GSMA South Africa Cape Town November 2011 · Any excess energy will charge the batteries. ... (no conversion) 90-98% 85-90% ... Slide 32 15.11.2011 > Rural electrification HYBRID

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15.11.2011

GSMA South Africa

Cape Town November 2011

Lars Olav Elstrøm,

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15.11.2011

HYBRID SYSTEM BUILDING BLOCKS

MAXIMIZE THE POWER OF RENEWABLES

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Solar

charger

DC/DC

Rectifier

AC/DC

Controller

Solar

charger

DC/DC

Rectifier

AC/DC

The challenge is to optimize and integrate, not just to put the system together

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SOLAR HYBRID FUNDAMENTALS


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Solar

charger

DC/DC

Rectifier

AC/DC

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Solar

charger

DC/DC

Rectifier

AC/DC

Sunny day

At a sunny day the load is powered

from solar. Any excess energy will

charge the batteries

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Solar

charger

DC/DC

Rectifier

AC/DC

Low sun days

When limited sun (cloudy days) the load

may be powered from both solar and

generator

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Solar

charger

DC/DC

Rectifier

AC/DC

During night

When no sun (rainy days or night time)

the load is powered from the batteries.

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15.11.2011


Solar

charger

DC/DC

Rectifier

AC/DC

When batteries are discharged to a

predefined level, generator will start to

recharge the batteries and power the

load

During night

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Remaining Capacity

020040060080010001200140016001800200022002400260028003000

8/1/2009

0:00

8/2/2009

0:00

8/3/2009

0:00

8/4/2009

0:00

8/5/2009

0:00

8/6/2009

0:00

8/7/2009

0:00

8/8/2009

0:00

8/9/2009

0:00

8/10/2009

0:00

8/11/2009

0:00

8/12/2009

0:00

8/13/2009

0:00

8/14/2009

0:00

8/15/2009

0:00

8/16/2009

0:00

8/17/2009

0:00

8/18/2009

0:00

8/19/2009

0:00

8/20/2009

0:00

8/21/2009

0:00

8/22/2009

0:00

8/23/2009

0:00

8/24/2009

0:00

8/25/2009

0:00

8/26/2009

0:00

8/27/2009

0:00

8/28/2009

0:00

8/29/2009

0:00

8/30/2009

0:00

8/31/2009

0:00

9/1/2009

0:00

RemCap

Genset start

Genset stop

> It takes >5 days before Generator starts after discharge from

90% to 50% capacity


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TECHNOLOGY COMPARISON


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Technology Contactor/Relay Switch mode Switch mode

Control ON/OFF PWM PWM

Galvanic

isolation

No No Yes

Regulated

output

No Yes Yes

No Yes Yes

Converter

efficiency

~100%

(no conversion)

90-98% 85-90%


Type 1 Type 2 Type 3

MPPT

Three major ‘solar charge control’ technologies

96,5% with Eltek

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PV panel characteristics:

> The output of a PV panel depends on

• Available solar energy

• PV panel temperature

• PV panel terminal voltage

• +++

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> Solar energy (Irradiation) varies during a day.

> PV panel temperature varies by ambient temperature and

irradiation

> PV terminal voltage is given either by

• Battery voltage with a Type 1 technology chargecontroller

• MPPT algorithm for Type 2 and Type 3

> Study some details from a hot area and how it will affect

the harvested PV energy.

(Constraints at the end of presentation)

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Solar energy, ambient temperature, PV temperature

Data from one random day, from a whole year of data

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Analyzing irradiation for one complete year Totally 3627 hours contributing14% of all daylight hours have 800W/m2

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Temperature distribution at 800W/m280% probability between 55oC and 70oC

Median at 64oC


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Operating batteries somewhere between

20% and 100% SOC

PV terminal voltage operating range

47.5V and 54.5V

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930W

760W

18% less energy

Battery charge voltage range setting the PV panel terminal voltage

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MPPT range, where the maximum available power is locatedA MPPT converter will operatewithin whole range

Battery charge voltage range setting the PV panel terminal voltage.A direct feed (Type 1) will operatewithin this range

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> The constraints of the Type 1 system has been identified

> Every irradiation level and panel temperature there will be:

• A maximum available energy

• A maximum energy that the Type 1 can give

• A minimum energy that the Typ1 can give.

> For a whole year the contribution from each irradiation level will be

according to their hourly distribution.

> Effect of partly shading not considered

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0,96 0,32 0,95 0,2 0,95 0,2 0,91 0,2 0,65 0,2

0,2 0,97 0,24 0,97 0,29 0,97 0,2 0,97 0,96 0,97

Corresponding battery SOC

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> From here it is all about probability and statistics…

• Best case and worst case conditions are not likely to dominate.

• Higher PV temperature will dominate

> Assume 20% less PV contribution from Type 1 (Including

conversion losses in the MPPT) on yearly basis.

> Type 1

• Needs 20% more PV panels to achieve same solar fraction

• Increased CAPEX OR

• 20% more energy from the generator.

• Increased OPEX

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Technology Contactor/Relay Switch mode

Control ON/OFF PWM

Galvanic

isolationNo Yes

Surge immunityFail safe operation

Regulated

outputNo Yes Energy priority

No Yes Energy yield

Converter

efficiency

~100%

(no conversion)96,5% System losses


Type 1 Eltek Impact

MPPT

Technology difference summary

Galvanic

isolationNo Yes

Surge immunitySafety

Regulated

outputNo Yes

Energy priorityCharge control

MPPT No Yes Energy yield

Converter

efficiency

~100%

(no conversion)96,5% System losses

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FINANCING SOLUTIONS


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ELTEK VALERE FINANCIAL SOLUTIONS

• Does it make sense to pay upfront for equipment that delivers you monthly income?

• Would an OPEX solution help your budgets?

• Would you buy more technology if you could buy now and pay later?

• Would you invest more quickly if the monthly saving was greater than your monthly cost?

• Our models typically require no CAPEX investment, where monthly savings are greater than the monthly payments you make – would that help with your business case to choose Eltek Valere?

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FINANCING

PROJECTS IN AFRICA

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HYBRID SITE ANALYSIS

� Site: Lagos, Nigeria

• 27KvA Generator

• 22% DOD

• 150A Recharge current available

• Peak Load 3Kw

• Average Load 2.5Kw (50A)

• FCU 1800M3/hr

� Breakdown of Analysis

• Generator run time – 06Hrs

• Battery run time – 18Hrs (Nicad Batteries)

• Load – 50A Average

• 6 Cycles per day

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INSTALLED HYBRID SITE ANALYSIS - GRAPHS

�Diesel Savings: 2160 liters per month = approx $3024 per

month ($1.4 per liter delivered to site)

�OPEX Savings : 75%

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> Rural electrification

HYBRID SITE ANALYSIS

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Eltek Valere – The Greenest Power in the Industry

Leading Through Example

Thank you for your time

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15.11.2011

Study constrains

> The output of a PV panel is limited by three major parameters.

• Level of energy coming from the sun (Irradiation [W/m2]

• Temperature [oC]

• Air mass (AM ,Height above sea level)

• Operation point

> The rating of a PV panel is given under Standard Test Conditions (STC):

• Irradiation 1000 W/m2

• PV panel temperature 25oC

• air mass AM 1.5,

> PV panel rating cont.

• A PV cell is a diode.

• A PV panel consists of multiple cells connected in series

• The nominal voltage of a panel in given by the number of cells, ie 60 cells gives a open circuit voltage of

~36V

• To improve the performance incase of shading, the cells are organized into strings protected by bypass

diodes.

Documents

GSMA South Africa Cape Town November 2011 · Any excess energy will charge the batteries. ... (no conversion) 90-98% 85-90% ... Slide 32 15.11.2011 > Rural electrification HYBRID