News from around the continent

LESOTHO

Construction of Polihali Dam and Transfer Tunnel set to start

The contract amount for the Polihali Dam is approximately M7.68 billion (R7.68 billion). The successful Polihali Dam bidder is the SUN JV, comprising main partners Sinohydro Bureau 8 (China), Sinohydro Bureau 14 (China), Unik Civil Engineering (South Africa), and Nthane Brothers (Lesotho). Subcontractors include Melki Civils and Plant Hire (South Africa), MECSA Construction (South Africa), SIGMA Construction (Lesotho) and Kunming Engineering (China).

Construction will be supervised by the Matla a Metsi JV, comprising GIBB (South Africa), MPAMOT Africa (South Africa), Tractebel Engineering SA/Coyne et Bellier (France), and LYMA Consulting Engineers (Lesotho).

The Kopana Ke Matla JV – which will construct the Polihali Transfer Tunnel – includes Yellow River Company (China), Sinohydro Bureau 3 (China) and Unik Civil Engineering (South Africa), the main joint venture partners. Subcontractors include Nthane Brothers of Lesotho, as well as Esor Construction and Mecsa Construction of South Africa. The contract amount for the Polihali Transfer Tunnel is approximately M9.2 billion. Construction will be supervised by the Metsi a SenquKhubelu Consultants (MSKC) JV. MSKC comprises Lesotho-based FM Associates and South African firms Zutari South Africa, Hatch Africa, Knight Piésold and SMEC South Africa, the main JV partners.

Phase II adds 2 325 million cubic metres in storage capacity to the Lesotho Highlands Water Project (LHWP) and will increase the current annual supply rate capacity from 780 to 1 270 million cubic metres, contributing towards meeting South Africa’s increasing water needs. The additional flow of water from Polihali will simultaneously increase power generation within Lesotho towards meeting its domestic needs and reducing the country’s dependence on electricity imports.

A concrete-faced rockfill dam, the Polihali Dam is like the majestic Mohale Dam, which was constructed in Phase I of the LHWP. It will create a reservoir on the Senqu and Khubelu rivers, with a surface area of 5 053 hectares. The infrastructure also includes a spillway, a compensation outlet structure and a minihydropower station.

The Polihali Transfer Tunnel will transfer water by gravity from the Polihali to the Katse reservoir – the centrepiece of the LHWP. From Katse, water is transferred via the delivery tunnel to the ‘Muela Hydropower Station constructed in Phase I, and then on to the Ash River outfall outside Clarens in the Free State on its way to Gauteng. The Polihali Transfer Tunnel works also include: the intake works and gate shaft at the Polihali reservoir; the outlet works and gate shaft at the existing Katse reservoir, with underwater connection to the lake; as well as access adits to the waterway and associated construction infrastructure.

The envisaged transfer tunnel will be approximately 38 km long with a nominal bore of 5 m. Both tunnel boring and drill and blast methods will be used to excavate the tunnel.

NAMIBIA

Waste buy-back centres

People in the city of Windhoek will now earn money from the sale of their household waste at two new waste buy-back centres that have been funded by the EU to the tune of €2.12 million (R37.9 million).

The facilities will receive the waste, process it and use it as raw material to make other items. The aim is to recycle 2 000 tonnes of solid waste through the gradual deployment of 100 collection units under the Improving Solid Waste Management in Windhoek project. The project will also create jobs and raise awareness of resource conservation among 6 800 students.

“Population growth has led to an increase in the amount of waste generated each month, which in turn has put a strain on the capital’s landfills and shortened their lifespan. We are trying to limit the amount of litter in the city,” says Fransina Kahungu, chairperson: Basic Service Delivery Committee, Windhoek Municipality.

Delegates officially breaking ground at the sites for the two buy-back centres in Katutura

MOZAMBIQUE

Renewable energy can help build a reliable power system

Wärtsilä – a global technology group – released a study on two separate power system expansion scenarios. The objective is to assess the financial and environmental impact and amount of renewable energy capacity that should be built into the Mozambican power system each year, leading to 2032.

The pressing challenge for Mozambique’s energy authorities is to ensure that the entire population gets affordable and uninterrupted access to electricity over the next decade. To meet the projected 1.3 GW of electricity peak demand increase by 2032, Mozambique must build significant new power capacity. A further 2 GW would be needed to support the planned development of the Beluluane Industrial Park in the Maputo province by 2037.

Going forward, the development of new gas resources presents tremendous opportunities to rapidly increase gas-to-power capacity in the country. But Mozambique can also rely on its wind and solar energy resources to rapidly increase power generation.

“Our study addresses some of the key questions facing energy authorities in Mozambique today, starting with the relative share that renewable energy should have in the country energy mix. Should Mozambique cap new renewable energy capacity to 100 MW each year as it currently wants to do? Or should it build more of it? What would the optimal power mix look like in each scenario? Answering these questions is crucial to informing power system planning and strategy in Mozambique,” explains Wallace Manyara, business development manager: Region South & East Africa, Wärtsilä Energy.

Wärtsilä presents and compares two potential power system expansion scenarios for Mozambique, one with renewable energy capacity additions capped at 1 GW by 2032, and the other where renewable capacity is allowed to reach 3 GW by 2032. Each scenario has been modelled with a worldleading power system modelling tool to identify the most optimal power mix to be built year-by-year to provide additional electricity supply reliably and at the lowest possible costs.

The study reveals that the scenario featuring a high share of renewable energy in the power mix will be the most affordable and sustainable way to meet electricity demand over the next decade. Paired with energy storage and flexible gas engines to ensure grid balancing needs, maximising renewable energy will help reduce carbon emissions by 5 million tonnes by 2032. This will also generate savings of US$84 million (R1.44 billion) when compared to a low renewable energy deployment scenario.

The most competitive power expansion plan outlined in the report combines almost 3 GW of new wind and solar capacity, together with 1 GW of flexible gas projects, 205 MW of energy storage capacity, and 50 MW of new hydropower capacity. It also plans for 1 GW of baseload gas projects to be built from 2022 to 2032 – including the 450 MW Temane gas power plant expected for delivery in 2024.