Page 13 - Energize May 2021

The Eskom Virtual Power Station (VPS) reduce the capacity required to be built under this programme.
programme operated effectively from 2012 Grid electricity in South Africa has a carbon footprint of 1 kg Co2eq per kWh of electricity
to 2017. Own generation was bid and produced. This reduces to 0,6 kg Co2eq for gas-fired generation and approximately 0,4 kg
dispatched daily by telephone instruction Co2eq for gas-fired CHP. Hydrogen is attracting significant interest worldwide as a carbon-
from Eskom. Experience with the Eskom free fuel. Hydrogen is produced using electricity to split water into its component hydrogen
VPS and a 12 MW gas powered own and oxygen. The oxygen is captured for commercial use or released into the atmosphere.
generation plant during the period above The hydrogen is captured, stored and available to be used as fuel later, producing water as a
shows that this is practical and effective. product of combustion.
The reinstatement of the Eskom VPS would The carbon footprint of gas-powered generation can be further reduced by blending of
encourage the uptake of own generation by hydrogen with gas fuel. Gas powered generation is currently able to support approximately
industry and commercial consumers. 20% hydrogen blending with indications this will increase to 60% or more over the next 20
Combined heat and power (CHP) years. As the proportion of solar and wind increases a situation arises where there is excess
projects, where the waste heat from gas electricity available during the day. This excess electricity can be utilised to produce hydrogen
powered generation is utilised for process which is stored and combusted during peak periods. Gas fired generation is cost effective and
heating (steam, hot water, or direct heating), unlikely to become obsolete in future.
dramatically increases the proportion of fuel
energy which is available as useful energy Other gap fillers
and reduces the carbon footprint of the Hydro electricity and pumped storage are great technologies, but the most suitable sites have
energy used. already been developed in South Africa and water supplies for hydro generation are limited.
Gas-fired CHP is cost effective at Large scale hydro-electric generation in central Africa is possible with transmission of power
current gas and electricity tariffs. The to Southern Africa. The DRC’s Inga project has not progressed significantly over the last 20
latest IRP and liberalisation of the own years due to political instability and a lack of unity of purpose between African governments.
generation licensing requirements creates Concentrated solar, while an elegant concept, is expensive compared to alternative technologies.
the environment for an exciting take-up of Battery storage is often proposed as the solution to utility scale peaking power.
gas-fired own generation. Unfortunately, battery stored power is only dispatchable to the extent that battery charge is
There are certain industrial heating available. It is prohibitively expensive other than for short term grid stabilisation, has significant
processes which are better suited to direct materials requirements together with pollution concerns around production and disposal. It
fuel combustion than electrical heating. The is unlikely that batteries will provide a significant proportion of the grid storage required to
availability of gas fuel will facilitate fuel switch compliment the PV generation being added to the grid.
projects further reducing load on the grid.
The availability of gas fuel must be Conclusion
improved to facilitate the above initiatives. The continued improvement of legislation to utilise existing excess industrial generation
This will be supported by the entry of LNG capacity, promote gas-fired CHP and change consumer behaviour to reduce morning and
into South Africa in the relatively near future. evening peaks provides the low hanging fruit to mitigate the current energy crisis.
The peaking capacity provided by This will require the encouragement of the entry of commercial scale LNG into South
the above measures will need to be Africa. This can be achieved in a short period, reducing the carbon footprint of the country, and
supplemented as required by the national without burdening the taxpayer.
Gas to Power programme. The above
measures have the potential to significantly Contact Ken Gafner, SDE, Tel 010 880-7600, keng@sde.co.za

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