Page 20 - Blue Valley Issue 5 2021

ESTATE NEWS

INVESTING IN SOLAR ELECTRICITY

iSTOCK: Tsvetan Ivanov

olar photovoltaic (PV) electricity has green, is able to transparently switch the power supply power to supply to the utility. The returns are
sustainable, price increase protection and from the PV to/from the utility. It is usually comparable to the first case, provided the price
Scontinuously available power benefits. programmed to supply all the available PV the utility pays is fair. This, however, will require
A very important issue is the solar PV financial energy first and draw the excess required from administrative engagement with the utility
costs and returns. The answer to financial the utility. This ensures maximum return from provider and it is not always provided as an
viability depends on the intended use of solar the PV investment. option by the utility providers. South Africa is
PV. moving in this direction.
This configuration applies to domestic as well
This article examines the financial aspects, as industrial and commercial users. It is more sCenario 2: PoWer outaGe
starting from the best return on investment particular for business use as most businesses ProteCtion anD Cost
(ROI) scenario. generally operate during sunlight hours and reDuCtion
can get the most financial benefit from solar The next best investment arises when the
sCenario 1: reDuCe eleCtriCitY PV during the day. This is why shopping centres user wants a degree of protection from short
Cost and even some heavy industrial users use power outages for around one to four hours,
The best PV ROI entails using free sunlight daylight solar PV, typically without storage. e.g., which is ideal for ongoing load shedding and
energy to replace bought electricity, without Makro parking lot roofs, some Gautrain station other electricity supply interruptions. These are
any energy storage. This means only using parking roofs and many factories which are irritating as well as being costly and disruptive
solar electricity during the day when the sun heavy daytime electricity users. The payback is to businesses.
is shining. The major capital costs are the solar relatively fast and can be three to five years.
PV panels and a suitable inverter. The inverter This entails using batteries to store enough
is a device that converts the direct current (DC) In other words, the savings from not paying for solar energy for when it is needed. It also entails
power from the PV panels to the 220v-240v the grid power will pay back the investment additional panels to generate the additional
alternating current (AC) power for household or in installing the solar panels and inverters in energy to be stored. This scenario does not
industrial usage. There are few costs entailed for around three to five years. After that period, the entail the complete independence of the utility.
the costly energy storage batteries. PV electricity will essentially be free. It merely provides a degree of protection from
brief power outages stemming from load
On overcast days, there will be very little solar A follow up to this first scenario is the selling shedding and short power failures.
PV electricity generated. On these days, the user of excess solar PV power to the utility. This
would have to draw on the utility grid (Eskom) only makes sense if the utility pays a fair price It also entails using a more costly hybrid inverter
to supplement the electricity supply. for the power supplied to it. In this case, the which can be programmed to balance the
utility essentially functions as an energy storage supply and demand optimally between the
In order not to have to continually switch battery. The power sold to the utility can offset panels, utility power and battery.
between the fluctuating solar PV electricity and the cost of power bought from the utility when
the utility supply, if this is available, a grid-tied the sun is not shining or at night. It typically The incremental financial costs and benefits
inverter would be recommended. This inverter entails additional panels to generate additional from the first scenario are reasonable. The

18 • Issue 5 2021• BLUE VALLEY NEWS