What is a photovoltaic (PV) system?• PV technology produces electricity directly from electrons freed by the interaction

of sunlight with a solar panel made of semiconductor material. The power provided is direct current (DC) electricity. The basic building block is known as a Solar cell. Many cells put together are known as a module, and many modules assembled together form an array. A PV system will consist of an array of modules generating DC electricity, an inverter and can be stored in battery storage banks.

Photovoltaic (PV) Hierarchy• Cell < Module < Panel < Array

Available Cell Technologies • Single-crystal or Mono-crystalline Silicon

• Polycrystalline or Multi-crystalline Silicon • Thin film

• Ex. Amorphous silicon or Cadmium Telluride

Monocrystalline Silicon Modules

• Most efficient commercially available module (17% - 21%)

• Most expensive to produce • Circular (square-round) cell

creates wasted space on module

Polycrystalline Silicon Modules

• Less expensive to make than single crystalline modules

• Cells slightly less efficient than a MONO crystalline (15% - 19%)

• Square shape cells fit into module efficiently using the entire space

Amorphous Thin Film

• Most inexpensive technology to produce

• Metal grid replaced with transparent oxides

• Efficiency = 8 – 12 %• Can be deposited on flexible

substrates • Less susceptible to shading

problems • Better performance in low light

conditions that with crystalline modules

Selecting the Correct Module • Practical Criteria

• Size • Voltage • Availability • Warranty • Mounting Characteristics • Cost (per watt)

Current-Voltage (I-V) Curve

Effects of Temperature

• As the PV cell temperature increases above 25º C, the module Vmp decreases by approximately 0.5% per degree C

Effects of Shading/Low Insolation

• As insolation decreases amperage decreases while voltage remains roughly constant

Shading on Modules• Depends on orientation of internal module circuitry relative to the

orientation of the shading.• SHADING can half or even completely eliminate the output of a solar array!

Series Connections• Loads/sources wired in series

• VOLTAGES ARE ADDITIVE • CURRENT IS EQUAL

• Loads/sources wired in parallel:

• VOLTAGE REMAINS CONSTANT• CURRENTS ARE ADDITIVE

Parallel Connections

What are the different types of rooftop solar PV systems?

• Grid Connected - These systems have no storage other than the grid itself. Any excess electricity generated from solar system is fed back into the grid. At night or during times of intense cloud cover, the installation draws power from the grid.

• Hybrid (Grid tied with Storage) - These systems are grid connected, but also

have some storage capacity by way of a small battery bank. They provide some measure of continuity when the grid goes down at the same time as there is not sufficient solar input.

What are the components of a photovoltaic (PV) system?• A PV system or a stand-alone system made up of different components. These

include PV modules (groups of PV cells), which are commonly called PV panels; one or more batteries; a charge regulator or controller fasten; an inverter for a utility-grid-connected system and when alternating current (ac) rather than direct current (dc) is required; wiring; and mounting hardware or a framework.

Electricity Terminology • Voltage

• Measured in Volts• Electrical potential

• Current• Measured in Amps• Rate of electron flow

• Resistance• The opposition of a material to the flow of an electrical current• Depends on

• Material • Cross sectional area• Length • Temperature

• Watt• Measure of Power • Rate of electrical energy• Not to be confused with Current!

• Watt-hour (Wh) is a measure of energy • Unit quantity of electrical energy (consumption and production) • Watts x hours = Watt-hours

• 1 Kilowatt-hour (kWh) = 1000 Wh

Types of Current• DC = Direct Current

• PV panels produce DC• Batteries store DC

• AC = Alternating Current • Utility power• Most consumer appliances

use AC• Electric charge changes

direction

Symbols and UnitsVoltage: E or V (Volts)

Current: I or A (Amps)

Resistance: R or Ω (Ohms)

Watt: W (Watt)

Typical Wattage Requirements Appliance WattageBlender 350

TV (25 inch) 130Washer 1450Sunfrost Refrigerator (7 hours a day)refrigerator/freezer (13 hours a day)

112

475

Hair Dryer 1000Microwave (.5 sq-ft)Microwave (.8 – 1 sq-ft)

7501400

Grid-Tied System Overview

Grid-Tied System• Advantages

• Easy to install(less components)

• Grid can supply power

• Disadvantages• No power if grid goes

down

Wire Components

• Conductor material = copper (most common)• Insulation material = thermoplastic (most common)

• Wire exposed to sunlight must be classed as sunlight resistant

Color Coding of Wires & Conduit• Electrical wire insulation is color coded to designate its

function and use

Alternating Current (AC) Wiring Direct Current (DC) Wiring

Color Application Color ApplicationBlack Ungrounded Hot Red (not NEC req.) PositiveWhite Grounded

ConductorWhite Negative or

Grounded Conductor

Green or Bare Equipment Ground

Green or Bare Equipment Ground

Red or any other color

Ungrounded Hot

• Cable: two or more insulated conductors having an overall covering

• Conduit: metal or plastic pipe that contains wires

Wire Size• Wire size selection based on two criteria:

• Ampacity• Voltage drop

• Ampacity - Current carrying ability of a wire

• Voltage drop: the loss of voltage due to a wire’s resistance and length

Safety Considerations• Unsafe Wiring

• Splices outside the box• Currents in grounding conductors• Indoor rated cable used outdoors• Single conductor cable exposed• “Hot” fuses

Safety Equipment• Disconnects • Overcurrent Protection

Grounding• Provides a current path for surplus

electricity to travel too (earth)

Solar Site & Mounting• Understand azimuth and altitude• Describe proper orientation and tilt angle for solar collection• Evaluate structural considerations • Pros and cons of different mounting techniques

Site Selection – Panel Direction

• Face true south

• Correct for magnetic declination

Altitude and Azimuth

Solar Pathfinder• An essential tool in finding a good site for solar

energy is the Solar Pathfinder• Provides daily, monthly, and yearly solar hours

estimates

Site Selection – Tilt Angle

Year round tilt = latitudeWinter + 15 lat.Summer – 15 lat.

Max performance isachieved when panelsare perpendicular to thesun’s rays

Solar Access• Optimum Solar Window 9 am – 3 pm

• Array should have NO SHADING in this window (or longer if possible)

General Considerations• Weather characteristics

• Wind intensity• Estimated snowfall

• Site characteristics • Corrosive salt water• Animal interference

• Human factors• Vandalism • Theft protection• Aesthetics

• Loads and time of use• Distance from power conditioning equipment • Accessibility for maintenance

Basic Mounting Options• Fixed

• Roof, ground, pole

• Integrated• Tracking

• Pole (active & passive)

Pole Mount Considerations

• Ask manufacturer for wind loading specification for your array

• Pole size• Amount of concrete

• Array can be in close proximity to the house, but doesn’t require roof penetrations

Tracking Considerations• Can increase system performance by:

• 15% in winter months• 30% in summer months

• Adds additional costs to the array • Require regular maintenance

Passive Vs. ActiveActive:

• Linear actuator motors controlled by sensors follow the sun throughout the day

Passive:Have no motors, controls, or gearsUse the changing weight of a gaseous refrigerant within a sealed frame member to track the sun

Roof Mount Considerations• simple and cheap to install• offer no flexibility in the orientation of your solar

panel.• can only support small photovoltaic units.• Penetrate the roof as little as possible• Weather proof all holes to prevent leaks

• May require the aid of a professional roofer

• Re-roof before putting modules up • Leave 4-6” airspace between roof and modules• On sloped roofs, fasten mounts to rafters not

decking

Building Integrated PV

Solar Energy Incentives

• Tax credits and deductions • 30% tax credit

• Local & state grant and loan programs

Hybrid System(With Batteries)

• Complexity• High: Due to the addition

of batteries

• Grid Interaction• Grid still supplements

power• When grid goes down

batteries supply power to loads

Battery Basics

Battery A device that stores electrical energy (chemical energy to electrical

energy and vice-versa) Capacity

Amount of electrical energy the battery will contain State of Charge (SOC)

Available battery capacity Depth of Discharge (DOD)

Energy taken out of the battery Efficiency

Energy out/Energy in (typically 80-85%)

The Terms:

Batteries in Series and Parallel • Series connections

• Builds voltage

• Parallel connections • Builds amp-hour capacity

Functions of a Battery

Storage for the nightStorage during cloudy weatherPortable powerSurge for starting motors

**Due to the expense and inherit inefficiencies of batteries it is recommended that they only be used when absolutely necessary (i.e. in remote locations or as battery backup for grid-tied applications if power failures are common/lengthy)

Batteries: The Details

Primary (single use)Secondary (recharged)Shallow Cycle (20% DOD)Deep Cycle (50-80% DOD)

Types:

Unless lead-acid batteries are charged up to 100%, they will loose capacity over time

Batteries should be equalized on a regular basis

Charging/Discharging:

Battery Capacity

Amps x Hours = Amp-hours (Ah)Capacity:

100 amps for 1 hour1 amp for 100 hours20 amps for 5 hours

Capacity changes with Discharge Rate The higher the discharge rate the lower the capacity and vice versa The higher the temperature the higher the percent of rated capacity

100 Amp-hours =

Rate of Charge or Discharge

Rate = C/T

C = Battery’s rated capacity (Amp-hours)T = The cycle time period (hours)

Maximum recommend charge/discharge rate = C/10

Battery Safety• Batteries are EXTREMELY DANGEROUS; handle with care!

• Keep batteries out of living space, and vent battery box to the outside

• Use a spill containment vessel• Don’t mix batteries (different types or old with new)• Always disconnect batteries, and make sure tools have

insulated handles to prevent short circuiting

Controller Considerations• When specifying a controller you must consider:

• DC input and output voltage• Input and output current• Any optional features you need

• Controller redundancy: On a stand-alone system it might be desirable to have more then one controller per array in the event of a failure

Inverter Basics

• An electronic device used to convert direct current (DC) electricity into alternating current (AC) electricity

Function:

Efficiency penalty Complexity (read: a component which can fail) Cost!!

Drawbacks:

Specifying an Inverter• What type of system are you designing?

• Stand-alone• Stand-alone with back-up source (generator)• Grid-Tied (without batteries)• Grid-Tied (with battery back-up)

• Specifics:• AC Output (watts)• Input voltage (based on modules and wiring)• Output voltage (120V/240V residential)• Input current (based on modules and wiring)• Surge Capacity• Efficiency• Weather protection• Metering/programming

What is net-metering?

• Net-meter (bi-directional meter) is having provision to record energy imported from the grid to meet the load and energy exported to the grid after self-consumption. Both energy import and export records in the net-meter. The difference between Export and Import readings is the actual energy consumed/delivered.

• The net meter records surplus energy exported to DISCOM grid. When your system generates less energy than your consuming load, the meter records energy imported from DISCOM grid.

How the billing and payments are made? i. The consumer shall receive monthly a net import/export bill indicating either net export to the grid or net import from the grid. ii. In case of net import bill, the consumer shall settle the same as per existing

norms. If it is a net export bill (after self-consumption), net credit amount payable will be deposited by DISCOM into consumer’s bank account, provided by consumer at the stage of submission of application. iii. The amount payable for net export of energy shall be as per APPC prevailing

tariff of GERC.iv. The credit if any shall be settled within 30 days from the date of meter reading and credited to the bank account through NEFT or settle in next billing cycle.

What is the annual energy generated from a 1 KW Solar Power plant?

• The usual benchmark for energy generated from a 1 KW Solar Power plant is considered as 1500 units. This is only a benchmark and should not be considered as the actual output for a given location. The amount of actual energy generated from a Solar Power Plant in a year depends on both internal and external factors. External factors which are beyond the control of a solar developer can include the following:

• Number of sunny days• Solar Irradiation• Day Temperatures• Air Mass

• The output also depends on the following internal factors all of which are within the control of a Solar Developer:

• Plant Location• Usage of Solar Tracking systems• Quality of equipment used• Workmanship of the EPC contractor• O&M activities

What permissions/clearances are required to setup a Solar PV Plant?

• A certain set of permissions need to be obtained and documents need to be submitted in order to setup a Solar PV plant. While these may vary from state-to-state, in order to get a Solar PV Project Accredited by Gujarat State Load Dispatch Center (Gujarat SLDC) for REC mechanism, the following are the statutory clearances and environmental clearances to be furnished:

• Industrial Clearance• Land conversion (Agricultural to Non-Agricultural)• Environmental Clearance Certificate from GPCB, Gujarat• Contract labour license from Gujarat Labour Department• Fire Safety certificate from Gujarat Fire Department• Latest tax receipt from the Municipal/Gram Panchayat for the factory land.• Auditor compliance certificate regarding fossil fuel utilization• Approval from Chief Electrical Inspector• Clearance from Forest department

Continued…• Also, all necessary approvals/agreements before start of Solar PV project

construction are to be furnished as and when necessary. These include the following:

• Land purchase• Power Evacuation arrangement permission letter from DISCOM• Confirmation of Metering Arrangement and location• ABT meter type, Manufacture, Model, Serial No. details for Energy Metering.• Copy of PPA (important as Preferential PPA projects are not eligible for REC mechanism)• Proposed Model and make of plant equipment• Undertaking for compliance with the usage of fossil fuel criteria as specified by MNRE• Details of Connectivity with DISCOM• Connectivity Diagram and Single Line Diagram of Plant• Any other documents requested by GEDA

125 KWp Solar PV Plant @WAGH-BAKRI

by TOPSUN ENERGY

LIMITED

Gujarat Tea Processors & Packers

Ltd(Wagh Bakri Tea Group)Site Address: Dholka,

Ahmedabad

The benefits from a 1 MWp Grid-parallel Solar PV Plant are as follows: • A Solar PV Plant is the greatest insurance against rising power tariff. • It produces power over its life at less than Rs. 4/unit (Considered -25 years)• PV Plants can reduce power bills by up to 70% (for day-based units).• A Solar PV Plant produces stable power throughout the day.• Accelerated Depreciation benefit available under Section 80 IA sub-section 4

(Income Tax) for projects executed & commissioned.• Good IRR’s = between 15% - 23% (factor dependent).• Solar PV Plants are virtually maintenance free.• Solar Plant can generate electricity for around 25 years.• Gujarat Govt.declared Solar Rooftop Policy in that you can feed your

extra power to Discom &  Discom will pay you money as per APPC Rate.• Additional REC (Renewable Energy Certificate) Rs.3.5/unit will sell to

those customer who need the REC.

Power generated by the system over a period of 25 years 3.35 Cr kwh

Initial investment by the beneficiary Rs. 6 Cr

Interest @ 12.5% till the payback has been achieved Rs. 2.5 Cr Guaranteed Generation 13,72,500 kWh per year

Cost of inverter replacement in 8th / 16th year Approx. Rs. 60 lakhs to Rs. 80 lakhs

Lifetime Savings Approx. Rs. 45-50 Cr

Accumulated cost for O & M for 25 yrs Rs.2.55 Cr(Considered 5 % escalation Y-O-Y)

Levelized Cost Of Energy Less than Rs. 4 /unitIRR 16 % IRR

IRR & LCOE : 1 MWp Solar PV Plant

Solar Capacity 1 MWpArea Required 10000-15000 Sq.m

Roof Type & Orientation PEB Structure, G.I Sheet– East West direction & South direction

Power Tariff per KWh Rs. 7 & above KWh

Guaranteed Generation 13,72,500 kWh per year

Annual Savings Rs. 96,07,500 per annum

Lifetime Savings (25 year life of Solar PV system ) Approx. Rs. 45-50 Cr

Guarantee 5 years guarantee of entire system.

Components MNRE Certified

Thank you…Contact Us:Jigar Patel+91-9978955773marketing.exe2@topsunenergy.comTopsun Energy Limited