Paper producer Sappi reports that it has achieved a 25% reduction in kilowatt hours consumption at its Tugela river pumpstation, in KwaZulu-Natal (KZN), after a new control system and other new hardware were installed last year.
Energy efficiency systems design and installation specialist Magnet performed a critical role in the Sappi Tugela river pumpstation upgrade project to ensure that high levels of energy savings, as well as a reduction in the peak-time load on State-owned power utility Eskom’s electricity grid are achieved.
“The greatest challenge was the initial part of the project, prior to pump replacement. A thorough audit and analysis were required, involving a series of measurements and calculations around pumping and processing capacities to achieve the best energy savings at the plant,” Magnet MD Brian Howarth says.
Sappi’s Tugela mill’s pumpstation has been fitted with the latest process control equipment, and is now capable of pumping the mill’s daily requirement of water in less than 20 hours, while the pumpstation previously ran continuously.
The installation of the new control equipment and pumps has enabled automatic start-ups, which was previously not possible. The new equipment has also reduced electricity consumption during normal operation, Magnet reports.
The upgrade of the river pumpstation allows for an average saving of 1,85 MW during peak demand periods, and an average of 0,185 MW energy saving throughout the rest of the day.
“It is a critical feature of this project that the overall plant demand is now always lower than the previous baseline. The savings have been verified in three separate audits by a university measurement and verification team, and have, in fact, exceeded the guaranteed values,” Howarth notes.
Further, the energy saving has been enhanced as Sappi is now able to shut down the entire pumpstation between 18:00 and 20:00 every night, reducing the strain on Eskom’s power grid.
There has been a shift in load from peak periods to off-peak periods, using existing water storage capacity without impacting on the supply of water to the mill.
“While the project initially involved only an audit of the current pumpstation, the need to implement Eskom’s demand-side management programme was identified and resulted in the size and scope of the project evolving into a comprehensive turnkey energy efficiency project,” Howarth concludes.
The Sappi Tugela river pumpstation project received the twenty-first Department of Energy/Eskom eta Award for industrial projects and was also nominated for the Sappi Technology Innovation Awards during last year.