Tronox Namakwa Sands invests R242-million in Saldanha BayOctober 28, 2014 by: admin
The Tronox-owned Namakwa Sands smelter took a big leap by investing R242-million in a cogeneration (cogen) plant, but it has exceeded the company’s expectations in terms of energy cost savings.
The 13.6 MW plant on South Africa’s West Coast uses waste gas that was previously flared into the atmosphere, to produce electricity.
“There was quite a lot of skepticism when we embarked on this project. But it has worked. You breathe a sigh of relief when you put R250-million on the line – and it works,” Tronox Namakwa Sands senior electrical engineer Peter Haley who lives in Langebaan told a South African National Energy Association meeting in Cape Town this week.
Haley pointed out that Namakwa Sands was on track to achieve its target of 70 GWh/y of exported energy, the equivalent yearly energy consumption of a small town or about 6 000 households.
Namakwa Sands’ operations have saved 10.3% in energy costs across all sites.
“The operational team on site interface with the smelter production team and it’s been very successful,” noted Haley, adding that a team of 14 people, who work in shifts around the clock, was set up to operate the cogen plant.
The cogen idea was sparked by diversified miner Exxaro in 2007. Board approval for the construction of the project was granted in 2011, while the ownership and operation was handed over to Tronox Limited, in which Exxaro has a 44.4% equity interest, following a broader deal between Exxaro and Tronox. The plant has been operational since February.
Design capacity is 1.7 MW per Jenbacher gas engine, with four units having been installed in each of the two engine rooms. Typically, the engines have a 60 000 hour operating life.
Haley explained that the cogen plant could only operate when both furnaces were running and generating consistent-quality gas.
Electricity was not exported to the Eskom grid and all energy was consumed internally.
Namakwa Sands, which is spread over 300 km along the West Coast, produces 10% of the world’s zircon, 5% of global pig iron and 8% of the world’s titanium dioxide.
Haley said the cogen project was motivated by the need to boost energy efficiency in the interest of a low carbon future and in becoming more environment-friendly.
He added that rapidly increasing electricity tariffs a few years ago had also contributed to the move to cogeneration.
But while Namakwa Sands had been successful in saving energy costs, it had been far from a money-spinner.
Haley pointed out that the value of carbon c
redits had plummeted, while the weak rand, and Eskom pricing, which was less aggressive than it was four to five years ago, had changed expectations.
The company had reworked its initial calculations, from a 17% to a 5% return on investment.
The cogeneration projec
t was also dealt a blow last month when one of the eight engines failed while running at full power, causing major damage to the cylinders. The engine was removed and returned to GE Jenbach to rebuild. It was expected to arrive back on site in December.
Despite the hurdles, Haley believed the Namakwa Sands cogeneration project has been a great success.