Renewable energy resources as an agent for sustaining infrastructure development and economic transformation of Eket local government area

Category
Renewable energy

ABSTRACT

Reliable  electric  power  supply  in any  country  as a result  of industrialization  is a prime  factor  /agent  for sustaining infrastructure development and Economic Transformation of that state. This paper will be limited to how this could contribute to sustaining infrastructure development and economic transformation of Eket Local Government of Akwa Ibom State. The electricity requirements of the world including Nigeria are increasing at an alarming rate and the power demand has been running ahead of supply. It is also now widely recognized that the fossil fuels (i.e. coal, petroleum and natural gas) and other conventional resources, at present being used for generation of electrical energy, may not be either sufficient or suitable to keep pace with the world’s ever increasing electrical energy demands. Also, generation of electrical power by coal-based steam power plants or nuclear power plants causes pollution, which is likely to be more acute in future due to the larger generating capacity on the one hand and greater awareness of the people to this issue on the other hand. The recent severe energy crisis has forced the world to develop new and alternative methods of power generation, which could not be adopted so far due to various reasons.  The non-conventional methods of power generation such as solar cells, fuel cells, thermo-electric generators, thermionic converters, solar power generation, wind power generation, geo-thermal energy generation and tidal power generation are now recommended.   This paper highlights the method of sizing the capacity of battery banks and solar panel design for 8-hour runtime for a total power demand of 1000 watts. Recommendation for the type of renewable energy source is emphasized.  Calculations  are  performed  to illustrate  the  design  and benefits  derived  from this source  of energy.


Introduction

Sizing of battery banks and Solar panels for use in the Renewable energy system

Battery bank sizing is the important aspect when designing   a   UPS   equipment.   Calculations   are required to obtain optimum parameters for a sustainable power bank. If the battery bank is oversized you risk not being able to keep it fully charged; if the battery bank is sized too small you won’t be able to run your intended loads for as planned. Many renewable energy (RE) systems incorporate batteries. Batteries can be used in all types of systems including: photovoltaic (preferred).wind power, Hydro electric generators, Hybrid renewable energy systems, other DC power sources.


Factors to consider for the design


Electrical Usage

The first thing to note is the amount of energy you will be consuming per day. It is desirable to do a careful  evaluation  of  exactly  what  loads (appliances,  electronics)  you  plan to use  and for what lengths of time. Keep track of this information on a load lists;you will refer to this list often for sizing other components as well, Your final  tally should be expressed in watt-hours per day If you know the kilowatt-hour(Kwh) per day just multiply that number by 1000 to determine the watt-hours per day.(Example:1Kwh =1000Wh)


Days of Autonomy

Next,  you  must  determine  the  days  of  battery backup that you want to have on hand. In other words, if you are unable to charge your batteries by any means, and you still need to draw power, you must provide this additional storage by increasing the   size   your   battery   bank,   if   your   primary electricity source is solar panels (solar energy), you must determine the average number of hours of sunlight. This information can be found in the data you have collected using your data-logging anemometer.  

In Eket local Government  Area the average sunlight is estimated at 6 hours per day (10AM to 4PM). This information is based on my study during this period of rainy season (worst case condition for the design).I f you are sizing a battery bank to be used in conjunction with an on-demand fuel powered generator, the number of days of backup will represent the number of days you wish to go without using your generator.


Depth of Discharge (DoD)

In this design, it is a requirement to consider the planned Depth of Discharge (DoD) of your chosen battery bank.Lead Acid batteries, sealed AGM Batteries sealed gel batteries are all rated in terms of charge cycles. A single cycle takes a battery from its fully charged state, through discharge (use) then back to full charge via recharging. The depth of discharge is the limit of energy withdrawal to which you  will  subject  the  battery  (or  battery  bank). Depth  of Discharge  is expressed  as a percent  of total capacity. The further you discharge a battery, the  fewer  cycles that battery will  be capable of completing.  Simply  stated,  deeper  discharge shortens battery life. Never discharge a deep –cycle Batter below 50% of its capacity; however many battery manufacturers recommend even shallower depth of Discharge (DoD).If you are only using the batteries occasionally as a backup system, you can factor in a DoD of 50% or perhaps more.


Temperature

Temperature affects battery life and also its capacity; always keep batteries in a ventilated area to maintain its efficiency.

Design strategy/Calculations

Step 1:

    Identify your system voltage say 12 volts.
    Assume that our total load is 1000 watt-hours per day.
    Three days of autonomy
    Planned depth Discharge of 40%

Battery bank ambient temperature average of say

60 degree F


Step 2: Multiply days of autonomy by total power demand in watt-hour/day

1000Wh/day i.e. 1000x3=3000Wh


Step 3: Identify Depth of Discharge (DoD) and convert to a decimal value divide the result step 2 by    this    value.     40%    DoD              we    have

3000/0.4=7500Wh.


Step  4:  derate  battery  bank  for  ambient temperature effect. Select the multiplier corresponding  to  to  the  lowest  average temperature your batteries will be able to be exposed  to.  Multiply  result  from  step3  by  this factor. Result is minimum Watt-hour  capacity of battery bank. From tables, 60degrees  correspond to 1.11, hence 7500x1.11=8325Wh.


Step 5: Divide result from step 4 by system voltage. The result obtained is the minimum amp-hour (Ah) capacity     of     the     required     battery     bank...

8325Wh/12V =693.75.

Approximate  this  to  700Amp-Hour  battery  bank. This will be required to supply power to a power inverter that will in turn power your home appliances.

Power  inverter  provides  uninterrupted  power  to run household electrical devices and offices. Power inverters are alternatives to electric power generators when it comes to supplying backup or standby power during power failure for hours. The power inverters convert Direct Current (DC) voltage from batteries to Alternative Current (AC) voltage used  by  appliances   in  our  homes  and  offices

.Inverters work with stored energy in the battery to

power homes and offices for hours depending on usage. The total power required to charge this battery bank assuming  6  hours  of  sunlight  from solar panel could be determined as follows:


Power from solar panels = Battery bank capacity x system voltage divide by average time for sunlight per day

Power=Voltage (V) x Current (A) (700Ah*12V)/6 h

=1400VA  =1400Watts

Benefits of the Renewable Energy Source (The Battery-Inverter System) Charged by Solar cells

1) Extended power backup: you will gain several hours of backup to meet your power needs every day. Inverter supplies you with over 10, 12, and 24 hours of power.

2) Zero Running Cost: The system requires no consumables  like diesel, petrol  or oil, saving  you lots   of   money   spent   on   power   generators, Minimize frequent breakdowns that are common with petrol and diesel alternators.

3) Noise free: Your renewable energy power source is noiseless. Now you can spare yourself that generator noise that is associated with the engine.

4) No oil spills on ground: The inverter uses no oil, causes no oil spill or dirt and is a clean appliance like other tools in your room.

5) No fumes: The inverter produces no fumes or smoke,   saving   your   environment   all   that   air pollution.

Finally, commercial establishments will find this system useful to enhance economic development. Banks find this useful to keep ATM machines functional. Other possible areas of application include hospitals, schools, hotels, supermarkets, filling stations and small scale businesses.


REFERENCES:

1.   A Course In Electrical Power by J. B. Gupta (S. K. Kataria & Sons).

2.   Power System Engineering by I. J. Nagrath & D. P. Kothari (TMH publishers).

3.   Fuel Cell Handbook,  Sixth Edition, U.S. Department  of Energy, National  Energy Technology  Laboratory, Strategic Center for Natural Gas, November 2002.

4.   Fuel Cell Systems Explained by Larminie, J. and Dicks, A., 2nd Edition, John Wiley, Chichester.