GLOBAL BANKING & MARKETS

Modelling and Potential of Negative Emissions Technologies, including Biomass-Enhanced CCS (BECCS)

D. Pignatelli, C. Sorensen, N. Mac Dowell N. McGlashan, M. Workman, N. Shah, P. Fennell p.fennell@imperial.ac.uk n.shah@imperial.ac.uk

• Scope of project

• Context

• Methodology

• Assessment of individual technologies

• Overall conclusions

• Next steps

Outline

Why Negative Emissions?

Set a ceiling price for emissions Reduces risk for hard-to-mitigate technologies

•  Initial scoping study to provide consistent potential and cost estimates for CO2 capture (negative emissions) technologies. – Supports comparison of feasibility and costs of particular technologies – Ramp up rates also included

•  Detailed model developed for two variants of promising technologies.

Scope of presentation

• Part of armoury of options to achieve 80% emissions reduction by 2050

• Key focus of UK 2050 targets is on mitigation (reduction) options – e.g. Demand reduction, supply decarbonisation

• However, negative emissions technologies are important: – where mitigation is not happening fast enough – where alternative abatement costs are too high – where non fossil fuel alternatives are not available – where lifestyle changes are too painful

• Some approaches to CO2 removal from the atmosphere could increase options available due to potential flexibility in location for deployment

Socio-Technological Context

• Class 1 = carbon positive CCS

• Class 2 = (near) carbon neutral CCS

• Class 3 = carbon negative CCS – Class 1: Usually producing hydrocarbons, CCS gets the carbon

footprint down to conventional hydrocarbon levels – e.g. LNG, coal-to-liquids, oil sands

• Class 2: Producing carbon free energy vectors: electricity, hydrogen or heat

• Class 3B: Biomass plus CCS (takes CO2 from the air)

• Class 3A: Technology to process air directly to capture CO2

CCS context: Class 1 – Class 2 – Class 3

Chalmers, H., Jakeman, N., Pearson, P. and Gibbins, J. (2009) “CCS deployment in the UK: What next after the Government competition?”, Proc. I.Mech.E. Part A: Journal of Power and Energy, 223(3), 305-319.

• For each potential option – Undertake a detailed thermodynamic analysis (in appendices, not

in draft report) – Undertake other relevant analyses

– Siting – Feedstock availability – Scaling up issues – Economics (capital and operating) – Ramping and associated constraints

– Summarise constraints

• Data for analyses are taken from public domain sources; some show very large variations in ranges (e.g. Biomass availability)

Initial Scoping Study – 6 potential options

• BECCS

• Artificial Trees

• Lime Soda process

• Augmented Ocean Disposal

• Biochar

Initial Scoping Study – 5 potential options

• Stage of development – most advanced of air capture technologies – Individual components have been built and test for some time

•  Key advantages – Strong economic incentive: primary product is power (+ heat) – Effectively ready to deploy

• Mitigation potential – Depends on biomass sourcing: realistic UK system will use a % of imports

Technology 1: BECCS

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0

2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Carbon Trust (2005) Kilpatrick et al (2008)

UK Biomass Strategy (2007) E4 Tech (2009)

MtCO2/yr

• Potential: the ultimate figures of 4-15% of emissions reflect generating 9-32% of power demand this way

• Barriers to adoption – As for CCS technology and related regulatory framework generally – Impact of large scale biomass plantation – Clarity on direct/indirect land use effects – Competition from liquid fuels markets

• Next steps - R&D pilot and scale up

• Life Cycle Analysis

• ETI study

Technology 1: BECCS

Chosen for further modelling

The  TESBIC  project  (BECCS)  

Ini4al  Study  of  BECCS  op4ons.  

28 Options for BECCS screened. Included Short, medium, and long term options for CCS component, with different variations of gasification and combustion.

Technology 2: Artificial Trees

•  Stage of development – very early stage – Can they compete with “real trees”?

•  Key advantages - can in principle be put anywhere – Need low carbon power – Need access to CO2 sink – Water?

–  "It is worth noting that the evaporation of water inside the regeneration chamber is matched by a similar amount of condensation or adsorption of the water on the resin material.“

–  Also mention of brine

•  Cost estimates highly variable and with a lack of independent scrutiny – Network costs may be as much as technology costs (diffuse sources) – No primary product – will be a late stage solution

• Mitigation potential large due to location flexibility

• Next steps – await trials data

• Stage of development – very early stage

•  Key advantages – based on existing components

• But – Could be quite capital intensive (treats a very dilute system (air capture), needs

high T calciner) – Requires significant energy inputs – will need low carbon fuel or CCS – No primary product

• Barriers to adoption- clean energy input; distribution network; planning barriers

• Next steps – more detailed engineering/economic evaluation

Technology 3: Lime Soda Process

• Stage of development – lime production is long established and can be fitted with CCS “readily” – Ocean disposal less well understood

• Key advantages – no need for CO2 storage – Could be coupled with solids looping (CaCO3-based) BECCS – Economic rationale for the process; by-product spent sorbent could be used

• Mitigation potential is large due to large reserves of relevant minerals

• Barriers to adoption – clean production of lime, risks associated with assault on marine environment; public acceptance

• Next steps – LCA to understand whole-life emissions (mining, size reduction, transport, ...), environmental biology, ...

Technology 4: Augmented Ocean Disposal Processes

Chosen for further modelling, particularly when integrated with BECCS

• Stage of development – Quite advanced; ancient process

•  Key advantages – simple distributed technology, can produce multiple products (syngas, pyrolysis oil) in advanced configurations – Could “piggy-back” on transportation fuel production – Supports soil conditioning and can improve productivity

Technology 5: Biochar

• Stage of development – Quite advanced; ancient process

•  Key advantages – simple distributed technology, can produce multiple products (syngas, pyrolysis oil) in advanced configurations – Could “piggy-back” on transportation fuel production – Supports soil conditioning and can improve productivity

•  Issues as per BECCS + scale up/scale out – will probably just happen... somewhere

• Mitigation potential

Technology 5: Biochar

0.0

20.0

40.0

60.0

80.0

2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Carbon Trust (2005) Kilpatrick et al (2008)

UK Biomass Strategy (2007) E4 Tech (2009)

MtCO2/yr

Results from Initial Scoping Study

Technology No.

of u

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inst

alle

d/af

loat

Am

ortis

ed c

ost o

f un

its ($

/teC

O2)

Wor

k in

put (

PJ/

yr)

Hea

t inp

ut (P

J/yr

)

Cos

t of e

nerg

y ($

/teC

O2

)

Raw

mat

eria

l inp

ut

(M.t/

yr)

Raw

mat

eria

l cos

t ($

/teC

O2)

Long

-term

UK

pot

entia

l (M

.teC

O2/y

r)

Rol

lout

tim

e fo

r max

po

tent

ial o

r 10%

of

UK

’s

CO

2 (yr

)

Tota

l cos

t ($

/tonn

e CO

2)

Artificial Trees [Lackner, 2009]

Today: 500 m2 trees – @ $200,000ea . 158,000 186 64.7 N/A 12.4 min min theoretically

unlimited - 206.1

Future: 500 m2 trees – @ $20,000ea . 158,000 18.6 64.7 N/A 12.4 40.5

Soda/Lime Process [Keith et al., 2006]

Contactors – 110 m ø x 120 m . 204 11.2 15.5 N/A 3.0 min min theoretically

unlimited - 142.8 NaOH regeneration system . N/A 87.8 35.7 481 40.8

CQuestrate – CaO basis Calcination plants . N/A 61.6 N/A N/A N/A

- - theoretically unlimited 10 63.9

Bulk carriers – 360,000 DWT . 10 2.19 6.11 N/A 0.10

Biochar

400 t/day slow pyrolysis kilns . 60 - 2.41 (118.1) (74.9) 5.12 - 26.7 12.1

BECCS Raw materials . N/A - N/A N/A N/A

2.96 - 46.2 11.2 Power plants . N/A - (96.8) N/A (330.6)

“Target”

Overview of Detailed Model(s)

Post-Combustion Ca looping Integration with ocean liming (Cquestrate)

Combustion

Fuel Air

Exhaust Gases, inc CO2

Power

Integrated Model(s) of all technologies

•  Flowsheet implemented in Aspen Plus

• Separate blocks for Calciner, Carbonator, ASU, Turbines and CO2 compression

• Key assumptions – 95 % CO2 capture (a little high, but does not affect overall results too much)

• Refrigeration COP in ASU 3

• Basic steam cycle efficiency 42.1 % for coal power plant (both heat and turbine systems require further optimisation)

• CAPEX 25 % higher for biomass systems

• Biomass cost $70 / ton: Coal cost $110 / ton. LHVs 16.2 and 27.3 MJ/kg.

• CO2 compressed to 74 bar

• Pumping costs included where necessary

• Retrofit reduces efficiency (heat integration poor)

Key Features and Assumptions of Model

Warning! First Pass… Requires significant optimisation! Efficiency penalty currently significantly more than the optimised case. (14 % vs 6 – 7 % for fully heat-integrated new build plant).

•  All costs rebased to $2011 using capital cost escalation curve1 •  Power island and boiler costs from GCCI2

•  Ancillary costs from McKenzie et al 20073

•  Availability between 90 % (PF Coal) and 75 % (Biomass + CCS + ocean liming).

•  Individual units sized and costed

•  Other Assumptions

1IHS, 2011, IHS Indexes, Available at: http://www.ihsindexes.com/, last accessed: 24/04/11.

2Global CCS Institute Strategic Analysis of the Global Status of Carbon Capture and Storage Report 2: Economic Assessment of Carbon Captureand Storage Technologies) 3 MacKenzie, A., Granatstein, D.L., Anthony, E.J., and Abanades, J.C., Economics of CO2 Capture Using the Calcium Cycle with a Pressurized Fluidized Bed Combustor. Energy & Fuels, 2007. 21: p. 920-926.

Key Assumptions - economics

Raw materials (Limestone)   = 25 $/tonne  Raw material transportation   = 10% of RM  Labour/Overheads   = 10% of Variable  Utility Requirements   = 15% of Variable  Maintenace & Repairs   = 5% of fixed capital  

Supplies   = 15% of maintenance  

Basic Aspen Model

Two stage steam turbine Drying and Combustion (PF)

Ca Looping

New Turbine

Fuel Properties

26%  

28%  

30%  

32%  

34%  

36%  

38%  

40%  

42%  

44%  

22%  

24%  

26%  

28%  

30%  

32%  

34%  

0%   20%   40%   60%   80%   100%  

Process  Efficiency  w

ithout  CCS  

Process  Effi

cien

cy  with  CC

S    

Biomass  Heat  Input  (%)  

Process Efficiency

Glad to see Larry’s figures agree…

-­‐2,000  

-­‐1,500  

-­‐1,000  

-­‐500  

0  

500  

1,000  

0.050   0.060   0.070   0.080   0.090   0.100   0.110   0.120   0.130   0.140  

Emission

 Factor  (gCO

2/kW

h)  

COE  ($/kWh)  

Emission Factor and Cost of Electricity

Boiler Configuration

Calciner Configuration

Process Efficiency

Emission Factor (gCO2/

kWhe)

Average Emission Factor with Cquestrate (gCO2/

kWhe) Coal-fired - 42.4% + 762 - Co-fired - 40.9% + 507 - Biomass -fired - 39.4% 0 - Coal-fired Coal-fired 27.9% + 55 - 70 Coal-fired Co-fired 26.8% - 158 - 283 Coal-fired Biomass -fired 26.9% - 569 - 690

Co-fired Coal-fired 27.2% - 210 - 339 Co-fired Co-fired 26.5% - 431 - 564 Co-fired Biomass -fired 26.3% - 826 - 952

Biomass -fired Coal-fired 25.7% -719 - -862 Biomass -fired Co-fired 25.6% -934 - 1074 Biomass -fired Biomass -fired 24.6% - 1,404 - 1545

Emissions Factors with and without Cquestrate

Selected Results CombusEon  ConfiguraEon  

Calcium  Looping  (Y/N)  

Calciner  ConfiguraEon  

Cquestrate  (Y/N)  

Cquestrate  Type  

Emission  Factor  (gCO2/

kWh)  

Process  Efficiency  

(%)  

COE  ($/kWh)  

AC  ($/tco2)  

Coal  (100%)   N   762   42.4%   0.053  

Coal  &  Biomass  (50:50)   N   507   40.9%   0.057   15.1  

Biomass  (100%)   N   0   39.4%   0.063   12.6  

Coal  (100%)   Y   Coal  (100%)   N   55   27.9%   0.095   59.5  

Coal  (100%)   Y   Biomass  (100%)   N   -­‐569   26.9%   0.107   40.6  

Biomass  (100%)   Y   Coal  (100%)   N   -­‐719   25.7%   0.112   33.0  

Biomass  (100%)   Y   Biomass  (100%)   N   -­‐1,404   24.6%   0.124   28.4  

Coal  (100%)   Y   Coal  (100%)   Y   On-­‐site   -­‐71   27.6%   0.095   51.1  

Coal  (100%)   Y   Biomass  (100%)   Y   On-­‐site   -­‐696   26.6%   0.107   37.3  

Biomass  (100%)   Y   Coal  (100%)   Y   On-­‐site   -­‐869   25.5%   0.112   30.3  

Biomass  (100%)   Y   Biomass  (100%)   Y   On-­‐site   -­‐1,558   24.4%   0.125   26.7  

Biomass  (100%)   Y   Biomass  (100%)   Y   Remote   -­‐1,545   24.6%   0.129   28.9  

Cheaper to mitigate CO2 using biomass than by CCS (supply limited). The more biomass used, the lower the avoided cost (limited by technical issues for co-firing). CCS efficiency penalty a little high (12 %) – better heat integration required. On-site Cquestrate reduces costs further (~ $2 / tCO2 in the biomass / biomass case, ~ $8 in the coal / coal case).

• A range of technologies have been assessed for negative emissions potential

• Of these, BECCS was identified as a most promising option

• The unique synergy between BECCS and ocean liming has been investigated

• The cost of electricity from such plants has been estimated, and found to be more than doubled

• However, the cost of CO2 avoided can be ~ $25- $60 / tonne CO2

• Significant scope for optimisation within the model should bring this cost down further.

Conclusions