Global
A combination of various sources of electricity seems to be the solution to unanswered
questions about power generation for the African mining industry. This includes gas (in
picture) and hydroelectricity sourced from Africa’s many rivers and dams.
hybrid solution behind the grid at equal
or lesser cost, with added reliability and
consistency in supply. In many instances,
renewable energy is significantly
cheaper than grid supply, so we are able
to offer a cheaper and more reliable
solution compared to the grid.
The reduced costs now make it possible
for mining compa nies to consider these
solutions. Mines have been aware of solar
and renewable energy but would mostly
look at renewable energy only from a
‘green’ perspective. Now it is all about
saving costs and reducing price and fuel
risks, while at the same time boosting
the social and environmental license to
operate.
With a real trend in reduction of
components like storage, we are now
in a position where it has become
economically viable for a mine to
look at this. We can design hybrid
plants that can produce electricity at
extremely low prices in many locations
across Africa. This is very attractive
for many mines.
Integrating hybrid for mines
Reliable and robust integration of
solar or wind into diesel or HFO
power stations at mines is a key
success factor. A number of companies
have developed hybrid technology
and solutions that enable seamless
integration of various power sources.
The hybrid controller is the heart
of the operation, and designing and
implementing it properly is of paramount
importance. juwi, a company specialising
in renewable energy, has put a lot of
engineering and development into that
process, ensuring that all sources in the
power system work seamlessly and balance
solar, diesel, wind, or battery so that there
is zero interruption to supply. It is all about
maintaining voltage, frequency, and the
power factor, no matter if the sun shines,
the wind blows, or a large mill ramps up.
This is what juwi excels at.
An effective monitoring system
At a typical mine site, the operator needs to
know every single detail about the power
supply. To improve visibility of supply, juwi
has developed a unique hybrid system called
SCADA, which gives miners visibility on
all generation assets and enables much
greater control and more clarity on power
generation costs. The system combines
all power sources and the operator and
management can see what is happening in
their power system in real time.
It gives a mining company comfort and
security if they have good visibility and
reliable supply. It allows them to track and
manage their costs. Many other similar
systems provide only separated views: one
for solar, one for diesel and maybe wind
and battery, but not integrated properly and
with high resolution. What the juwi hybrid
SCADA does is bring it all together into
one system that monitors and combines
everything and gives the operator easy
access. To date, no one else has successfully
operated a large hybrid power plant at a
mine for longer. That experience and data
enable us to offer mines critical advantages.
Many companies are designing thermal
power plants, or solar or wind systems, but
there are very few who really understand
the needs of mining operations and even
less that have the ability to integrate solar
or wind with fossil power at a mine site. b
About the author
David Manning is global head of hybrid
and Arnim Schön is sales manager
sub-Saharan Africa at juwi Renewable
Energies.
juwi has built large solar farms in South
Africa and off-grid systems all over the
continent. The company installed the
first-ever grid-connected solar system
in sub-Saharan Africa. This project was
built in 2007 in Rwanda.
AUGUST 2018 MINING MIRROR
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