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Peter Omenda and Silas SimiyuKenGen

Geothermal Potential of the Geothermal Potential of the Kenya Rift: energy estimates Kenya Rift: energy estimates

based on new databased on new data

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• Kenya relies on three major sources of energy in the electricity sub sector: – Hydropower (57 %) – Fossil based thermal (32 %) – Geothermal (12 %).

IntroductionIntroduction

Hydro57%

Thermal32%

Geothermal12%

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Olkaria DomesField

Olkaria NortheastFieldOlkaria Central

Field

Olkaria WestField

Olkaria NorthwestField

Olkaria SoutheastField

Olkaria EastsField

Olkaria I

Olkaria III

Olkaria II

Greenhouses

Oserian power plant

Legend WellPlant location

Olkaria DomesField

Olkaria NortheastFieldOlkaria Central

Field

Olkaria WestField

Olkaria NorthwestField

Olkaria SoutheastField

Olkaria EastsField

Olkaria I

Olkaria III

Olkaria II

Greenhouses

Oserian power plant

Legend WellPlant location

Olkaria Fields

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Geothermal InstallationsGeothermal Installations

• Four Power plants have been installed at Olkaria, namely:

Current– Olkaria I 45 MW– Olkaria II 70 MW– Olkaria III 13 MW– Oserian 2 MWTotal 130 MW

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Immediate additional Installations Immediate additional Installations (By 2010)(By 2010)

• Olkaria II Extension 35 MW• Olkaria III Expansion 24 MW• Olkaria IV Development 70 MW• Eburru Development 2.5 MW• Oserian II 2 MW

Total 133.5 MW

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Geothermal Occurrence in KenyaGeothermal Occurrence in Kenya

• Geothermal areas are located within the Kenya Rift

• Rift has been magmatically active since 25 Ma.

• Last magmatic activity occurred few hundred years ago

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High Temp Geothermal AreasHigh Temp Geothermal Areas• 14 high temp

geothermal areas identified in the rift

• 130 MW at Olkaria• Exploration drilling has

been done at Eburru• Detailed surface studies

done on 7 others

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Resource assessmentResource assessment• Mainly volcano (caldera) hosted

systems• Based on Olkaria experience

– 30-35 MW/km2

– Centralized heat sources– Similar permeability/hydrological structure

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Heat SourcesHeat Sources

• Shallow magma bodies:– magma chambers (5-

10km)– Dike swarms

• High geothermal gradient:– Thin crust (20-30km)– Upwelling mantle (50

km)

As imaged by gravity, seismics and geological models

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Suswa volcanoSuswa volcano• Late Pleistocene

caldera volcano• Geothermometry

temp >300oC

Suswa caldera

Island blockOuter caldera

Inner caldera

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Suswa volcanoSuswa volcano• Low resistivity

anomaly (15-20 ohm-m) within the caldera

• Power potential is estimated to be over 2-400 MW

Outer caldera

Inner caldera

Island block

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Longonot volcanoLongonot volcano• Large caldera

volcano and a summit crater

• Youngest activity less than 300 yr BP

Summit craterOuter caldera

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Longonot volcanoLongonot volcano

• Reservoir temp (>300oC) from geothermometry

• Estimated potential is more than 700 MWe based on >30km2 potential area

210 215 220Eastings (km)

9890

9895

9900

9905

210000 215000 220000

0579111213141517182021232731343944474955606687107

2004 MT

2006 MT

MT at 2000 mbsl

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Eburru Volcano• Pleistocene

caldera volcano • 6 exploration wells

drilled• Maximum

temperature is 285oC

Geological map of Eburru

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GeophysicsGeophysics--MTMT

• Heat source under the eastern volcano

• Resource Potential: >60 MW

• Pilot 2.5MW plant planned for 2007/8

191 192 193 194 195 196 197 198 199

Easting (km)

9926

9927

9928

9929

9930

9931

9932

9933

Nor

thoi

ngs

(km

)

EW-01EW-02

EW-03

EW-04

EW-05 EW-06

06791012152022232425262729

3341455065100150242289360451579

Cedar Hill

Lion Hill

Eburru FarmEburruPeak

- m

LegendMT sounding Volcanic centre

Geothermal wellCrater

Road Fault

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Menengai VolcanoMenengai Volcano• A large caldera volcano

on the rift floor (>70km2)• Low resistivity (<15

Ohm-m) at 2000 mbsl

MT Resistivity at 2000 mb s.l and proposed well site locations.

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Menengai volcanoMenengai volcano• Geothermometry

indicate temp (>300oC)

• Estimated power potential is over 1,000 MWe based on >48km2 potential area

Conceptual model of Menengai prospect

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Arus & Lake BogoriaArus & Lake Bogoria• Plio-Pleistocene flood

lava field• Has hot springs,

spouting springs, fumaroles hot grounds

• Manifestations are structurally controlled

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Bogoria/Arus areaBogoria/Arus area

• High heat flow covers large areas of Arus-Bogoria and Baringo areas

160 170 180Eastings (km)

-30

-20

-10

0

10

20

30

40

50

60

70

80

Nor

thin

gs +

10,

000

(km

)

15

25

35

45

55

65

75

85

Menengai crater

MenengaiOlbanitablock

Arus &L. Bogoriablock

L. Baringoblock

The Equator

°C

Arus

L. Baringo

L. Bogoria

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Lake BaringoLake Baringo• No central volcano• >200oC reservoir is

present in the western region

• Heat source is due to dike swarms and plutonic intrusions

165000 170000 175000 180000 18500056000

61000

66000

71000

76000

81000

BarMT01

BarMT03

BarMT04

BarMT05

BarMT06

BarMT07

BarMT08

BarMT09

BarMT10

BarMT11

BarMT12

BarMT13

BarMT14

BarMT15

BarMT17

BarMT24

Chepkoiyo well

056810131415171819212325293341454790151200242289360451579

m

Endao

Loruk

RUGUS

KECHI

LORUK

Ngambo

Napiyet

Lemuyet

Salabani

Nosuguro

Komolion

KOKWOMOW

Loiminange

NAKURATABEM

KOKWA ISLAND

Lesukut Island

Lekoros Island

Rongena Island

Parmalok Island

KAMPI YA SAMAKI

Longicharo Island

Lake Baringo

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Korosi volcanic complex• Korosi is a Pleistocene

volcanic complex• Geothermometry

indicates temperatures of more than 250oC

Korosi

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Korosi volcano

• Main heat source is located northern part of the volcano

• Potential is more than 200 MW

164 166 168 170 172 174 176 178 180 182 184 186 188 190 192 194

Eastings (Km)

78

80

82

84

86

88

90

92

94

96

98

100

Nor

thin

gs (K

m)

KorMT01

korMT02

KorMT03

KorMT04

KorMT05

KorMT06

KorMT07

KorMT08

KorMT09

KorMT10

KorMT11

KorMT12

KorMT13

KorMT14

KorMT15

KorMT16

KorMT17

KorMT18

KorMT19

KorMT20

KorMT21

KorMT22

KorMT23

KorMT24

KorMT25

KorMT27

KorMT26

KorMT28

KorMT29

KORMT32

KORMT33

KorMT35KorMT36

KorMT31

Legend

MT location

0122.533.253.3753.545678912143035405070120

Kinyach Crat er

LORUK CENTRE

CHESIRIMION

CHEPKO KECH

TUWA

KOKORE ADO MEYO N

NAGORETEI

SERONI

TANGULBEI

-m

L. Baringo

L. Tilam

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PakaPaka volcanovolcano• Detailed surface

investigations is currently being undertaken

• Last magmatic activity was <200 yrs

• High potential is expected due to high T fumaroles and other manifestations

Paka caldera

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Silali• Large caldera volcano• Has the largest hot springs in

the Kenya rift – 1,000l/s at 45-60oC discharge

• Planned for detailed investigations in 2007

• Large generation capacity is highly anticipated (>1,000MW?)

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Emuruangogolak and Barrier volcanoes

• Emuruagogolak and Barrier are large caldera volcanoes north of Silali

• Youngest volcanic activity in the rift occurred at Barrier

• Large potential is expected of more than 1,200MW between the two

Emuruagogolak caldera

Barrier volcanic complex

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Other prospects• Lake Magadi in the

south• Elmenteita near Eburru• Ol Banita north of

Menengai• Akira area south of

Longonot

Shombolevolcano

L Magadi

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ConclusionsConclusions• Current estimates suggests that

over 5,000MWe can be generated from the known resources in the rift

• Deep exploratory drilling is urgently required to prove the reservoirs