Interconnectors – conduits for SADC energy integration

THE SOUTHERN African Power Pool (SAPP) has identified six priority transboundary transmission projects that are expected to improve connectivity and electricity trading in the region by 2017. The priority projects, estimated to cost US$5.6 billion, are part of a portfolio of short to medium-tem projects being pursued by SAPP with the aim of increasing the availability of electricity in the region and connecting non-participating SADC Member States to the regional power grid.

Mozambique-Malawi Interconnector

The priority transmission projects are the Mozambique-Malawi interconnector; the Zimbabwe-Zambia-Botswana-Namibia (ZiZaBoNa) interconnector; South Africa energy strengthening project;

Zambia-Tanzania-Kenya interconnector; interconnection of Angola; and the Mozambique energy backbone projects. There are three categories of priority transmission projects. The first category is made up of transmission projects that aim to alleviate congestion. The ZiZaBoNa project falls in this group. The second group are those projects to interconnect non-operating members. This mainly concerns evacuating power to the United Republic of Tanzania from Zambia and Mozambique, as well as connecting Angola to the regional grid. The last category involves transmission projects related to new generation projects such as Mozambique backbone project. The interconnection of Angola, Malawi and the United Republic of Tanzania to the regional grid has been one of SAPP’s priorities for several years. All three Member States are presently not interconnected to the SAPP grid.

Mozambique-Malawi Interconnector The Mozambique-Malawi Transmission Interconnection Project is expected to be completed by 2015 and will connect Malawi to the SAPP, allowing two-way energy trade between the two countries. This will ensure much-needed diversification in Malawi’s electricity supply and allow the export of any off-peak power surpluses. It will also provide Mozambique’s energy sector with a new revenue source. Under the project, Mozambique will build about 135 kilometres of 220 kiloVolt (kV) transmission line and extend the existing Matambo substation while on the Malawi side, approximately 75 km of 220 kV transmission line will be constructed and a new 220 kV substation installed. The interconnection will allow Malawi to have access to the SAPP market through Mozambique interconnected grid with Zimbabwe and South Africa. Malawian President Joyce Banda signed the agreement with her Mozambican counterpart, Armando Guebuza, during a state visit to Mozambique in May. ZiZaBoNa The transmission interconnector project has the capacity to increase power trading among participating utilities, as well as provide an alternative power transmission route and help decongest the existing central transmission corridor that currently passes through Zimbabwe. The ZiZaBoNa project will help to provide another wheeling path and, therefore, increase trade between the northern and southern parts of SADC.

The initial capacity of the transmission interconnector will be 300 megawatts (MW), which will later be increased to 600MW. The project is to be implemented in two phases. The first phase will cover the construction of a 120- kilometre 330 kilovolt line from Hwange Power Station to Victoria Falls where a switching station will be built on the Zimbabwe side. The line will extend to a substation at Livingstone in Zambia. The second phase will involve the construction of a 300-km 330kV line from Livingstone to Katima Mulilo in Namibia, through Pandamatenga in Botswana. The Zimbabwe-Zambia interconnector will be built as a high voltage line with a transmission capacity of 430kV. However, it will operate as a 330kV line during the first phase. The ZiZaBoNa project will be organised as a Special Purpose Vehicle, to be incorporated as a company in Namibia. The four utilities will take 20 percent each of the equity. According to SAPP, the project should be ready for implementation by 2016. South Africa strengthening transmission South Africa has embarked on a 10-year programme to extend or reinforce its transmission system and build new power stations as part of measures to improve the reliability of supply. Additional power stations and major power lines are being built on a massive scale to meet rising electricity demand in South Africa. According to Eskom's Transmission Development Plan (2011 to 2020), the utility requires investment of around R166 billion up to 2020 to strengthen its capacity. This is expected to grow to more than a trillion rand by 2026. Ultimately Eskom plans to double its capacity to 80,000MW by 2026. The project will result in several new transmission lines being added to the system, with over 6,000 km of 765kV and over 8,000 km of 400kV lines either approved or proposed over the 10-year horizon. Major network reinforcements are proposed to increase supply to the Cape (South and West) and Kwa Zulu Natal (East) grids. There will also be integration of new power stations in Limpopo province into the Eskom and SAPP grid.

This will require significant investment in transmission infrastructure as the power stations are far from the main load centres. New high-voltage direct-current (HVDC) lines are also planned to enable export of excess power from Waterberg directly to load centres in Gauteng and Kwa Zulu Natal requiring 1,700km of 800kV constructed HVDC lines. These new transmission lines form part of the long-term strategy to develop a main transmission backbone from which regional power corridors can be supported. The backbone and regional power corridor network structure will allow for greater security of supply as power from new power stations is integrated more efficiently into the transmission network, enabling regional trade through the SAPP grid. Zambia-Tanzania-Kenya Interconnector To integrate its power market, the COMESA-EAC-SADC Tripartite – comprising the Common Market for Eastern and Southern Africa, East African Community and SADC – needs infrastructure to support additional energy generation as well as regional transmission. Existing power interconnectors in the Tripartite region are inadequate for long distance transmission and unsuited for regional systems integration. The Tripartite, in collaboration with SAPP and the East African Power Pool (EAPP), has prioritised the development of critical interconnectors, including the Zambia-Tanzania-Kenya (ZTK) interconnector to improve regional integration and energy trade within and between the SAPP and EAPP. Covering a distance of 1,600 km, the interconnector will have a capacity of 400MW, and will be constructed as a double circuit 400 kV line in sections from Pensulo in Zambia to Isinya in Kenya DRC-Angola Interconnector This is one of several projects aimed at connecting non-operating members of SAPP to the regional grid. It will involve the construction of a 400kV transmission line from the DRC to Angola, enabling trade between the two countries. The DRC has vast electricity generation capacity that could be useful to the fast-expanding Angolan economy, which is buoyed by massive investments in mining and construction sectors.

Mozambique backbone project This involves construction of a new electricity transmission line from Tete, in the Zambezi Valley, to Maputo. This line, known officially as the "Centre-South (CESUL) Project" and unofficially as "the backbone" of the Mozambican electricity grid, is crucial for carrying power southwards from planned new power stations in Tete. These include the planned dam at Mpanda Nkua, 60km downstream from the existing dam at Cahora Bassa, a second power station at Cahora Bassa, and coal-fired power stations built by the mining companies Vale and Rio Tinto. Without a new power line, the electricity generated at these new power stations cannot reach the Maputo area or be exported to South Africa. CESUL will involve the construction of 1,340 km of 400 KV alternating current transmission line and 1,250 km of 500 KV line, with the capacity to carry 3,100 MW of power. Eight new sub-stations will be built, and two existing ones will be expanded. The African Development Bank has agreed to help finance the construction the transmission line, estimated to cost US$1.8 billion. The bank has pledged to provide up to US$ 400 million for the project.