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3. Sizing of Hybrid PV/Batteries Bank/Diesel Generator System 265

and batteries and to operate the DG for minimum periods at lower output powers.
Reducing the periods of operating the DG enables using lower quantities of diesel,
thus reducing the amount of emitted pollution. The process of system sizing should
guarantee minimum overall system cost and/or minimum produced pollution
emitted by the DG.
The PV solar panels supply the required power to the load and provide excess
produced power to the batteries bank during daytime. However, the batteries supply
power to the load during periods when no sunlight is available, during night times,
and during transition periods when turning ON the DG. Conversely, the DG supplies
power to the load and provides some excess power to charge the batteries whenever
the load required power is not satisfied during either the day or night times. It is
assumed in the simulations that the PV solar subsystem and the batteries storage
bank are the main energy supply sources to the load, while the DG operates only
when both the PV panels and batteries bank available powers are not sufficient to
satisfy the load demanded power. The loss of load probability (LLP) parameter is
used in the optimization process to guarantee supplying the load with power 24 h
a day [17,18]. It is set to zero for the hybrid energy system.

t sim
P
Power supplied P load
t¼0
LLP % ¼ (8.15)
t sim
P
P load
t¼0
3.1 DESCRIPTION OF THE LOAD INVESTIGATED
The load used in the investigation of this chapter represents a typical house in the
Middle East. It has five major rooms (three bedrooms, one guest room, and one
living room), two bathrooms, kitchen, and basement [19]. The list of equipment
and parts used in the house and their relative power consumption per hour are shown
in Table 8.2. The number of each part used per room in the house is described in
Table 8.3. Note that it is assumed that all bedrooms have the same parts. The power
consumption is calculated for every day in a week for each room based on the
following process. The 24-h of the day are divided into hourly intervals of operation,
except the period in the night time between 11:00 p.m. and 6:00 a.m., which is
defined as a single interval. Each part in the house contributing to the power con-
sumption in every time interval is identified and its usage period is used in the hourly
load calculation. The power consumption per hour is identified based on common
usage of equipment and parts in the house. The power consumption calculation in
each interval is performed over one full week to address load variation in a full
day during working days and weekend days. The total power consumption in a
week is then averaged over 7 days to find the average power consumption in each
interval. Finally, to find the total average monthly power consumption, the total
average daily power consumption is multiplied by the number of days of each