Geothermal Potential of the Kenya Rift: energy estimates based on new data. Peter Omenda and Silas Simiyu KenGen

Transcription

1 Geothermal Potential of the Kenya Rift: energy estimates based on new data Peter Omenda and Silas Simiyu KenGen 1

2 Introduction Kenya relies on three major sources of energy in the electricity sub sector: Hydropower (57 %) Fossil based thermal (32 %) Geothermal (12 %). Geothermal 12% Thermal 32% Hydro 57% 2

3 Olkaria Fields Greenhouses Olkaria Central Olkaria Northwest Field Field Oserian power plant Olkaria Northeast Field Olkaria II Olkaria I Olkaria West Field Olkaria III Olkaria Easts Field Legend Well Plant location Olkaria Southeast Field Olkaria Domes Field 3

4 Geothermal 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 MW Total 130 MW 4

5 Immediate additional Installations (By 2010) Olkaria II Extension Olkaria III Expansion Olkaria IV Development Eburru Development Oserian II Total 35 MW 24 MW 70 MW 2.5 MW 2 MW MW 5

6 Geothermal 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 6

7 High 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 7

8 Resource assessment Mainly volcano (caldera) hosted systems Based on Olkaria experience MW/km 2 Centralized heat sources Similar permeability/hydrological structure 8

9 Heat Sources As imaged by gravity, seismics and geological models Shallow magma bodies: magma chambers (5-10km) Dike swarms High geothermal gradient: Thin crust (20-30km) Upwelling mantle (50 km) 9

10 Suswa volcano Late Pleistocene caldera volcano Geothermometry temp >300 o C Outer caldera Island block Inner caldera Suswa caldera 10

11 Suswa volcano Low resistivity anomaly (15-20 ohm-m) within the caldera Power potential is estimated to be over MW Outer caldera Island block Inner caldera 11

12 Longonot volcano Large caldera volcano and a summit crater Youngest activity less than 300 yr BP Outer caldera Summit crater 12

13 Longonot volcano 9905 Reservoir temp (>300 o C) from geothermometry Estimated potential is more than 700 MWe based on >30km 2 potential area MT 2006 MT MT at 2000 Eastings (km) mbsl

14 Pleistocene caldera volcano 6 exploration wells drilled Maximum temperature is 285 o C Eburru Volcano Geological map of Eburru 14

15 Heat source under the eastern volcano Resource Potential: >60 MW Pilot 2.5MW plant planned for 2007/8 Geophysics-MT Northoings (km) EW-05 EW-04 EW-01 EW-06 EW-03 Cedar Hill Eburru Peak EW Easting (km) MT sounding Geothermal well Lion Hill Legend Crater Eburru Farm Road 15 - m Volcanic centre Fault

16 Menengai Volcano A large caldera volcano on the rift floor (>70km 2 ) Low resistivity (<15 Ohm-m) at 2000 mbsl MT Resistivity at 2000 mb s.l and proposed well site locations. 16

17 Menengai volcano Geothermometry indicate temp (>300 o C) Estimated power potential is over 1,000 MWe based on >48km 2 potential area Conceptual model of Menengai prospect 17

18 Arus & Lake Bogoria Plio-Pleistocene flood lava field Has hot springs, spouting springs, fumaroles hot grounds Manifestations are structurally controlled 18

19 80 Bogoria/Arus area 70 L. Baringo block L. Baringo High heat flow covers large areas of Arus- Bogoria and Baringo areas Northings + 10,000 (km) Arus & L. Bogoria block Arus L. Bogoria C The Equator Menengai Olbanita block Menengai crater Eastings (km) 19 15

20 Lake Baringo No central volcano >200 o C reservoir is present in the western region Heat source is due to dike swarms and plutonic intrusions BarMT17 BarMT03 Chepkoiyo well Endao BarMT01 LORUK BarMT04 BarMT06 NAKURATABEM BarMT13 KAMPI YA SAMAKI Loruk KOKWOMOW BarMT09 BarMT08 Rongena Island BarMT24 Lekoros Island Lake Baringo Parmalok Island Salabani KOKWA ISLAND BarMT15 Ngambo Komolion Longicharo Island KECHI Lesukut Island BarMT07 Lemuyet RUGUS BarMT11 Loiminange BarMT14 Napiyet BarMT10 Nosuguro BarMT12 BarMT m

21 Korosi volcanic complex Korosi is a Pleistocene volcanic complex Geothermometry indicates temperatures of more than 250 o C Korosi 21

22 Korosi volcano Main heat source is located northern part of the volcano Potential is more than 200 MW Northings (Km) KorMT35 KorMT05 KOKORE CHESIRIMION KorMT09 KorMT16 KorMT06 TUWA KorMT13 CHEPKOKECH KorMT07 KorMT15 KorMT04 KorMT17 ADOMEYON L. Tilam KorMT08 KorMT22 KorMT11 Kinyach Crat er KorMT31 KorMT29 KorMT36 KorMT28 NAGORETEI KorMT20 kormt02 KorMT26 KorMT19 KorMT18 KorMT01 SERONI KorMT03 KorMT21 KORMT32 -m KorMT10 KorMT12 KorMT25 KorMT24 TANGULBEI KorMT14 80 Le ge nd LORUK CENTRE 78 L. Baringo KorMT23 KorMT27 KORMT33 MT location Eastings (Km) 22

23 Paka volcano 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 23

24 Silali Large caldera volcano Has the largest hot springs in the Kenya rift 1,000l/s at o C discharge Planned for detailed investigations in 2007 Large generation capacity is highly anticipated (>1,000MW?) 24

25 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 25

26 Other prospects Lake Magadi in the south Elmenteita near Eburru Ol Banita north of Menengai Akira area south of Longonot L Magadi Shombole volcano 26

27 Conclusions 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 27