Most people in South Africa have become used to the term energy availability factor (EAF) as a measure of the Eskom power stations’ (combined) performance. Yet it is doubtful if many people understand what this term really means in practical terms, let alone how to compute it technically and scientifically, unless you have worked in operating Eskom power plants.
I will attempt to share with ordinary South Africans what EAF really means and what those that operate Eskom power stations would have to do to keep acceptable EAF between 70% and 80%, which would translate to the country not being subjected to any load shedding at all.
Literature abounds in the lexicon of power generation. We shall discuss this in due course. For now, we focus on what the immediate tasks should be. This is in light of the man-made destruction of Eskom, resulting in energy poverty. For almost a month to date Eskom has been focusing on this primary indicator and South Africa is down to Level 2 load shedding.
Professor Anton Eberhard warns that Eskom should not count its chickens before they hatch. Of course, we counted the paddles that the noisy green lobby bestowed on the nation, so Eskom, applying science, knows the eggs are to hatch and they will not rot. This is how it works.
What exactly makes and constitutes the EAF:
Knowing that Eskom EAF is the bone of contention and key performance indicator (KPI) for an Eskom CEO and group executive of generation, in this article I have decided not to deviate from using the generally agreed definitions of what constitutes the EAF. These definitions are actually covered by Eskom in its glossary of terms on its website.
Among these is the generally accepted capacity loss factor in relation to the EAF. And those who have operated Eskom power plants speak of the 80:10:10 principle as a good measure of the middle-aged Eskom power stations fleet.
According to these numbers, 80% availability of a power station or fleet is a generally accepted EAF. The 20% unavailability of a power station or fleet consists of planned capacity loss factor (PCLF) making up 10%, with unavailability and unplanned capacity loss factor (UCLF) plus other capacity loss factors (OCLP) making up the other 10% of plant unavailability.
Eskom operates on the principle of that 80% of its power plants have to be available and only 20% should be on either planned or unplanned maintenance.
Two weeks ago, Eskom reported marked improvement in the EAF. Some energy industry observers and I, who have operated Eskom power plants, continue to weigh in on the recent good performance (EAF) and have cheered with science as to how Eskom should keep the planned maintenance and unplanned maintenance within the 80:10:10 operating principle.
To this end we recommend the following: First, keep the Eskom planning going strong. It is said that the top five power specialists who know better about ensuring that the power generation system matches the grid demand (keeping the system inertia and frequency stable) are sitting at Simmerman. Eskom is encouraged to use them more to work in harmony with the head of generation to achieve well-executed planning.
Second, delay closure of the Eskom coal fleet due for decommissioning. Last week, the weekly reporting by the electricity minister demonstrated that the so-called old Eskom power stations are responsible for the good performance that we are seeing.
These power stations are as follows:
– Camden power station: achieved 64.3% EAF.
– Kriel power station: achieved 65.9% EAF.
– Duvha power station: achieved 72.7% EAF. (Mind you, an entire Unit 3 boiler is still not rebuilt).
– Medupi (brand new, but has been having teething challenges): achieved 91% EAF.
– Lethabo power station: achieved 99% EAF.
What this tells is that there has to be a better plan between matching the decommissioning of the ageing coal power stations and the reality that the country needs electricity. This reveals that better planning between decommissioning ageing power plants and bringing in new capacity, whether renewable energy (intermittent) or baseload power, requires putting the interests of the country first.
The green lobby surely should have learnt from the addles that Eskom produced under André de Ruyter. We can be guided by system design to count our eggs.
In the next article I will delve deep into the holistic factors that Eskom has at its disposals to match the National Agenda of the Just Energy Transition with the current excellent performance of the ageing coal power stations.
Hlathi Zak Madela is an executive director of the South African Energy Forum (SAEF) and chairman of EIFSA (Economic Interventions Forum of South Africa). He is also a member of the Engineering League of Progress (ELP), an NPC encompassing engineering practitioners that have a vision to drive engineering solutions for growth and development. W/S: www.elop.org.za. He is a chemical engineering graduate from Wits University with 25 years’ work experience in the energy industry.
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