CCS: South African (Eskom) context

Presentation to the Octavius CCS conferenceBy Gary de Klerk

18 November 2015Rev1.1

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Content of the presentation

About Eskom

CO2 in South Africa

Base case plants for Octavius

The water challenge

D13.4 findings

D25.2 integration

Conclusion and Way forward

About Eskom Holdings SOC Ltd

• Strategic 100% state-owned electricity utility, strongly supported by the government

• Supplies approximately 95% of South Africa’s electricity

• Performed 159 853 household electrification connections during the year

• As at 31 March 2015:– 5.3 million customers (2014: 5.2

million) – Net maximum generating capacity

of 42.0GW – 17.4GW of new generation

capacity being built, of which 6.2GW already commissioned

– Approximately 368 331 km of cables and power lines

– 41 787 employees in the group (2014: 46 919)

Nuclear

Gas

Coal

Hydro

Pumped Storage

Generation capacity – 31 March 2015

85.1%5.7%

4.4%3.4%1.4%

42.0GWof nominal capacity

Electricity sales

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1.4%, [1.4%]

7.0%, [6.8%] 13.8%, [14.1%]

5.4%, [5.1%]

5.5%, [5.7%]

24.7%, [25.1%]42.1%, [41.9%]

Residential

Industrial

International

Electricity volumes by customer type1

Commercial and agricultural

Municipalities

Mining

Rail

• Declining electricity volumes (0.7% below prior year) were largely caused by:

o Impact of industrial action in platinum sector

o Contraction in the gold mining sector

o Closure of the Bayside aluminiumsmelter

o Depressed commodity prices

• Load shedding led to sales of 548GWh being foregone

• Independent Power Producer capacity of 1.8GW is connected and providing power to the grid

Environmental performance (as at 31 March 2015)

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Water 2014/15 2013/14 2012/13

Specific water consumption, l/kWh sent out 3 1.38RA 1.35RA 1.42

Net raw water consumption, Ml 313 078 317 052 334 275

EmissionsCarbon dioxide (CO2), Mt 4 223.4 233.3RA 227.9

Sulphur dioxide (SO2), kt 4 1 834 1 975RA 1 843

Nitrous oxide (N2O), t 4 2 919 2 969 2 980

Nitrogen oxide (NOx) as NO2, kt 5 937 954RA 965

Particulate emissions, kt 82.34 78.92RA 80.68

Relative particulate emissions, kg/MWh sent out 4 0.37RA 0.35RA 0.35

WasteAsh produced, Mt 34.41 34.97RA 35.30

Ash sold, Mt 2.5 2.4 2.4

Ash (Recycled), % 7.3 7.0RA 6.8

Asbestos disposed, tons 991.0 458.0 374.6

National GHG Trajectory (Source DEA)

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Storage Potential (Compiled by Council for Geoscience, 2010)

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Octavius Base Cases

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Units

800MWe Bituminous Coal Case

(DOOSAN/E.ON)

ROAD Project (E.ON)

Porte Tolle(ENEL)

South African

New Build(ESKOM)

South African

CO2capture Retrofit

(ESKOM)Gross Electrical power output

MWe gross 819 1107 660 817 798

Steam Parameters MS/HR/bar 600/620/270 600/620/285 604/612/252 600/610/260 560/570/245

Capture Plant Size MWe 819 250 250 817 400

Five base cases were selected for evaluation within the OCTAVIUS project with the 800MWe advanced supercritical bituminous coal case being the lead case for this project

Ambient Conditions

2015/11/20 9

1.100 MWFurnace: 17m x 24m

PS Medupi, 800 MWFurnace: 16m x 23m

800 MW EUFurnace: 16m x 19m

Ambient Site Conditions EU Case South African Case

Ambient Temperature °C 15 23.7

Ambient RelativeMoisture % 60 50

Ambient Pressure(absolute) mbar 1,013 913

Flue Gas Volume Flows Am3/h 2,585,590 3,258,213

Cooling Medium Temperature °C 18.2 23.7 (dry cooling)

Condensing Pressure (absolute) mbar 48 133

Lower efficiency and larger air/gas volumes

Bigger plant to achieve the same output

=

Water Conservation

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What

Water Conservation

How Why

▪ Reduction in process water consumption/losses

▪ Cascading of water from high to low quality without the discharge of liquid effluents (ZLED)

▪ Absorption of liquid effluents by ash

▪ Evaporation of effluents during bottom ash quenching & evaporation from wet ash dams

▪ Incorporate effluent concentration treatment steps in the process

▪ Reduced pollution levels in surface and ground water

▪ All new coal fired power plants will be dry cooled

▪ Direct Dry Cooling (ACC)

▪ Indirect Dry Cooling (tower)

Water consumption reduced from 2 l/kWh to:

▪ < 0.2 l/kWh without FGD

▪ < 0.4 l/kWh with wet FGD

Water conservation“the environmental impact of any such strategically important activities must still beminimised or preferably avoided by means of technological, institutional, or mitigatorymanagement practices” Department of Water Affairs

Forced Draught Dry Cooling

11 (Source: Octavius D25.2 and GEA)

Site conditionsAmbient temperature 33°CAtmospheric pressure near ground level 84.04 kPa (a)

Approximate dimensionsHeat exchanger bundle face area 2800 m2

Heat exchanger platform footprint 3220 m2

Key parametersRequired duty 203.4 MWthInitial temperature difference (ITD) 22°CRange 14°CCold water temperature 55°CHot water temperature 69°CNumber of fans 112Total fan power 3.28 MWTotal pumping power 0.95 MW

Dry Cooling: Design for range of CW temperature

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Optimised post combustion capture

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Flow Diagram CO2 post combustion capture including split flow and lean vapourcompression option (source: Octavius D13.4)

Performance (Source: Octavius D13.4)

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Integration: New Build & Retrofit Case

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(Source: Octavius D25.2)

Reboiler

CO2Condenser

Retrofit Interface Considerations

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(Source: Octavius D25.2)

• Layout including dry cooling system and major pipelines (Steam pipeline, Cooling water ducts, Condensate)

• Modification of IP/LP cross over pipes

• Turbine water ingress protection

• Steam conditioning at the reboiler end of the steam line – desuperheatingusing condensate

• Heat integration: Retrofit case – CO2 stream is limiting thermal capacity, but cooling water system of CO2 condenser still necessary to allow for transient condensate flow?

• Risk analysis of potential leaks from one stream to another must be investigated

Thermocompressors: Option to eliminate throttling at IP/LP crossover

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(Source: Octavius D25.2)

1. Cold reheat extraction to boost the IP/LP cross over pressure at loads of 60% and 40% to avoid throttling at the IP/LP cross over.

2. Combining the IP/LP cross over flow with lower pressure LP extraction steam at 100% and 80% load to improve efficiency of the extraction.

3. IP extraction 2 to boost the IP/LP cross over pressure at loads of 60%.

4. IP extraction 1 to boost the IP/LP cross over pressure at loads of 40% (The motive pressure of IP extraction 2 was too low to perform this duty at 40% load.)

Thermocompressors: Option to eliminate throttling at IP/LP crossover

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1

2

3

4

Thermocompressors: Performance

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(Source: Octavius D25.2)

• Thermocompressor including actuator approx. 100 k€.

1

2

3

4

New Build: Undersize LP turbine

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(Source: Octavius D25.2)

New Build: Undersize LP turbine

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(Source: Octavius D25.2)

• LP turbine exhaust annulus area from 4 x 5.5m2 to 2 x 8.4m2 (-24%.)• Capital cost saving 1.7% of owner’s total project cost. (Estimated using

PEACE software by Thermoflow inc.)

Conclusions

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• No significant limitations identified for post-combustion capture technical feasibility

• This work still requires assumptions still to be refined by:• Further process design across range of conditions and operating

scenarios• Preliminary layout• Scoping the extent of all modifications and equipment required

(compression, transportation and storage included)• Review with original equipment manufacturers

Way forward

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• The South African government published a Draft Carbon Tax Bill for public commentwith a view to it becoming law in 2016. The tax will be phased in over a period of time toallow for smooth transition in adopting cleaner and more efficient technologies;

• Eskom could achieve up to 80 % of its emissions exempted for the first phase of theimplementation of Carbon Tax;

• The immediate opportunity is linked to thermal efficiency improvement (1-2 years);• Initiatives like BAPEPSA and biomass co-firing can be the medium term solution (2-5

years);• CCS can be seen as a long term opportunity to reduce emissions (+10 years);• Long term goals will be achieved by the following initiatives:

• National CCS standard development and definition of “carbon capture ready”(ISO/TC 265 CCS);

• Implementing of the Roadmap for CCS in South Africa (SACCCS) addressinggeological storage potential;

• Establishing a National Carbon Capture Pilot Plant in South Africa for local andregional skills development.

Thank you