CGE Greenhouse Gas Inventory Hands-on Training Workshop Energy Sector

1. CGEGreenhouse Gas Inventory Hands-on Training WorkshopEnergy Sector

2. Outline of course (continued) • Fugitives • References • Coal mining and handling • Oil and natural gas systems • Data issues

3. Energy Sector – Fugitive Emissions

4. Introduction • Fugitives: the sum of emissions from accidental discharges, equipment leaks, filling losses, flaring, pipeline leaks, storage losses, venting and all other direct emissions except those from fuel use • Mainly methane • Entrained CO2 can be significant in some cases • Minor N2O emissions from flaring

5. Sources of fugitives • Solid fuels (primarily coal) • mining, handling, processing and storage • Oil and natural gas systems • exploration, production, processing, refining, transmission, storage and distribution

6. Coal mining and handling • Release of trapped methane during mining • In-situ methane content of coal can vary widely • Most fugitive emissions occur at the mine • Some residual emissions occur from post-mining handling / processing activities

7. Surface vs. Underground • Two types of coal mines • Higher emissions for underground mines • Emissions increase with depth of mine • Emissions also depend on gas content of coal • Some gas may remain in the coal • 60%–75% gas released during mining activity

8. Abandoned mines • Emissions may continue after the mines have stopped producing coal • Typically, emissions decline rapidly once deep mine coal production stops • In some cases, emissions by the surrounding strata may be significant and continue for years afterwards. • Coal waste or reject piles are minor source of emissions • Flooding of mines can prevent emissions

9. Controlling emissions • Degasification wells • Gas conservation • Flaring • Use of catalytic combustors on the outlet of ventilation systems for underground mines

10. Monitoring and activity data • Methane content of exhausted ventilation air (Tier 3) • Coal production (Tier 1 or 2) • Imports and exports by type of coal • Post-mining emission, likely to be minor • Information on the depth of each mine (Tier 2)

11. Tier 1 and Tier 2 • Tier 1 global average emission factors • Tier 2 country or basin-specific emission factors based on actual CH4 content of coal mined

12. Tier 3: Underground mines • Underground mines generally must have ventilation and degasification systems for safety reasons • Often also degasification wells around mining area • Can use data to estimate emissions or to develop more specific emission factors • When methane recovery from degasification wells occurs before mining, emission should be reported in year coal was actually extracted

13. Coal mining issues… • Initial focus can be on most “gassy” mines for Tier 3 approach, and apply Tier 1 or 2 for other mines. • Tier 3 not likely to be feasible for surface mines or post-mining • Methane recovered and combusted for energy should be included in fuel combustion emissions • No inventory method provided for coal fires • Significant quantities of CO2 can also be released during mining

14. Coal mining data issues (cont.) • Coal statistics usually include primary (hard coal and lignite) and derived fuels (patent fuel, coke oven coke, gas coke, brown coal briquettes, coke oven gas and blast furnace gas). Peat may also be included. • No information is typically provided on the method of mining (i.e. surface or underground) or the depth of the mines. A conservative approximation is to assume that lignite coal is surface mined and bituminous and anthracite coal is from underground mines. • Some useful unpublished data, including mine depth, are available from IEA upon special request.

15. Coal mining references • Coal statistics are available for most countries from the • U.S. Energy Information Administration (EIA) <www.eia.doe.gov> • United Nations Statistics Department (UNSD) <http://unstats.un.org/unsd/> • International Energy Agency (IEA) <www.iea.org>

16. Oil and natural gas systems • Equipment leaks • Process venting and flaring • Evaporation losses (i.e. from product storage and handling, particularly where flashing losses occur) • Accidental releases or equipment failures

17. Emission rates depend on… • Characteristics of hydrocarbons being produced, processed or handled • Conventional crude oil • Heavy oil • Crude bitumen • Dry gas • Sour gas (more than 10 ppmv of hydrogen sulphide (H2S)) • Associated gas • Equipment numbers, type and age • Industry design, operating and maintenance practices • Local regulatory requirements and enforcement i.e., methane content of fuel and leakiness of equipment

18. Emissions from venting and flaring depend on… • The amount of process activity • Operating practices • On-site utilization opportunities for methane • Economic access to gas markets • Local regulatory requirements and enforcement

19. Accidental releases… • Difficult to predict • Can be a significant contributor • Can include: • Well blowouts • Pipeline breaks • Tanker accidents • Tank explosions • Gas migration to the surface around the outside of wells • Surface casing vent blows • Leakage from abandoned wells

20. Size of the facility • Oil and gas systems tend to include many small facilities • Exceptions • Petroleum refineries • Integrated oil sands mining and upgrading operations • Small facilities likely to contribute most of the fugitive emissions • Less information available for smaller facilities

21. Oil / Gas composition Raw natural gas and crude oil contains: • a mixture of hydrocarbons • various impurities including H2O, N2, argon, H2S and CO2 • Impurities are removed by processing, treating or refining H2S • Sour gas if more than 10 ppmv of H2S • Sweet gas if less than 10 ppmv of H2S • The concentration of H2S tends to increase with the depth of the well

22. Acid gas • By-product of the sweetening process to remove H2S • May contain large amounts of raw CO2 • Regardless of how processed… • sulphur recovery unit • flared or vented • …the raw CO2 is released to the atmosphere

23. Patterns of emissions • Emissions increase as you go upstream through system • Emissions decrease with concentration of H2S in the produced oil and gas

24. Equipment leaks • Tend to be continuous emitters • Low to moderate emission rates • All equipment leaks to some extent • Only a few per cent of the potential sources at a site actually leak sufficiently at any time to be in need of repair or replacement. • If less than 2% of the total potential sources leak, the facility is considered well-maintained

25. Sources of equipment leaks • Valves • Flanges and other connections • Pumps • Compressors • Pressure relief devices • Process drains • Open-ended valves • Pump and compressor seal system degassing vents • Accumulator vessel vents • Agitator seals • Access door seals

26. Trends in equipment leaks • Less leakage as toxic nature of material increases • Less leakage where gas has been odorized (thus less leaking in sour gas sections of systems) • More leakage where equipment is subjected to frequent thermal cycling, vibrations or cryogenic service

27. Storage losses • Boiling or flashing losses of methane occur from storage tanks • Occurs at production and processing facilities where hydrocarbon liquid flows directly from a pressure vessel where it has been in contact with natural gas

28. Methodologies • Tier 3: Requires detailed inventories of equipment, infrastructure and bottom-up emission factors • Tier 2: Based on a mass balance estimate of the maximum amount of methane that could be emitted • Only for oil systems • Based on gas to oil ratios • Tier 1: Uses national oil and gas production data and aggregate emission factors

29. Fugitives data • Poor quality and incomplete data about venting and flaring is common • Contact industry representatives for standard practices to split venting and flaring • Data about equipment leaks at minor facilities is unavailable or incomplete • Well-site facilities • Field facilities

30. Fugitives data (cont.) • Collection of activity data for fugitives sources is difficult and resource intensive… • There are no real shortcuts available • First step can be to interview experts in industry on common practices and processes… • …have them compare national practices with those of countries with a known emissions profile (e.g. an Annex I country).

31. Venting and flaring data • Flared if gas poses an odour, health or safety concern • Otherwise vented • Often inconsistencies in vented and flared volumes reported by companies • Problem with some vented volumes being reported as flared

32. Oil and gas system data issues • International production data are expressed on a net basis (i.e. after shrinkage, losses, reinjection, and venting and flaring) • Crude oil normally includes hydrocarbon liquids from oil wells and lease condensate (separator liquids) recovered at natural gas facilities. May also include synthetic crude oil from oil sands and shale oil • Infrastructure data is more difficult to obtain than production statistics

33. Oil and gas system data issues (cont.) • Information on the numbers and types of major facilities, types of processes used at these facilities, numbers and types of active wells, numbers of wells drilled, and lengths of pipeline are typically only available from national agencies • Information on minor facilities (e.g. wellhead equipment, pigging stations, field gates and pump stations) may not be available, even from oil companies • The only infrastructure data potentially required for the Tier 1 method are well counts and lengths of pipeline • Facility information only required for IPCC Tier 3

34. Oil and gas system references • Other methodology manuals: • American Petroleum Institute (API) <www.api.org> • Canadian Association of Petroleum Producers (CAPP) <www.capp.ca> • Canadian Gas Association (CGA) <www.cga.ca> • Gas Technology Institute (GTI) <www.gastechnology.org> • Oil and gas statistics: • U.S. Energy Information Administration (EIA) <www.eia.doe.gov/neic/historic/hinternational.htm> • United Nations Statistics Division (UNSD) <http://unstats.un.org/unsd/methods/inter-natlinks/sd_natstat.htm and http://unstats.un.org/unsd/databases.htm> • International Energy Agency (IEA) <www.iea.org/statist/index.htm>

35. Oil and gas system references (cont.) • Oil and Gas Journal <www.ogjresearch.com>: • Some infrastructure data (number of wells, gas plant listing, major project announcements) • Worldwide refinery, pipeline and gas processing projects • Historical refinery, pipeline and gas processing projects • Worldwide oil field production survey • Worldwide refining survey • Worldwide gas processing survey • Enhanced oil recovery survey

36. Documentation & reporting • Transparency and documentation are the most important characteristic of national inventories! • Unless it is documented, then there is nothing to show that it was done or done correctly • Electronic reporting greatly facilitates the work of the UNFCCC Secretariat

37. Final remarks… A national inventory is not a research project… It is a national program that works closely with statistical and research institutions to create high quality emissions data.

38. Quiz 20 minutes

39. Quiz answers • Energy Quiz 1 (key).doc

40. Nitrogen Oxides (NOx) • Indirect greenhouse gases • Fuel combustion activities are the most significant anthropogenic source of NOx • Energy industries • Mobile sources • Two formation mechanisms: • "fuel NOx" • “thermal NOx"

41. Carbon monoxide (CO) • Indirect greenhouse gas • Majority from motor vehicles, but also from small residential and commercial combustion • Intermediate product of the combustion process

42. Non-Methane Volatile Organic Compounds (NMVOCs) • Indirect greenhouse gases • Product of incomplete combustion • Mobile sources and residential combustion, especially biomass combustion • Low emissions for large-combustion plants

43. Sulfur dioxide (SO2) • Aerosol precursor • May have a cooling effect on climate • Concentration increases with burning of fossil fuels that contain sulfur • Closely related to the sulfur content of fuels

44. Quiz 20 minutes

45. Quiz answers • Fugitives Quiz 1 (key).doc

47. EFDB exercise • Look up available CH4 emission factors for biomass–agricultural wastes used for any type of fuel combustion… http://www.ipcc-nggip.iges.or.jp/EFDB/find_ef_s1.php

48. EFDB search results

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