In the light of recent #climatestrikes around the world, Prof Ntshengedzeni Sampson Mamphweli’s work as director
of Centre for Renewable and Sustainable Energy Studies (CRSES) is more
important than ever.
CRSES, based in the Faculty of Engineering, serves as a national
hub for postgraduate studies into the development of renewable and sustainable energy.
This includes bioenergy, solar photovoltaics, solar thermal, wind and hydro
power options. The Centre, which also conducts anything from initial
feasibility studies to highly technical investigations into new technologies,
was established in 2007. A decade later, Prof Mamphweni followed in the
footsteps of outgoing founding Director Prof Wikus van Niekerk, when he became dean
of the SU Faculty of Engineering in mid-2017.
For his talk on 16 October 2019 as part of the Division of
Research Development’s Forward with Research Impact lecture series, Mamphweni
will be focusing on thermochemical and biological techniques can be used to
convert biomass into energy. It takes place at 13:00 in the Old Main Building
South Africa’s renewable energy future
South Africa has committed to supplying at least 32% of its energy
needs by 2030 through clean technology and renewable energy sources. This is
the target set out in the Integrated Resource Plan 2018.
“Although it’s higher than the national target, I think at least 40%
is possible for us,” challenges Mamphweli, who is inspired by the likes of India,
a country heading towards a 90% renewable energy target.
Among his many responsibilities, he coordinates renewable energy research
between South Africa and India, under the BRICS banner. This initiative will ensure
more combined research projects and student exchanges between the countries.
He also drives stronger coordination of renewable energy research matters
between African universities and centres, as co-director of the Centre of
Excellence in Energy. This forms part of the African Research Universities
Although he’d like to see that more of the technologies that have
been developed or studied at local universities over the past decade actually
be implemented, he remains a realist.
He believes the country can be pricewise competitive when it comes
to producing the infrastructure needed to generate wind energy, biogas and
solar thermal energy. The much cheaper photovoltaic infrastructure available
via China is however a totally different story. An option would be to aim for
at least the partial assembly of technology on the home front, to ensure that
jobs are created locally.
Mamphweli’s renewable energy expertise was shaped through his
studies of biogas and syngas (synthetic) production, with waste materials such
as wood waste, mealie cobs and manure as fuel. If he could have his way, there
would be more biodigesters to generate biogas in back gardens in South Africa
than is currently the case. Such technology would also be used in urban areas,
instead of only being dotted around the countryside. He also sees room for
municipal sewage works to generate their own electricity, using the methane gas
that is in any case generated as part of their mandatory cleaning of wastewater,
and is currently merely burnt.
A biodigester, in short, is a dome-shaped, roofed construction
made from brick, plastic or steel fitted into the ground. It is filled with waste
that may be animal dung or even human faeces. When water and bacteria interact
with it, the material decomposes to release methane gas. An outlet pipe then takes
the gas to whatever needs to be powered – be it a gas engine, a gas turbine or
a stove. Gas can also be trapped in a canister or special bag for later use.
Biodigesters are widely used in China and India. While explaining
the basics behind it, Mamphweli makes quick sketches on a blank piece of paper.
After years of experimentation, he knows that it takes a near-perfect 50/50
match between manure and water to generate methane gas.
“About 25 kg of cow dung gives you 1 cubic meter of gas. That’s 6
kilowatt hours or six units of electricity, with which you can cook for five to
six hours,” he sets out, making the technology look deceptively easy.
As a panel member of the National Biogas Platform, he however knows
that there’s more to it than just trapping gas. One has among others to do gas
scrubbing, which is a way of purifying and filtering the gas.
He acknowledges that some people find feeding such systems with
available dung from livestock too tedious a household chore, even if it is
giving them free energy. There are ways to sidestep such qualms, too, he says. The
solution is to basically connect the system directly to a household’s sewage
“What you need is an inlet and an outlet, and a container to trap
the gas in,” Mamphweli explains, still sketching away. Pre-empting the groans
of the squeamish, he quickly adds: “You don’t even have to come in contact with
it (the effluent).”
One of his PhD students has recently started to build a
biodigester on the University’s Mariendahl experimental farm outside
Stellenbosch. Manure, obtained from the pigsties on the farm, will be used to produce
and capture methane gas, which will drive a 10 kW gas engine. If successful, it
can be used to power outdoor lighting on the farm.
Mamphweli came to Stellenbosch via the University of Fort Hare,
where he started as an Eskom Research fellow in 2005. It was in the Eastern
Cape where he started to think about the nitty-gritty of biomass conversion, as
part of the PhD in Physics he obtained in 2010. It was about biomass
gasification. After graduating, he started research on biogas digesters. It led
to hundreds of biodigesters and solar panels being installed in the rural
Eastern Cape and areas bordering on Lesotho as part of his research endeavours.
He’s always had a particular affinity for physics. Today, he
laughs at his younger self who tried to explain everything happening around him
to his teenage friends in terms of physics. In his final matric exam he scored
100% for the subject, but was let down by the chemistry part, which he did not
like during his days at high school.
This younger self dreamt of becoming a pilot, and as a second
choice, a doctor. However, after matriculating from Lwenzhe Secondary school in
Limpopo in 1997, the would-be bespectacled professor wasn’t even invited for an
interview by the national carrier’s cadet academy. A lack of funds stopped him
in his tracks after being accepted for medical studies at MEDUNSA.
“The letter (of acceptance) indicated how much I had to pay and
all that. It was about R20 000 that I needed, which we did not have at
home. I did not have a bursary, so I walked into the University of Venda, and
applied to study there,” he remembers how it came about that he started to
study 20 kilometres from home.
His choice fell on environmental science, because of his soft spot
“I told myself that one day I’d be working in the Kruger National
Park,” Mamphweli remembers the challenge he put himself.
That’s one dream that did materialise. After completing his
honours degree, Mamphweli found himself in the Kruger Park between 2002 and
2004, studying the impact of elephants on the trees along rivers to the
southern side of Africa’s oldest nature reserve. He used the time and data
collected to complete a masters degree on the subject.
“I still think my best life was in the Kruger National Park,” says
this avid birder with also has a penchant for fast cars. “I go there every
chance I get.”
He had the option of studying elephants for his PhD too, but was
intrigued by an advert for a PhD position to study biomass gasifiers at the
University of Fort Hare, as part of the Eskom Research Fellowship Black
Researchers Development Program.
“I am not at all, not at all sorry about that decision,” he
reiterates, saying that he believes he is making an impact on community level
by the installation of biodigesters, and also on a national level.
“I love nature, but I also love the energy side of things,” says
the professor, who is currently editing a book on independent power producers