Namibia, the southwest African country whose desert lines the coast, may soon have to temper its love for renewable power — at least until the grid can catch up.
In just a few years, the nation that’s considerably bigger than Texas but with only around 2.5 million people, installed almost 55 megawatts of generation from renewables and has projects under construction for another 121 megawatts, according to NamPower, the state-owned utility.
The total installed capacity combined with committed renewable generation “is reaching the threshold the grid can accommodate,” the utility said in an emailed reply to questions.
The comments illustrate the limits of how quickly wind and solar farms can penetrate nations before bigger investment is required in the power distribution network. Unlike traditional power plants that can run round the clock, renewables feed electricity to the grid only when the sun shines or the wind blows.
Technically, Nambia can handle about 275 megawatts of renewables, which is about half of the midday load, the utility said, citing 2017 studies. The country relies on imports for about 60 percent of its electricity, mainly from South Africa’s state-owned Eskom Holdings SOC Ltd., according to a 2017 annual report.
Africa presents huge opportunities for developers of renewable-energy plants, since wind and solar are quicker and sometimes cheaper to build than coal and natural gas plants. While renewable sources such as wind and solar can leapfrog traditional generation, they do not provide consistent 24-hour baseload electricity.
Namibia’s biggest domestic source of power is the Ruacana hydropower plant near the border with Angola. It depends on the seasonal run of the Kunene River.
NamPower is dependent on Eskom to perform “load following,” when a power plant adjusts its output as demand for electricity fluctuates throughout the day, the company said. Eskom didn’t immediately reply to an email seeking comment.
Reaching a bottleneck hasn’t deterred Namibia from adopting more renewables in the future as it aims to reduce power imports. The National Integrated Resource Plan includes an allocation for biomass power plants with capacity of as much as 200 megawatts.
Concentrated solar power is also called for in the plan. That technology concentrates the sun’s energy on heating a liquid that drives power turbines. Because the liquid can retain heat for a time after the sun goes down, those systems also can be used to store energy and deliver power to the grid at predictable times.
— With assistance by Michael Cohen