Rouna Two Hydo Refurbishment

Rouna 2 hydro power station is the spine of Port Moresby’s generation requirements. Constructed in 1967 at a cost of K8.6 million, the station is situated on the Laloki River 35 kilometresfrom the city. Initially the station was fitted with three 6 megawatts (MW) generating sets but in 1969 two additional sets were installed to give Rouna 2 a total installed capacity of 30MW.

Unlike its sister hydro stations Rouna 1&3 and 4, Rouna 2 marks one of PNG’s greatest engineering achievements. It was excavated out of solid rock, 150 meters beneath the bed of the river. Water to the turbines is diverted from the Laloki River by a gate-type weir, where it then passes through screens to a vertical steel-lined pressure shaft where it falls 150 meters to the underground machine hall and onto the turbine blades. The weight of the water spins the turbines and they, in turn, spin the generator sets which produce electricity. The electricity is then transmitted to substations at Boroko and Konedobu in Port Moresby by 66kV transmission lines.

Over the decades, the station’s generation output had slumped to below half its capacity while Port Moresby’s demand for electricity increased exponentially. PPL, through its board and management, saw the looming doom and embarked on its first mission to secure funds for a total refurbishment and rehabilitation of the hydro station. K120 million was released to PPL by a consortium of financial institutions led by BSP and ANZ and in 2006, PPL signed major contractor VA Tech Hydro to carry out the project.

In 2009, the station was ready. The new features included three new units (5, 4 and 1) upgraded from 6 MW to 8 MW, with new generators, turbines and Main Inlet Valves (MIV).The machines boast technological advances in turbine and generator design, which sees a 33 per cent increase in electricity output using the same volume of water.Other technological advances on the machines included a new computerised automation, protection, excitation, synchronisation and governor system, and a water cooling system.Unit 2 also has these features and new MIV and electrical systems, while its generator and turbine retained while unit 3 was unchanged for standby purposes.

Other new features of Rouna 2 Power Station included a new 110Vdirect current system for units 5, 4, 1 and 2, new 11 kV power cables running from the generators to the transformers, modified station ventilation, air conditioning and smoke extraction systems, new fire fighting and fire detection systems, new station and unit compressed air system, and new emergency escape facilities via the tailrace.

The refurbishment of Rouna 2 marks PNG Power’s first fully funded venture using its on balance sheet. It set the precedence that PNG Power is able to handle multi million projects to improve its services to its consumers.