Synthesis

Tremblay, Alain; Varfalvy, Louis; Roehm, C. L.; Garneau, Michelle

doi:10.1007/978-3-540-26643-3_27

Cited by 10 publications

(22 citation statements)

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“…Xiangxi Bay of TGR has an approximate CH 4 flux to the Middle Yangtze River 24 , both of which are in the subtropical climate zone. CH 4 fluxes in the TGR are much smaller than those data from water bodies of tropical zone such as Petit Saut and Miranda 33 34 , but larger than those from the reservoirs in temperate zone and frigid zone such as Quebéc and Lokka 6 11 . This verifies that CH 4 emissions were correlated to latitude 3 .…”

Section: Discussionmentioning

confidence: 68%

Methane formation and consumption processes in Xiangxi Bay of the Three Gorges Reservoir

Wang

Xiao

et al. 2014

Sci Rep

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Indoor simulation experiment was carried out to evaluate the formation and consumption rates of methane (CH4) in Xiangxi Bay of the Three Gorges Reservoir (TGR), China. The results show that both the CH4 formation and consumption rates were significantly positively correlated with temperature. CH4 efflux decreased with rising temperature due to its potential increasing oxidation rate. CH4 oxidation in surface sediments accounted for 51.8% of the total production and it even reached to 77.4% at 35°C. The methane oxidation rate in water column ranged from 1.26 to 4.65 mg/(m2h), of which the average and greatest rate accounted for 46.7% and 73.9% of CH4 production respectively under the condition of 30 m water column and 35°C. The methane oxidation may increase by 41.04 mg/(m2h) under average water level of TGR (160 m), and most methane resulted from sediments can be oxidized in the water column.

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Section: Discussionmentioning

confidence: 68%

Methane formation and consumption processes in Xiangxi Bay of the Three Gorges Reservoir

Wang

Xiao

et al. 2014

Sci Rep

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“…Bubbles come as bursts and not as a steady flow, with uneven bubbling events estimated contain a significant proportion of the total amount of methane released. , Gas transport can also be mediated by aquatic plants, macrophytes . Methane bubbles are usually measured using funnels or eddy covariance or echosounders …”

Section: Climate Impact Of Hydropowermentioning

confidence: 99%

“…It is important to understand that emissions vary in time and space due to spatial features, weather, and seasonal effects. , A proper assessment has to address these variations through measurements that extend over seasons, ideally supplemented with modeling exercises that serve to build a mechanistic understanding of the processes involved. , Emissions also change over the lifetime of the reservoir. It is well recognized that emissions are highest in early years and decrease as the initially flooded biomass has decayed.…”

Section: Climate Impact Of Hydropowermentioning

confidence: 99%

Addressing Biogenic Greenhouse Gas Emissions from Hydropower in LCA

Hertwich¹

2013

Environ. Sci. Technol.

158

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The ability of hydropower to contribute to climate change mitigation is sometimes questioned, citing emissions of methane and carbon dioxide resulting from the degradation of biogenic carbon in hydropower reservoirs. These emissions are, however, not always addressed in life cycle assessment, leading to a bias in technology comparisons, and often misunderstood. The objective of this paper is to review and analyze the generation of greenhouse gas emissions from reservoirs for the purpose of technology assessment, relating established emission measurements to power generation. A literature review, data collection, and statistical analysis of methane and CO2 emissions are conducted. In a sample of 82 measurements, methane emissions per kWh hydropower generated are log-normally distributed, ranging from micrograms to 10s of kg. A multivariate regression analysis shows that the reservoir area per kWh electricity is the most important explanatory variable. Methane emissions flux per reservoir area are correlated with the natural net primary production of the area, the age of the power plant, and the inclusion of bubbling emissions in the measurement. Even together, these factors fail to explain most of the variation in the methane flux. The global average emissions from hydropower are estimated to be 85 gCO2/kWh and 3 gCH4/kWh, with a multiplicative uncertainty factor of 2. GHG emissions from hydropower can be largely avoided by ceasing to build hydropower plants with high land use per unit of electricity generated.

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“…There is growing interest and concern regarding greenhouse gas emissions, mainly carbon dioxide (CO 2 ) and methane (CH 4 ), from lakes and reservoirs − . Organic-rich sediments in lakes and reservoirs are thought to be ‘hot spots’ of methanogenesis in particular, from which CH 4 can escape to the atmosphere via four major pathways - ebullition (bubbling), surface diffusion, advection through plants, and exposure of anoxic CH 4 -rich deep waters to the atmosphere during convective mixing events (turnover) .…”

Section: Introductionmentioning

confidence: 99%

Extreme Methane Emissions from a Swiss Hydropower Reservoir: Contribution from Bubbling Sediments

DelSontro

Mcginnis

Sobek

et al. 2010

Environ. Sci. Technol.

251

213

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Methane emission pathways and their importance were quantified during a yearlong survey of a temperate hydropower reservoir. Measurements using gas traps indicated very high ebullition rates, but due to the stochastic nature of ebullition a mass balance approach was crucial to deduce system-wide methane sources and losses. Methane diffusion from the sediment was generally low and seasonally stable and did not account for the high concentration of dissolved methane measured in the reservoir discharge. A strong positive correlation between water temperature and the observed dissolved methane concentration enabled us to quantify the dissolved methane addition from bubble dissolution using a system-wide mass balance. Finally, knowing the contribution due to bubble dissolution, we used a bubble model to estimate bubble emission directly to the atmosphere. Our results indicated that the total methane emission from Lake Wohlen was on average >150 mg CH(4) m(-2) d(-1), which is the highest ever documented for a midlatitude reservoir. The substantial temperature-dependent methane emissions discovered in this 90-year-old reservoir indicate that temperate water bodies can be an important but overlooked methane source.

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Synthesis

Cited by 10 publications

References 0 publications

Methane formation and consumption processes in Xiangxi Bay of the Three Gorges Reservoir

Methane formation and consumption processes in Xiangxi Bay of the Three Gorges Reservoir

Addressing Biogenic Greenhouse Gas Emissions from Hydropower in LCA

Extreme Methane Emissions from a Swiss Hydropower Reservoir: Contribution from Bubbling Sediments

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