The Eskom UCG Experience

Presented at :

6th Annual CTL & Coal Gasification 2011 Conference

28th Feb to 1st Mar 2011, Brisbane, Australia

Chris GrossDr Mark Van der Riet

Corporate Services DivisionEskom Holdings LtdSouth Africa

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Content

1. Context

2. Eskom’s UCG Strategic Drivers

3. Majuba Coalfield, South Africa

4. Eskom UCG Program

5. Environmental Impacts

6. Risk Status

7. UCG Performance

8. Conclusions

Context

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Context

• Coal is one of South Africa’s largest primary energy resources.

• Eskom presently generates 88% of its electricity from coal.

• This predominance will decrease, with the introduction of alternative energy carriers to mitigate the impact of the continued usage of coal.

• Coal will however remain a predominant, albeit reducing primary energy carrier for the foreseeable future in RSA.

• Eskom has therefore run a comprehensive Clean Coal Technology research and development program for several decades, to explore, identify and demonstrate solutions for continued coal usage.

• Underground Coal Gasification (UCG) is one of the advanced clean coal technology options being demonstrated by Eskom

2012/02/28 52012/02/28 Eskom Holdings Limited Reg No 2002/015527/06 5

Context - Eskom Plant mix

TOTAL 27 stations 44 175MW

Type Number Nominal capacity

Wind energy 1 station 3MW

Coal-fired

Gas/liquid fuel

turbine

Hydroelectric

Pumped storage

Nuclear

13 stations

4 stations

6 stations

2 stations

1 station

37 755MW

2 426MW

661MW

1 400MW

1 930MW

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Context - Eskom Primary Energy

2009/10 : 246,566 GWh Net

Eskom’s UCGStrategic Drivers

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Eskom Strategic Direction

• Becoming a high performing organisation

• Leading and partnering to keep the lights on

• Reducing our carbon footprint and pursuing low carbon growth opportunities

• Securing our future resource requirements, mandate and the required enabling environment

• Ensuring our financial sustainability

• Setting up for success

Purpose : To provide sustainable electricity solutions to grow the economy and improve the quality of life of

people in South Africa and in the region.

Vision : One of the World’s Top 5 Power Companies

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Eskom’s UCG Strategic Drivers

1. Security of supply

2. Clean energy

3. Flexibility

4. Utilize Unminable Coal

5. Lower cost option

Lower C02

Emissions

Modularity, lead time

Competitive R/MWh

Potentially 350GWe

Baseload option

Better utilisation than conventional

mining

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Potential RSA Applications

27 Potential Sites

• RSA coal resources quoted at 194.4 Bt (1998, DME Bulletin 113)

• Eskom geological records for coal offers received but considered unminable coal = 45 Bt= potentially 350 GW

• The remaining coal resources :194.4 Bt – mined –minable = 100 Bt ?

Source : S Walker, Major Coalfields of the World, IEA CCC/32, June 2000

Majuba Coalfield,South Africa

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Majuba Colliery at closure : 1993

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Why choose Majuba for UCG ?

• Majuba coal field was found to be unminable by conventional means due to dolorite intrusions, heat affected coal and seam displacements

• Coal seam 280-300 metres deep

• Eskom owned the Mineral Rights

• Land used for cattle farming, and Eskom owns the farm land

• Study showed that gas could be co-fired with coal at Majuba power station giving a direct use for the gas.

• Study also showed that gas could be used as a fuel for a modern, high efficiency IGCC power station.

Dolorite intrusions

Majuba 4100MW power station

Eskom UCG Program

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Majuba UCG

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Eskom UCG Development Plan

2002

Scoping Study

2003

Pre-feasibility

Study

2005

Site

Characterisation

20th January 2007

Commissioned

5000 Nm3/h pilot plant

on Majuba coalfield

Done

To do

Current

28th October 2010

Commissioned

15000 Nm3/h co-firing into

Majuba power station

U2Comm

U3Comm

U4Comm

U5Comm

U6Comm

Commission

U1Comm

Apr 2009 Dec 2011 Sep 2015Mar 2015 Mar 2020 Sep 2022

ConstructionDesign

ConstructionDesign

Demonstration Plant

2100MW 1st Proof-of-Concept Plant

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UCG Project Progress

• UCG technology scan - April 2001

• Scoping study highlighted potential at Majuba colliery - Nov 2002

• Pre-feasibility study confirmed Majuba potential - Dec 2003

• Site characterisation study confirmed the potential - July 2005

• Commissioned a 3-5000 Nm3/h pilot plant - 20 Jan 2007

• First electricity generated from UCG gas at Majuba - 31 May 2007

Eskom flarestack – 20 Jan 2007

100 kW converted diesel gensetEskom has licenced UCG technology fromErgo Exergy Technologies Inc. (Canada)

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UCG Project Progress

Co-firing :

• Commissioned new co-firing gas treatment plant – Jun 2010

• Commissioned new 7km x 600mm NB pipeline to Majuba power station – Jun 2010

• Gas co-fired into Majuba U4 - 28 Oct 2010

UCG-OCGT demo plant :

• Design study underway for a demonstration plant comprising 250,000 Nm3/h gas production and a 100 – 140 MW gas turbine plant

15,000 Nm3/h gas

treatment plant

Gas Pipeline to Majuba

power station

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Eskom 100 – 140 MWUCG Demo Plant Layout

Water Wash Condensate

Removal

GasCompressor

Steam StrippingAmmonia Removal

Phenol Recovery

SulphurRemoval

Condensate

Gas H2S/NH3

Flue Gas

SCR NOX Abatement

Gas Turbine/

Generator

Raw Water

Phenols

Particulates and Oils

Sulphur

Pipeline - TXField PipingWells & Drilling

UCGTechnology

GeoSciences

Compressors

Air

Balanceof Plant

Electricity

Electricity

Water

Water

Emergency Flarestack

MajubaCo-fire

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UCG Phased Development

This figure explains UCG modularity, and the technology roll-out

Pilot Demo 1st Proof-of-Concept Plant

5-15,000 Nm3/h

250,000 Nm3/h

3,800,000 Nm3/h

100-140 MW OCGT Approx 250-350 MW CCGT per unit X multiple units = approx. 2100 MW

+ +

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1000 ha ?

Eskom UCG Expansion

5 ha ?

Gas Production Rate

& Investment :

Coal Resource Requirement :

The Demonstration and 1st Proof-of-Concept Plant will have a design life of 35 years. The Mineral Rights of both are required before

investing in the Demonstration Plant

The Demonstration and 1st Proof-of-Concept plant are extensions of the research initiated by

the Pilot Plant

Demo(250,000 Nm3/h)

Pilot(15,000 Nm3/h)

1st Proof-of-Concept

Plant(3,800,000 Nm3/h)

Environmental Impacts

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Environmental Impacts : Water

• Baseline water sampling performed of aquifers, including coal seam

• Water from surrounding aquifers monitored from shallow and deep boreholes, in concentric rings surrounding the process

• UCG is monitored extensively with piezometers (for measuring pressure & temperature)

• No UCG contamination evident

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Environmental Impacts : Air

• Baseline air quality tests done prior to UCG

• Permanent meteorological station on the UCG site monitors wind speed/direction, ambient temperature, barometric pressure

• Eskom’s continuous ambient emission monitoring stations monitor meteorological parameters, SO2, NO2, O3, PM10 etc.

• Additional comprehensive audit completed for : meteorological parameters, CO, CO2, SO2, H2S, NO, NO2, BTX, NH3, PM10 , PM2.5etc.

• Permanent monitoring site to be established

• UCG-IGCC promises a reduction in greenhouse gas emissions, compared to conventional power stations

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Environmental Impacts : Land

• Comprehensive plan in place with management and rehabilitation procedures. Regular audits done.

• Baseline flora & fauna survey and soil tests done prior to UCG starting up

• Majuba site shows natural vegetation re-establishes rapidly after drilling disruption

• Surface impact minimal post-gasification

• Subsidence is being monitored at Majuba using devices for conventional underground monitoring. The potential strata collapse has also been modelled.

• No subsidence observed yet.

Risk Status

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Risk Status – Feb 2011

Risk Rank Mitigation

Environmental HighMonitoring, design,engagement

Permitting &Licences

High Engagement

Cost Creep &Financial

Medium Project management

Resources &Skills

Medium Recruitment & training

ScheduleCreep

Medium Project management

UCG Performance

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Coal Seams

Majuba Seam Detail

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Eskom’s UCG Production Data

Operating Data - 20 Jan 2007 to 20 Jan 2011 :

• Total coal consumed/gasified = 34 663 tons

• Total gas produced = 131 719 400 m3

• A representative CV of the gas was 4.2 MJ/Nm3

• The average efficiency is 72 % (coal @ 20 GJ/ton)

• Current gas production rate = 11500 m3/hr (6768 cfm)

• Average well exit temperature = 168 ºC (344 ºF)

• Maximum well exit temp (normally temporary) = 430 ºC (806ºF)

• Average water consumption = 0.58 litre per kg of coal.

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UCG Gas Composition

• Gas composition varies with the lifetime of the production well, and between production wells.

• Gas composition depends on the operating parameters such as P and flow, and also on the design of the underground gasifier.

• Incorrect gasifier design or operation can result in the gasifier running in combustion mode.

• The final volume of gas is a blended average from several production wells.

UCG Gas - major components only

Composition (% by vol)

Hydrogen H2 15 - 19

Oxygen O2 0.2

Water Vapour H2O 5

Atm. Nitrogen N2 47 - 55

Carbon Monoxide CO 7 - 12

Carbon Dioxide CO2 17 - 19

Methane CH4 3 - 5

Calorific Value LHV MJ/Nm3 3.5 - 5.1

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Lessons Learnt

• UCG is not trivial. It requires a methodical implementation strategy, and extensive investment in skills to plan & execute, and capital.

• Eskom therefore licensed the UCG technology from Ergo Exergy Technologies Inc. (Canada)

• Base-level geological and hydrogeological data is essential, so a comprehensive prospecting program is required.

• Have several alternative sites to select from.

• Mining legislation in South Africa did not consider UCG when it was drafted, specifically whether it is legislated as gas extraction or coal mining.

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Lessons Learnt

• The quality of in-seam water is important, as this water comes to surface with the UCG gas, eg. the presence of chlorides can cause corrosion.

• The merging of mining, petrochemical and electricity industries requires a combination of laws (eg. MHSA and OHSA)

• Eskom adopted a phased investment approach, which has :

• Advantages : reduced investment risk, simultaneous learning process during development (both staff and stakeholders), technology optimisation

• Disadvantages : delayed implementation & delayed ROI

Conclusions

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Conclusions

• UCG is a promising clean coal option which allows the effective extraction and use of previously unminable RSA coal resources

• UCG has a role to play in the reduction of greenhouse gases and has possible potential for carbon capture and storage

• The Eskom UCG pilot has been operating reliably since Jan 2007 – 49 months and counting !!

• No environmental concerns have been noted to date

• Eskom has embarked on the phased research, development and demonstration of the technology, culminating in the 1st Proof-of-Concept Plant comprising approximately 2100 MW

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THANK YOU

Eskom UCG website URL :

http://www.eskom.co.za/c/14/underground-coal-gasification/