Fresh off commissioning a 45MW solar plant in its Hardap region, Namibia has announced it’s planning to spend some 63.9 million US dollars on a new 50MW solar power plant, the construction of which would start in 2020.
This is all part of Namibia’s plan to reduce its reliance on hydroelectric power, but also to cut its dependence on electricity generation in other countries.
Nambia imports power from neighbours South Africa - which has electricity supply problems of its own - Zambia and Zimbabwe. Of course, this is unsustainable, so the government is forging ahead with its own generation plans.
The encouraging thing of course is that it’s going green, increasing its spend on renewable energy.
Africa has some of the best sun in the world, and the sunlight that falls on this beautiful continent is ideal for energy generation.
Some countries are already capitalising on this; South Africa has some of the best irradiation levels - that’s quality sunlight capable of producing power - in the world.
The country is churning out 1 979 MW cumulatively from solar power alone, and a further 2 094 MW from wind power.
Morocco is aiming to produce 42% of its power from solar power by 2020. It’s an ambitious goal, but when you consider that its Noor Ourzazate concentrated solar power complex in the world, it’s not that far-fetched.
Situated on the edge of the Sahara Desert, Morocco is perfectly positioned to make use of solar energy, and they’ve done it in a novel way.
There are two ways to generate electricity using the sun: photovoltaic and concentrated solar power. Photovoltaic cells convert sunlight directly into energy, whereas concentrated solar power focuses the sunlight via mirrors and other tools into a concentrated beam, which in most cases is then used to drive a heat engine.
Morocco’s plant uses the concentrated beam which reaches 500 degrees Celsius, to melt salt, which stays hot enough at night to deliver power for three hours.
The plant itself is huge - it’s roughly the size of Manhattan, at around 3 000 hectares. It generates 580 MW - enough electricity to power a city the size of Prague, which has a little more than 1.3 million residents.
Morocco currently generates 35% of its energy needs through renewable means.
Elsewhere on the continent, there are also strides being made in Rwanda, Ghana is building a 155 MW plant, Kenya’s 54.6 MW Garissa plant went live in November 2018, and Algeria has plans to generate 12 GW within the next 11 years.
So, how does it work?
Let’s talk about photovoltaics, or PV, first. PV utilises photovoltaic cells, which simply convert sunlight into energy via the photovoltaic effect. This is a physical and chemical phenomenon seen in some elements.
The problem here is scalability. It takes up a lot of space and requires a lot of sunlight. But, there’s a settlement in Germany that is completely off the grid, being powered by rooftop solar panels, and they get half the annual sunshine of Kenya.
PV panels used to be expensive, but the costs are coming down internationally as technology advances. The storage of the energy also used to be a problem, but those costs are also coming down.
These panels can either be mounted to be static, or could have sunlight trackers to maximise the exposure to the sun.
Now, let’s talk about concentrated solar power, or CSP. With CSP, a system of mirrors is aimed at maximising the irradiation by concentrating all the gathered sunshine on one point, such as a solar tower. Think of it as using a magnifying glass to start a fire. You’re magnifying and concentrating the sunlight to heat a tower.
The heat is used to either drive a heat engine, which will use the heat to generate electricity, or the heat could be used to drive a thermochemical reaction, with electricity generation being among the effects of the reaction.
These plants are usually built in a circle, or arc formation. In Morocco’s case, the plant uses a combination of CSP and PV.
While these plants have the potential to produce massive amounts of energy, one of the downsides is that it requires direct, uninterrupted sunlight, like your magnifying glass, so any cloud cover or shade of any kind would hamper your generation capabilities.
On the other hand, PV can also use diffuse radiation, so it doesn’t necessarily require a clear day. The problem with PV, is that it can only generate power during the day, so it’s not very effective after the sun goes down, which is usually when the demand for electricity goes up.
CSP though, because it can use thermal energy storage, like storing the heat in molten salt like they do in Morocco, so it can keep generating electricity in the dark.
I hope you’ve now got a better understanding of solar power and how Africa is innovating in this space. This is NewsByte on ANAplus; we make Africa matter.
* #NewsByte with Lance Witten is a product of the ANA+ digital channel. Find them on YouTube.