maximum power put on the grid.

He stated that in addition to this, Kainji and Jebba Gencos do not get capacity payments for their available generation capacities by the Nigerian Bulk Electricity Trading Plc (NBET).
He also said the frequent request to turn off the plants turbines were detrimental to their efficiency because the turbines were not designed for such intermittent operational mode.