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

Transcription

1 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

2 Outline Scope of project Context Methodology Assessment of individual technologies Overall conclusions Next steps

3 Why Negative Emissions? Set a ceiling price for emissions Reduces risk for hard-to-mitigate technologies

4 Scope of presentation Initial scoping study to provide consistent potential and cost estimates for CO 2 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.

5 Socio-Technological Context 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

6 CCS context: Class 1 Class 2 Class 3 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 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),

7 Initial Scoping Study 6 potential options 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)

8 Initial Scoping Study 5 potential options BECCS Artificial Trees Lime Soda process Augmented Ocean Disposal Biochar

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10 Technology 1: BECCS 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 Mt CO2 /yr Carbon Trust (2005) Kilpatrick et al (2008) UK Biomass Strategy (2007) E4 Tech (2009)

11 Technology 1: BECCS 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 Chosen for further modelling

12 The TESBIC project (BECCS)

13 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.

14 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

15 Technology 3: Lime Soda Process 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

16 Technology 4: Augmented Ocean Disposal Processes 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,... Chosen for further modelling, particularly when integrated with BECCS

17 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

18 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 Mt CO2 /yr Carbon Trust (2005) Kilpatrick et al (2008) UK Biomass Strategy (2007) E4 Tech (2009)

19 Results from Initial Scoping Study Technology Artificial Trees [Lackner, 2009] No. of units installed/ afloat Amortised cost of units ($/te CO2 ) Work input (PJ/yr) Heat input (PJ/yr) Cost of energy ($/te CO2 ) Raw material input (M.t/yr) Raw material cost ($/te CO2 ) Long-term UK potential (M.te CO2 /yr) Rollout time for max potential or 10% of UK s CO 2 (yr) Total cost ($/tonne CO2 ) Target Today: 500 m 2 $200,000ea. 158, N/A theoretically min min unlimited - Future: 500 m 2 $20,000ea. 158, N/A Soda/Lime Process [Keith et al., 2006] Contactors 110 m ø x 120 m N/A 3.0 NaOH regeneration system. N/A min min theoretically unlimited CQuestrate CaO basis Calcination plants. N/A 61.6 N/A N/A N/A Bulk carriers 360,000 DWT N/A 0.10 Biochar - - theoretically unlimited t/day slow pyrolysis kilns (118.1) (74.9) BECCS Raw materials. N/A - N/A N/A N/A Power plants. N/A - (96.8) N/A (330.6)

20 Overview of Detailed Model(s) Fuel Air Combustion Exhaust Gases, inc CO 2 Power Post-Combustion Ca looping Integration with ocean liming Integrated (Cquestrate) Model(s) of all technologies

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22 Key Features and Assumptions of Model Flowsheet implemented in Aspen Plus Separate blocks for Calciner, Carbonator, ASU, Turbines and CO 2 compression Key assumptions 95 % CO 2 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. CO 2 compressed to 74 bar Pumping costs included where necessary Retrofit reduces efficiency (heat integration poor)

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

24 Key Assumptions - economics All costs rebased to $ 2011 using capital cost escalation curve 1 Power island and boiler costs from GCCI 2 Ancillary costs from McKenzie et al Availability between 90 % (PF Coal) and 75 % (Biomass + CCS + ocean liming). Individual units sized and costed Other Assumptions 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 = 15% of Supplies maintenance 1 IHS, 2011, IHS Indexes, Available at: last accessed: 24/04/11. 2 Global 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, : p

25 Basic Aspen Model New Turbine Drying and Combustion (PF) Two stage steam turbine Ca Looping

26 Fuel Properties

27 Process Efficiency Process Efficiency with CCS 34% 32% 30% 28% 26% 24% 44% 42% 40% 38% 36% 34% 32% 30% 28% Process Efficiency without CCS 22% 26% 0% 20% 40% 60% 80% 100% Biomass Heat Input (%) Glad to see Larry s figures agree

28 - 2,000 Emission Factor and Cost of Electricity Emission Factor (gco2/kwh) - 1,500-1, COE ($/kwh) 500 1,000

29 Emissions Factors with and without Cquestrate Boiler Calciner Configuration Configuration Process Efficiency Emission Factor (g CO2 / kwh e ) Average Emission Factor with Cquestrate (g CO2 / kwh e ) Coal-fired % Co-fired % Biomass -fired % 0 - Coal-fired Coal-fired 27.9% Coal-fired Co-fired 26.8% Coal-fired Biomass -fired 26.9% Co-fired Coal-fired 27.2% Co-fired Co-fired 26.5% Co-fired Biomass -fired 26.3% Biomass -fired Coal-fired 25.7% Biomass -fired Co-fired 25.6% Biomass -fired Biomass -fired 24.6% - 1,

30 CombusEon ConfiguraEon Calcium Looping (Y/ N) Selected Results Calciner ConfiguraEon Cquestrate (Y/ N) Cquestrate Type Emission Factor (gco2/ kwh) Process Efficiency (%) COE ($/ kwh) Coal (100%) N % Coal & Biomass (50:50) N % Biomass (100%) N % Coal (100%) Y Coal (100%) N % Coal (100%) Y Biomass (100%) N % Biomass (100%) Y Coal (100%) N % Biomass (100%) Y Biomass (100%) N - 1, % Coal (100%) Y Coal (100%) Y On- site % Coal (100%) Y Biomass (100%) Y On- site % Biomass (100%) Y Coal (100%) Y On- site % Biomass (100%) Y Biomass (100%) Y On- site - 1, % Biomass (100%) Y Biomass (100%) Y Remote - 1, % Cheaper to mitigate CO 2 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 / tco 2 in the biomass / biomass case, ~ $8 in the coal / coal case). AC ($/ tco2)

31 Conclusions 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 CO 2 avoided can be ~ $25- $60 / tonne CO 2 Significant scope for optimisation within the model should bring this cost down further.