State power utility Eskom is poised to move ahead with the conversion of its open-cycle gas turbines (OCGTs) to dual-fuel facilities, with contracts having been placed with two international technology providers.
In December, Public Enterprises Minister Lynne Brown indicated that the conversion of the units to enable them to operate on both diesel and gas could cost R1.8-billion, a figure that has not as yet been confirmed by Eskom.
Group executive for generation Matshela Koko tells Engineering News that contracts have been signed with Sulzer for the conversion of the nine Ankerlig units and Siemens for the five Gourikwa units.
All 14 units will be converted during planned outages in 2016, with the first two units scheduled for shutdowns during the first quarter of 2016. The outages are planned based on the running hours of each gas turbine.
The conversion is being done despite the fact that Eskom is yet to secure gas to replace diesel. It is possible, though, that PetroSA, which uses gas at its Mossel Bay gas-to- liquids facility, could begin supplying the first Gourikwa unit, which is in close proximity to Mossgas, late in 2016.
“We will convert during the scheduled outages and then wait for the gas,” Koko explains, adding that it is unlikely that any of the units will operate on gas before December.
The conversion will give Eskom the option, though, to begin consuming gas once it becomes available, with the Independent Power Producer (IPP) Office having indicated in early January that a tender for the country’s first floating gas import terminal could be released in the first half of 2016.
IPP Office head Karen Breytenbach was quoted by Reuters as saying that government hoped to launch a request for prequalifications in the first quarter of 2016 for a floating storage and regasification unit, followed by a request for proposals in the second quarter before making an award by the end of 2016.
She said the aim was to begin importing liquefied natural gas by 2018/19.
Eskom’s decision to move ahead also comes amid heavy criticism of both its use of expensive diesel fuel and its extensive deployment of the OCGT plants, which are designed as peaking plants, over the past few years.
In fact, the utility’s claim for an additional R8-billion for diesel costs is a key feature of the National Energy Regulator of South Africa’s (Nersa’s) hearings into a R22.8-billion Regulatory Clearing Account application for the 2013/14 financial year of the third multiyear price determination. Eskom spent R10.6-billion on diesel during the year, which was significantly higher than the Nersa-approved amount of R2.5-billion.
Other Projects
Meanwhile, Eskom group executive for capital Abram Masango has also confirmed with Engineering News that the contract for the restoration of the Majuba coal silo, which collapsed on November 1, 2014, triggering an intense phase of load-shedding, has also been placed.
A joint venture of Stefanutti Stocks and Rula began mobilising on site in early January and the contract will involve the rebuilding of the silo and the strengthening of the other two silos on site. The interim solution that was installed to enable the power station to return to service will be retained as a permanent backup to ensure coal handling redundancy into the future.
The contract is valued at around R500-million and should be completed during the second half of 2017.
In addition, a technical adjudication of three bids to replace the Duvha 3 boiler, which exploded in March 2014, is also under way and the contract will be awarded before the end of March.
Koko indicates that Eskom and its insurer have eventually agreed on a like-for-like replacement, with the insurer initially proposing an alternative and cheaper configuration – a solution that did not sit comfortably with the utility.
“The insurer has agreed to pay for the solution on condition that we place the contract by the end of March,” Koko explains, indicating that the unit should re-enter commercial operation in 2020.