Environmental Engineering Reference
In-Depth Information
barriers, to ensure the viability of the project and to allow for a contract that would be
easy for the customer to understand, Sol Solar targeted buildings with certain con-
sumption characteristics. Speci
cally, the technical feature essential for the suc-
cessful implementation of the project was the existence of a centralized water heating
system. The original agreement was that Sol Solar would cover 100 % of the cost of
the installation, with ICAEN agreeing to reimburse 30 % and the City Council of
Barcelona another 15 %. However, due to the fact that this was the
rst project of its
kind in the city, the municipal legislation did not stipulate a viable formula to deliver
the payment to the involved ESCO and in the end, a negative response was given.
Therefore, the homeowners
association agreed to be responsible for the uncovered
15 % of the installation costs. Additionally, during the 6-year contract period, the
homeowners
'
association pays the calculated monthly baseline amount; the actual
consumption is paid to the natural gas company while the difference between the
actual consumption and the baseline is paid to Sol Solar. It is also interesting to note
that besides the kWh saved, Sol Solar
'
s monthly invoice informs the customer about
the number of kilograms of CO
2
avoided and the m
3
of natural gas that do not need to
be imported. Once a year, any deviations from the calculated consumption are
resolved. When the contract terminates, ownership of the installation is turned over to
the homeowners
'
'
association, at which point they will only pay for their actual
consumption (roughly 50
60 % less than the baseline consumption). If desired, Sol
Solar shall offer a maintenance contract to ensure that the installation continues
performing optimally in return for 10 % of the yearly natural gas savings.
During the
-
rst 3 months of operation, the installation has saved the equivalent of
30,000 kWh, representing a 32 % savings compared to the historical consumption
during the same period. According to the president of the homeowners
'
association,
the results have been consistent and highly satisfactory in the
rst 8 months of
operation. As a consequence, these signi
cant savings have reversed the initial
skepticism expressed by some neighbors. With regards to the expected barrier cre-
ated by unfamiliar contract conditions and payback period calculations, our inter-
viewee expressed that no dif
culties were encountered. The only unforeseen issue
was the necessary reinforcement of the roof in order to support the weight of the
solar panels, which was a minor inconvenience. Worth mentioning is the fact that
the project
s success has attracted international attention and has been visited by a
commission interested in replicating it in the Italian residential sector (Table
2
).
This demonstrates that existing ST technology is suf
'
ciently mature and reliable
to be
nanced via the ESCO model. However, our case analysis concludes that, in
Table 2 Performance of the ST technology utilized in the Sol Solar residential project
Yearly ST panel efciency
1,250 kWh/m
2
(capturing 70 % of Barcelona
'
s solar energy)
Yearly energy savings
150,000
180,000 kWh
-
Yearly emissions reduction
31,500 kg to 37,800 CO
2
kg
12,766
-
15,320 reduction m
3
of natural gas
Yearly fuel imports avoided
Estimated payback period
6 years
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