Global
Delving into renewables
The hybrid
renewable
energy
solution is
now firmly on
the agenda
of the African
mining sector,
writes David
Manning and
Arnim Schön.
W
ith the promise of significant cost
savings and security of power supply
in unreliable grid and remote off-grid
regions, the African mining sector is putting
hybrid renewable energy solutions firmly on the
agenda.
Traditionally, power supply in the African
mining sector is sourced from fossil fuels, diesel,
and heavy fuel oil (HFO). These are often
off-grid because of the remote location of mine
sites. Traditionally, diesel and HFO have been
the primary supply of energy in off-grid areas.
However, transporting diesel to remote areas is
difficult, expensive, and carries risk, both from a
commercial and an environmental perspective.
With the development of hybrid power solutions
at competitive costs, mines are now looking at the
alternatives.
High electricity costs
In mining, electricity normally comprises about 20%
to 30% of the operational costs. Reducing power
costs will obviously have a substantial effect on the
bottom line of a mine. Renewable energy has not
always been viewed positively by mines; however, it
does make economic sense.
Today, a hybrid solution is regarded as a more
attractive solution for mines because it is both cost
effective and reliable. One of the reasons mines
require hybrid energy rather than being entirely
dependent on renewables or diesel, is that mines
normally operate on a 24/7 basis, 365 days a year,
and are highly dependent on continuous operations.
[6] MINING MIRROR AUGUST 2018
The start-up and shutdown of a mine and processing
plant can take several hours, and any period of no
power is extremely detrimental to operations.
At a mining operation, the stability of power
supply is critical. A mine cannot afford any losses or
power cuts. This would have a major impact on the
operation, and to restart a processing plant or mill can
take up to a day. Production losses will be excessive.
Historically, mines were hesitant to look at
pure renewable solutions that were daylight and
weather dependent. Hybrid bridges the gap; it
allows mines to run renewables when the sun
shines, and when there is wind, to fall back on
diesel and battery storage for reliability.
Cheaper batteries
Battery technology is becoming cheaper and
installations driven by batteries are becoming
more viable. Batteries enable solar or wind power
plants and make it possible for mines to transition
seamlessly from renewable energy to diesel without
interruption of supply.
Another advantage of combining renewable
energy and battery storage with a grid or fossil-fuel
power source is the ability to stabilise the grid.
With batteries, the reach of renewables expands
significantly. Intermittency and weather dependency
almost disappear. This means cheaper, more reliable,
and cleaner power for off-takers.
With improved technologies and decreasing costs
of renewables and storage, the cost of grid supply
electricity and renewable energy is generally on
a par. What we are able to do is put a renewable/
Hybrid systems are gaining popularity for the operation of mines in remote regions.
The mine in picture is located in the Limpopo Province of South Africa.