The Sunday News
Dumisani Nsingo Senior Business Reporter
THE refurbishment of the Bulawayo Thermal Power Station at a cost of $87 million which will see an additional 90 megawatts (MW) being channelled into the national grid is expected to be completed in 2018 as the country forges ahead towards reducing its power deficit. Addressing stakeholders at an Environment Impact Assessment meeting on Monday,Zimbabwe Africa Infrastructure Development Group environmental management consultant Engineer Martin Manuhwa said the new technology, Circulating Fluidised Bed Combustion (CFBC) to be introduced at the Bulawayo Power Station would significantly reduce tariffs while the refurbishment work was expected to be completed in 2018.
“Tariffs for thermal power stations are 14 cents per kilowatt while those for hydro power stations are 3 cent per kilo watt. However, this latest technology through its intervention and efficiencies will reduce to much lower tariffs. This project is most likely to be completed in mid-2018,” said Eng Manuhwa said.
Speaking at the same meeting, another environment consultant Mr Mukai Mawanza said the proposed project would involve replacing existing chain grate boilers with CFBC boilers and refurbishment of turbo-alternators and Balance of Plant (BOP).
“After the refurbishment, the plant will add 90 megawatts (MW) to the national grid. The entire plant is estimated to require approximately 11 million litres of raw water per day for power generation. It is proposed that this water be abstracted from Khami Dam,” Mr Mawanza said.
The boiler plant scope involves the design, manufacture, erection and commissioning of 2×45 MW CFBC.
All existing steam pipework, valves and steam receivers up to Steam Stop Valve at the turbine shall be replaced.
“The CFBC technology gives the boilers the capacity to burn a wide range of coal grades and provides for better management of boiler emissions through the addition of limestone, this technology is also recommended by the World Health Organisation. The technology will likely bring a lot of employment because the gypsum realised from the process will be used by the construction industry,” said Mr Mawanza.
The limestone which is added into the boiler to burn with the coal is used to precipitate out sulphate during combustion, which also allows more efficient heat transfer to the boiler water tubes. It thus acts as a sorbent which captures sulphur dioxide and expels it as gypsum. Furthermore, the heated precipitate coming in direct contact with the tubes increases the efficiency.
“Securing adequate supply of raw water is a key deliverable of the repowering project. This will involve laying a 20-kilometre long pipeline from Khami Dam to Bulawayo Power Station. It is ZPC’s intention to use existing servitudes to lay the pipeline,” said Mr Mawanza.
The main power plant building shall, however, retain the turbine generator area, steam generator areas, auxiliary bay area, electrical equipment area, central control room, turbine generator floor levels remain the same for all the units as that of existing units and the same
“Crane facilities in the Generator Transformer bay. The existing raw water supply and storage system shall be redesigned for laying a new pipeline for transporting raw water from Khami Dam which is about 20 kilometres from the power station.
“The existing coal handling system and coal storage area shall have to be rearranged and the radler coal conveyor system shall be changed to belt conveyor system for feeding the coal to the banker in boiler house,” Mr Mawanza said.
Bulawayo United Residents Association chairman Mr Winos Dube said the additional power output from the station was a welcome development which will improve availability of power.
“The refurbishment of the Power Station and the additional power output to be realised thereafter is an exciting development. As residents we always welcome things with meaningful development which excite consumers. Since the beginning of this year we haven’t had much load shedding and the addition power output comes as a relief to us,” Mr Dube said.