Small Hydro Plants & Small Utility-Scale Solar Should Replace Zimbabwe’s Ailing Small Thermal Plants

When I was in primary school, in Mutare, Zimbabwe, a fairly large dam was being build in our province, Manicaland. Osbourne Dam, on the Odzi River, was built by the Italian firm Salini Costuttori SpA. Osbourne Dam supplies water to irrigation schemes in Chimanimani and Chipinge districts. Back then in my junior school days in the early 1990s, I would ask my older brothers why the design did not include some small hydroelectric power plant? I thought surely the project managers could add a 10 MW plant or something and contribute a quite a bit to the grid.

Another large dam has been built since then, this time in Masvingo Province. The Tokwe Mukosi Dam in Masvingo province is now the country’s largest inland dam. The good news is that there is also a proposed 12 MW power plant due to be installed at Tokwe Mukosi. Some other small hydropower plants have also come up around the country, such as Nyangani Renewable Energy’s 15 MW Pungwe B plant. These small renewable plants contribute some much needed clean electricity to Zimbabwe’s severely constrained energy grid. We need more of these plants around the country wherever projects can be found to be viable. It is not always easy going though, and there are some bumps along road, such as the recent currency dispute between the utility company and an independent power producer.

Kenya’s impressive renewable energy generation statistics got me thinking about how Zimbabwe can also step up its game on the renewables front. Renewables provided 92.3% of Kenya’s electricity generation in 2020! In Q3 of 2021, of the 2,203 GWh from the Zimbabwe Power Company, Kariba Hydro Power Station contributed 64% of the total energy production. Hwange Coal Power Station supplied 33% and the small coal power plants contributed 3%.

The share of clean electricity will go down quite a bit next year once the new units at the new 600 MW coal power plant in Hwange come online. Zimbabwe has small thermal power plants in Bulawayo, Harare and Munyati, that are not doing to well as seen below:

These plants were built in the 1940s. Although some refurbishments have been carried out over the years to try to boost their output, they are all still struggling. There could be an opportunity to decommission Zimbabwe’s ailing small coal power plants and repurpose them. Perhaps install some utility-scale storage at those three sites. Maybe some 40 MW/ 120 MWh Megapacks or something at each of those sites to store power during the off peak times and discharge as needed to support the grid. They could add some solar as well, say at Munyati for example, if the space allows.

I haven’t seen Zimbabwe’s presentation at COP26, but it seemed like a good opportunity to pitch this kind of thing. South Africa recently announced an $8.5 billion deal at COP26 to decommission and repurpose some of its coal plants and roll out renewable energy. This will be done through a partnership with the governments of France, Germany, the United Kingdom, and the United States, as well as the European Union, to support a just transition to a low carbon economy and a climate resilient society in South Africa.

Initiatives to add more small hydro plants or small-scale utility solar plants to compliment the larger Kariba Hydro power station need to be accelerated. These small plants are much cheaper to build and can add more capacity to the system fairly quickly as compared to large centralized plants. There has been talk of proposed refurbishments at these small thermal power plants. $70 million upgrades have been proposed for Harare power station, for example. An $87 million line of credit from the Government of India to add 60MW at Bulawayo has also been looked at. With the new 600 MW coal plant at Hwange already under construction and coming online next year, there is surely no need for more coal power plants. The Harare coal plant today was hovering at around only 13 MW from the installed 80 MW. It may be cheaper to get this 13 MW from a small hydro or small utility-scale solar. Due to the current electricity generation constraints at the country’s aging power plants, the power company implements power rationing cycles, known as load shedding. The industrial and mining sectors have traditionally been the largest consumers of electricity as shown below:

Source: AFDB Zimbabwe Infrastructure report 2019

Accelerating the adoption of rooftop solar plants at these campuses could relieve pressure on the grid during the day. Each of these small thermals are producing less than 15 MW. So, 30 or so 1 MWp rooftop plants in each of these locations could really help during the day to relieve pressure during the day. This would be a better proposition than continuing to nurse the aging small thermal plants.

Zimbabwe has an installed electricity generation capacity of about 2,300 MW. Current demand peaks at around 1,800 MW in the winter months. Peak demand is slightly lower during the rest of the year at around 1,500 MW. During the night from 10pm to 5am, demand drops to below 900 MW. It is really the daytime load that urgently needs a ramp-up in generation to meet the demand.

The new 600 MW coal plant at Hwange, which is an extension of the current 920 MW plant, is a joint venture between Sino Hydro and ZPC. With China recently announcing that it will stop funding overseas coal projects, it could mean it will become very difficult to fund the refurbishments at the small coal plants in the near future. The African Development Bank also announced that it will stop funding coal projects. Now is the time to sell a good story about shutting down old coal plants and transitioning to renewables. South Africa is doing this quite well. Let’s hope Zimbabwe gets in on this.