Civil Engineering Reference
In-Depth Information
•
expected economic life of the plant.
•
operating and maintenance cost.
•
average selling price of the energy generated from the farm.
A detailed multivariable profitability analysis with the above parameters
is always required before making financial investments. Potential investors
can make initial profitability assessment using screening charts. The follow-
ing sections present easy-to-use profitability charts for initial screening of
the wind and pv power plant sites.
15.6.1
Wind Farm Screening Chart
Figure 15-4
is a wind farm profitability screening chart based on cost of capital
(discount rate) of 8 percent, project life of 15 years, initial cost of 1,100 Euro-
pean currency units per kW capacity, and the operating and maintenance cost
of 3 percent of the initial project cost.
The chart takes into account the inflation
at a constant rate, i.e., the costs and revenues rising at the same rate. The
taxes on sales, if any, must be deducted from the average selling price before
it is entered in reading the chart. An example for using the chart follows:
At a site with 7.5 m/s wind speed at hub height, the profitability index would
be zero (a break-even point) if the energy can be sold at 0.069 ECU/kWh. If
the energy price is 0.085 ECU/kWh, the profitability index would be 0.30,
generally an attractive value for private investors. At a site with only 7 m/s
wind speed, the same profitability can be achieved if the energy can be sold
at 0.097 ECU/kWh.
3
15.6.2
pv Park Screening Chart
Similar screening charts for pv stand-alone or grid-connected systems are
shown in
Figures 15-6
and
15-7
.
For these charts, the yearly energy delivery
4
E
in kWh/year is defined as the following:
y
E
=⋅
K
H
⋅
P
kWh year
(15-12)
y
p
y
pk
where K
= performance ratio of the system
p
H
= yearly solar irradiation in the plane of the modules, kWh/m
/year
2
y
P
= installed peak power under the standard test conditions of
1 kW/m
pk
solar irradiation, the cell junction operating tempera-
ture of 25°C and the air mass of 1.5.
2
The pv energy conversion efficiency of the modules is included in P
The
pk.
typical values of K
for well designed systems are 0.7 to 0.8 for gird-connected
p
