Page 3 - Issue 4 2023

COVER STORY

Thank you, gas, for my cup of tea

by Wayne Glossop, Wärtsilä

itting at my computer at the end of a typically grey week here in Johannesburg, To date, South Africa has been
I hear my inverter switch from the now-depleted batteries back to the grid, thus attempting to undertake LNG-to-Power
Sallowing the small amount of sun escaping through the clouds time to top up the projects for over a decade (some would
batteries for another time. Relieved to know that I can still turn on the kettle and enjoy a argue for more than two decades).
cup of tea, as a power systems engineer, I also appreciate that this inconspicuous switch These have typically been in the form
symbolises one of the biggest growing issues facing the South African power system of ‘mega CCGT (Combined Cycle Gas
today, that is, how can South Africa maintain a reliable power supply amidst of the Turbines)’ types of projects with
constant changes and challenges facing our power system? nothing materialising due to a host of
This article is not intended to proclaim a ‘two-year turn-around plan’ nor propose reasons (think: politics at play; weak
a miraculous ‘three-step power recovery programme’, but rather present an evidence- technical solutions; underdeveloped gas
based view on a specific technology, that few can deny plays a critical role in the infrastructure; policy gaps - you name it).
immediate and future stabilisation of our power system, namely, gas. Often the topic of In more recent times though, through
divisive and polarised views, a brief scan of recently published studies and expert opinions the IPP Office’s ‘Risk Mitigation IPP
commenting on the need and the role of gas in South Africa, yields an approximately Programme,’ we now see a handful of
80% consensus view that gas is a key element to provide flexible capacity to support gas projects comprising about 1,4 GW of
renewable energy. The remaining 20% consists of the extremist views that no gas should the 2 GW allocation being awarded (with
be considered or that baseload gas is needed to replace our coal fleet. many more bids having been made).
A recent study by Meridian Economics titled: “Resolving The Power Crisis Part B: And while it is unfortunate that the
An Achievable Game Plan To End Load Shedding”, succinctly captures some of the key programme, and more so the gas projects
characteristics, and realities, of gas power in South Africa . The study describes gas than others, have been experiencing set-
(alternatively, diesel) as primarily a provider of peaking capacity and recognises that backs due to ongoing legal challenges,
there is an urgent need to consider the addition of 1.35GW of thermal peaking capacity, the programme can be hailed as a
preferably in the form of ICE (internal combustion engine) technology to be built by 2024 success for recognising and valuing a
as an ‘insurance’, should there be a delay in the other measures proposed. If we translate variety of technologies which are able to
this into load factor numbers, a gas plant serving both the ‘peaking’ and ‘insurance’ provide reliable and dispatchable energy
functionality could experience load factor ranges of 5-30%, as is currently experienced by to the power system.
the (supply constrained) diesel OCGT’s (open-cycle gas-turbines). A random week taken These technologies include wind
from Eskom’s data portal confirms this as per the image below. turbines; solar PV; battery energy
storage systems; reciprocating gas
engines; and diesel backup in varying
combinations. And, when viewed as a
collective, mirror the technologies one
would typically see in the results of an
optimised power system dispatch model.
So, despite the ‘warts and bumps’ in its
design (the suggestions proposed by
Meridian Economics are worth a read)
the programme does dispel a few myths
Figure 1: Eskom operates their diesel OCGT’s within a wide range of load factors to accommodate
the erratic supply/demand imbalances. [Source: Eskom website]. traditionally associated with LNG-to-
power projects.
Wartsila’s own studies echo these views in principle but place more emphasis on the The first myth debunked is that
‘insurance’ role that gas plays in the power system. Our modelling reveals that gas plays one requires a long-term LNG supply
an important role in maintaining a reliable supply under numerous “real world” events agreement to match the length of the
that are, and will, continue for the foreseeable future. Such events include adverse PPA (Power Purchase Agreement).
weather phenomena; catastrophic coal fleet failures; major transmission line failures; Not true. The rules of the RMIPPP
and undue delays for new capacity to be commissioned. All of these factors, which in accommodate gas supply changes after
reality are experienced on a continuous basis, result in load capacity factors ranging year 6 to more competitive (and likely
from 5 to 50%. cleaner) alternatives.
To help contextualise and enrich our discussion on the role of gas power in South The second myth it dispels is that
Africa, it may be worthwhile to reflect on some current and historical developments LNG-to-power projects can only be
which talk to the need for, and possibilities around, gas for South Africa. banked off large-scale baseload CCGT-

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