Grid Connected Solar PV Workshop

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e8-159

e8/PPA

Grid Connected

Solar PV Workshop

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Programme

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DAY COUNT DAY COUNT DAY COUNT DAY COUNT DayDayDayDay

Dr. Wade

ALL

Lunch Time

Data acquisition, collection and analysis

Quiz

Economics of Grid Connected Solar

Practical works - system design (afternoon tea as desired)

Lunch Time

Mini grid (PV hybrid systems within minig-grid)

KANSAI

13:00 PV Hybrid system (Various type of power source) Morning tea

15:00 Afternoon tea

ALL

Normal Grid(Examples of grid connected system)

Quiz

10:15

ALL

<5. Review and Closing ceremony> <5. Review and Closing ceremony> <5. Review and Closing ceremony> <5. Review and Closing ceremony>

09:00 Course review and evaluation

Farewell Lunch Review of Previous Day

Morning tea

10:30 Closing Ceremony & Provision of Certification Quiz

What is e8? 09:00

09:30

Solar panels, specifications, rating and general characteristics Practical works with solar panels

General Inverter characteristics - types, history and general concepts 10:15 Afternoon tea e8ＧＳ 10:30 08:15 Dr. Wade 15:30

Interaction with the grid. Stability, penetration, islanding, net-metering Morning tea

14:00 14:30 16:00～16:30

　e8/PPA Grid Connected Solar PV Workshop Program

Resposibility Resposibility Resposibility Resposibility 12:00 (Mon)

<1. Overview of Grid Connected Solar, Solar Panels> <1. Overview of Grid Connected Solar, Solar Panels> <1. Overview of Grid Connected Solar, Solar Panels> <1. Overview of Grid Connected Solar, Solar Panels>

Course Opening Ceremony

ALL 16:00～16:30 Program Program Program Program

Overview of Grid Connected Solar Applications

08:00 Time Time Time Time 13:00 Site surveys Lunch Time 10:00 15:00 PPA / KANSAI 08:00 Day 5 Day 5Day 5 Day 5 _10:00 11:30 08:00 (Fri) ALL

<2. Inverters and BOS for Grid Connected Solar> <2. Inverters and BOS for Grid Connected Solar> <2. Inverters and BOS for Grid Connected Solar> <2. Inverters and BOS for Grid Connected Solar>

08:30

13:30

Larger installations. Paralleling Strings for increased power output 10:15

11:15

Morning Tea

BOS components and their characteristics

12:00 Lunch Time

13:00

Technical requirements for grid interconncetion (continuation)

Review of Previous Day

Exercise - technical requirements for grid interconnection 16:00～16:30 15:15 Site visit Day 1 Day 1Day 1 Day 1 Day 2 Day 2Day 2 Day 2 (Wed)

Utility Responsibilities - standards and inspections

Matching string characteristics to the Inverter

13:00

Steps for installing a typical residential grid-connected PV system Review of Previous Day

10:45 10:00 (Wed) Day3 Day3Day3 Day3

08:30 Technical requirements for grid interconncetion (continuation) (Thu)

10:15

08:00 08:30

Review of Previous Day

Day4 Day4Day4 Day4 10:00 Morning tea Quiz ALL KANSAI ALL

SHS, mini grid (PV mini grid) 08:00

10:00

Guidline of Construction & maintenance 09:30

14:30

11:00 Technical requirements for grid interconncetion

12:00 12:00

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CV's

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Luis Calzado Project Advisor - Photo - Delegate from: e8 General Secretariat 505 de Maisonneuve Blvd. Lobby Montreal H3A 3C2 Canada Tel.: +1 (514) 392-8908 Fax: +1 (514) 392-8900 e-mail: [email protected] PROFESSIONAL BACKGROUND

Since 2005 e8 General Secretariat

- Project Committee Member - Policy Committee Member

- Project Advisor, e8 Tuvalu solar power project - Project Advisor, e8 Nicaragua Hydro CDM Project - Project Advisor, e8 Maghreb Water and Electricity - Project Advisor, e8 Education for Sustainable Energy

Development project

- Project Advisor, e8 Rural Electrification Project Sub-Saharan Africa

- Project Advisor, e8 Rural Electrification Project Western Africa - Project Advisor, e8 Photovoltaic System Workshop, Pacific

Islands

- Project Advisor, e8 Demand Side Management Workshop, Pacific Islands

- e8 member ESED Committee Member

1993-1995 Abotel and Hostotel .

- Information Technology consultant - Database creation and administration

EDUCATION 2007- 2009

2001-2005

McGill University (Montreal, Canada)

Post -Graduate Degree International Business Queen's University (Kingston, Canada)

Bachelor of Electrical Engineering

1999-2001 Alliance Française (Paris, France)

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LANGUAGES English Spanish French Italian Fluent Fluent Fluent Conversational ASSOCIATIONS

Institute of Electrical and Electronic Engineers (IEEE) Ordre des Ingenieurs du Quebec (OIQ)

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Takaya FUYUKI

Delegate from:

The Kansai Electric Power Co., Inc 3-6-16 Nakanoshima Kita-Ku Osaka 530-8270 Japan Tel.: +81-(6)-6441-8821 Fax: +81-(6)-6441-4277 e-mail: [email protected] PROFESSIONAL BACKGROUND Aug. 2008 -Oct. 2010

The Kansai Electric Power Co., Inc The Kansai Electric Power Co., Inc The Kansai Electric Power Co., Inc

The Kansai Electric Power Co., Inc ((((KANSAIKANSAIKANSAI)))) KANSAI

- Head Office System Planning Group

power system planner Apr. 2004

-Aug. 2008

The Kansai Electric Power Co., Inc The Kansai Electric Power Co., Inc The Kansai Electric Power Co., Inc

The Kansai Electric Power Co., Inc ((((KANSAIKANSAIKANSAI))))KANSAI

- Kyoto Branch Office

substation maintenance engineer, substation designer, power system planner

EDUCATION

2002-2004 1998-2002

Graduate school of OSAKA University Graduate school of OSAKA University Graduate school of OSAKA University Graduate school of OSAKA University

Department of Engineering Science, Electrical Engineering OSAKA

OSAKA OSAKA

OSAKA UniversityUniversityUniversityUniversity (Japan)(Japan)(Japan)(Japan)

Department of Engineering Science, Electrical Engineering

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Taiichi Kaizuka Project Manager Delegate from:

The Kansai Electric Power Co., Inc 3-6-16 Nakanoshima Kita-Ku Osaka 530-8270 Japan Tel.: +81-(6)-6441-8821 Fax: +81-(6)-6441-4277 e-mail: [email protected] PROFESSIONAL BACKGROUND Since 2010 KANSAI

Manager, International cooperation group Work for e8 and international relationship

2008-2010 KANSAI

Manager, Network Wheeling Center

Power Wheeling for Power Produce and Supplier

2005-2008 The Federation of Electric Power Companies of Japan

Deputy general Manager, Power System Planning and Operation

Engaged in deregulation of Japanese Power Utilities

2001-2005 KANSAI

Manager, Power system planning

Planning of 500kV power system, Forecast of system peak demand

1999-2001 KANSAI

Manager, Electric Power Engineering Electric power engineering of Power Quality

1997-1999 KANSAI

Assistant manager, Office of operation and maintenance office

Operation and maintenance of substation

1996-1997 Japan Electric Power Information Center

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1990-1996 KANSAI

Electrical Engineer

Planning of power system, Design of 77kV substations

EDUCATION

1984-1988 Osaka University (Osaka, Japan)

Bachelor of Electronic Engineering

1988-1990 Osaka University (Osaka, Japan)

Master of Electronic Engineering

ASSOCIATIONS

The institute of Electrical Engineers of Japan (IEEJ)

LANGUAGES

Japanese Mother tongue

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Tomohiro KANNO Project Leader Delegate from:

The Kansai Electric Power Co., Inc 3-6-16 Nakanoshima Kita-Ku Osaka 530-8270 Japan Tel.: +81-(6)-6441-8821 Fax: +81-(6)-6441-4277 e-mail: [email protected] PROFESSIONAL BACKGROUND

Since Jun.2009 The Kansai Electric Power Co., IncThe Kansai Electric Power Co., IncThe Kansai Electric Power Co., IncThe Kansai Electric Power Co., Inc ((((KANSAIKANSAIKANSAIKANSAI))))

- Project leader of e8/PPA DSM workshop

- Project leader of e8/PPA Grid-Connected PV system workshop - Assistant of e8 ESED project

- Accounting Management of Paris Office

Apr.2007 The Kansai Electric Power Co., IncThe Kansai Electric Power Co., IncThe Kansai Electric Power Co., IncThe Kansai Electric Power Co., Inc ((((KANSAIKANSAIKANSAIKANSAI))))

- Kyoto Branch Officebusiness strategic planner

EDUCATION

2003-2007 WASWDA UniversityWASWDA UniversityWASWDA UniversityWASWDA University (Tokyo, Japan)(Tokyo, Japan)(Tokyo, Japan)(Tokyo, Japan) Department of Politics and Economics

LANGUAGES

Japanese Mother tongue

English Very Good (speaking, reading, writing)

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Herbert WADE

-

- Delegate from:

90/40 Bangkapi Condo ‘S’ Soi 121 Lad Phrao

Bangkok 10240 THAILAND Tel.: +662-733-7061 Fax: +662-733-7061 e-mail:[email protected] PROFESSIONAL BACKGROUND

1993-Present 5ndependent Consultant

- Renewable energy, rural electrification, development policy

1989-1993 South Pacific Institute for Renewable Energy (Tahiti)

- International Programme Manager

1984-1993 UN Pacific Energy Development Programme (Fiji)

- Senior Energy Planner/Deputy Project Manager

1982-1984 Fiji Department of Energy

- Director

EDUCATION

1961 United States Naval Academy, (Annapolis, Maryland, USA)

BSc (Engineering)

1967 University of Rhode Island (Kingston, R.I., USA)

MBA (Management)

PUBLICATIONS

2002 Herb Wade, Solar Project Development, NESCO, Paris

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1994 Liebenthal, Mathur, Wade, World Bank Technical Paper 244, “Solar Energy: esons from the Pacific Experience”

1985 Gowan, Wade, “A Manual for Rnewable Energy Assessment, An

Energy Planner’s Guide”, East West Center, Hawaii, USA

1983 Herb Wade, “Building Underground”, Rodale Press, Emmaus, PA,

USA

LANGUAGES

English Native

Thai Limited Conversational

French Limited Conversational/Technical reading

Russian Limited reading

ASSOCIATIONS

International Solar Energy Society American Solar Energy Association

International Association for Solar Energy Education Arizona Solar Energy Association

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Day 1

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1 T h e e 8 : I m p le m e n ti n g S u s ta in a b le E n e rg y D e v e lo p m e n t W o rl d w id e

Implementing Sustainable Energy

Development Worldwide

e8 Member Companies

• 10 major electricity companies from the global electricity sector

• At the recent Tokyo Summit, the e8 opened its membership to the major companies of the emerging countries

• New member (2010): Eletrobras (Brazil)

• New partner (2010): Comisión Federal de Electricidad (Mexico) as partner

HQ EDF RWE ENEL TEPCO KANSAI RusHydro AEP Duke Energy Eletrobras

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e8 Strategic Objectives

• Develop joint policy frameworks and implement

related initiatives;

• Take joint positions on global electricity-related

issues;

• Provide human capacity building assistance on the

efficient generation and use of electricity;

• Demonstrate replicable small-scale renewable

energy projects. 4 T h e e 8 : I m p le m e n ti n g S u s ta in a b le E n e rg y D e v e lo p m e n t W o rl d w id e

The e8 Fields of Expertise

Project Management Strengthening

e8 Activities

Environmental Impact Assessment Clean Coal Technology Rural Electrification Renewable Energy Institutional Strengthening Power Plant Efficiency Demand Side Management

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e8 Projects and Activities

Worldwide

E7-107 E7-82 E7-81 Projects Capacity Building Completed • Mexico Nicaragua Ecuador Bolivia Chile Paraguay Jordan Egypt Tunisia Lebanon Syria Burkina Faso, Benin, Niger South Africa Zimbabwe Madagascar Bulgaria Georgia Tajikistan India Bhutan Bangladesh Thailand Indonesia Mongolia China Laos Malaysia Tuvalu Kenya Maghreb Cameroon Philippines 6 T h e e 8 : I m p le m e n ti n g S u s ta in a b le E n e rg y D e v e lo p m e n t W o rl d w id e

e8 Capital Projects

• Jordan: AIJ project on thermal power plant efficiency improvements

[Completed, 2000]

• Indonesia: AIJ project on renewable energy supply systems in

Indonesia (solar, wind, hybrid, micro-hydro) [Completed, 2000]

• Benin, Burkina Faso, Niger (W Park): Solar power systems for

rural electrification and water supply. [Completed, 2003]

• Bhutan: CDM-registered project supplying hydro-electricity to a

remote village in Bhutan. [Completed, 2005]

• Ecuador (Galapagos): Re-powering using renewable energy

systems such as wind. [Completed, October 2007]

• Tuvalu (Pacific Islands): Grid-connected solar power installations in

Tuvalu. [Completed, February 2008]

• Ifugao (Philippines): mini hydro project (200 kW) for the preservation

of Ifugao's ancient rice terraces[Completed , December 2009]

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e8 CDM Projects

The Bhutan Mini Hydro Power Project (70 kW) was the

first e8 project to be officially registered as a Clean

Development Mechanism (CDM) project under the terms of the Kyoto Protocol. It was also the first project to be

registered in the Himalayan Kingdom of Bhutan.

The San Cristobal, Galapagos, Wind Project (2.4 MW):

The project was registered as a CDM project with UNFCCC in May 2008. 8 T h e e 8 : I m p le m e n ti n g S u s ta in a b le E n e rg y D e v e lo p m e n t W o rl d w id e

e8 Human Capacity Building

Activities

• Seminar on Electricity Interconnection (Ethiopia) [Completed, 2009]

• Solar PV, Design, O&M (Pacific Islands)[Completed, 2008-2009]

• Monitoring Hybrid System & Sustainability (Indonesia)

[In implementation]

• Financing Sustainable Electrification Dialogues Workshops

2009-2013 [2 workshops Completed 2009-2010; 6 workshops over the next 3 years]

• DSM workshop (Pacific Islands) [Completed, 2009-2010]

• Grid Connected Solar PV, Design, O&M (Pacific Islands)

[In development 2010]

• Industrial Energy Efficiency for emerging economies

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Education for Sustainable

Energy Development

-

ESED

• The ESED was created to support outstanding

students in pursuing advanced studies in sustainable energy development and to encourage meaningful contributions to the collective body of knowledge about the subject.

• The Programme targets students from developing countries and economies in transition who plan to undertake post graduate studies in areas directly related to sustainable energy development. • 9 Post-doctoral scholarships and 55 Masters

scholarships awarded since 2001.

Galapagos Wind Project

(Completed 2007)

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Tuvalu Solar Power Project

(Completed 2008) (Completed 2008) 12 T h e e 8 : I m p le m e n ti n g S u s ta in a b le E n e rg y D e v e lo p m e n t W o rl d w id e

Ifugao

-

Ambangal

Mini

-

Hydro

Power Project

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www.e8.org

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Grid Connected Solar PV Workshop Republic of Palau

November 1-5,2010

Overview of Grid-Connected Solar PV

Dr. Herbert A. Wade Dr. Herbert A. Wade P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

What is Grid

-

Connected Solar

• Solar panels convert sunlight to DC electricity

• An electronic inverter, converts the DC from the solar panels to AC and synchronizes with the grid

• Very simple physically with only two major components

– Solar panels – Inverter

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e8 / P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Misconception about Grid Connected PV

• Grid connected solar does NOT feed its power to the building first then the surplus goes to the grid. All the solar power goes into the grid and all the building power comes from the grid.

– The electricity the building uses from the grid is offset by a credit for the energy fed into the grid from the solar

This typically is through the use of two meters,

one for the energy coming into the building from the grid and one metering the energy going into the grid from the solar

P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Overall System for Grid

-

Connected PV

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Concept of Net Metering

• Net metering is intended to allow solar PV to send energy into the grid at one time and for the user to take out the equivalent energy at another time

– Important for residences since daytime use when the sun is brightest is lowest. Most residential usage is in the evening

– Not so important for buildings with high A/C loads since then the maximum load occurs when the solar is strongest P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Net Metering Concept in the Pacific

• Usually net metering relies on two meters but one meter can be used if it can run backward when power is going into the grid.

– Also special electronic meters that read energy flows both ways can be obtained

• Net metering needs to be arranged to send forward credit for surplus energy delivered to the grid with an annual accounting.

– Solar tends to be seasonal so some months there may be a surplus sent into the grid from solar and some months there will be more used from the grid than sent by the solar

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Net Metering

–

Payment for Surplus

• At some time once a year the total energy delivered to the grid from the solar is subtracted from the total energy delivered to the building from the grid. If there is a

surplus of energy sent to the grid by the solar over the year, a payment may be made

Payment for Surplus Energy from PV

– May be legally required or may be up to the utility

May range from zero up to more than the per

kWh retail charge.

If zero encourages users to keep the scale of

PV small enough so there is never an annual surplus

If greater than retail power rates, encourages

large installations to make money

Real cost saving to the utility is in fuel as

adjusted for the cost of maintaining spinning reserves and for grid maintenance

» Major cost savings for PIC utilities since the great majority of per kWh cost is fuel

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Effect on Utility Rates

• If many residential customers were to add solar to their buildings, as much as 20% of the load could be lost. This can affect the cost of electricity delivery since investment and maintenance is not reduced though fuel requirements are lower

– PIC per kWh energy delivery costs are a

combination of fuel cost and the cost of operations and maintenance

– Typically 60%-80% of per kWh costs are fuel for PIC utilities

– Fuel cost would be reduced while the cost of operations would stay the same but spread over 20% fewer kWh sold

– Cost per kWh delivered could rise around 5%-10% according to what percentage of kWh cost is fuel

Components

–

Solar Panels

• Solar Panels (modules)

– Crystalline (single crystal and polycrystal cells)

Smallest physical size per Wp of capacity

Proven useful life of 20+ years in the Pacific

– Thin film

Cheapest type of panel (currently ~US$2/Wp

When new, may be a better performer than crystalline panels in the tropics for grid connected systems

Not proven for long life in the tropics

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e8 / P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0 • Panel interconnections

– Panels connected in series “strings” to provide proper voltage for inverter input

– Connections may be through the use of “quick connect” push-in connectors or screw-type junction boxes

Due to prior bad experiences there are

concerns about the long term quality of quick-connect (MC-4) cable quick-connections in the highly corrosive and high temperature island environment

Panel Connections for Grid-Connected Solar

Connector Pair (- & +)

Individual connectors

Melting of connector

in service in Fiji

caused by resistance

heating due to salt

corrosion

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Panel

connections

using standard

junction box

Panel Mounting

• Roof mount

– Lowest cost – No land needed – Fastest installation

– Maintenance more difficult – May have orientation problems

– Replacing or repairing the roof means removing and reinstalling the panels

• Ground mount

– Expensive

– Need significant land area

– Very flexible for array arrangement and orientation

– Easy to access for testing and maintenance – Panels remain cooler than on roof mount

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Niue School ~20 kWp (top roof mount) and

Hospital ~31 kWp (bottom ground mount)

Mounting on Flat Roof (

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Panel orientation

• In most places, for the most kWh per year, tilt at

about the latitude angle toward the equator.

– Provides output that peaks fairly sharply between 11 and 12 noon. ~US$0.45 per kWh

– Some places (such as Palau) have seasonal solar energy patterns that make the optimum tilt not equal to the latitude angle

Wiring

• Wire must be large enough to pass peak currents without significant voltage drop

– Maximum energy loss of 2% is ok • Insulation must be able to withstand high

temperatures, high levels of weather exposure and high levels of sunlight (UV) exposure as well as the voltage of the string.

– Typically double insulated cable with the external insulation highly resistant to UV and high

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• Converts DC from panels to grid quality AC • Automatically disconnects if grid fails

– Typically senses and disconnects due to

Frequency variations

Voltage variations

Excessive rate of frequency variation

Excessive rate of voltage variation

Other parameters such as over temperature,

over current, etc.

• Reconnects automatically after sensing at least five minutes of normal grid operation and there are normal conditions in the inverter itself

Inverter

– Allowable input DC voltage varies with some models allowing less than 200V and others to over 1000V

– Output voltage and frequency programmable – Most inverters can be easily paralleled or used in

multi-phase configurations

– Often installed with many paralleled inverter units in a rack or on a wall for larger systems

– May include an isolation transformer or be direct connected

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Inside one residential sized inverter (1.7 kW).

Note the emergency DC disconnect handle at

the bottom left and AC connection bottom right

Small Inverters

Large Scale Inverter (over ~50 kW)

• Rack of paralleled inverters for larger scale PV Grid Connection

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Bank of 100 kW inverters

Photo by SMA P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Wall of 1.7 kW inverters (6 in parallel for each phase) during wiring at the Niue hospital.

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• Inverters should be sealed with no active components exposed to the air, only heat exchangers and the transformer.

– Absolutely avoid inverters with a cooling fan that blows ambient air onto the circuit board if it is to be installed where corrosion is a problem – most Pacific Islands.

Inverters for the Pacific Islands

DC Disconnects, Lightning, and Earthing

• Electrical codes for Australia, New Zealand and

the US all require each string to have its own

DC disconnect switch

• Lighting protection is optional but often installed

– Lighting surge suppressors do wear out so must be monitored

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Lightning surge suppressors and DC disconnect

switches for each string

• Typical circuit for one inverter module

– Multiple strings per inverter

– Note two meters, one for the solar and one for the use by the client

• More inverter strings equals more power

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Niue Hospital System

• 18 inverters (3 phase system)

• 36 strings of five 170 Wp panels each (total 1.7kW per inverter, 30.6kWp of panels)

• Ground mounting designed to resist category 5 cyclone • 200V nominal DC feed voltage

• 3 phase feed-in at Hospital transformer

Maintenance

• Panels require very low maintenance and have a long life (20+ years). Most problems are with the

packaging.

– Clean when necessary (usually only if some object blows onto the panels, dirt and dust usually is not a problem)

Should be cleaned at commissioning because

manufacturing residue may remain on glass – String voltage and current should be checked for

consistency between strings at least weekly through the data link to the inverter

if one string is consistently low relative to the

others, probably a connection or wiring problem exists

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Corrosion due to water entry

Discoloration of material used for cell encapsulation

Delamination of cells from the glass cover P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

• Inverter failures follow the “bathtub” curve:

Most failures occur early (within 2 years) then

maybe 10 years pass with very low failure

rates then the failure rate starts to rise rapidly.

• Prepare for 15% failures during the first couple

of years by having spares in stock.

• Monitor inverter outputs for consistency

among inverters at least weekly and preferably

every afternoon

• Most inverter problems can only be fixed by

replacement of the inverter with a spare. Local

repair of most problems is impossible.

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The key to operational maintenance is the use

of the data presentation capability of the

inverters and associated data loggers for use

with a computer (e.g. SMA’s ‘Webbox’). Every

inverter and every string is constantly

monitored and data made available to a laptop

or networked computer for checks of operation

and for initial troubleshooting.

The output of any string or inverter that is seen

to be significantly different from the others is a

sign of a problem to be checked.

Operational Maintenance

Other Maintenance

• Check the status of lightning arresters monthly (indicator color)

• Clean heat exchanger surfaces and check fan operation on inverters at least monthly

• Examine panels at least annually for corrosion, delamination or discoloration and problems with mountings

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Warranties

• Panels (read the fine print!!!)

– Physical problems 5 to 10 year warranty with panel replacement

– Output warranty 20-25 years. Obligation is only to provide replacement of lost capacity

Generally useless, mainly for PR purposes

• Inverter

– Typically 5 years with 10 years or more usually available at extra cost

– Usually does not pay for shipping which can be expensive

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Grid Connected Solar PV Workshop Republic of Palau

November 1-5,2010

Panels for Grid-Connected Solar PV

Dr. Herbert A. Wade Dr. Herbert A. Wade P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Solar Panels

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_{Photovoltaics}

• The term photovoltaics (PV) refers to the conversion of light energy (in this case light from the sun) to DC electricity.

• The technology used today dates from the 1950s and became commercial in the 60’s when power for space craft was provided by solar photovoltaics

• Today PV generation is by combinations of solar panels with size rated by the maximum Watts of electricity they can produce under a set of standard conditions

Solar Panel Power Rating

• Panels are rated in Watts Peak (Wp).

• This is the maximum number of Watts power that the panel should produce if:

– it is exposed to 1000 W/m2 _{of sunlight}

– The sunlight is coming straight onto the panel – The panel is clean

– There is a cell temperature of 25°C

– The sunlight passes through an air mass of 1.5

(about a 45°angle above the horizon)

– Power from the panel is delivered to the load at the maximum power point of the panel (the optimum loading)

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Actual Panel Output

• Solar energy is almost never is great enough to provide 1000 W/m2_of solar radiation. Typically 800-900 W/m2 _{is the highest seen on clear} days at noon.

• In the tropics, solar cells are 50C to over 60C. Higher cell temperatures result in lowered output of 10% to 15% over rated values

• Panels rarely face directly toward the sun, surface reflections increase and output decreases as a result

• There is often a mismatch between the load and the panel resulting in a few percent reduction from the rated value.

Panel Types

• Single Crystal construction. Each cell is a single crystal of silicon. This is the oldest design and provides the highest light to electricity conversion efficiency. Round cells are made initially but they may be cut square. Panel made up of many cells connected in series. Very reliable.

• Polycrystalline construction. Each cell includes several large

crystals of silicon. Cells can be any shape. Almost as high efficiency as single cells. Panel made up of many cells connected in series. Excellent reliability.

• Thin film construction. Silicon or other PV material is put in a very thin layer onto metal or plastic. Mass production is relatively easy and theoretically can be cheaper than crystal based panels. Efficiency low to medium. Reliability varies from poor to good. Sometimes called “amorphous” panels.

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e8 / P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l e 8 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1

0

_{Panel appearances}

Single crystal cell

Polycrystalline Cells

Thin Film panel

Panel construction

• Top layer is glass or in some cheap panels, clear plastic.

• The middle layer is the active PV material. In the case of crystalline cells, many individual cells are connected in series to make a panel (sometimes called a “module”). Each cell produces about 0.5 to 0.6 volts. The area of the cell determines the Amperes it can produce with modern cells providing 5-8A under full sun conditions.

• Backing for panels is typically a special plastic called Tedlar though sometimes glass. Thin film panels may have a backing that is ceramic or metal as well as possibly glass or plastic.

• Cells are embedded in a clear plastic material between the top layer and the bottom layer. This is called the encapsulant and serves to help waterproof the panel and to reduce internal reflections that would lower panel efficiency.

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Panel construction

Typical solar PV panel construction cross section P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Terminology

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Recommended Specifications

• Panels

– Must be able to be connected to provide an output appropriate to meet the input requirements of the inverter

– Screw type wire terminals with lock washers or polarized MC-4 plugs and cables

– Monocrystalline or polycrystalline construction with glass cover and aluminum or stainless steel frame

– Meet international standards for construction and are certified by testing at an international test center

Key Characteristics

• Number of cells determines the output voltage

• Voc= the open circuit voltage which is the voltage across

the terminals with no load attached

• Varies little with the amount of sun but falls as cell temperature goes up

• 0.5V to 0.6V per cell

• Isc= Short circuit current which is the Amperes measured

directly across the terminals with no load attached • Varies directly with the amount of sun

• Impp= Current delivered at the maximum power conditions

under standard test conditions (STC)

• Vmpp= Voltage delivered at the maximum power

conditions under standard test conditions

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Voltage

-

Ampere Relationship

Drawing copyright GSES

Solar

Level Affects Mainly Amperes

Effect of changes in insolation on panel current and voltage

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Connecting Panels

• Connecting panels in series (+ terminal of one panel connected to – terminal of the next) results in adding the voltage of the series connected panels

• Easy with plug and cable type connections. The positive connector and the negative connector mate

• Connecting panels in parallel (+ terminal of one panel connected to + terminal of the other and – terminal of one panel connected to – terminal of the other) results in adding the amperes produced by each panel.

• Requires a junction box since cable plugs/sockets do not mate P P A D S M W or ks hop Fi ji Is la nds N ov em be r 2-6, 2 00 9 /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b l /P P A G ri d C o n n e c te d S o la r P V W o rk s h o p R e p u b lic o f P a la u ic o f P a la u --N o v e m b e r 1 N o v e m b e r 1 --5, 2 0 1 0 5 , 2 0 1 0

Increasing Array Voltage

Panels can be connected in series to increase output voltage. A series connection will work well only if the panels have the same ampere rating.