Assingment2

Renewable Energy System 402 Assignment 2

1 Satinderpal Singh (14413919)

Renewable Energy Systems 402

ASSINGMENT 2

Stand – Alone PV System

REPORTED BY:

SATINDERPAL SINGH (14413919)

DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING



Contents

INTRODUCTION .................................................................................................................................. 5

1. Preliminary Calculations ................................................................................................................. 6

1.1. Power Demand and Daily Energy Need of Farm.................................................................... 6

1.1.1. Steady – State Power demand ......................................................................................... 6

1.1.2. Surge Power demand ...................................................................................................... 6

1.1.3. Daily Energy requirement of the Farm house ................................................................. 7

1.2. Total DC Load and System Voltage ....................................................................................... 7

1.3. Insolation and PV array supply demand ................................................................................. 8

1.3.1. Insolation at the site ........................................................................................................ 8

1.3.2. PV array supply during worst month .............................................................................. 8

1.4. PV Sizing ................................................................................................................................ 9

1.4.1. Ah/day Produced from one string of PV ......................................................................... 9

1.4.2. Number of Parallel string ................................................................................................ 9

1.4.3. Number of Modules in One string .................................................................................. 9

1.4.4. AC output energy from designed PV array ................................................................... 10

1.5. Energy output and Load demand over 12 months of the year .............................................. 10

1.6. Annual load demand supplied by Designed PV system ........................................................ 12

1.7. Useable Storage required in the battery bank ....................................................................... 13

1.8. Total storage capacity of the battery ..................................................................................... 13

1.9. Minimum storage require to have discharge rate less than 5 hours ...................................... 13

1.10. Generator Sizing ............................................................................................................... 13

1.11. Annual energy Supplied by the Generator ........................................................................ 14

1.12. Schematic of Hybrid Power System ................................................................................. 14

2. Selection of Components .............................................................................................................. 15

2.1. Battery selection .................................................................................................................... 15

2.2. Inverter Charger Selection .................................................................................................... 16

2.3. Selecting Charger Controller ................................................................................................ 18

2.4. Selecting generator ................................................................................................................ 20

3. Performance of Designed System ................................................................................................. 21

3.1. Calculations using selected components values .................................................................... 21

3.2. System Costs ......................................................................................................................... 23

3.2.1. Capital Cost of the system ............................................................................................ 23



3.2.2. Running Cost of the System .......................................................................................... 24

3.2.3. Cost of Electricity ......................................................................................................... 25

4. References ..................................................................................................................................... 26

List of Figures and Tables



Figure 1: Steady - Power demand over 24 hours for the farm house ........................................ 6

Figure 2: Surge Power required over 24 hours for farm house ............................................................... 6

Figure 3: Insolation at the site during 12 months of the year .................................................................. 8

Figure 4: Connection diagram of the PV .............................................................................................. 10

Figure 5: Inverter energy output and Load demand over the 12 months of the year. ........................... 11

Figure 6: Schematic of standalone hybrid power system ...................................................................... 14

Figure 7: EXIDE 8RP670NX Battery bank configuration ................................................................... 16

Figure 8: Victron Energy 24/3000/70 inverter charger for the designed Standalone PV system ......... 18

Figure 9: Morningstar TS45 charge controller used for Stand - alone PV system ............................... 19

Figure 10: ABLE 2500W Petrol Generator for the designed standalone PV system ........................... 20

Table 1: Total energy demand of each equipment .................................................................................. 7

Table 2: Power output and Demand during different months of the year ............................................. 11

Table 3: Load energy required per month and energy Output per month of the designed PV system 12

Table 4: Comparing two batteries for the selection of required battery for the battery bank ............... 15

Table 5: Comparing two inverters for right selection of inverter ......................................................... 17

Table 6: comparing charger controllers for the selection...................................................................... 19

Table 7: Comparing two generators for the selection for the standalone PV system ........................... 20



INTRODUCTION

Stand – alone PV systems are used where grid supply is not available. As compare to grid

connected PV system standalone PV systems are more complex and expensive because of

extra storage batteries required for the system. Although Stand – alone PV system are

expensive and complex but they are very useful in the providing energy in remote areas

where grid supply is not available because without grid electricity become more valuable.

The main part of the Stand – Alone PV system is PV array, charge controller, Battery bank,

inverter charge and Backup generator. Function of charger controller is to avoid over

charging and controlling the battery voltage. The voltage of the battery determines the system

voltage. Invert charger covert Dc power of battery to Ac power for the load and convert Ac

power from generator to DC power to charge batteries. Backup generator play important role

in providing energy when PV array is unable to meet the load requirement due to bad

insolation from the sun. Figure 6 shows the complete schematic diagram of the hybrid Stand

– alone PV system.

The purpose of this assignment is to design the stand – alone PV system for the remote area

farm house near Bridgetown, Western Australia. The main objective is to of the design is to

minimize the unit price produced from the system so that it is affordable for the customer.



1. Preliminary Calculations

1.1. Power Demand and Daily Energy Need of Farm

1.1.1. Steady – State Power demand

Figure 1: Steady - Power demand over 24 hours for the farm house

From the plot of steady state power in figure 1 the maximum power demand is 1595 Watt at 6

PM.

1.1.2. Surge Power demand

Figure 2: Surge Power required over 24 hours for farm house

1595

0

200

400

600

800

1000

1200

1400

1600

1800

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Po

wer

(W

att

)

Hour of the Day

Total Steady - State Power over 24 hours

2250

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Po

we

r (W

att)

Hour of the Day

Surge Power Demand over 24 hours



From the surge power plot over 24 hours in figure 1 the maximum surge power required is

2250 W at 8 AM.

1.1.3. Daily Energy requirement of the Farm house

Load Steady

– state

Power

(active)

(Watt)

Stand-

by

Power

(Watt)

Hours

of

Active

Mode

Active

Mode

Energy

(Wh/day)

Stand – by

Mode

Energy

(Wh/day)

Total Energy

For the

equipment

(Wh/day)

Lights 15*8

= 120

5 120*5

= 600

600

TV 150 4 3 150*3

= 450

4*(24 – 3)

= 84

450+84 = 534

Water Kettle 1000 0.25 1000*0.25

= 250

250

Washing

Machine

250 5 0.5 250 * 0.5

= 125

5*(24 – 05)

= 117.5

125+117.5 =

242.5

Laptop 20 3 3 20*3

= 60

3*(24 – 3)

= 63

60+63 = 123

Refrigerator 300 24 1300 1300

Table 1: Total energy demand of each equipment

Total energy requirement of the farm house = 600 + 534 +250 +242.5 + 123 + 1300

= 3049.5 Wh/day

1.2. Total DC Load and System Voltage

Total dc load = 𝑎𝑐 𝑙𝑜𝑎𝑑 (

𝑊ℎ

𝑑𝑎𝑦)

𝐼𝑛𝑣𝑒𝑟𝑡𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑐𝑦=

3049.5

.90 = 3388.33 Wh/day

System voltage for the maximum power demand of 1595 W = 24 V

Total dc Load (Ah/day @ System Voltage of 24 V ) = 𝑇𝑜𝑡𝑎𝑙 𝑑𝑐 𝑙𝑜𝑎𝑑

𝑆𝑦𝑠𝑡𝑒𝑚 𝑣𝑜𝑙𝑡𝑎𝑔𝑒

= 3388.33

24 = 141.18 Ah/day



1.3. Insolation and PV array supply demand

1.3.1. Insolation at the site

Figure 3: Insolation at the site during 12 months of the year

From the figure 3 the worst insolation is during month 6 (June). The insolation during month

6 = 2.3 KWh/m2/day

The peak – sun hours per day in month 6 = 2.3 hours/day

1.3.2. PV array supply during worst month

Design month solar percentage = 50%

Total load = 141.18 Ah/day

Energy require from PV each at invert input = Design solar percentage * Total load

= 141.18 * 0.50 = 70.6 Ah/day

2.3

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12

Inso

lati

on

(K

Wh

/m2/d

ay

)

Month of the year

Insolation over 12 months



1.4. PV Sizing

Rated Voltage of Scotty Poly 180 PV module (@ STC) (VR) = 36.3 V

Rated Current of Scotty Poly 180 PV module (@ STC) (IR) = 4.95 A

1.4.1. Ah/day Produced from one string of PV

Ah/day from one string of Scotty Poly 180 PV = Peak – Sun hour * IR * Coulomb

efficiency*Dirt and mismatch efficiency

Coulomb Efficiency of lead acid battery = 92%

Peak – sun hours during worst month = 2.3 Hours

Dirt and Mismatch efficiency = 93 %

Ah/day from one string = 2.3 * 4.95 * 0.92 * 0.93 = 9.741 Ah/day

1.4.2. Number of Parallel string

Number of parallel string = Supply required form the PV

Ah

day from one string

= 70.6

9.741= 7.24 ≈ 𝟕

Using 7 parallel string will over slightly under size the PV array.

1.4.3. Number of Modules in One string

Modules in series = System voltage / VR

= 24/36.3 = 0.6611 ≈ 1

As 0.6611 numbers of modules are not possible the modules per parallel string is 1.



Figure 4: Connection diagram of the PV

1.4.4. AC output energy from designed PV array

PV array output during worst month = IR * Peak-Sun Hours * number of string * mismatch ef

= 4.95 * 2.3 * 7 * 0.93 = 74.116 Ah/day

Battery output = PV array output * Coulomb efficiency

= 74.116 * 0.92 = 68.19 Ah/day

AC power at inverter output = System voltage * Battery output * Inverter efficiency

= 24 * 68.19 * 0.90 = 1472.84 Wh/day

1.5. Energy output and Load demand over 12 months of the year

Peak sun hours during worst month (month 6) (Pw) = 2.3 Hours

Power at inverter output during worst month (month 6) (PW) = 1472.84 Wh/day

Power in any month N (PN) ∝ Peak – sun hours in month N (IN)

𝑃𝑁

𝐼𝑁=

𝑃𝑊

𝐼𝑊 ⟹

𝑃𝑁

𝐼𝑁=

1472.84

2.3

PN = 640.36 * IN Wh/day

N= 1,2,3,4,5,6,7,8,9,10,11,12.

Using above equation power output of the different month of the year can be calculated.



Month Peak – Sun Hours

Inverter Energy

output

(Wh/day)

Load Demand

(Wh/day)

Jan 7.8 4994.85 3049.5

Feb 6.8 4354.48 3049.5

Mar 5.5 3522.01 3049.5

Apr 3.8 2433.39 3049.5

May 2.8 1793.02 3049.5

June 2.3 1472.84 3049.5

July 2.4 1536.88 3049.5

Aug 3.2 2049.17 3049.5

Sep 4.2 2689.53 3049.5

Oct 5.7 3650.08 3049.5

Nov 7 4482.56 3049.5

Dec 7.9 5058.89 3049.5

Table 2: Power output and Demand during different months of the year

Figure 5: Inverter energy output and Load demand over the 12 months of the year.

The energy generated during some months 10, 11, 12, 1, 2 is more than the energy demand

from the load and there is deficit in the energy during months 4,5,6,7, and 9.

0.00

1000.00

2000.00

3000.00

4000.00

5000.00

6000.00

1 2 3 4 5 6 7 8 9 10 11 12

Ene

rgy

(Wh

/day

)

Month of the year

Energy Output and Load Demand

Power output of System

Load Demand



1.6. Annual load demand supplied by Designed PV system

From table 2 the load demand per month and Output power of the system per month can be

calculated by multiplying Wh/day with the number of days in the month.

Month

Energy

Generated by

the PV system

(KWh/month)

Energy demand

of load

(KWh/month)

Difference in

the energy

produced and

load demand

(KWh/month)

Load energy

Supplied by

the PV system

(KWh/month)

Jan 154.84 94.53 60.31 94.53

Feb 121.93 85.39 36.54 85.39

Mar 109.18 94.53 14.65 94.53

Apr 73.00 91.49 -18.48 73

May 55.58 94.53 -38.95 55.58

June 44.19 91.49 -47.30 44.19

July 47.64 94.53 -46.89 47.64

Aug 63.52 94.53 -31.01 63.52

Sep 80.69 91.49 -10.80 80.69

Oct 113.15 94.53 18.62 94.53

Nov 134.48 91.49 42.99 91.49

Dec 156.83 94.53 62.29 94.53

Total Energy (KWh/Year) 1113.07 919.62

Table 3: Load energy required per month and energy Output per month of the designed PV system

Negative difference in the energy produce and load demand means that there is deficit in the

energy. This deficit can be filled by the stand alone generator.

During the excess energy is wasted during months with positive difference between the

produced energy and load demand because storage unit is only designed to store energy

required for the load.

Annual Energy supplied by the designed PV system = 919.62 KWh/year

Annual energy demand of the load = 1113.07 KWh

Percentage of load demand supplied by the system = 919.62

1113.07 × 100 = 𝟖𝟐. 𝟔𝟐%

The annual deficit of the energy is 17.38 % which will be supplied by the stand alone

generator.



1.7. Useable Storage required in the battery bank

Days of storage required for the battery bank = 3 days

Useable storage (Ah) = Total load (Ah/day) * Days of storage required

Useable storage = 141.18 * 3 = 423.54 Ah

1.8. Total storage capacity of the battery

Discharge Rate = 3 days = 72 hours

Minimum temperature at the site = - 5.1̊ C

Maximum depth of discharge (MDOD) = 80%

From above information (T, DR) = 100%

Total storage capacity of the battery = 𝑈𝑠𝑒𝑎𝑏𝑙𝑒 𝑠𝑡𝑜𝑟𝑎𝑔𝑒 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 (𝐴ℎ)

𝑀𝐷𝑂𝐷 ×(𝑇,𝐷𝑅)=

423.54

.8 ×1

= 529.43 Ah

1.9. Minimum storage require to have discharge rate less than 5 hours

Minimum storage = 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑙𝑜𝑎𝑑 𝑝𝑜𝑤𝑒𝑟 ×5

𝑆𝑦𝑠𝑡𝑒𝑚 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 ×𝑀𝐷𝑂𝐷=

1557 ×5

24 × .80 = 414.36 Ah

The total storage capacity of the batter (529.43 Ah) is more than the required minimum

storage (414.36 Ah).

1.10. Generator Sizing

Charging time for the generator to charge battery bank = 10 hours

Inverter efficiency = 90%

Total storage capacity = 529.43 Ah



System voltage = 24 V

Generator Size = 𝑇𝑜𝑡𝑎𝑙 𝑆𝑡𝑜𝑟𝑎𝑔𝑒 𝐶𝑝𝑎𝑐𝑖𝑡𝑦×𝑆𝑦𝑠𝑡𝑒𝑚 𝑉𝑜𝑙𝑡𝑎𝑔𝑒

𝐶ℎ𝑎𝑟𝑔𝑒 𝑡𝑖𝑚𝑒 ×𝑐ℎ𝑎𝑟𝑔𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑐𝑦=

529.43 ×24

10 × 0.90

=1411.80 W

1.11. Annual energy Supplied by the Generator

Total load per annum = 1113.07 KWh/year

Annual energy produced by generator = (1 - % Energy supplied by the PV)*Total annual load

= (1 – 0.8262) * 1113.07 = 193.45 KWh/year

Percentage of energy supplied by the generator = (193.45/1113.07)*100 = 17.38 %

From table 3 total annual energy produced by the PV system can be calculated by adding the

generated power of each month generated by designed PV system.

Total energy produced by the PV system = 1155.03 KWh/year

Energy supplied to the load by the PV system = 919.62 Kwh/year

Energy wasted during a year = 1155.03 – 919.62 = 235.41 KWh/year

Percentage of energy wasted = (235.41/1113.07)*100 = 21.15 %

1.12. Schematic of Hybrid Power System

Figure 6: Schematic of standalone hybrid power system



2. Selection of Components

2.1. Battery selection

Desired Rating for the Battery Bank

From the calculation in the part 1, desired values for the battery bank are:

Voltage of battery bank = 24 V

Total storage capacity required = 529.43 Ah

Depth of discharge for battery bank = 80%

Type of Battery = Lead – Acid battery

Most of the batteries available in the market are less than 24 V. The desire voltage of battery

banks with the minimum capacity of 529.43 Ah can be made by connected several batteries

in the series.

Comparing Batteries for Battery Bank

Reference [1] and [2] provides the source of data given the table 4.

Manufacturer EXIDE RAYLITE

Model 8RP670NX MIL 17S

Type of Battery Lead - Acid Lead - Acid

Voltage of Single battery 8 V 6 V

Storage capacity of single

battery @ 25̊ C 670 Ah 600 Ah

Number of cycles at 80%

Discharge depth 1500 Cycles 1500 Cycles

Number of batteries

required in series for

Battery Bank

24/8 = 3 Batteries 24/6 = 4 Batteries

Price of a battery $1,420 $ 1,156.41

Price of Battery bank 3 * $1420 = $4,260 4 * $1,156.41 = 4,625.64

Table 4: Comparing two batteries for the selection of required battery for the battery bank

From the table 4, both the batteries compare have enough storage required 529.43 Ah for the

designed system. The number of cycles for the life is same for both EXIDE and RAYLITE

batteries. To meet the system voltage 4 EXIDE batteries are require to be in series to build a

battery bank and if RAYLITE battery is considered then only 3 batteries are need to be in

series for the battery bank.



From above reason it is clear that both batteries are technically compatible for the battery

bank of the system but the economically there is a significant difference in the cost of both

the batteries. The battery bank of EXIDE 8RP670NX cost $365.64 than the RAYLITE MIL

17S battery bank. As the main objective of the design is to minimize the unit price of energy

produced then EXIDE 8RP670NX is a good option to select for the system.

Selected battery for the Battery Bank = EXIDE 8RP670NX

Number of batteries in series = 3

Number of parallel strings = 1

Total storage of the battery bank = 670 Ah

Figure 7: EXIDE 8RP670NX Battery bank configuration

2.2. Inverter Charger Selection

Surge power required by the load = 750 + 1500 = 2250 W

Maximum steady state demand = 1557 W



Desired Rating for the Battery Bank

Desire Inverter Characteristics

Continuous output power at 40̊ C = 1595 W

Input DC voltage = 24 V

Output AC voltage = 240 V

Output frequency = 50 Hz

Peak power = 1595 + 2250 = 3845 W

Efficiency = 90%

Desire Charger Characteristics

AC input voltage = 240 V

DC output voltage = 24 V

Nominal Current to battery for 10 hours charging = Battery storage / 10 = 524.9/10 = 52.49 A

Comparing Inverter Chargers


Manufacturer Victron Energy SMA

Model 24/3000/70 SI2224

Inverter Characteristic

Continuous Output Power

@ 40̊ C 2200 W 1600 W

Input Dc Voltage 19 – 33V 16.8 – 31.5

Output Ac Voltage 230 V 202 – 253V

Output Frequency 50 Hz 50 Hz

Peak Power 6000 W 5000 W

Efficiency 94 % 93.6 %

Charger Characteristics

AC input voltage 187 – 265 V 172.5 – 250 V

DC Output Voltage 24 V 24 V

Rated current to battery 70 A 80 A

Price $2,972.20 $3,969.45

Table 5: Comparing two inverters for right selection of inverter



Comparing Victor Energy 24/3000/70 and SMA S12224 inverter charger it is clear that both

inverters meet the technical desire requirement. Victron Energy 24/3000/70 inverter has

capacity of delivering steady – state power of 2200 W at maximum temperature at the site,

which is oversize than the required 1595 W. The other inverter charger in the comparison

SMA S12224 has a steady – state power rating very near to the required value. Both inverter

chargers can easily withstand the peak power due to surge and both have nearly equal

efficiency.

Although Victron Energy 24/300/70 inverter charger is oversized than the required rating but

it is still cheaper than SMA S12224. As we want to keep the cost low as possible it is good

option to select Victron Energy 24/300/70 and it easily meet the technical and safety

requirement of the system and high rating of power for Victron Energy 24/3000/70 allow

space for expansion to supply extra load in future.

Selected Inverter charger = Victron Energy 24/30/70

Figure 8: Victron Energy 24/3000/70 inverter charger for the designed Standalone PV system

2.3. Selecting Charger Controller

Rated current for the Schott poly 180 PV = 4.95 A

Number of Parallel strings of PV = 7

Voltage of PV array = 36.3 V

Desire Charger Characteristics

Solar input = 7 * 4.95 A = 34.65 A



Load output = 34.65 A

System voltage = 24 V

Maximum solar input Voltage - >=36.3 V

Comparing Charger Controllers


Manufacturer Morningstar Xantrex

Model TS45 C40

Solar Input Current 45 A 40 A

Output Current 45 A 40 A

System Voltage(Battery

Voltage) 12 -48 V 12 – 48 V

Maximum Solar Input

Voltage 125 V 125 V

Price $257.64 $ 275.62

Table 6: comparing charger controllers for the selection

Two charge controllers are compared in the table 6 for the selection purposes. Both Morning

stat TS45 and Xantrex C40 meet the desired technical requirements of the system. Both

inverters are capable at system voltage of 24 V and both can with stand the maximum solar

input of 36.3 V. Regarding current rating both chargers available in the market are oversize

than required 34.65 A current rating, TS45 have current rating of 45 A and C40 have 40 A

current rating. Technically it is better to select C40 because its current ratings are near to

desired rating.

Above reasons make Xantrex C40 a favourite for the selection but considering the cost of

both of the charger Morningstar TS45 is about $17.98 cheaper than C40. As our main aim of

the design is to keep the price of electricity low the selection of Morning TS45 will more

appropriate.

Selected charger controller = Morningstar TS45

Figure 9: Morningstar TS45 charge controller used for Stand - alone PV system



2.4. Selecting generator

Desired Rating for the Generator

Output Power Rating = 1411.80 W

Output Voltage = 240 V

Frequency output = 50 Hz

Comparing Generators


Manufacture Honda Able

Model Dunlite Petrol Generator

Output Voltage 240 V 240 W

Output Power 2000 W 25000 W

Fuel Unleaded Petrol Unleaded Petrol

Price $795 $499

Table 7: Comparing two generators for the selection for the standalone PV system

Table 7 shows that both compared generator meet the technical requirements for the system.

Both generators are rated higher than the required 1411.80 W. Honda Dunlite has a rating of

2000W and Able petrol generator have a rating of 2500 W. As both generators are technically

suitable for the system then cost of the generator will determine the selected generator. As

our objective is to design low cost selecting Able petrol generator will be a good choice

because it is $296 cheaper than Honda generator. As the rating of Able generator is higher it

will charger battery soon.

Selected generator = ABLE Petrol Generator

Figure 10: ABLE 2500W Petrol Generator for the designed standalone PV system



3. Performance of Designed System

3.1. Calculations using selected components values

Efficiency of the inverter (Victoron Energy 24/30/70) = 94%

Total dc load = 𝑎𝑐 𝑙𝑜𝑎𝑑 (

𝑊ℎ

𝑑𝑎𝑦)

𝐼𝑛𝑣𝑒𝑟𝑡𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑐𝑦=

3049.5

.94 = 3244.15 Wh/day

The total dc load of system has decreased to 3244.15 Wh/day from 3388.33 Wh/day due to

improve in the efficiency of the inverter from 90% to 94%.

New dc load in Ah/day = 3244.15

24 = 135.1729 Ah/day

Energy require from PV each at invert input = Design solar percentage * Total load

= 135.13 * 0.50 = 67.56 Ah/day

Number of parallel string = Supply required form the PV

Ah

day from one string

= 67.56

9.741= 6.93 ≈ 𝟕

In the calculations in the part 1 using 7 PV was under size but with the efficiency of victron

inverter efficiency t PV’s are perfect number for the system load required to be supplied

during worst moth of insolation.

AC output energy from designed PV array

PV array output during worst month = IR * Peak-Sun Hours * number of string * mismatch ef

= 4.95 * 2.3 * 7 * 0.93 = 74.116 Ah/day

Battery output of chosen EXIDE 8RP670NX = PV array output * Coulomb efficiency

= 74.116 * 0.92 = 68.19 Ah/day

Energy need to be supplied during worst month = 0.5 * Total load per day

= 0.5 * 3049.5 = 1524.75Wh/day



AC power at inverter output = System voltage * Battery output * Inverter efficiency

= 24 * 68.19 * 0.94 = 1538.36 Wh/day

Above calculations shows that design system can easily meet the energy needed to be

supplied during worst month of insolation. As 1524.75 Wh/day is needed to be supplied

during worst month and design system is capable to supply 1538.36 Wh/day during worst

month of insolation.

Battery

Total storage battery required to store 3 days energy (preliminary calculations) = 529.43 Ah

Capacity of selected battery bank = 670 Ah > 529.43

Selected battery bank can store 3 days of load energy and even provide some extra storage to

supply for over load or surge power.

Generator

Power rating of selected Generator = 2500 W

Time to charge selected battery bank = 𝑇𝑜𝑡𝑎𝑙 𝑆𝑡𝑜𝑟𝑎𝑔𝑒 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦×𝑆𝑦𝑠𝑡𝑒𝑚 𝑉𝑜𝑙𝑡𝑎𝑔𝑒

𝐺𝑒𝑛𝑟𝑎𝑡𝑜𝑟 𝑠𝑖𝑧𝑒 ×𝑐ℎ𝑎𝑟𝑔𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑐𝑦

= 529.43 ×24

2500 × 0.94 = 5.40 Hours

The selected Able petrol generator of 2500 W power rating will charge the selected battery

bank in 5.40 Hours.



3.2. System Costs

3.2.1. Capital Cost of the system

PV Array Cost

Estimated cost of PV for per Watt [9] = $4/W

Rating of Schott Poly 180 PV = 180 W

Cost of one PV module = $4/w * 180 W = $720

Number of PV used for standalone system = 7

Total cost of PV array = $720 * 7 = $5040

Battery Bank Cost

Cost of one battery = $1,420

Number of batteries used in a battery bank = 3

Total cost of battery bank = 3 * $1420 = $4,260

Inverter Charger Cost = $2,972.20

Charge Controller cost = $257.64

Generator cost = $ 499

Installation + BOS Cost = 20% (PV $ + Battery bank $ + inverter $ +controller $+generator$)

= .20($5040 + $4260 + $2972.20 + $257.64 + $499)

=$2605.768

Capital Cost of the System = $5040 + $4260 + $2972.20 + $257.64 + $499 + $2605.768

= $15634.60



3.2.2. Running Cost of the System

Generator Fuel Cost

Price of Generator electricity = $0.25/KWh

Annual energy produced of the generator = 193.45 KWh/Year

Annual running cost of the generator = 193.45 Kwh/year * $0.25/Kwh

= $48.3625/Year

Running cost of the generator over 25 years = $48.3625/year * 25 = $1209.06

Battery Maintenance Cost

Life of the battery bank = 9Years

Life of PV array = 25 Years

Number of battery bank require over 25 years = 25 / 9 = 2.77 ≈ 3

Number of replacement of battery bank required after installation = 3 – 1 =2

Cost of battery maintenance over the life time = 2 * battery bank cost

= 2 * $4260 = $8,520

Cost of maintenance of the battery per year = $8520/25 = $340.8/Year

Running cost of the system per year = $48.3625 + $340.8 = $389.162/year

Running cost over 25 Years = $1209.06 + $8520 = $9729.06



3.2.3. Cost of Electricity

Energy supplied by the system per annum = $1113.07 KWh/year

Energy supplied by the system in 25 years = $1113.07 KWh/year * 25

Cost of energy = 𝐶𝑎𝑝𝑖𝑡𝑎𝑙 𝐶𝑜𝑠𝑡+𝑅𝑢𝑛𝑛𝑖𝑛𝑔 𝑐𝑜𝑠𝑡 𝑜𝑣𝑒𝑟 25 𝑌𝑒𝑎𝑟𝑠

𝐸𝑛𝑒𝑟𝑔𝑦 𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑦𝑠𝑡𝑒𝑚 𝑜𝑣𝑒𝑟 25 𝑦𝑒𝑎𝑟𝑠

= $ 15634.60+$9729.06

1113.07𝐾𝑊ℎ

𝑌𝑒𝑎𝑟 ×25 = $0.9115/KWh

Cost of energy produced by the system is $0.9115/KWh.



4. References

[1] A. Energy. (2011, 26/.8/2012). Raylite Battery 6V 600Ah @ C100. Available:

http://www.apolloenergy.com.au/Renewable-Energy-Components/Raylite/MIL17S

[2] G. solar. (2011, 26/09/2012). Going solar Lead Acid batteries. Available:

http://www.goingsolar.com.au/pdf/catalogue/GS_11-12_batteries.pdf

[3] A. Energy. (2011, 27/09/2012). Sunny Island 2200W 24V 80 Inverter Charger.

Available: http://www.apolloenergy.com.au/Renewable-Energy-Components/Inverter-

Chargers/SI2224

[4] A. Energy. (2011, 27/09/2012). Victron 24V 3000W Inverter/Charger. Available:

http://www.apolloenergy.com.au/Renewable-Energy-Components/Inverter-

Chargers/MultiPlus-24-3000-70-16

[5] A. Energy. (2011, 27/09/2012). Morningstar Tristar 45A controller. Available:

http://www.apolloenergy.com.au/Renewable-Energy-Components/Regulators/TS45

[6] B. Directs. (2012, 27/09/2012). Xantrex C40. Available:

http://www.batteriesdirect.com.au/shop/product/12790/C40.html

[7] M. 4U. (2012, 27/09/2012). New honda camping genrator for sale - 2.5Kva Dunlite.

Available: http://www.machines4u.com.au/view/advert/2-5Kva-Dunlite/25183/

[8] Machines4U. (2012, 27/09/2012). New Able camping genrators for sale - PETROL

GENRATOR

Available: http://www.machines4u.com.au/view/advert/PETROL-GENERATOR-2-8KVA-

240VOLT/30726/

[9] G. M. Masters, Renewable and Efficient Electric Power Systems, 2004.

http://www.apolloenergy.com.au/Renewable-Energy-Components/Inverter-Chargers/SI2224

http://www.apolloenergy.com.au/Renewable-Energy-Components/Inverter-Chargers/SI2224

Assingment2

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