ticking bomb or rwanda's salvation · lake nyos limnic eruption disaster 1986 > 1700 killed...

127 Apr. 06 Lake Kivu - ticking bomb..

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Lake Kivu -

Ticking bomb or Rwanda's salvation

Jørgen S. Steenfelt

COWI A/S


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Contents

Killer lakes, Rwanda, Natural gas

Project & involvement

Facts and suppositions for Lake Kivu

Potential risks and consequences

Monitoring and action planning

Environmental concerns

Future


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Preamble

"Killer lakes" in Africa

CO2-rich lakesMonoun & Nyos

Eruptions 1984, 1986


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Lake Nyos limnic eruption disaster 1986

> 1700 killed

> 3000 cows

countless animals


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Lake Kivu

"Killer lakes" in Africa

CO2-rich lakesMonoun & Nyos

Eruptions 1984, 1986

Methane-rich Lake Kivu

Saturation not imminent


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Rwanda - background


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Rwanda - background

Genocide 19941 M killed; 2 M fled

Population 8.4 M

26 338 km2

GNI/capita (2003) US$ 220

51% in poverty; (70% in rural areas)

1500 km to ocean


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Rwanda - background

1990 1995

Deforestation: civil war; lack of energy


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Rwanda - background

Wood burning for cookingdrying tea …..

Fossil fuel expensive


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Rwanda - salvation?


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Salvation?

Lake Kivu - Gas Extraction project KP1

GisenyiPilot plant

KibuyePower plant

Size 2400 km2

Surface 1463 m

Depth 485 m

Water vol. 550 km3

CO2 (STP) 330 km3

CH4 (STP) 57 km3

CH4/year +0.25 km3


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Methane - a Natural Gas

NG Oil Coal

NO's 43 142 359

SO2 0.3 430 731

Part. 2 36 1333

Greenhouse effect:

Methane = CO2 × 20-25!


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Pipelines (DK; EU)

LNG ships (terminals)

liquid: -161° (1/600)

flammable only in 5-15% fuel/air ratio

Methane - a Natural Gas

Transport of NG

Over land


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Methane - a Natural Gasterrorist threat?


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Gas Extraction Project

Kibuye Stage 1 Power Limited (KP1)


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Kibuye Stage 1 Power Limited (KP1)

Public-Private-Partnership GoR and Dane Associates

Build-Own-Operate basis

Production and processing plant 198,000 m3 methane/day

35 MW power plant

Deliver to national grid at 5.25 US¢/kWh(33 øre/kWh!)

49 year gas concession from GoR to Daneat Gisenyi & Kibuye - up to 200 MW


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COWI A/S hired by World Bank Independent Engineer

Review of KP1 project (by HAZOP's)

Pilot platform Gisenyi

KP1 production platform

9 km pipeline to shore

Power plant

Transmission & substation design;Network capability

Estbl. Expert Committee on Lake stability


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Expert Committee -work by internet & meetings


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Expert Committee

Establish Expert Committee charge

address concern that lake could erupt

independent report on lake stability

influence from KP1

needs and recommendations for: monitoring & supervision of lake stability

complement or dovetail EIA

Draft Report early April


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Facts and supposition on Lake Kivu

Deep water gas establ. 1935

Numerous scientific expeditions

Dangerous; exploitable

CO2 and CH4


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Facts and supposition on Lake Kivu

Deep water gas establ. 1935

Numerous scientific expeditions

Dangerous; exploitable

CO2 and CH4© Dr. Klaus TIETZE


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Methane deposits in Lake Kivu

Main CH4 basin

4 "non-productive"

Cumulated gas volume (km3)

Depth(m)


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Scientific expeditions and evidences

45 y production; Gisenyi

5 M m3 water & 1.5 M m3(STP) CH4/year

© Dr. Klaus TIETZE © Dr. Klaus TIETZE

German expedition 1974/75Numerous profilesDensity measurements

Tietze 1978, 2000


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Scientific expeditions and evidences

Lahmayer & OSAE, 1998Bathymetric survey

Halbwachs, Tietze, Lorke, Mudeharanwa 2002(Mt. Nyiragongo eruption; sub-water lava inflow)

Schmid, Halbwachs, Wehrli2003/4; New profilesSchmid et al 2004, 2005

Support from WB, UN, EU, GoR, GoC and NGO's


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Sources of gasgeological - chemical -biological

Magmatic CO2 from active volcanoes

Decomposition of organic matter

Bacterial reduction of magmatic CO2???

Assisted by heat flux and ground water flow


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Methane concentration with time

d(m)

CH4 (mmol/l)

Schmid et al. (2004)

Partial pressure (MPa)

Over 30 years: 15-20% increase in methane

Decreased stability with CH4 as "detonator"


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Vertical profiling

Tell tales: Temperature - conductivity - density

depth

[m]

1.00510.0

0

4850.9950.0

density without pressure effect [g/cm³] -- in-situ density [g/cm³]electrical conductivity [mS/cm]

0.021.0

1000.031.0

pressure [dbar]temperature [°C]

L A K E K I V U– main basin –

© Dr. Klaus TIETZE

HL1

GL3HL4

GL4

HL5

GL5

HL6GL6HL7

GL1

HL2

GL2

HL3

HL1

GL3HL4

GL4

HL5

GL5

HL6GL6HL7

GL1

HL2

GL2

HL3


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Gradients and stability

BiozoneDeep water

Mixing Limited mixing

d(m)

Temperature [°C]

Density: temperature - concentration - pressure

Mixing: molecular -temperature -external winds

Change: trigger event


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Gradients and stability

Temperature [°C]

d(m)

Temperature [°C]

Double diffusive layering (heat/salt diffus.=100)

Influence by global warming?


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Density gradients and stability

H L 1

G L 3H L 4

G L 4

H L 5

G L 5

H L 6G L 6H L 7

G L 1

H L 2

G L 2

H L 3

s tab ility [10 -6 / m ]

© D r. K laus T IE T Z E

L A K E K I V U- m a in b as in -

0 100

d(m)

(δρ/δz)/ρ [10-6/m]


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Capping layers - "flexible lids"

H L1

G L3H L4

G L4

H L5

G L5

H L6G L6H L7

G L1

H L2

G L2

H L3

s tab ility [10 -6 / m ]

© D r. K laus T IE T Z E

L A K E K I V U- m a in b as in -

0 100

Biozone

Major gas deposit

d(m)


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Eruption risks

Gas accumulationin lake

Gas accumulationin sediment

Volcanic activity


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Eruption risks



Volcanic activity

Earthquakes


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Eruption risks



Volcanic activity

Earth quakes

Gas extraction per se or malfunction

Others dropping anchor -unidentified mech.


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Sizes and consequences of eruptions


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Sizes, causes and consequences of outbursts

Moderate local Large scale Catastrophic 100-10 000 m3 1 km3 300 km3

Tsunami wave

Spont. erupt. sediment

Accidental rupture of prod. pipe

Lava inflow >2002 eruption

Closer to sat. point + trigger

Combinations

Eruption at lake bottom

Large scale lava inflow

Major earthquake

10's 10 000's Millionsplatform downwind val. entire "valley"


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Production & stability forecast

0

25

50

75

100

1950 2000 2050 2100 2150

Year

p/psat

(%)

current

3 "KP1"

6 "KP1"


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Production & stability forecast

Significant uncertainties - BUT

No action ⇒ catastrophe 2166

1 "KP1" - insufficient measure

3 "KP1" - production "forever"

6 "KP1" - production to 2200

Political challenge/choice

Production "forever"risk at current level

"empty" lakeeruption risk eliminated

0

50

100

1950 2050 2150


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Experience from Lake Monoun

Lake Monoun - Total Gas Pressure (bar)

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8

Dep

th (

m)

20032006saturation line

Pipe Inlet


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Experience from Lake Monoun

Lake behaves as bath tub

To eliminate risk pipe near bottom

Gradient layer sinks

Gradient layer "sharpens"


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Monitoring - actions


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Monitoring - actions

Action planning for stability of lake– Amount of extraction -

more plants

– Re-injection water quality position vs. capping layers

– CO2 management

"Save the world" -"safeguard project"– Separate & inter-connected


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Recommended actions

Establish Monitoring Group long-term benefits & stability– Ministries, outside consultant,

professors, sponsors

Commission Baseline studyIndependent scientific team

Set up local Institute– Scientists from Rwanda-Congo

Commission repeats of Baseline study (5-10 years)


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Scope for Monitoring Group

Initiate Baseline studyevaluate outcome

Set up Local Institute & define scope– Approval from GoR and GoC

– Manning - equipmenttraining - reporting

– Evaluate annual reports

Re-evaluate production conditions"forever" or "emptying"

Initiate regular updates of Baseline study & evaluate


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Monitoring - Baseline studyeliminate/reduce errors and uncertainties

Baseline study (external)– reproducible, repeatable

parameters for action plan

– Establish comparable data trend - single event

– All inclusive for decision making - 10 year updates

– Use staff at Local Institutetraining

– Hand over equipment for continuous monitoring


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Monitoring - Local Instituteeliminate/reduce errors and uncertainties

Scope for Local InstituteContinuous monitoring

– Frequent CTD profiling around extraction point(s)(for Developer)

– Annual profiling in Lake Kivu(for Steering Committee)

Other activities– Volcanic, earthquake monitoring

– Check influence of "events"

– Improve meteorological data

– Fish yield


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Monitoring -impact of "KP1"

Extract water:7.5 105 m3/day at -320 m

Produce CH4: 2.3 105 m3 /day

Re-inject water below bio-zone (-90 m)

Overall small impact(25 - 50% CH4 recharge/y)

Project monitoring to fit overall programme


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Environmental issues at large

Extraction benefits the environment

Panoramic beauty Virunga range deceitful

Nyiragongo (2002-2004) sulphur gas release = all other in the world

Per day: 17,000 - 24000 t (up to 57,000 t)


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Environmental issues at large

Volcanoes orders of magnitude worse

Acid rain and destruction of crops in large area


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Future work


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Future work

Activity Action Time

Review EC-report IFC/WB April

Review of IE-report IFC/WB May

Final issue EC 15/5opinion and report

Follow Pilot Plant testing IE July/Aug.

Proposal for further work IE Ongoing

KP1 production Dane 2007


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Conclusion by IE & EC


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Conclusion by IE & EC

Technical Evaluation Report

No drastic conclusions

Project will function as designed

EI observations basis for improvements

Expert Committee Report

Based on risks, environment & economy

Only viable option is: gas extraction

Venting the gas: worse from all points

To do nothing is unacceptable (criminal)

ticking bomb or rwanda's salvation · lake nyos limnic eruption disaster 1986 > 1700 killed...

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