GOING GREEN
installation and are less complex since they don’t require
a battery system. There are also no storage losses involved
during the lifetime of the array. This type of system is
suitable for telecom stations near cities or areas with
reliable grid connection. It’s possible, however, to add a
battery to store the excess generated power instead of
releasing it to the grid.
Standalone solar power systems
These are solar power systems that are not connected
to the utility grid and require a battery system to store
the excess power produced. These systems may use an
auxiliary power source apart from the PV array, such as
wind or most commonly diesel generators. Such systems
are called standalone hybrid systems. This is suitable for
remote telecom stations.
In order to perform an economic evaluation of grid-
connected PV systems for use in telecom base stations,
PVSYST software was used to get an estimate of the
number of the photovoltaic cells and inverters required for
several sizes of installation as well as the performance of
a system in London. The specification of the solar module
used in the experiment was as follows: Mono-crystalline
PV cells, standard module design and 25-degree mounting
(optimised angle for London latitude). With the simulation
results, a calculation was made to get the estimate of
the initial investment, payback time and CO2 savings for
several PV systems. Initial cost for a 4kW grid connected
system is £10,000, with a payback time of approximately
13 years and CO2 savings during the system lifetime (25
years) of around 35 tonnes; the same results for a 10kW
grid-connected system are, £23,000, 13 years and 70
tonnes respectively.
In locations with higher solar radiation, the payback
time reduces as the same kW can be generated with a
smaller panel area, thus reducing the initial cost. Where
zero refrigeration is used for cooling the IT equipment,
this allows a reduced total kW provision and again, smaller
panel area and initial cost.
It’s recommended to use a grid-connected system in
areas with an adequate power supply since standalone
systems are more complex than grid-connected ones
due to the presence of battery systems in addition to the
inverters. If the utility grid isn’t reliable, or non-existent in
case of remote areas, a standalone PV system can be the
solution.
As adoption and investment in PV energy increases,
this technology will continue to be improved. These
improvements include more efficient PV cells and both
battery and inverter efficiency and lifetime increases.
While PV panels and components prices decrease, the use
of solar power in the data centre industry will strengthen
over time. Any attempt at reducing the carbon footprint
is helpful and the use of solar energy, even starting on a
small scale, installation of solar panels accomplishes this. n
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