1

Non Nuclear Technology: Renewables

Toshiya NANAHARACentral Research Institute of Electric Power

Industry (CRIEPI), Tokyo, Japan

WNU-SI in Canada

July 9, 2008

2

Future Options for Energy to Copewith CO2 Problems Except for Nuclear

• Cleaner fossil fuels and their efficient use,

• Renewable energy,• Energy efficiency in buildings,

appliances, transport and industry,• Carbon capture and storage,

etc.

3

Renewables for Electricity Production

• Hydro: small-scale hydro,• Solar: photovoltaic, etc.• Wind: wind turbines• Geothermal: conventional and innovative• Biomass: wood chip, biogas, residue, etc.• Ocean: wave, tide, etc.

etc.

High Growth

4

Outline of Presentation[Main target]

Photovoltaic and wind power[Outline]1. Technology outline and recent trend2. Advantages and disadvantages3. Characteristics from the viewpoints of

electricity grid

5

Photovoltaics Generation (PV)

AC

Solar Cells

Inverter�

DC

•System Interconnection Type•Stand-Alone Type

•System Interconnection Type•Stand-Alone Type

•Single crystal•Multicrystal•Amorphous

•Single crystal•Multicrystal•Amorphous

Tradeoff between cost and efficiency

Solar Irradiation

6

Photovoltaic GenerationSolar Cells:

Single crystal Type

Installed in 1995

[Photo] By courtesy of Dr. Nakaoka

7

Wind Energy Converter (WEC)

WindTurbine

Generator,etc.

Gear, etc.Wind

Mechanical Equipment

Electric Output

Electrical Equipment

Fully understanding wind power requires various backgrounds.

8

Wind Farm

Otonnrui Wind Farm (Horonobe, Hokkaido)

21MW = 750kW x 28

[Photo] By courtesy of Horonobe Town

9

Site Suited for Wind Farms

• Availability of wide land,• Access to a good road,• Easy access to transmission (or

distribution) lines,• Not-included in natural park,• High wind speed.

etc.

10

PV Capacity in the World

[Data source] NEDO HP http://www.nedo.go.jp/nedata/top.htm

Others

Australia

Nether-lands

USA

Germany

Japan20042,596MW

0

500

1,000

1,500

2,000

2,500

3,00019

92

1994

1996

1998

2000

2002

2004

Year

Cap

acity

(MW

)

PV capacityWorld Total

11

WEC Capacity in the World

[Data source] NEDO HP http://www.nedo.go.jp/nedata/top.htmWindPower Monthly HP http://www.windpower-monthly.com/WPM:WINDICATOR

Denmark

China

Italy

UKOthers

India

Spain

USA

Germany

2007(Start)74GW

5,00010,00015,00020,00025,00030,00035,00040,00045,00050,000

1995

1997

1999

2001

2003

Year

Cap

acity

(MW

)

Wind PowerWorld Total

12

PV & WEC Capacity in Japan

0

1, 000

2, 000

3, 000

4, 000

5, 000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010Fi scal Year

Inst

alle

d Ca

paci

ty�

iMW�

j

Phot ovol t ai c

Wi nd Power

� FAct ual s � FPr oj ect i on( METI )� @ ( Tar get case)

[ Sour ce] METI commi t t ee' s r epor t , NEDO Home Page, et c.

0

10, 000

20, 000

30, 000

40, 000

50, 000

60, 000

1980 1990 2000 2010 2020 2030Fi scal Year

Inst

alle

d Ca

paci

ty�

iMW�

j

Phot ovol t ai c

Wi nd Power

� FAct ual s � FPr oj ect i on( METI )� @ ( Max. Ef f or t s case)

[ Sour ce] METI commi t t ee' s r epor t , NEDO Home Page, et c.

13

Key Issues In the Presentation

• Advantages and disadvantages– Comparing renewables with the other

energy sources could be a highly controversial issue.

• Renewables viewed from electricity grid– The other aspects of renewables:

distributed generation / intermittent generation.

14

Outline of Presentation

1. Technology outline and recent trend2. Advantages and disadvantages3. Characteristics from the viewpoints of

electricity gridof photovoltaic and wind power generation.

4. Closing remark

15

Advantages of Renewables• Non-exhaustive carbon-free

energy source.Generally speaking, they are:• Supposedly environment-

friendly energy,• More easily accepted by public,• Technology improvement in recent

years, etc.

16

Disadvantages of RenewablesGenerally speaking,• They have low power density;• Their capacity factor is mostly not so high.

Thus, they are mostly expensive than conventional energy.

• Their output is unstable;• They sometimes needs provision for

environmental impacts.etc.

17

Emission of Power SourcesE

mis

sion

by

1 kW

h E

lect

ricity

g-CO2/kWhCO2 equivalent

Fuel

Equipment, Operation

ex Considered Process for Coal Thermal

Mining Transpor-tation

ElectricityProduction

Ash disposal

PowerSource

Coa

l The

rmal

Oil

Ther

mal

LNG

The

rmal

LNG

CC

Phot

ovol

taic

Win

d Po

wer

Nuc

lear

Geo

ther

mal

Smal

l hyd

ro

18

19

Required area(order)

Capacity factor

Photovoltaic 10-2kW/m2 11% (Japan)

Wind Power 10-3kW/m2 15-30%

Biomas Power 10-4kW/m2 Depending on fuel availability

Therma 100kW/m2 90%

Renewable Energy Capacity Factor

20

0

10

20

30

40

50

60

70

Photovol-taic

Wind Power

Thermals

Prod

uctio

n co

st(\/

kWh)

WithCapacityValue

Production Cost of Renewables

Cost of renewables is decreasing. However, the following measures are generally introduced due to their high cost:

• Institutional measure: feed-in-tariff, renewable portfolio standard, etc.

• Subsidy for installation, etc.

[Data source] New Energy Subcommittee of the Advisory Committee for Energy

21

[Data source] NEF HP http://www.solar.nef.or.jp/system/html/taiyou_sys080508.pdf

0

20

40

60

80

100

120

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

PV

syst

em c

ost (

104 ye

n/kW

)

InstallationBOSSolar cell

106.2 107.4

93.9

69.071.075.8

84.4

69.668.366.167.5

22

0.0

0.2

0.4

0.6

0.8

1.0

1.2

”-“

d�o—

Í(pu)

Ž ž� �

‚ P“ ú

0.0

0.2

0.4

0.6

0.8

1.0

”-“

d�o—

Í(pu)

Ž ž� �

� ° � °Ž ž� X“ Ü

“ Ü� ‰̂J

Ouputpower (pu)

Ouputpower (pu)

23

Pros and Cons of Photovoltaics[Advantages]• Applicable to various places (residence, etc.),• Low maintenance requirement,• Small environmental impact : noise, etc.,• Familiar to many people, etc.[Disadvantages] • Low energy density: solar insolation:1kW/m2,• Low capacity factor: about 12%,• Intermittent output: dependence of on weather,• Not economically viable, etc.

24

Pros and Cons of Wind Power[Advantages]• Relatively low cost in renewables, • Larger capacity factor than PV’s at a windy

site, etc.[Disadvantages]• Challenges in harnessing wind,• Low energy density,• Intermittent large output fluctuation due to

weather,• Environmental impacts – noise, scenery, etc.• Windy area not densely resided area

→ weak grid, etc.

25

Challenges in Harnessing Wind

• Turbulence is inevitable.• Its power is proportional to third power

of its velocity.• Wind turbines are used under severe natural

conditions: eg, gust, lightning, typhoon.

• Difficulty in adjusting a turbine to a specific wind conditions,

• Reliability of a wind turbine,• Requirement of maintenance works, etc.

26

Closing Remark (pt.2)• Renewables, as a matter of course,

have their inherent pros and cons. How do you assess them in comparison with the other energy sources?

• Most renewables take advantage of interconnecting to a power system. This causes another important aspects of renewables discussed later.

27

Outline of Presentation1. Technology outline and recent trend2. Advantages and disadvantages3. Characteristics from the viewpoints of

electricity gridof photovoltaic and wind power generation.

4. Closing remark

28Action Plan of IEA to respond to the Request of G8 Summit

• Cleaner fossil fuels• Renewable energy: ………….. A dedicated

international group of experts …. will speed development of common technical and policy approaches to integrating intermittent renewable energy into electricity grids.

• Energy efficiency in buildings, appliances, transport and industry

• Carbon capture and storage

29

Challenges in Connecting Renewables• Distributed

generators interconnected to weak grid;e.g. PVs to low-voltage distribution lines (100/200V)

• Intermittency of output power with difficulties in accurate output forecasting.

Transmission

Distribution

30

Intermittency of Renewables• Outputs of PV and wind turbines contains

large fluctuations difficult to predict. • Their output could be very low in case of

peak demand.

In a power system, supply have to match demand at all times.

31

Trend in Impacts of Wind Powerpenetration Area of impacts Major Impacts

small

large

Local(Distribution)

Sub-transmission

System-wide(Transmission)

•Power quality: eg,voltage

•Load flow: congestion

•System security,•Supply-demand-

balance

32

107V

95 V

Local Impacts #1: Voltage Fluctuations

107V

95 V

33

Local Impacts #2: Malfunction of Relay

Faultw/o DGs

w/ DGs

Fault current 100A

Change in fault current at a substation

Malfunction of protective relay

Fault current 80A Fault current 10A

34

” z“ d� ü

• Ï“ d� Š

ƒ Xƒ Cƒ bƒ `

Local Impacts #3: Islanding

DGs may continue their operation after a circuit breaker opens. It will hinder system restoration and, in the worst case, the fault cannot be removed.

35

Penetration that Could Cause the Problems

Expected technical problems Penetration of DGs problems occur [Note]

Voltage fluctuation due to reverse power flow More than 5 to 20%

More than 40%

More than 20%

More than 20 to 30%

Faults can cause-- Increase of short circuit

capacity -- Malfunction of a protective

relay operation-- islanding

[Note] Penetration rate: ratio to distribution line capacity. They are sample values obtained for the worst casethrough experimental and simulation studies.

36

System Impacts #1: Intermittency• Their large scale integration requires

more flexibility (eg, reserve) in a power system.

How the flexibility is improved or maintained in a future power system?

• Capacity value* of PVs and WECs: not so high (controversial issue)

Needs for back-up power

* Capacity value: an index that shows how the power source is reliable when it is needed.

37

[Source] NEDO report, NEDO-

NP-0012

Sample Output of WECs

5 10 15 20 25 300

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

“ ú

•½‹

Ï�o—

Í(pu)

T4’ n“ _�@2000” N12ŒŽ

5 10 15 20 25 300

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

“ ú

•½‹

Ï�o—

Í(pu)

‘ S’ n“ _‚ Ì� o—Í• Ï“ ®�@2000” N12Œ Ž

Smoothing

Output of a WEC

Total Output of 30 WECs

Dec./2004 Site T4

Dec./2004Out

put (

pu)

Out

put (

pu)

38

Example of Japan

39System Impacts #2: Trip Due to Volt. Sag

[Source] Juan F. Alonso-Llorente, “Integration of wind Generation within the Power System - Experiences from Spain,” Eolica Mediterranean, Rome, September, 2005.

40

Impacts and Their CountermeasuresQuant. Major Impacts Countermeasures

small

large

•Power quality: eg,voltage

•Load flow: congestion

•System security

•Supply-demand-balance

• Variable speed machine• FACTS (eg, SVC)

• Output curtailment• System reinforcement

• Fault-ride-through capability

• Output forecast• Electric storage• Demand response• Hydrogen

41

42

Closing Remark (pt.3)• Integration of renewables to a power

system presents a technological challenge.

• New generation technologies including renewables tend to be not so flexible as conventional ones. Are there any measures to improve the flexibility of the future generation mix?

43

Outline of Presentation

1. Outline and recent trend2. Advantages and disadvantages3. Characteristics from the viewpoints of

electricity gridof photovoltaic and wind power generation.

4. Closing remark

44

Closing Remark: a Personal View• Almost all energy technologies will be needed

to resolve the future energy problems. Renewables would be surely one of the promising candidates. What is your scope on the future energy system with nuclear, renewables and other energy sources?

• System-wide scope would become more important in the future. For example, in assessing the new energy such as renewables, due attention should be paid to power delivery, end-use, etc. aspects.

45

Thank you very much for your attention.

46

Future Options and Time Span

Short term Medium term(CO2 Problem)

Long term (Depletion of resources)

Efficient use of energy

Renewable energy

Cleaner fossil fuel

Carbon capture and storage

47

Thermal /NuclearHydro

BiomasMunicipalWaste

Wind

Sweden2000

Renew-ables

Renewables: Difference among Countries

[Data source] IEA, “Renewables Information 2002”

Electlic energy mix (Denmark)

Electlic energy mix (Sweden)

Thermals

Renewables

Biomas

Denmark2000

Wind

48

0

10

20

30

40

50

60

70

Photovol-taic

Wind Power

Thermals

Prod

uctio

n co

st(\/

kWh)

WithCapacityValue

Production Cost of Renewables

Cost of renewables is decreasing. However, the following measures are generally introduced due to their high cost:

• Institutional measure: renewable portfolio standard, feed-in-tariff, etc.

• Subsidy for installation, etc.

[Data source] New Energy Subcommittee of the Advisory Committee for Energy

49

Distribution line 10km

Substation

Point A

WP WP WP

Voltage at point A

(V)

6400

6500

6700

6800

�kW

)

0

200

400

600[Wind power]

Wind Power

6600

Sample Impacts of WEC on Voltage

min. min.

50

51

52

53

Data source WindPower Monthly HP http://www.windpower-monthly.com/WPM:WINDICATOR

Wind Power Capacity in the World

0

5,000

10,000

15,000

20,000

25,000

Ger

man

y

US

A

Spa

in

Indi

a

Den

mar

k

Chi

na

Italy

UK

Por

tuga

l

Net

herla

nds

Fran

ce

Can

ada

Japa

n

Oth

ers

Cap

acity

(MW

)

Start 2001Start 2007

54Capital cost for residential PV

systems of 3kW

�104\�

Production cost �\/kWh

�

[Data source] NEDO HP http://www.nedo.go.jp/nedata/top.htm

55

Distributed Generators (DGs): Tentative Definition by CIGRE

• Not centrally planned (by the utility),• Not centrally dispatched,• Normally smaller than 50-100 MW,• Usually connected to a distribution

system.

DGs: uncontrollable small generators at the places not previously expected