Small thermal plants promising for Africa
Small-scale power generation plants driven by hydrocarbon sources
and biomass are still likely to play a valuable part in rolling out
electricity in regions of Africa unserved by grid power and where
renewable resources are insufficient to sustain a reliable energy supply.
According to Chris Dalgliesh, partner and principal environmental
consultant at SRK Consulting’s Cape Town office, the lack
of a secure baseload energy supply in certain areas can be a
key inhibitor to local or regional investment and economic
development, and many countries, especially those not on a grid,
are looking beyond the traditional large-grid model to create
broader access to electricity.
Though the trend is leaning more towards renewables, thermal
plants also have the potential to augment supply from renewable
energy sources in localised power generation projects, ensuring
continuous electricity supply. While extensively involved in
environmental impact assessments (EIAs) for renewable energy
ventures, SRK has also provided EIAs and compliance reviews for
projects like small thermal power stations and closed-circuit gas
turbine power plants.
While gas is a relatively clean source of power compared to
hydrocarbons such as heavy fuel oil (HFO) and coal, the most
common environmental impacts of thermal plants — such as carbon
emissions, high water consumption, noise, and vibrations — can
now be suitably managed to meet the relevant legal compliance
requirements. Emissions can be reduced by improved scrubbing
technologies as well as by selecting lower-sulphur hydrocarbon
sources, though cannot match renewable sources in this respect.
“These impacts are much more manageable today than they
were in the past,” said Sue Reuther, principal environmental
consultant at SRK Consulting. “Closed-circuit water systems have
substantially reduced the hydrological impact of these plants, and
there are well-understood mitigation measures to insulate noise
and vibration where plants are close to residential areas.”
Even in regions where traditional fossil fuel sources are not easily
available, there is scope for using agricultural waste as a biomass
source to feed a thermal power plant. Considerable success has
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“In some cases, a small thermal plant generating 25–100MW of
power can be a more affordable developmental intervention for
a local area, especially if it does not incur the often-prohibitive
costs of transmission infrastructure across long distances,” said
Dalgliesh. “Our experience in various parts of the world suggests
that countries well-endowed with coal, gas, or oil, as well as surplus
biomass and combustible waste, can benefit from these options
while responsibly managing the environmental impacts.”
Chris Dalgliesh, partner and principal environmental consultant
at SRK Consulting.
been achieved, for instance, in the recycling of bagasse from sugar
cane in co-generation plants in various parts of Africa.
“Turbine technology is readily available to leverage the value of
biomass sources; an option which could link constructively to
agricultural production in Africa’s rural areas,” said Dalgliesh.
Waste-to-energy power plants are also attractive propositions, as
they meet the dual purpose of treating waste and generating power.
Maintaining high temperature in furnaces is key to ensuring
effective and safer incineration of these waste streams. “On some
remote sites, we often notice that waste is simply incinerated,
with no attempt to use the calorific value of the waste to generate
energy,” said Dalgliesh.
He concluded that while renewable energy is set to play a larger
and more environmentally sustainable role in the global energy
mix, a pragmatic and responsible approach to the potential of
small-scale thermal power plants could contribute substantially to
improving conditions and supporting development in marginalised
areas of Africa. b
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