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communities from the First category of LRSG are eligible
for subsidies up to 80% of the investment. (Communities
from the whole mountain/ highlands. region are entitled to
60% subsidies). Furthermore, Croatian Bank for rebuilding
and development (HBOR, [8]) provides help by financing
such projects with just 4% interest on the loan [9], and in
combination with ZOFU the interest can be lowered to 2%.
If indeed investor (local community or local electricity
provider) succeeds in paying just 20% of the investment,
then the investment into basic 500 Wp PV system becomes
only 826 €, the total yearly cost 169 € (monthly bill of just
14€) and energy cost of solar electricity 0.35 €/kWh, which
looks much more attractive.
The problem that remains is the missing part of the
electricity load (about 1/3 of total, primarily in few winter
months) which is not covered by PV solar. Sizing the PV
system to satisfy the load throughout the year is out of
question: such PV system would be about 2.5x larger (and
as much costlier) and the percentage of unused energy
would be enormous 43% (in comparison with 2% in the 500
W basic system). One option is to accept that in one part of
the year the supply will be inadequate. The other option is to
add a small back-up diesel genset to the basic PV system.
The simulation showed that the addition of a 2 kW diesel
genset could cover all missing load. It would add to the
investment cost about 30€/year, and would spend about 200
liters of diesel per year.
D. Larger solar PV system
The other analyzed load, L2, estimated to be L2 = 1100
kWh/year was obtained when the electricity consumption of
some additional household appliances is included, i.e. added
to the basic needs (L1). These appliances were in interviews
declared as important but not essential. They include TV,
the refrigerator, some additional small appliances, and
possibly a milking machine and a washing machine (the
later ones if all above appliances would be of A+ class).
The analysis of seasonal variation of L2 group (Fig. 5) of
electrical appliances has shown somewhat different
distribution throughout the year than L1, which was
basically uniform (Fig. 4). The consumption of some
appliances from the group L2 (TV, washing machine..) are
also expected to be essentially constant throughout the year,
but some other (and larger) appliances (the refrigerator,
milking machine...) are expected to have larger consumption
in the summer part of the year. Hence, L2 is expected to be
somewhat preferentially distributed in summer part of the
year.
Simulations had shown that a PV system having peak
power 1 kWp (7.5 m 2 of the mono-Si modules), and 700 Ah
battery storage would be adequate, i.e. using the same
criteria for sizing: such system would fully satisfy load
during the summer months, and partly during the rest of the
year. The main results of simulations are shown in Fig. 5.
Due to somewhat different yearly distribution of the L2
load, the yearly solar fraction coverage of L2 is higher
(81%), the solar energy that consumer can use (Eused) is
also relatively higher, and unused energy is very small (just
3% of Eavailable).
Energy (kWh/month)
140
120
100
80
60
40
20
0
system: 1000 Wp si-mono
storage: various batteries
Eavailable
Eunused
E missing
Eused 700 Ah
Eused 500 Ah
Eused 300 Ah
Eused 200 Ah
Eused 100 Ah
Load L2
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Fig.5: Delivered and used solar energy at Busevic location, larger load,
larger system. The influence on Eused of reducing the storage capacity is
also shown.
The price of this 1 kWp system and the price of the PVproduced
energy is calculated in the analogous way as for
basic system. For the realization of this 1 kWp system on
the fully commercial basis (all taxes and expenses included)
the investment would be 7879 €, the yearly cost over the
warranted lifetime of modules would be is 1008 €/year, and
the energy cost is 1.05 €/kWh (960 kWh/year). Again, if
investor could benefit from subsidies and actually pay 20%
of the full price, the actual price of investment, yearly cost
and energy cost would be 1576 €, 302 €/year and 0.32
€/kWh, respectively.
Satisfying the part of the load L2 that is not covered by
solar (19%) is much less critical if this larger PV system is
used. First, that load (213 kWh/year, of which 42 kWh in
the worst month, December) can be covered with a similarly
small genset as in the case analyzed for basic PV system.
More importantly, the 1kW PV system would practically
cover basis needs (L1) throughout the year, so, with some
inconvenience in few winter months, users could avoid
genset altogether. One of advantages of PV is that devices
are modular, so if a larger, say 2kWp system would be
needed at some later time, it could be easily added later. It is
important to say that if once in the future the remote user (or
cluster of remote users, forming micro-grid) would be
connected to the grid, the investment into PV would not be
lost: for the user, the PV-system would continue to provide
considerable savings in electricity, and for the grid provider,
it would mean that lower installed power (and less
expensive system to bring it to the user) would be needed.
V. SOCIO-ECONOMIC AND ENVIRONMENTAL ASPECTS
Environmental aspects: The proposed site in Busevic is a
war-devastated location, 3 km away from the nearest local
electricity network. The only feasible alternatives for the
households are the diesel generator and RES. Given that the
generator is environmentally unfriendly solution, the RES
remain the most reasonable choice. Furthermore, since
winds are not sufficiently strong in the area, nor the suitable
hydropower sources exist nearby, a PV remains a good and
environmentally favorable solution. The installation of PV
is not polluting, has no negative impacts on the nature, and
is in line with the new legal initiatives in Croatia regarding
the wider incorporation of RES. Furthermore, PV system is
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