For a long time, Malawi has been grappling with the challenge of power outages which has resulted in the interruption of commercial and social work transactions. The worst period of such power blackouts is from 2014 up to date. All this while, industrial work, business activities and social services have been affected.
To solve this problem, Electricity Supply Corporation of Malawi (Escom) through the Millennium Challenge Account (MCA) is building state-of-the-art power transmission substation at Phombeya in Balaka which will be transmitting power to Nkhoma Substation in Lilongwe.
The Director of Systems and Market Operations at Escom Jeford Banda says that with this project, Escom will be able to supply power not only to the country but also to neigbouring countries.
The economy will be boosted
Once this substation is completed, Malawi’s economy will be boosted in a number of ways. Escom says Malawi Power System is currently isolated. It is not connected to the regional power System called SAPP (Southern Africa Power Pool). Such an isolated system is unstable and limited in terms of access to additional power when it is required as it depends on its own generation capacity.
“The interconnector will enable Malawi access power from SAPP. This will also give an opportunity to trade power—buying when in deficit and selling when in surplus. It will also assist in stabilising power supply since the Malawi Power System will be operating in a much bigger and stable regional Power System. Hence the economic activities will be enhanced by providing adequate, secure and reliable power,” says Banda.
How will power be distributed in the country?
Escom says that currently power generated from Nkula, Tedzani and Kapichira power stations is transmitted to Lilongwe and the central region at 132kV. In Lilongwe, the voltage is stepped down to 66kV/33kV/11kV through sub transmission substitutions and distribution stations within the region.
Once voltage is stepped up from 132kV to 400kV at Phombeya Substation, it will be stepped down from 400kV to 132kV at Nkhoma Substation and further to 66kV, 33kV and 11kV through the high voltage transmission and distribution substations within the central region.
“The generation substations are interconnected. Thus power is generated at 11kV and stepped up to 66kV and 132kV for transmission. Some of the power generated at Kapichira and Tedzani is wheeled to Nkula Substation where it enters the 132kV and 66kV national grid and is then transported to Central Region and Northern Region through Golomoti Substation. Power is also transmitted from Nkula, Kapichira and Tedzani to Blantyre and various districts in Southern Region at 132kV and 66kV,” says Gift Chindebvu, MCA’s representative.
Through the interventions of Millennium Challenge Corporation (MCC), power will be transmitted at132kV from Chintheche to Luwinga Substation and Bwengwu Substation. Thus a new power line (132kV) is being constructed (steel towers) linking Chintheche-Luwinga-Bwengu.
The new Luwinga, and Bwengu substations will be stepping down voltages from 132kV to 66kV, 33kV and 11kV for distribution to consumers.
Benefits of transmitting power at high voltage
The new power line being constructed on steel towers will improve power reliability in the north due to reduced outages which occurs every time Escom engineers are replacing or working on the wooden poles, studies reveal.
Furthermore, transmitting power at high voltages reduces the power losses due to transmission and also improves system voltages.
Power interconnection projects with other countries
Escom says the Mozambique-Malawi Interconnection Project will involve the construction of a 400kV line from Matambo Substation in Mozambique to Phombeya Substation. It is expected to start operating in 2020/2021.
“The Phombeya Substation Project under MCC is not only the first phase of the Malawi 400kV Transmission Backbone Project running the whole length of Malawi from south to north, but will also provide the base for the interconnection point with the neighbouring country of Mozambique,” explains Banda.
There will also be other interconnections with the other two neighbouring countries of Zambia and Tanzania.
Zambia Interconnection will be from new Nkhoma Substation and Tanzania interconnection will be from Bwengu Substation in Rumphi where there will be a major 400kV substation in the north on the 400kV transmission backbone line from Nkhoma Substation that will pass through Kasungu and Mzimba.
This means power from Phombeya will be transmitted to Nkhoma and then to Bwengu. Phombeya will be the distributor.
Sources say that Mozambique also plans to extend the 400kV transmission line from Phombeya Substation to the eastern side of Mozambique (Nampula) to feed power to this region of Mozambique through Malawi.
Other sources of electricity
Malawi has relied on hydro electricity all along but government is planning to introduce other forms of power such as wind and coal. Kammwamba Project is an example. This will be a coal fired power station that will be connected to Phombeya. It is envisaged that the plant operation and commissioning will be in phases. First units are targeted in 2019 (2 x 50MW), 2020 (2 x 50MW) and 2021 (2 x 50MW).
“The design of Phombeya Substation provides for feeding in power not only from Kammwamba Coal Fired Power Plant, but also from Kholombidzo Hydropower Station as well which will be developed at Matope, just upstream of Zalewa Bridge on the Shire River,” Escom says.
Phombeya Substation is thus the a major national and regional interconnection Substation in the south of Malawi, just like Nkhoma Substation is in the centre and Bwengu Substation is in the north.
What about the Fiber Optic Cable?
All new Escom transmission lines are designed to carry Fibre Optic cable. This is for internal use, for monitoring, system protection and control and data acquisition.
Banda says: “Through a special agreement, the fibre connectivity advanced by government will be hung on Escom facilities [poles and towers] for secure and quick connectivity to government facilities in the country, according to sources.”
How will the Phombeya Substation operate?
The entire Escom system is interconnected. Power flow is meshed from all generation plants through the interlinked transmission system. The control, monitoring and supervision are through the Supervisory Control and Data Acquisition (Scada) System.
This facility, through fibre communication links and other communication modes, provides means to operate and control equipment remotely from the central control system in Blantyre at National Control Centre (NCC).
Thus, Phombeya Substation will not only be a facility that will embrace technological operating system but also will be the final piece in a power jigsaw puzzle. n