Geothermal Potential of the Kenya Rift: energy estimates based on new data Peter Omenda and Silas Simiyu KenGen 1
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
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
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
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 133.5 MW 5
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
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
Resource assessment Mainly volcano (caldera) hosted systems Based on Olkaria experience 30-35 MW/km 2 Centralized heat sources Similar permeability/hydrological structure 8
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
Suswa volcano Late Pleistocene caldera volcano Geothermometry temp >300 o C Outer caldera Island block Inner caldera Suswa caldera 10
Suswa volcano Low resistivity anomaly (15-20 ohm-m) within the caldera Power potential is estimated to be over 2-400 MW Outer caldera Island block Inner caldera 11
Longonot volcano Large caldera volcano and a summit crater Youngest activity less than 300 yr BP Outer caldera Summit crater 12
Longonot volcano 9905 Reservoir temp (>300 o C) from geothermometry Estimated potential is more than 700 MWe based on >30km 2 potential area 9900 9895 9890 107 87 66 60 55 49 47 44 39 34 31 27 23 21 20 18 17 15 14 13 12 11 9 7 5 0 2004 MT 2006 MT 210 215 220 MT at 2000 Eastings (km) mbsl 210000 215000 220000 13
Pleistocene caldera volcano 6 exploration wells drilled Maximum temperature is 285 o C Eburru Volcano Geological map of Eburru 14
Heat source under the eastern volcano Resource Potential: >60 MW Pilot 2.5MW plant planned for 2007/8 Geophysics-MT Northoings (km) 9933 9932 9931 9930 9929 9928 9927 EW-05 EW-04 EW-01 EW-06 EW-03 Cedar Hill Eburru Peak EW-02 9926 191 192 193 194 195 196 197 198 199 Easting (km) MT sounding Geothermal well Lion Hill Legend Crater Eburru Farm Road 15 - m 579 451 360 289 242 150 100 65 50 45 41 33 29 27 26 25 24 23 22 20 15 12 10 Volcanic centre Fault 9 7 6 0
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
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
Arus & Lake Bogoria Plio-Pleistocene flood lava field Has hot springs, spouting springs, fumaroles hot grounds Manifestations are structurally controlled 18
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) 60 50 40 30 20 10 Arus & L. Bogoria block Arus L. Bogoria C 85 75 65 0 The Equator 55-10 45-20 -30 Menengai Olbanita block Menengai crater 35 25 160 170 180 Eastings (km) 19 15
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 81000 76000 71000 66000 61000 56000 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 BarMT05 165000 170000 175000 180000 185000 m 579 451 360 289 242 200 151 90 47 45 41 33 29 25 23 21 19 18 17 15 14 13 10 8 6 5 0 20
Korosi volcanic complex Korosi is a Pleistocene volcanic complex Geothermometry indicates temperatures of more than 250 o C Korosi 21
Korosi volcano Main heat source is located northern part of the volcano Potential is more than 200 MW Northings (Km) 100 98 96 94 92 90 88 86 84 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 120 70 50 40 35 30 14 12 9 8 7 6 5 4 3.5 3.375 3.25 3 2.5 2 1 0 82 KorMT10 KorMT12 KorMT25 KorMT24 TANGULBEI KorMT14 80 Le ge nd LORUK CENTRE 78 L. Baringo KorMT23 KorMT27 KORMT33 MT location 164 166 168 170 172 174 176 178 180 182 184 186 188 190 192 194 Eastings (Km) 22
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
Silali Large caldera volcano Has the largest hot springs in the Kenya rift 1,000l/s at 45-60 o C discharge Planned for detailed investigations in 2007 Large generation capacity is highly anticipated (>1,000MW?) 24
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
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
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