The chief operating officer of Eskom, a South African electricity supplier, warned in May that the government urgently needs to start building new production capacity. He referred to a new construction program that has been around for at least a decade.
The country 2019 Integrated Resource Plana document approved by the cabinet setting out a timetable for the decommissioning of coal-fired power plants and the addition of 44 GW of new capacity, including 18 GW of wind power and 8 GW of solar power (photovoltaic).
The country is already far behind in this program, limping with antique power plants and regular power outages. Outages a regular occurrence which estimated to cost the country’s economy about $ 1 million an hour.
South Africans are all too aware that there is an energy crisis. However, in my work on energy systems and transitions, I began to ask questions about the true nature and extent of this, and how Eskom should respond. My views are provided by Eskom’s data portal, which is a rich resource for learning about South Africa’s complex electricity system. The purpose of the portal is to share detailed information on electricity demand and supply. It has hourly data on energy sources, storage levels and load reduction rates (power outages).
I analyzed the demand and supply data for the first half of May 2022. It revealed three main trends: demand fell; power outages are not as great as they could be; and there is an opportunity to get more out of the system by using renewable energy sources.
Power supply and demand trends in South Africa
The data reveals three main trends for public utilities. First, Eskom reduced demand by 6 GW (about 21%) within a year. This is because many non-paying customers have been disconnected and several large customers, including industrial users such as mines, are now generating their own electricity.
The figure below compares demand for two days, one from June 2021 and the other from May 2022. It reflects actual demand, not Eskom’s supply. The difference in demand is amazing. At this rate, South Africa will simply not need Eskom in five years.
The second interesting finding is that the amount of power outages is small compared to the total energy delivered. In the week from 12 to 19 May 2022, Eskom transmitted 4271 MWh of electricity and cut 70 MWh, which is only 1.6% of the energy produced, as shown in the figure below.
I highlight this to show that power outages could be much worse unless the reconstruction program begins soon. One of the reasons why power outages attract a lot of media attention is that consumers bear a disproportionate share of energy outages compared to Eskom’s regular customers.
For example, below Level 4, where power outages can last for more than five hours a day, lower end users only have power for 67% of the day – meaning 33% of their power outages. But the total energy savings in the whole system is 10%. This suggests that Eskom is consciously maintaining supply to its anchor customers – large industrial users and essential services – even during a power outage.
The final issue is that Eskom can get more capacity from its pumped water systems. These systems use extra energy at night to pump water into high storage dams, from which water is released during the day to meet the greater demands of the day. In the week of 12-19 May, the capacity utilization of the pumped water is only approx 38%.
If there had been enough energy during the day to fill the reservoirs, Eskom would have been able to increase its production capacity by 1.7 GW early in the evening, taking full advantage of the pumped hydropower and avoiding load reduction. This daytime energy could have come from the renewable energy program if the Department of Minerals and Energy had adhered to the construction schedule.
The possibilities of Eskom
What opportunities does Eskom have in addition to starting the construction program?
To answer this question, we need some basic knowledge about energy systems. South Africa has a diverse energy system. Electricity is obtained from coal (the largest source), wind, solar, hydropower, nuclear, diesel and imports.
Wind, solar and nuclear energy cannot be controlled by the operator. Gas, water, pump water and diesel can. Coal is somewhere in between. As a system operator, Eskom is responsible for matching all resources to demand.
The difficulty is that both supply and demand are variable, as shown in the figure above for solar panels. It’s like running a catering event when you have no idea how many guests will be there or how many meals will be delivered.
So Eskom follows a few simple rules (like other power system operators). The rules require you to first use sources that you cannot control (wind, solar and nuclear), then add coal-fired power plants and then fill them with hydropower and pumped water. And if there is still a shortage, bring in gas and diesel turbines.
The most obvious solution to Eskom’s immediate problem is twofold:
- bring in more renewable energy, especially wind and solar energy procurement program for independent power generators
- better use should be made of pumped hydropower, using any low-cost additional energy source that can be obtained from independent power generators and elsewhere.
This approach has been outlined in my previous publication which covers the procurement program for independent power generators. I criticized the program’s requirement for stand-alone power generators and argued that interconnecting generators reduces costs and increases system flexibility. It is this layout that will provide a solution to short-term problems within the national network.
In the longer term, the country needs to properly implement the 2019 Integrated Resource Plan, even if it conflicts with the coal, gas and oil sectors of the Ministry of Minerals and Energy. interests.
If the country does not start the 2019 plan now, it will lead to the cessation of Eskom as an energy producer, as users will be forced to turn to other sources.
What is needed for South Africa’s ailing energy supplier to continue to operate – SABC News
Source link What is needed for South Africa’s ailing energy supplier to continue to operate – SABC News