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Renewable power in Namibia risks becoming too much for its power grid

Namibia 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 of only about 2.5-million people has installed almost 55MW of generation from renewables and has projects under construction for another 121MW, 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 e-mailed 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 275MW of renewables, which is about half of the midday load, the utility said, citing 2017 studies. The country relies on imports for about 60% of its electricity, mainly from Eskom, 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 did not immediately reply to an e-mail seeking comment.
Reaching a bottleneck has not 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 200MW.
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.