by Alexander Jan Ham (Pr.Eng.), Eskom (retired)
While the government’s draft Integrated Resource Plan (IRP2019) is very thorough and makes impressive reading, it lacks decisiveness and urgency of focused action. The time has come to stop planning and start implementing.
Eskom has frequently acknowledged the serious financial situation it finds itself in. Since there is no benefit in analysing, yet again, how Eskom got itself into this situation, we should focus on the best and fastest way forward and at the least possible cost. Firstly, Eskom must stop doing “patch-up” short term repairs to its plant after forced shutdowns.
Original equipment manufacturers (OEMs) should be contracted to undertake the necessary refurbishments to the fatigued plants and be allowed outage time to complete such work. OEMs are more capable in examining fatigued plant which they originally designed and built, than Eskom’s power station staff are.
This is the best way to improve the shockingly low plant availability factor.
Transmission grids in the USA and Europe are interconnected across national or state boundaries with other independent generators which provides great stability. Reliability of supply at constant frequency and voltage is essential. The maintenance of this is much more difficult with a stand-alone transmission grid spanning several thousand kilometres such as ours.
With the power demand on our grid currently peaking at about 30 000 MW, no battery system in the world, can instantaneously meet sudden large increases in demand. This can only be achieved by rapidly ramping up the output of plant already in operation and at partial output. This is an essential dynamic factor to bear in mind in deciding the extent to which we can depend on renewable energy systems.
Currently, Eskom’s generation system from its large coal-fired units has about 56 large steam turbine generator units with a combined rotating inertia of about 14 000 tonnes which helps to maintain grid stability in the event of sudden load changes. If our grid frequency drops from 50 to 49,85 Hz, automatic load-shedding takes effect to protect the instability which could escalate into a total system blackout lasting several days.
Portions of the electricity supply grids in Germany, UK and Australia have recently experienced such grid failures due to an over-dependence on wind-powered generators. Power grid system stability studies indicate that stand-alone grids such as ours should not rely on more than about 26% of the total demand being supplied by wind power. While solar power generation is not as variable as wind, seasonal weather changes can have a significantly negative effect on their output.
The fact that the blades of a wind generator are rotating does not indicate its extent of output. Generally, full output is only achieved at wind speeds above 30 km/h and 50% output at wind speeds of around 18 km/h. For land-based wind generators output will only be achieved for a total of about 3000 h pa and on an unpredictable basis.
Our only reliable option for large energy storage is from pumped water energy storage systems. However, because of plant inefficiencies we recover less power than we put in. Such generating systems cannot therefore be reflected as net electricity generating capacity.
Furthermore, it takes many minutes to get the system to commence generating. Being essentially a dry country South Africa’s total hydro potential is small, less than 7% (480 GWh). Base load generating plant must therefore form the backbone of our power system and offer a total capacity of at least 65% of our system demand. We can only assume to be able to reliably import about 4% of our needs from outside of our borders at present (currently from Cahora Bassa).
How then should the baseload of 65% of our total requirements be generated? We have the following options open to us which we should commit to now if we intend to progressively decommission our older coal fired power stations:
- Import liquified natural gas (LNG) to fuel our present and future gas turbine combined cycle base load and peak load generating turbines.
- Commence controlled and regulated fracking of suitable rock strata areas which could yield significant supplies of natural gas for power generation at much lower costs than imported LNG.
- Seek international partners to develop our Brulpadda gas fields in the Outeniqua Basin without delay. However, as all these systems still generate carbon dioxide, and we have committed ourselves to reduce such emissions, we need to seek other long-term less-polluting solutions.
We fully respect the desire to decarbonise Eskom’s operations but must appeal to all that we have important humanitarian demands which cannot be ignored. Hence this must restrain our desired rate of change. Many people residing in our country, many of whom are more financially privileged than the financially struggling majority, understandably view environmental issues from a first world perspective. We appreciate their concerns and insistence that South Africa must implement changes in accordance with the Paris environmental agreement the government signed. However, this is no longer realistic for South Africa.
Change we must but the dramatic Coronavirus pandemic will cause us to compromise our previous plans, due to our failed economy. If we do not implement fracking soon, we will have to continue to rely on coal-based power generation. Perhaps it would be best to contract large International power generating companies to build, own and operate all new large coal stations, since Eskom has demonstrated it inability to comply our stringent air pollution control laws at its power stations.
The power utility continuously applies for “temporary” exemptions, claiming that it cannot afford to install the essential particulate, NOX and SOX filter systems. Furthermore, it seems incapable of maintaining the particulate filter systems already installed at most of its power stations.
Eskom’s transgressions of our national air pollution laws, and the fact that significant carbon capture and large-scale storage will not be possible here in the near future, leaves us with the only other realistic alternative for base load generation: nuclear power.
Eskom’s Koeberg nuclear power station has provided excellent service over 36 years. The power utility has adequate coastal sites already procured around our coast for at least 13 000 MW. Proven, safe and cost-effective nuclear power plants are available today from China, South Korea and Russia.
Surely an IPP agreement could be negotiated with any one of these, starting now as the lead time to build and commission takes at least 8 to 10 years. Finally, we need to be realistic in our desire to depend almost entirely on renewable energy to satisfy most of our electricity needs in the future. It is impossible! The time has arrived for action and implementation before the next “black swan” event is upon us.
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About Alex Ham
Alexander Jan Ham, (Pr.Eng.), is a former executive director of Eskom’s Engineering Technology division, now retired. Ham has over 50 years’ experience in this field both locally and internationally and keeps abreast of international developments and experience in this broad field. Having followed closely the evolution of Eskom since it was nationalised in 1996 and its gradual demise, he says he feels compelled to commit his recommendations in the hope that some influential person will take note of them and become inspired to act. This article is written in his private capacity.