Page 232 - Hybrid-Renewable Energy Systems in Microgrids

Techno economic feasibility analysis of different combination of hybrid systems 209

2.1.1 Photovoltaic system component analysis

The standalone photovoltaic system (SAPV) system components act as generation,
conversion, storage and transfer of energy. Converter and batteries are used for con-
verting and storing the electricity. The SAPV system consist of series connected
10 PV modules of 100 Wp each. The capital cost of 1 kWp system is $350. Using
cost of PV module as $0.35/Wp the replacement cost of PV is $35 (10% of capital
cost) [40,41]. The system is connected to AC load through the converter and has
a 20 year lifetime. The derating factor and ground reflectance are taken as 77%
and 20%. The temperature parameters are temperature coefficient of power −0.48
(%/°C), nominal operating cell temperature 47°C and efficiency at standard test con-
dition is 10%.
The SAPV system incorporates batteries as a backup source for maintaining con-
stant voltage during generation shortage. The battery used in the present study is lead
acid battery Surrette S4KS25P. The capital cost and replacement cost for one unit of
this battery were considered as $800 and $520 respectively [42]. The lifetime of con-
verter is 15 years, inverter efficiency is 90% and rectifier efficiency of 85% is used as
details of SAPV components.

2.1.2 Sensitivity analysis
The optimum configuration of the SAPV system under a set of specified input vari-
ables is found using sensitivity analysis. HOMER performs multiple optimizations and
evaluates the effect of change in inputs to outputs. In this study PV system monthly,
yearly optimum tilt angle and tilt angle equal to latitude are used as sensitive variable
for PV power production and economic analysis.

2.1.3 PV array
The HOMER models the PV array to generate power in direct proportion to incident
global solar radiation (SR) on tilted surface. The PV array output power (P ) is calcu-
PV
lated by following equation.
H
P = f PV Y PV T (11.1)
PV
H ref PPV=fPVYPVHTHref

where f is PV array derating factor which indicates decrease in the output of
PV
PV array due to dust on panel, elevated temperature and wire loss, Y is rated
PV
2
capacity of the PV array (kW) and H is standard SR (1 kW/m ) for rating the
ref
capacity of PV array. The rated or peak capacity of a PV array is the amount of
2
power that PV array produce under standard test condition (SR 1 kW/m , ambient
temperature 25°C).