Boost for plans to float solar panels at Kariba

Tapiwanashe Mangwiro

ZIMBABWE’S plans to expand power generation at the Kariba South Power Station beyond the rated capacity of 1 050 megawatts (MW) received a major boost last week after the African Development Bank (AfDB) issued a tender invitation for qualified experts to express interest in providing consultancy services for a floating solar plant in the giant water reservoir.

While the country’s largest power facilities, Hwange and Kariba South stations, have a combined installed capacity of 2 570MW, actual production is limited due to old and unreliable equipment at the former and limited water at the latter because of drought.

As such, the Government mooted the idea of a floating solar plant to take advantage of the potential presented by the vast water body, covering hundreds of square kilometres along the mighty Zambezi River, with the initial target being to produce 100MW, over and above what Kariba South is currently able to produce.

Significant latitude exists to scale up output from the new solar plant, once it comes into operation.

Notably, the Government hinted scope exists for private players to also come on board to utilise the opportunity for solar energy presented by the extensive water body.

A growing number of such systems exists in China, France, Indonesia, India, Japan, South Korea, the United Kingdom, Singapore, Thailand and the United States.

Kariba Dam, constructed between 1955 and 1959 and located on the border between Zambia and Zimbabwe along the transboundary Zambezi River, is managed by the Zambezi River Authority (ZRA), a statutory body created and jointly managed by the two countries.

Said AfDB in the tender invitation note: “The African Development Bank invites eligible consulting firms to indicate their interest in providing services under the Sustainable Energy Fund for Africa’s Africa Hydropower Modernisation Programme to support the bank and its clients as consultants for the preparation of a feasibility study for the floating solar project on the Lake Kariba reservoir.”

The consultant would conduct feasibility studies on the Kariba Dam solar plant site to assess the financial and technical viability of the project.

This would include the technical specifications for grid integration and the development of financing and business models for implementing the work.

The consultant would also be required to evaluate the socioeconomic impact of the project on the surrounding communities.

“Both Zambia and Zimbabwe, as well as the entire Southern African Power Pool region, suffer power supply deficits. The shortfalls faced by the two countries are compounded by regular poor hydrology affecting the Zambezi catchment and overutilisation of the reservoir due to a shortage of supply from other sources.

“The addition of floating solar would therefore increase capacity and improve utilisation of the resulting hydro/solar system. It would also provide a substitute for some fossil-fuelled plants that are due for decommissioning and enable better hydrologic regulation,” AfDB said.

The bank further said the expressions of interest must be submitted by no later than June 15, 2024.

According to the tender document details, the project is aimed at maximising the hydropower potential of the Kariba Dam complex, increase solar capacity and enhance the efficiency of the combined hydro/solar system.

Energy and Power Development Minister Edgar Moyo recently told this publication that the floating of solar panels on Lake Kariba would be done in phases.

He, however, said the Government was yet to finalise the project’s final capacity as grid impact studies were still being conducted.

The Southern African Development Community member states have for many years only made limited investments in new power generation, hence the region-wide energy crisis, which has also been worsened by the adverse effects of climate change.

In an interview on Thursday, energy expert and former Zimbabwe Electricity Supply Authority chief executive officer Engineer Ben Rafemoyo said green energy was the way to go, given the adverse effects of climate change on hydropower.

He said the floating of solar panels in the dam was feasible, as such projects have already been carried out elsewhere in the world, and if successfully implemented, would complement the hydropower generation at the giant water reservoir.

“I think it is a positive move. It also helps to reduce evaporation within the dam itself while, at the same time, it is a conducive environment for solar production.

“Of course, you know, our Lake Kariba is used for boating, fishing and other recreational activities, so it is a question of demarcating areas where they will lease out for solar production.

“These solar floating plants are becoming more and more common around the world, so this is a positive move as far as I am concerned,” he said.

Eng Rafemoyo said implementing the project on land had some limitations in that once the solar panels were installed, for instance on agricultural land, that area would never be used for that purpose.

“Yet in the dam like Kariba, the water is still there and when they instal them (solar panels), they know the maximum height that water can ever rise within the dam, so there is no interference. Whether it is low or full, it makes no difference.

“All they are saying is that the whole area, close to 300 kilometres of the dam, from one end to the other, is just lying idle,
with the water evaporating into the atmosphere.

“The idle space, which happens to be the space above the water in the dam, is where the idea of floating solar panels comes into mind. Whether there is El Niño or no El Niño, if we are talking of going green energy, this is the way to go,” he said.

According to the International Renewable Energy Agency, Zambia had a total solar deployment of 124MW as of the end of 2023, while Zimbabwe had developed 41MW from such renewable energy facilities.