MechChem Africa June 2018

Towards a sustainable energy mix for Africa

Compared with the rest of Africa, SouthAfrica is well endowed, with a robust, centralised generating and transmission system of about 35 GW of installed capacity. Elsewhere in Africa, emergent networks are becoming a reality, with mini-grids that are gradually becoming more connected. Paul Fitzsimons, general manager power and energy, and Louwrens van der Merwe, sustainability consultant at GIBB engineering and architecture summarise some challenges and opportunities.

Paul Fitzsimons

Louwrens van der Merwe

I n Africa, access to affordable power remains a major issue for the economic wellbeing of the continent. The question of how this power will be supplied is one all countries are grappling with at present. In the emergent network space, solar power is becoming the installationof choice. The Inter- national Solar Alliance is targeting 1 000GW to be installed by 2030. There is clearly a growing appetite for renewable energy in Africa, but there is a triangle of dependence between security of

supply, environmental management and af- fordability issues – the IEA’s ‘Energy triangle’. Every territorymust find its own ideal way of balancing these considerations. There are certain key trends that drive the way these considerations interact. The reliability of existing grid service providers is a big issue throughout Africa. Typically, 30% of African countries experience an outage of some sort once every three or four days. But consumption is low. Typically, sub-Saharan African per capita electricity consumption

remains a few hundred kWh a year. The av- erage suburban Johannesburg resident will consume in tendayswhat the averageAfrican resident consumes in a year. While energy access has increased in sub- Saharan Africa, with about 150-million more people gaining access to electricity over the past ten years, it has not kept pacewith popu- lation increase. Against this backdrop, (apart fromthe centre of Australia) Africa has about the best solar resource in theworld. Typically, it’s about three times better than Europe.

Can we get 100% of our energy from renewable sources? I s there enough space for all the wind turbines and solar panels to provide all our energy needs? What happens when the sun doesn’t shine and the wind doesn’t blow?Won’t renewables destabilise the grid and cause blackouts? issues. They demonstrate that there are no roadblocks on the way to a 100% renew- able future. gap – during low wind and solar periods or unusually dark European winters, for example. Luckily, this is a problem that a country like South Africa, with very little seasonality in solar supply, does not need to worry about too much.

“While several of the issues raised by the Heard paper are important, one must realise that there are technical solutions to all the points they raised, using today’s technology,” says the lead author of the response, Tom Brown of the Karlsruhe Instituteof Technology. “Furthermore, these solutions areaffordable, especiallygiven the sinking costs of wind and solar power,” says ProfessorChristianBreyer of Lappeenranta University of Technology, who co-authored the response. Another co-author of the response, now former CSIR employee Tobias Bischof- Niemz, says: “It’sbeyondany scientificdoubt that a renewables-led energy system is technically feasible, and recent technology cost developments for solar and wind have nowmade it economically viable too, which is good news indeed for sun- and wind-rich countries such as South Africa.” Brown cites as the worst-case solution, hydrogen or synthetic gas produced with renewable electricity for use during times when imports, hydroelectricity, batteries, and other storage options fail to bridge the

In a review paper last year in the high- ranking journal Renewable and Sustainable Energy Reviews , Benjamin Heard and col- leagues presented their case against 100% renewable electricity systems. They doubted the feasibility of many of the recent scenarios for high percentages of renewable energy, questioning everything from whether renewables-based systems can survive extreme weather events with low sun and low wind, to the ability to keep the grid stable with so much variable generation. Now scientists have hit back with their response to the points raised by Heard and colleagues. The researchers from the Karlsruhe Instituteof Technology, theSouth African Council for Scientific and Industrial Research(CSIR),LappeenrantaUniversityof Technology, Delft University of Technology and Aalborg University have analysed hun- dreds of studies from across the scientific literature to answer each of the apparent

More importantly, the stability of the gridposes specific challenges inSouthAfrica with existing low-levels of interconnectivity with neighbours. For maintaining stability thereareaseriesoftechnicalsolutions,from rotating-flywheel grid stabilisers to newer electronics-based solutions. The scientists have collected examples of best practice by grid operators from across the world, from Denmark to Tasmania. The response by the scientists has now appeared in the same journal as the original article by Heard and colleagues. “There are some persistent myths that 100% renewable systems are not pos- sible,” says Brian VadMathiesen of Aalborg University. “Our contribution deals with thesemyths one-by-one, using all the latest research. Now let’s get back to the business ofmodelling low-cost scenarios toeliminate fossil fuels from our energy system, so we can tackle the climate andhealth challenges they pose.” q

24 ¦ MechChem Africa • June 2018