Page 59 - Energize August 2022

TECHNICAL

Similarly, do bifacial PV panels deliver
sufficiently more energy to make them
cost-effective when compared to single-
faced PV panels?
This question is difficult to answer because
it depends on so many variables. Surely,
if one pays the same price per watt for a
module with bifacial generation as one
pays for a module with only front side
generation, the choice is clear. That is
assuming the frontside generation is rated
the same for both modules. The backside
generation depends on the bifacial factor
and the available sunlight on the backside.
Figure 5: Bifacial module performance on dual-axis tracker
Again, by using LCOE calculations, as
other studies have also shown, bifacial PV
We assume that dual-axis trackers are more expensive than single-axis trackers. Does panels are cost effective.
one recover sufficient additional energy from a dual-axis tracker to make them cost- In our Enlit Africa presentation, we
effective? reported a zero-to-3% gain from bifacial
Dual axis tracked systems are more expensive from a rand-per-kW of installed PV capacity modules on dual axis trackers in the winter
perspective. However, the CSIR uses the levelised cost of electricity (LCOE) as the key and a 2-to-7% gain in summer months
metric when procuring new PV systems. (Figure 5). On our fixed rack platform, we
The LCOE is the relation between the total cost of the system and the total energy reported a 7% gain from bifacials relative to
production during the system lifetime. As such, LCOE indicates the cost to produce other high efficiency monofacial modules
electrical energy. (Figure 6).
The LCOE balances the upfront cost, the operations and maintenance costs, and the
electrical energy production of the system over a 25-year lifetime, resulting in the dual How would you summarise this study?
axis tracked system becoming more competitive on a rand-per-kWh basis. When we look Were your findings significantly different to
at utility scale PV, the commercial sector prefers single axis tracked systems over dual-axis your expectations? Besides presenting your
tracked systems, so they must be more cost-competitive than dual-axis tracked systems. findings to the Enlit Africa Conference, how
will your report be used in South Africa?
The findings are consistent with industry
expectations, so no real surprises. I think
we need to better understand the true
cost of operations and maintenance over
the lifetime of a PV system. This has a big
impact on financial returns, especially when
PV modules fail to perform at expected
levels. The CSIR PV module quality and
reliability lab can help clients reduce the
risk of installing poor quality modules when
specific test requirements are included in
the supplier contracts.

Send your comments to
Figure 6: Bifacial module performance on fixed rooftop rogerl@nowmedia.co.za

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