Assessment of Technologiesfor Mitigating Global Warming

Yoichi KayaResearch Institute of Innovative

Technology for the Earth ( RITE ) , Japan

Contents

1. Threats of global warming 2. Mitigation scenarios 3. Nuclear power: its role and future issues4. Wind power and photovoltaics: their trends

and limitations5. Biomass6. Other renewables7. Role of CCS8. Concluding remarks

Europe

Atlantic Ocean

Fig. Thermohaline circulation and European Climate

GW

Thermohalinecirculation

Mechanism of Breakdown of Thermohaline circulation

Rise in temp. of North Atlantic

Melting of ice and snow

More rainfall

Lighter surface water

Less driving force of water sinking down

Breakdown of thermohaline circulation

-20 -10 0 10 20 30

＞５，０００

３－５，０００

１－３，０００

＜１，０００

2004

1957

Depth: m

Speed Svnorth

Fig. Slow down of thermohaline circulation in the Atlantic

Source:Bryden,H.L. et al, Nature, Dec.2005

0

10

20

30

40

50

60

70

80

90

100

400 500 600 700 800 900 1000 1100 1200

CO2 concentrations (ppmv)

Prob

abili

ty o

f TH

C c

olla

pse

(%)

Murphy(2004)Annan(2006)Hegerl(2006)

Fig. Possibility of the Collapse of Thermohaline Circulation (THC)

CO2 concentration in the air-present and future-

1. 1800 280 ppm2. Present 380 ppm3. EU 2 degree target 450 ppm

( due to M.Weiss, March, 2005)4. Avoidance of THC collapse 550 ppm

( with 90 % confidence )

ｐｐｍCO2 concentration in the air

Fig. CO2 emission for stabilizing its concentration in the airSource: IPCC TAR technical summary

550ppm

Presentlevel

Reforestation

CO2

Sequestration

Nuclear Power

OtherRenew. Energy

Photovoltaics

Fuel Switching

Energy Saving

0

5

10

15

20

25

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100Year

Car

bon

emis

sion

s an

d re

duct

ions

(GtC

/yr)

Energy SavingFuel SwitchingPhotovoltaicsOther Renewable EnergyNuclear PowerCO2 SequestrationReforestationNet CO2 Emission

among Fossil Fuels

Net Carbon Emissionsin 550ppmv Case

Net Carbon Emissionsin Reference Case

Technological Options for 550 Technological Options for 550 ppmvppmv StabilizationStabilization

Non-carbon primary energy

1. Nuclear power2. Renewables (‘new’ )1) wind power / photovoltaics2) biomass 3) geoheat and other ambient energy4) space solar power (SSPS)

3. Fossil fuels with CCS

0 20 40 60 80 100

U S A

U K

G erm any

Finland

Japan

S w itzerland

K orea

S w eden

B elgium

France

nuclear

％

Fig. Share of nuclear in power supply (kwh、2001)

World average

Rate of change in carbon intensity of primary energy : 1980-2000

Carbon intensity = CO2 emission

primary energy

actual data nuclear moratoriumat 1980

OECD coutries

Japan

- 0.6 % / year

- 0.5 % / year

0.0 % / year

+ 0.3 % / year

Future key issues on nuclear power

Basis: Nuclear is almost indispensable in decarbonized future.

1. How to scrap and build present reactors?ex. Japanese case ( see the figure )

2. How and where to dispose nuclear wastes?3. How to improve public acceptance?

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1 4 7 10 13 16 19 22 25 28 31 34

原発容量

万ｋｗ

年図4．日本の原発の累積年齢構造（容量ベース、２００4年現在）

２０１０２０２０２０３０ ４０歳到達時期

0

2

4

6

8

10

12

14

16

18

Germ

any

Spain

USA

Denm

ark

India

Italy

Neth

erland

s

Japa

nwind power

GW

Fig. Capacity of wind power（２００４）

0

5

10

15

20

25

30

35

40

45

50

'95 '96 '97 '98 '99 '00 '01 '02 '03 '04

w ind pow er

GW

Fig. Total capacity of wind power ( World)

0

200

400

600

800

1000

1200

Japa

nGe

rman

y

USA

Aust

ralia

Neth

erland

s

Spain

Italy

Fran

ce

PV

MW

Fig. Capacity of Photovoltaics （２００４）

3.4 % (2030)0.9 GWJapan

20% ( 2030)3.1 GWDenmark

6 % (2020)6.8 GWUSA

---------8.3 GWSpain

25% (2025)16.6 GWGermany

Future target( % of elec.power )

Capacity(2004)

Table. Present and future target of wind power

1 plant

1,500plants

Fig. time variability of outputs of wind power(Germany)

Fig. Time changeability of photovoltaics

Output changeability of wind power / photovoltaics

1. Outputs of wind power and photovoltaics(WP/PV) change randomly with time.

2. Some of grid power plants are used for satisfying the relation

total supply = total demand3. Then

the facility cost of these grid power plants

external cost of WP/PV due to output changeability

External cost of WP / PV- Japanese case -

1. Corresponding power plants :oil fired power plants

2. Their capacity utilization ratio: low20 -30 %

3. Costs 10 -14 Yen per kwh ( 8 – 11 US cents )

Limits of WP / PVdue to output changeability

1. Their output changeability innevitably requires installation of those power plants which adjust their outputs so as to satisfy the condition

total supply = total demand2. Facility costs of these power plants are

additional costs of the grid solely due to introduction of WP/PV. = too heavy burden→ capacity of WP/PV << grid capacity

traditionalhydropowerheatbiofuel

New renewables biofuel

Fig. Renewables in the world:2002

Traditional use

Key issues of new biomass- when large production needed -

1. Low energy conversion efficiencysolar E to biomass: 1-2 % how to improve it?

2. Competition with food productionenergy plants such as potatoes, sugarcanesand corn are eatable

Possible solution: utilization of plant wastessuch as plant leaves, stems, etc.

Two candidates for future renewable energy supply

1. Use of ambient energy resources forlow temperature heat supply ( residential )

2. Space solar power system ( SSPS ) for large scale stable power supply

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

U K C anada G erm any U S A Japan

heat ratio

Fig. Share of heat in residential energy demand

How to satisfy residential heat demand

1．Passive use of solar powerex. Passive house in Germany

2. Active use of solar powerintroduction of solar heater,etc.

3. Utilization of ambient energy resourcesas low temp. heat source of heat pump

P0 Heat demand D

Ph

αe COP low temp.ambient energy sources

D ＝α・COP・P (1)

Energy gain from ambient energy sources

F = P０－Ph = ( 1/αh - 1/ αe・COP ) (2)

Utilization of low temp. geoheat in residential sector

Primary E αh

conversion tosecondary E

powergeneration

heatpump

Ambient energy sources

Conditions: 1) large heat capacity2) available almost everywhere

1. water ponds, rivers, reservoirs, ocean, etc.

2. air3. shallow underground: geoheat

merits and demerits of geoheat

Merits1. Available almost everywhere2. Temperature higher than other ambient

energy resourcesex. 10 deg. in celcius at the depth of 10 m

( in winter, Sapporo, Japan)Demerits: high cost at present

２００Japan

９．０００France

４２．０００Switzerland

５０，０００Germany

５００，０００USA

total number of houses

Table: Number of houses utilizing geoheat

Potential of low temp. geothermal E- share in residential E, Japan -

1. COP of heat pumpgeothermal: 10 degrees in Celsium ( Sapporo, 10m deep )

supply temp. Theoretical real 30 deg. ( room?) 15 8 ?

50 deg. ( water?) 8 6 ?2. Availability of low temp. geothermal ( potential )

Share in primary energy in Japanresidential

commercial totalCOP=5 3.7 % 2.5 %

6.2 %COP=10( heating) 4.3 3.0 7.3

Photo-voltaics

Magne-tron Rectenna

DC power Micro wave PowerOutput

Laseroscillator

Solarcells

Laser PowerOutput

Fig. Two types of Space Solar Power System ( SSPS )

Fig. Space Solar Power System :source JAXA

Merits and demerits of SSPS

Merits1. Stable power supply ( little output

changeability )2. Large scale power generation possibleDemerits1. High costs

Reforestation

CO2

Sequestration

Nuclear Power

OtherRenew. Energy

Photovoltaics

Fuel Switching

Energy Saving

0

5

10

15

20

25

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100Year

Car

bon

emis

sion

s an

d re

duct

ions

(GtC

/yr)

Energy SavingFuel SwitchingPhotovoltaicsOther Renewable EnergyNuclear PowerCO2 SequestrationReforestationNet CO2 Emission

among Fossil Fuels

Net Carbon Emissionsin 550ppmv Case

Net Carbon Emissionsin Reference Case

Technological Options for 550 Technological Options for 550 ppmvppmv StabilizationStabilization

CO2 Capture and Storage (CCS)

Role of CCS

1. Fossil fuels now occupy about 87% of the worldprimary energy. We need the technology to reduce CO2 emissionin the air while utilizing fossil fuels.

use of CCS2. CCS is not new but comprised of known technologies, therefore

easily put into practice. CO2 capture: separation of CO2 from natural gas CO2 storage: CO2 for enhanced oil recovery ( EOR)

3. CCS has a considerably large potential in reduction of CO2 emission.

→ CCS is a technology to be utilized as the bridge between the present society and the future decarbonized society

Present Activities of CCSred letters: being planned

SNOVHIT

SLEIPNER

IN SALAH

ORCWEYBURNMILLER

GORGON

Source: ＰａｕｌＦｒｅｕｎｄ’s Presentation in RITE’s workshop

Potential of Underground Storage of CO2

Acquifer 8,000 Gt

Depleted oil / gas fields 1,000

Adsorption on deep coal mines 300

emission of CO2 in the world 24 / yearTotal reduction in CO2 emission within 21st century to achieve 550 ppm 1,000 – 3,000

Summary (1)1. Decarbonization of primary energy is a “must” in the long

run.2. Nuclear power is indispensable in the future decarbonized

society. 3. Wind power and photovoltaics which outputs are

changeable with time have high external costs when connected to the grid.

Therefore their capacity should be limited, compared with the demand size of the grid.

4. Utilization of various types of ambient energy sources including geoheat should be promoted.

Summary (2)

5. R&D of space solar power system(SSPS) should be promoted to achieve large scale stable power supply.

6. CO2 capture and storage (CCS ) will be utilized widely in the world as a bridging technology from fossil fuel occupied world to non carbon world.