It is difficult to imagine the modern world without electricity grids that distribute energy to industry and private households.
This energy is used to drive machines that wash our clothes, brew tea and coffee, control our security and connect us to the world.
The possibility of getting electricity from power points gives us the opportunity to manage our electricity production on a national level to find the cheapest and most sustainable combination of resources to generate electrical power.
It is important for the welfare of any country that electricity be obtained at the lowest price possible to keep the costs of products and services that consume energy, low.
Sustainable energy generation means we must not saw off the branch on which we sit in the process. For example, by degrading our environment or using up resources.
What resources should South Africa use to deliver electricity to its citizens and companies?
South Africa is blessed with lots of sunshine, wind, coal, uranium (for nuclear energy), and has access to gas from neighbouring countries.
While sunlight and wind are free and never run out, the other fuels cost money and can be used up. However, we have to use other fuels when the sun does not shine and the wind does not blow.
By knowing enough about the weather, we can calculate the best mix from the costs of a kilowatt-hour of energy generated from each of the resources.
The Energy Centre of the CSIR in Pretoria carried out a study to determine the lowest-cost electricity mix for South Africa. It used a globally-used software package called Plexos which simulates electric power systems based on models for electricity demand, weather and cost development.
It takes into account power generation costs, including installing power plants, maintaining and running them and fuel costs.
The study simulated the future of electric power supply in South Africa until 2050 and found the most economical mix for the country consisted of solar energy (from photo-voltaic panels), wind energy, the existing coal power stations, and gas and diesel turbines.
Economical
Gas and diesel turbines are like back-up generators that are expensive to run but can, within minutes, add electric power to the grid and compensate for power variations with the cheap but fluctuating resources of sunlight and wind.
Together with ramping up the power production from coal stations on a time-scale of hours, these flexible sources can balance the fluctuations of sunlight and wind without the need for energy storage, which would add energy losses and is expensive.
The reason the most economical mix does not contain additional nuclear and coal resources is simple: electric power generation from solar and wind currently cost only 60 percent of the price of electricity from coal and nuclear and relative prices are expected to drop further.
With the cautious estimate that the relative solar and wind prices will not decrease in the next 35 years, the study found that the solution with large contributions from wind and solar would save the country R25 billion a year in 2030, increasing to R80bn a year in 2050, compared with the energy mix proposed by the Department of Energy in its Integrated Resource Plan (IRP) 2016 Draft.
Opposite to the CSIR findings, the department’s master plan claims the most economic power generation requires adding mainly nuclear and coal power stations instead of solar and wind farms.
Although the IRP 2016 is based on simulations carried out by a department team using the same software used in the CSIR study, the results are different because the department team used old pricing and constrained the solar and wind power that can be added to the grid per year by about 1 gigawatt (a million kilowatts) without explanation.
This limitation is unjustified and can be seen by comparing the wind power supplies other countries added (for example, in 2015, China added 30GW, Germany 6GW, and Brazil 3GW). The optimal solution of the CSIR study would require building 2GW of solar and 3GW of wind power a year, which is feasible. On request from the Ministerial Advisory Council on Energy (Mace), the department’s IRP team released a second study without the restrictions on the building capacity of wind and solar plants.
Its results are similar to those from the CSIR Energy Centre: The least-cost mix does not contain any new nuclear power and relies mainly on wind, solar and coal power. But, like the IRP 2016 study, it uses old pricing for wind and solar power generation.
After analysis of the information given, Mace in October recommended to the Minister of Energy, Tina Joemat-Pettersson, to rerun the study, without limits for new-build wind and solar farms, but with their actual costing to correct the least-cost scenario in the IRP 2016 draft.
However, the IRP 2016 draft was published on November 22, ignoring the recommendations of Mace.
Now the public can and should comment on the IRP 2016 draft, and have until March 31 to do so.
The necessary information is given on the department’s website. We feel the CSIR study, and the department’s second study without artificial constraints, identify optimal energy mixes without the new-build nuclear component, strongly suggests scrapping the nuclear deal - the purchase of nuclear power stations at a cost to South Africa estimated at R1 trillion (including interest rates).
We support the Mace recommendations and look forward to a future in which the country can spend up to R80 billion more per year on worthy goals such as education or poverty eradication.
* The authors are physicists from Durban. To comment on the IRP 2016 draft before the March 31 cut-off go here.