Methane Emissions

Natural sources

Major natural sources include wetlands, termites and release from onshore and offshore geological sources. Recently, living vegetation has also been suggested as an important natural source of CH4. Of the globally significant sources of CH4 to the atmosphere, natural sources are currently outweighed by anthropogenic sources. Together they emit some 582Tg CH4 each year, with 200Tg arising from natural sources (Denman et al, 2007). Given the estimated global CH4 sink of 581Tg per year, the...

Biogeochemistry of methane production

Methane Rice Fields

Methane production in natural wetlands, and in rice paddies, is a process occurring in strictly reduced (anoxic) conditions (see also Chapter 2). The creation of these conditions is controlled by both chemical and microbiological soil properties (Conrad, 1989a, 1993 Neue and Roger, 1993). Aerobic, drained soils become completely anoxic after flooding because of the barrier to entry of atmospheric oxygen presented by the water layer the rate of diffusion of oxygen and other gases through water...

Methanogenic archaea

Formate Methanogenesis

Methanogens are microorganisms that produce CH4. They are strictly anaerobic and belong to the archaea. They are a phylogenetically diverse group, classified into five established orders Methanobacteriales, Figure 2.1 General scheme of the anaerobic digestion process Figure 2.1 General scheme of the anaerobic digestion process Methanococcales, Methanomicrobiales, Methanosarcinales and Methano-pyrales, and further divided into 10 families and 31 genera (Liu and Whitman, 2008). Methanogens have...

The potential for VAM processing

As the air volumes that must be processed for abating VAM emissions are very large, the modularity of the processing system is important. VOCSIDIZERs are arranged in groups of four units on two levels in a so-called 'VAM cube', each capable of processing 250,000m3 h-1 of ventilation air. Large installations consist of multiple VAM cubes, each with a footprint of approximately 500m2 (Figure 12.3). Figure 12.3 An installation of two VOCSIDIZER 'VAM cubes' for processing 500,000m3 hof coal mine...

Sedimentary seepage

Climate Bakhar

Gas seepage in sedimentary hydrocarbon-prone (petroliferous) basins includes low-temperature CH4-dominated (generally around 80-99 per cent v v) gas manifestations and exhalations related to the following four classes 2 onshore seeps (independent of mud volcanism) 4 offshore (submarine) macro-seeps (including seafloor mud volcanoes). Such gas manifestations have historically been an important indicator of subsurface hydrocarbon accumulations, and still drive the geochemical exploration for...

National greenhouse gas emission inventories

To facilitate the reporting and review within the framework of the Climate Convention, credible and comparable data from countries are needed. Therefore, the IPCC in collaboration with the UNEP, WMO, the International Energy Agency (IEA) and the OECD have developed draft Guidelines for National Inventories of Greenhouse Gas Emissions and Sinks. These Guidelines were officially adopted by the Parties to the Convention as the common methodology for national inventories. The draft guidelines have...

Rice production

Thailand Rice Production Statistics

Rice is grown under a variety of climatic, soil and hydrological conditions in the world, from northeastern regions of China (53 N) to southern regions of Australia (35 S) and from sea level to altitudes of more than 2500m. It grows well in flood-prone areas of South and Southeast Asia (in as much as 5m of floodwater) and in drought-prone upland areas of Asia, South America and Africa (Neue and Sass, 1994). Nowadays, more than 90 per cent of the harvest area of rice is located in monsoon Asian...

Field measurement of landfill methane emissions and laboratoryfield measurements of methane oxidation

Flu Box Landfil Surface Methane

Unlike for CH4 emissions and oxidation in wetlands, soils and rice production systems during the last two decades, there have not been comprehensive regional field campaigns addressing landfill CH4 emissions. In large part, because landfills are discrete sites dispersed across the landscape, field campaigns to date have focused on specific sites and have rarely included multiple seasons or years. Previous summaries, mostly for small-scale (chamber) measurements, have reported positive emission...

Experimental laboratory studies

The earliest laboratory study reporting an emission of CH4 from leaves was conducted in the late 1950s at the Academy of Sciences of Georgia (Tbilisi) on emissions of volatile organic compounds (VOCs) from leaves of willow and poplar tress (Sanadze and Dolidze, 1960). In that study, mass spectrometric analysis was used to scan the volatile emissions of leaves incubated in 1.5 litre glass containers. Based on their mass spectra they concluded that plants released CH4 as well as ethane, propane,...

Factors influencing methane production in anaerobic systems

Of course, the amount of CH4 formed in anaerobic systems largely depends on the nature of the substrates present. Table 10.1 gives a few examples of the biogas or CH4 production from different substrates determined in laboratory experiments. For the anaerobic conversion of organic compounds, the amount Table 10.1 Typical biogas or methane production potential at 35 C of different (co)substrates (days) (m3 kg-1 VS) (m3 CH4 kg-1 VS) Source Braun (2007) Pabon Pereira (2009) of CH4 that is produced...

Existing and evolving tools and models for landfill methane generation oxidation and emissions

Historically, at the time of the first full-scale landfill gas recovery and utilization projects (1975-1980), predictive tools were developed to estimate the theoretical quantity of recoverable CH4 for commercial gas utilization projects (for example see EMCON Associates, 1980). These tools generally had two forms (1) empirical 'rule of thumb' calculations for the annual recoverable CH4 based on the mass of waste in place, or (2) theoretical firstorder kinetic models of various forms that were...

Natural gas losses

With natural gas being composed of 90 per cent CH4, its loss to the atmosphere during extraction, processing and supply can represent a significant component of local and national CH4 emissions budgets. Globally, such natural gas-related CH4 emissions are estimated to result in the emission of 25-50Tg CH4 yr-1 (Wuebbles and Hayhoe, 2002) and on a par, if not greater than, losses due to coal mining. In 2007 in the US, CH4 emissions from natural gas systems totalled 104Tg CO 2-eq, making this...

The geographical distribution of biomass burning

The locations of biomass burning are varied and include tropical savannas, tropical, temperate and boreal forests, and agricultural lands after the harvest. The burning of fuelwood for domestic use is another source of biomass burning. Global estimates of the annual amounts of biomass burning from these sources are estimated in Table 7.2 (Andreae, 1991). Table 7.2 Global estimates of annual amounts of biomass burning and of the resulting release of carbon to the atmosphere Table 7.2 Global...

The global methane budget

The global CH4 budget is composed of a wide range of sources (see Table 1.1 and also Figure 4.5 in Chapter 4) balanced by a much smaller number of sinks, any imbalance in these sources and sinks resulting in a change in the atmospheric concentration. There are three main sinks for CH4 emitted into the atmosphere, with the destruction of CH4 by hydroxyl (OH) radicals in the troposphere being the dominant one. This process also contributes to the production of peroxy radicals, and it is this that...

Introduction and background

Landfill CH4 accounts for approximately 1.3 per cent (0.6Gt CO2-eq yr1) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49Gt (Monni et al, 2006 US EPA, 2006 Bogner et al, 2007 Rogner et al, 2007). For countries with a history of controlled landfill-ing, landfills can be one of the larger national sources of anthropogenic CH4 for example, US landfills are currently the second largest source of anthropogenic CH4 after ruminant animals (US...

References

Abichou, T., Chanton, J., Powelson, D., Fleiger, J., Escoriaza, S., Lei, Y. and Stern, J. (2006a) 'Methane flux and oxidation at two types of intermediate landfill covers', Waste Management, vol 26, no 11, pp1305-1312 Abichou, T., Mahieu, K., Yuan, L., Chanton, J. and Hater, G. (2006b) 'Effects of compost biocovers on gas flow and methane oxidation in a landfill cover', Waste Management, vol 29, pp1595-1601 Babillotte, A., Lagier, T., Taramni, V. and Fianni, E. (2008) 'Landfill methane fugitive...

Domestic wastewater

Methane emissions from domestic wastewater for each treatment system or discharge step can be calculated using a default maximum CH4 producing capacity (B0) that is corrected by multiplication with the methane correction factor (MCF) of the wastewater treatment system used. From the MCFs in Table 10.2 it becomes clear that recovery of CH4 in such systems is very important. The total amount of degradable organics in the wastewater (TOW) is corrected for organics removed as sludge (S) and the...

Global vegetation emissions and related uncertainties

The first extrapolations from laboratory measurements to the global scale (Keppler et al, 2006) suggested that vegetation could constitute a substantial fraction (62-242Tg yr-1) of the total global emissions of CH4 (see Introduction). This large figure was derived by using mean sunlit and dark emission rates for leaf biomass scaled by day length, duration of growing season and total net primary productivity (NPP) in each biome. Alternative extrapolations of the same data were subsequently...

Methane oxidation

Part of the CH4 produced by methanogens is consumed by CH4-oxidizing bacteria, or methanotrophs. It is known that microbially mediated CH4 oxidation, in particular aerobic CH4 oxidation, ubiquitously occurs in soils and aquatic environments, where it modulates actual CH4 emission (for example Conrad, 1996b). In rice paddy fields, it is possible that a part of the CH4 produced in anaerobic soil layers is oxidized in aerobic layers such as the surface soil-water interface and the rhizosphere of...

Wetland emission estimates

Global emissions of CH4 from wetlands range between 100 and 231Tg CH4 yr1 in six studies reviewed by Denman et al (2007), which is to be compared with a range of global total sources ranging from 503 to 610Tg CH4 yr1. Regardless of all uncertainties, and common for all these studies, is that wetlands is placed as the largest single source of atmospheric CH4, even when considering all anthropogenic emissions. It is interesting to note that the mean estimate and variation between wetland emission...

Anaerobic reactor systems

Solid waste and wastewater may be treated on-site or transported to a centralized wastewater treatment plant or digester. Anaerobic treatment may be one of the first steps in the treatment of such waste streams. Technologically, a distinction can be made between 'low-rate' systems with long hydraulic retention times and 'high-rate' systems in which the hydraulic retention time is relatively short (de Mes et al, 2003). Septic tanks are also commonly used for house on-site treatment but these...

Impact of water management

Figure Cultivation Rice

As indicated above, CH4 production is a process occurring under anaerobic conditions in strictly reduced (anoxic) conditions. For such conditions to establish, soils usually have to be flooded or completely waterlogged for at least several days without interruption. During drier periods oxygen enters the soil, redox potentials rapidly increase again and CH4 production ceases. This is often the case in rainfed rice production, where CH4 emissions are on average only about one third of those in...

Emissions from manure

Phone Tree Template

There are several ways to treat manure that is produced on a farm (Figure 10.4). Emissions from manure related to storage, treatment and handling are also a result of anaerobic fermentation processes, which partially take place due to the presence of enteric bacteria that are excreted into the manure by the animals. On-site or central digestion is a recognized pathway for the treatment Figure 10.2 Maximum solubility of methane at different temperatures Source Data for Henry's constant taken...

Emissions from wastewater

Wastewater may be of domestic or industrial origin. The degree of treatment varies. Wastewater may be discharged directly in (coastal) surface water or treated prior to discharge (Figure 10.5). Wastewater in developed countries is usually treated in conventional centralized aerobic treatment plants. Industrial wastewater may be treated (in-plant) for process water recirculation and prior to discharge. Depending on the nature of the industry this treatment may also be anaerobic. Wastewater from...

Conclusions trends and broader perspectives

Landfill CH4 is a small contributor to global anthropogenic greenhouse gas emissions. The broader implementation of cost-effective landfill gas recovery and utilization systems can achieve additional reductions in landfill CH4 emissions. Moreover, landfill gas utilization can assist local communities by providing renewable energy benefits to offset fossil fuel use. Methanotrophic CH4 oxidation in cover soils, in association with the transport limitations provided by the cover materials,...

Impact of rice cultivation systems

Rice is a unique crop in that it is highly adaptable and can be grown in very diverse environments (Yoshida, 1981). The ecosystems within which rice is grown may be characterized by seasonal change of temperature, rainfall pattern, depth of flooding and drainage, and by the adaptation of rice to these agroecological factors. In addition, the degree of water control available is a useful tool to classify rice ecosystems because it characterizes management design for improving productivity (Huke...

Global emission estimates

Global Estimates Emissions Species

Global emission estimates for natural geological CH4 sources are listed in Table 4.1 the latest estimates are also summarized in Figure 4.4. Figure 4.4 Estimates of methane emissions from geological sources Source Based on data from Etiope et al (2008) Figure 4.4 Estimates of methane emissions from geological sources Source Based on data from Etiope et al (2008) For global submarine emission estimates, a dual approach was utilized based on the seep flux and on the amount of geological CH4...

Methane from landfills

Methane is formed in landfills by methanogenic microorganisms (methanogens). The CH4 generation is higher with a high organic matter content. The CH4 is formed over a shorter time period where there is a higher content of easily degradable material, such as fruit and vegetable waste. The CH4 emission shows a time lag after the point at which waste is landfilled. The CH4 emission in time can be estimated by a simple first-order decay function. Research in The Netherlands, in which measured...

Scalingup calculations and global CH4 budgets

Procubitermes

Scaling-up calculations by Martius et al (1996), Sanderson (1996), Bignell et al (1997) and Sugimoto et al (2000) used differing assumptions and principles, but all four agree that CO2 fluxes by termites are in the range 2-5 per cent of the total from all terrestrial sources. 2 per cent is a large figure for a single insect order with about 0.01 per cent of the global terrestrial species richness, but is nevertheless only a minor source in the context of the whole C budget. With CH4 emission,...

Some questions and clarifications

What about abiogenic non-volcanic methane A third, apparently minor, category can be attributed to emissions of abiogenic (inorganic) CH4 in non-volcanic areas. These emissions may derive from low-temperature (non-hydrothermal) serpentinization processes and mantle degassing through deep faults (Abrajano et al, 1988 Sano et al, 1993 Hosgormez et al, 2008). Although several onshore areas of abiogenic seepage are known (for example in Turkey, the Philippines and Oman), fluxes have been studied in...

Methane combustion and flaring

Ideally, any CH4 generated during wastewater treatment and the digestion of solid wastes like manure and domestic sewage sludge should be recovered and used as an energy source. There are incentives from governments to promote the use of biologically generated CH4 as a replacement for natural gas. However, in most cases the biogas generated in digesters is used for electricity generation with combined heat and power (CHP) generators. In most European countries electricity from biogas is...

Oilrelated emissions

The geological formation of oil can result in large CH4 deposits (as natural gas) being closely associated with the oil reserves. During drilling and subsequent extraction, the trapped CH4 may therefore be released to the atmosphere in large quantities. Oil itself only contains trace amounts of CH4 and so the bulk (97 per cent) of related CH4 emissions is likely to occur at the oil fields, rather than during refinement (3 per cent) and transportation (1 per cent) (US EPA, 2006). Global...

Ventilation air methane

Methane in air is explosive at concentrations between 5 per cent and 15 per cent. Safety is achieved by balancing concentrations sufficiently below or sufficiently above this range. To address this coal mine CH4 safety issue, large volumes of ventilation air are pushed through mines in order to dilute the CH4 released down to safe levels i.e. below the lower explosion limit (LEL). This leads to concentrations of VAM of 1 per cent or lower. However, the high volumes of ventilation air being...

Sources of methane emissions from natural gas and oil infrastructure

Natural gas and oil infrastructure accounts for over 20 per cent of global anthropogenic CH4 emissions. Methane gas emissions occur in all sectors of the natural gas and oil industries, from drilling and production, through to processing and transmission, to distribution and even end use as a fuel. The natural gas infrastructure is composed of five major segments production, processing, transmission, storage and distribution. The oil industry CH4 emissions occur primarily from field production...

Methane emission reductions from natural gas

Methane emissions from fossil fuel exploration could potentially increase in the near future. While looking for unconventional fossil fuel resources, CH4 hydrates have recently attracted increasing attention. As each cubic metre of Table 13.1 Country reported CH4 emissions from oil and gas for 1990 and 2000, and a scenario for 2010 Table 13.1 Country reported CH4 emissions from oil and gas for 1990 and 2000, and a scenario for 2010 CH4 hydrate contains up to 170m3 of CH4 gas, the CH4 hydrate...

Global impacts of biomass burning

On an annual global basis, biomass burning is a significant source of gases and particulates to the atmosphere. The gaseous and particulate emissions produced during biomass burning are dependent on the nature of the biomass matter, which is a function of the ecosystem and the temperature of the fire, which is also ecosystem dependent. In general, biomass is composed mostly of carbon (about 45 per cent by weight) and hydrogen and oxygen (about 55 per cent by weight), with trace amounts of...

Role of organic matter and nutrients

In rice cultivation, as in any other form of agriculture, it is necessary to sustain soil fertility by returning plant nutrients to the soil. Plant residues, green manure from intercrops or the aquatic plant Azolla and its associated N-fixing blue-green alga Anabaena azollae, human faeces and animal manure are the most important forms of organic fertilizers used in rice crops. Since the 'green revolution' in the 1960s introduced new varieties with increased yields and nutrient requirements,...

Net methane efflux from termites

Termites (worker caste) isolated in the laboratory have been reported to produce CH4 at rates ranging from undetectable levels to 1.6pmol g-1 h-1 (Brauman et al, 1992 Bignell et al, 1997 Nunes et al, 1997 Sugimoto et al, 1998a, 1998b). Zimmerman et al (1982) first drew attention to the potentially large quantities of CH4 emitted by termites. Their estimates were 75-310Tg yr-1, equivalent to 13-56 per cent of global sources. However, subsequent estimates of annual CH4 emissions from termites...

Successful demonstration of VAM processing

The only VAM technology that has so far proven to be commercially feasible on a large-scale basis is a system at the West Cliff Colliery of BHP Billiton, Australia (Somers and Schultz, 2008). The installation is called WestVAMP (West Cliff Colliery Ventilation Air Methane Plant) and is based on the VOCSIDIZER technology developed, patented and supplied by MEGTEC Systems. Using VAM at a concentration of 0.9 per cent, high-grade steam is generated and used to drive a conventional power plant...

Which options are available to reduce methane emissions and what are the costs of the options

Various authors have made estimates of the costs of measures per tonne of CH4 emission reduction. With some technical measures, CH4 emissions can be significantly reduced and experience of these measures has been developed in actual CH4 reduction projects. A body of literature is available on measures to reduce CH4 (for example AEAT, 1998 IEA, 1999 Hendriks and de Jager, 2000 De la Chesnaye and Kruger, 2002 Graus et al, 2003 Gallaher et al, 2005 Delhotal et al, 2005 Harmelink et al, 2005)....

Option 22 Reduction ofbiodegradable waste to landfill

Waste to landfill can be reduced by recycling, open composting, closed composting or incineration. Paper recycling is the most profitable option with a 'cost' of - 2200 per tonne reduced CH4. Option 23 Reduction ofbiodegradable waste to landfill by composting or incineration Open composting is expensive with a cost of 1000 per tonne reduced CH4. Incineration of waste costs 1423 per tonne reduced CH4 and 'closed composting' costs as much as 1800 per tonne reduced CH4.

Fossil fuel exploitation

For CH4 emissions from fossil fuel exploitation it is assumed that the most profitable measures would be taken first. Therefore, increased maintenance is assumed at a 'cost' of- 200 per tonne CH4 in 1990 and increased on-site use of otherwise vented gas at a cost of - 100 in 2000 and 2025. Other measures are taken later in time at a cost of 100 in 2050, 200 in 2075 and 300 in 2100. In 1990, the introduction of improved inspection and maintenance is assumed. In 2000 and 2025 extra measures are...

Kyoto Protocol

Further reductions of greenhouse gases after 2000 were negotiated in Japan in 1997 in the Kyoto Protocol. An average reduction of greenhouse gas emissions of 5 per cent between 1990 and the commitment period of 2008 to 2012 was agreed between the industrialized nations. Europe agreed to a reduction of 8 per cent, Japan 7 per cent and the US 6 per cent. The US later withdrew from the Kyoto Protocol, but the Kyoto Protocol came into force in February 2005 following ratification by Russia. A major...

Introduction

Sources of atmospheric CH4 in the biosphere have until recently been attributed to originate from strictly anaerobic microbial processes in wetland soils and rice paddies (Chapters 3 and 8), the guts of termites and ruminants (Chapters 5 and 9), human and agricultural waste (Chapter 10), and from biomass burning (Chapter 7), fossil fuel mining (Chapter 12) and geologic sources including mud volcanoes and seeps (Chapter 4). However, in early 2006, Keppler et al published a surprising report of...

On the determination of characteristics and costs of emission reduction options

In this section, a number of issues important for the assessment of greenhouse gas emission reduction options will be considered. I start with some definitions and then discuss the possibilities to estimate the costs of reduction technologies. The options can be evaluated using supply curves. Two types of measures can be distinguished that reduce (with respect to a given baseline development) the emissions of greenhouse gases efficiency improvements and volume measures. Efficiency improvement...

Methane inventories

For CH4, comprehensive inventory methods are currently at a relatively early stage of development, and results still have wide uncertainty ranges. Part of this problem is associated with the difficulty in translating local flux measurement results into emissions estimates for larger areas, such as countries or continents. Another part of the problem is related to the complexity of processes involved in biogenic production of CH4, for example, by microorganisms in anaerobic soils (Chapter 2)....

Cost estimates of six reduction strategies

The total cost estimates for the different reduction packages are estimated relative to the baseline reduction strategies P1 and Q1. The cost estimates are given in terms of US 1990 for six time steps between 1990 and 2100. The estimates beyond 2025 must be interpreted with caution because the reduction strategies P1 and Q1 are based on a number of important implicit assumptions about future economic policies at the macroeconomic and sectoral levels, Table 13.7 Worldwide costs in US 1990...

Methane and Climate Change

Dave Reay, Pete Smith and Andr van Amstel First published in 2010 by Earthscan Copyright Dr David R. Reay, Professor Pete Smith and Dr Andr van Amstel, 2010 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as expressly permitted by law, without the prior, written permission of the publisher. Earthscan Ltd, Dunstan House, 14a St Cross...