Page 233 - Hybrid-Renewable Energy Systems in Microgrids

210 Hybrid-Renewable Energy Systems in Microgrids

The PV module consists of parallel and series combinations of solar cells which
are fabricated in wafer or semiconductor layers. The incident SR is converted into
electricity with solar cell energy conversion efficiency (η) as shown below.

P
η = m
η=PmHT×A H T × A

where P m is solar cell output power at its maximum power point and A is surface area
of solar cell.

2.1.4 Economic analysis

In HOMER simulation the main objective is to minimize the sum of NPC by search-
ing optimum system configuration having the lowest value of NPC. The total NPC
includes all costs, that is operation and maintenance, replacement, buying power, pen-
alties, etc. The important economics parameter total NPC (C NPC ), capital recovery
factor (CRF), and levelized cost of energy (COE) are as follows.

C
C NPC = TAC (11.2)
(,
CNPC=CTACCRF(i,PL) CRFi P )
L

i(1 + i) n
CRFi n) = n (11.3)
(,
CRF(i, n)=i(1+i)n(1+i)n−1 (1 + i) − 1

C
COE = TAC (11.4)
COE=CTACLp+Ld+Egs L p + L d + E gs

where P L is project lifetime, C TAC is total annualized cost, i is annual real interest, n
is number of year, L p is primary load, L d is defferable load, and E gs is per year energy
sold to grid.

2.1.5 Input variables
The project's lifetime is taken as 25 years with an annual real interest rate of 2.5%
[43]. The system fixed capital cost is considered as $62.75 for the whole project and
the system fixed operation and maintenance cost is $12.55/year. The system fixed
capital costs include construction, labor wages, and other costs.

2.1.6 Analysis
Homer simulates HSs with different configurations, removes the infeasible ones
(which do not meet given constraints), ranks the feasible configuration with total NPC