Methods for detecting and quantifying leakage emissions of carbon dioxide and methane using atmospheric measurements at fixed locations

Transcription

1 Methods for detecting and quantifying leakage emissions of carbon dioxide and methane using atmospheric measurements at fixed locations David Etheridge CSIRO Oceans and Atmosphere Flagship CSIRO Energy Flagship CO2CRC IEA GHG MONITORING NETWORK AND MODELLING NETWORK COMBINED MEETING MORGANTOWN, WV, USA, AUGUST 2014

2 ATMOSPHERIC MONITORING in Geologically Storing Carbon: Learning from the Otway Project Experience, P. Cook (ed.), CSIRO Publishing, Also: Andrew Feitz (Geoscience Australia), Matthias Raab (CO2CRC), Padarn Wilson (ANU)

3 Atmospheric monitoring of land-air emissions The atmospheric domain is an important part of a monitoring program Health and safety, regulatory, carbon accounting, public assurance Verify whether CCS is a viable climate mitigation measure Continuous, unattended, not invasive, economical Must distinguish CCS CO 2 from background, especially ecosystem Potentially detect, attribute and quantify potential leakage How to verify techniques in the absence of real CCS leakage?

4 Climate mitigation and CCS leakage Max leak 0.01% per year for sustainability (Enting et al., 2009, Shaffer, 2010, Haughan and Joos, 2004) Less than 0.01% per year very likely (IPCC 2005) ~1000 tco2/yr for a 10 Mt CO2 store

5 CO2CRC Otway Project Micromet, fluxes Continuous concentrations CO2, CH4 Flask sample isotopes, tracers 65 kt fluid injected ~20% M CH4

6 Arcturus atmospheric station No CCS proceeded CH4 emissions from coal mines

7 CO2 and CH4 concentrations Otway and Cape Grim injection

8 CO2 and CH4 concentrations Arcturus

9 Background concentration variations C = C B + C L Several approaches to find C B : Cape Grim baseline station (Tasmania) Cape Grim plus ecosystem and dispersion model (TAPM-CABLE) Statistical model (Arcturus data) Cape Grim and filtered Otway data removing stable and high ecosystem flux periods Otway pseudo upwind (filter and wind sectors) Otway 2-point monitoring All are approximations

10 Modelled concentration perturbations 1000 tco2/yr 700 m away IJGGC 2008

11 Coupled ecosystem-dispersion model Clean Air Society Perth 2008

12 Background variations and filtering Filter criteria: Wind direction WD: clean air sector (south east to southwest) Friction velocity, u*: dispersion Ecosystem flux, Fc Shortwave radiation, SW: Proxy of stability and ecosystem flux

13 Filtered CO2 and CH4 concentrations Otway and Cape Grim

14 Histograms Otway (filtered) background (Cape Grim CO2) Pre-inject Post-inject

15 Pseudo upwind background for 1-point monitoring

16 Pseudo upwind background histograms

17 Source sector background (pseudo upwind) CO 2 at CRC-1 Sample only CH 4 at CRC-1 Tracer at 16.7% Molar tpd CH tpd CH tpd CH4 Similar for Naylor Sample only

18 Forward model simulations with analytical dispersion model Gives estimate of emission for given ΔCO2 (this example: neutral stability) 1000 tonnes CO2 /year = 32 g CO2 /s (~2 metres)

19 background = pseudo upwind CO 2 at CRC-1 Sample only CH 4 at CRC-1 Tracer at 16.7% Molar tpd CH tpd CH tpd CH4 Similar for Naylor Sample only

20 Kolmogorov-Smirnoff (KS) test Using CO 2 measurements Significant detection Significant detection Using CH 4 measurements as tracer of CO 2

21 Bayesian analysis: posterior distribution of source strength Posterior PDF tonnes 1 day 7 CRC 1 6 Naylor :1 decisive threshold CO 2 measurements Posterior PDF tonnes 1 day tonnes CO 2 per day CRC 1 Naylor 100:1 decisive threshold CH 4 measurements as tracer of CO Equivalent tonnes CO 2 per day

22 Bayesian upper limits on source strength Source area CRC-1 Naylor CO 2 t CO2/day CO 2 using CH 4 as tracer t CO2/day CH 4 t CH4/day

23 Pre-inject post inject background = filtered Otway LoFlo CO2 pseudo upwind

24 Assumptions, strengths, limitations of filter/pseudo upwind method Prior knowledge needed of likely source region Background source locations constant Ecosystem fluxes can vary (hours to years) Slow to accumulate evidence Suitable for long term surveillance Once detected, leak can be further investigated, located and quantified (e.g. Using multi point network, flux monitoring...)

25 2-point monitoring and Bayesian analysis of Otway controlled release LOCATING AND QUANTIFYING GREENHOUSE GAS EMISSIONS AT A GEOLOGICAL CO 2 STORAGE SITE USING ATMOSPHERIC MODELING AND MEASUREMENTS JGR in press 2014 Ashok K. Luhar 1,4,, David M. Etheridge 1,4, Ray Leuning 2,4, Zoe M. Loh 1,4, Charles R. Jenkins 3,4, Eugene Yee 5 Corresponding author: A. K. Luhar, CSIRO Marine and Atmospheric Research/Centre for Australian Weather and Climate Research, Station Street, Aspendale, Victoria, 3195 Australia. (Ashok.Luhar@csiro.au)

26 Conclusions One point monitoring can provide sensitive long term surveillance of leakage Suitable way to estimate the background Needs continuous measurements of concentration and meteorology Detection, quantification, location more powerful with CH4 CH4 in fluid CH4 in reservoir natural gas, coal gas, unconventional gas emissions or other tracer (continuously measured) Follow up detection with techniques to quantify, locate leak Multiple point monitoring is better if possible