a wide range for both under the condition of uninterrupted power
supply around the year, calculates the NPC and provides the lowest
cost solution.
The same results have been initially obtained for all the consid-
ered locations and installation years for the capacity of the battery;
0.58 kW h (56 cells: 7 serial
8 parallel). This is actually the min-
imum battery capacity under the condition of 2 days minimum
autonomy with a daily demand of 0.25 kW h and considering
90% maximum DoD. For all the considered locations the iHOGA
optimization calculates the resulting minimum battery capacity
as the ideal solution. In other words, making the battery bigger
would result in a higher NPC, even if the bigger battery would
allow for a smaller PV generator. Higher NPC solutions are dis-
carded by iHOGA. As indoor installation of the battery is assumed
here, the resulting lifetime is similar for the different locations. For
the 2015 installation, the Li-ion cells would have to be replaced
after 4 years of operation. For the 2020 installation the battery
would have a lifetime of 8 years. For the 2025 and 2030 installa-
tions the battery lasts the entire lifetime of the installation of
10 years. This extending battery lifetime is due to the higher num-
ber of cycles for new generation batteries.
A qualitative adjustment for the battery capacity for the instal-
lation year 2020 could be performed at this point. The lifetime of
8 years for the battery does not result convenient in an installation
of a lifetime of 10 years. Opting for a Li-ion battery with the
capacity of 0.725 kW h (see
Table 2
) would conveniently extend
the lifetime of the battery to 10 years to match with the installa-
tion’s lifetime and overcome the need for any replacements. This
is not the ideal solution in terms of iHOGA modeling, but it implies
a minor NPC difference (less than 3%), while providing a big
advantage.
Table 4
summarizes the results of the iHOGA optimization for
the PV generator. Locations that have the same optimization out-
come for the PV generator size are grouped together. This however
does not imply that these locations have the same PV generator
tilt; the ideal tilt as modeled by iHOGA is indicated for each loca-
tion at the end of
Table 4
. As it can be observed, the required PV
generator size becomes smaller for later installations. For instance,
for India a PV panel of 120 Wp would be required for the installa-
tion year 2015, while a 100 Wp panel would suffice for 2030. This
drop is the result of the better long-term performance of the later
PV panel (the 10 years efficiency degradation is 8% for the 2020
module, but only 6% for the 2030 model), the use of an MPPT after
2020 and the improved battery roundtrip efficiency.
Due to the better solar conditions, a smaller PV generator is
required for instance for Tanzania than for India. This, however,
implies a small difference in the installation’s NPC; roughly below
€
40. As a consequence, it’s more convenient to opt for one over-
dimensioned SHS solution that widely covers the geographic areas
of South Asia, Southeast Asia and Subsaharan Africa, than provid-
ing a costly tailored solution for each location. The installation cal-
culated in
Table 4
for India and Southern Pakistan provides the
required PV generator size, i.e. 120 Wp on the short term, dropping
to 100 Wp on the long term. This generator together with the