scholarly journals Toward consistency between bottom-up CO<sub>2</sub> emissions trends and top-down atmospheric measurements in the Los Angeles megacity

2015 ◽  
Vol 15 (20) ◽  
pp. 29591-29638 ◽  
Author(s):  
S. Newman ◽  
X. Xu ◽  
K. R. Gurney ◽  
Y.-K. Hsu ◽  
K.-F. Li ◽  
...  
Keyword(s):  
Los Angeles ◽  
Natural Gas ◽  
Co2 Emissions ◽  
Power Plants ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Fossil Fuel Combustion ◽  
Atmospheric Measurements ◽  
Bottom Up ◽  
Gasoline Taxes

Abstract. Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO2 contributions from fossil fuel combustion for both sites and broken those down into contributions from petroleum/gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena CO2 emissions from fossil fuel combustion during the Great Recession of 2008–2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. For natural gas, inferred emissions are out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but are consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 emissions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare emissions from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in fall and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA megacity domain when wind directions are considered.

scholarly journals Toward consistency between trends in bottom-up CO<sub>2</sub> emissions and top-down atmospheric measurements in the Los Angeles megacity

2016 ◽  
Vol 16 (6) ◽  
pp. 3843-3863 ◽  
Author(s):  
Sally Newman ◽  
Xiaomei Xu ◽  
Kevin R. Gurney ◽  
Ying Kuang Hsu ◽  
King Fai Li ◽  
...  
Keyword(s):  
Los Angeles ◽  
Natural Gas ◽  
Power Plants ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Fossil Fuel Combustion ◽  
Atmospheric Measurements ◽  
Bottom Up ◽  
Gas Combustion ◽  
Natural Gas Combustion

Abstract. Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO2 contributions from fossil fuel combustion (Cff) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena Cff during the Great Recession of 2008–2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. The trend of CO2 contributions to the atmosphere from natural gas combustion is out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but is consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 contributions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare Cff from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in autumn and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA megacity domain when wind directions are considered.

scholarly journals A global map of emission clumps for future monitoring of fossil fuel CO<sub>2</sub> emissions from space

2019 ◽  
Vol 11 (2) ◽  
pp. 687-703 ◽  
Author(s):  
Yilong Wang ◽  
Philippe Ciais ◽  
Grégoire Broquet ◽  
François-Marie Bréon ◽  
Tomohiro Oda ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Land Surface ◽  
Urban Areas ◽  
Power Plants ◽  
Fossil Fuel ◽  
Large Fraction ◽  
Point Sources ◽  
Bottom Up ◽  
Large Power ◽  
Data Product

Abstract. A large fraction of fossil fuel CO2 emissions emanate from “hotspots”, such as cities (where direct CO2 emissions related to fossil fuel combustion in transport, residential, commercial sectors, etc., excluding emissions from electricity-producing power plants, occur), isolated power plants, and manufacturing facilities, which cover a small fraction of the land surface. The coverage of all high-emitting cities and point sources across the globe by bottom-up inventories is far from complete, and for most of those covered, the uncertainties in CO2 emission estimates in bottom-up inventories are too large to allow continuous and rigorous assessment of emission changes (Gurney et al., 2019). Space-borne imagery of atmospheric CO2 has the potential to provide independent estimates of CO2 emissions from hotspots. But first, what a hotspot is needs to be defined for the purpose of satellite observations. The proposed space-borne imagers with global coverage planned for the coming decade have a pixel size on the order of a few square kilometers and a XCO2 accuracy and precision of <1 ppm for individual measurements of vertically integrated columns of dry-air mole fractions of CO2 (XCO2). This resolution and precision is insufficient to provide a cartography of emissions for each individual pixel. Rather, the integrated emission of diffuse emitting areas and intense point sources is sought. In this study, we characterize area and point fossil fuel CO2 emitting sources which generate coherent XCO2 plumes that may be observed from space. We characterize these emitting sources around the globe and they are referred to as “emission clumps” hereafter. An algorithm is proposed to identify emission clumps worldwide, based on the ODIAC global high-resolution 1 km fossil fuel emission data product. The clump algorithm selects the major urban areas from a GIS (geographic information system) file and two emission thresholds. The selected urban areas and a high emission threshold are used to identify clump cores such as inner city areas or large power plants. A low threshold and a random walker (RW) scheme are then used to aggregate all grid cells contiguous to cores in order to define a single clump. With our definition of the thresholds, which are appropriate for a space imagery with 0.5 ppm precision for a single XCO2 measurement, a total of 11 314 individual clumps, with 5088 area clumps, and 6226 point-source clumps (power plants) are identified. These clumps contribute 72 % of the global fossil fuel CO2 emissions according to the ODIAC inventory. The emission clumps is a new tool for comparing fossil fuel CO2 emissions from different inventories and objectively identifying emitting areas that have a potential to be detected by future global satellite imagery of XCO2. The emission clump data product is distributed from https://doi.org/10.6084/m9.figshare.7217726.v1.

Evaluating the Carbon Embedded in the US Public Water Supply

2011 ◽  
Author(s):  
Kelly M. Twomey ◽  
Michael E. Webber
Keyword(s):  
United States ◽  
Carbon Dioxide ◽  
Water Supply ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Public Water Supply ◽  
Fossil Fuel Combustion ◽  
The Us

The United States uses approximately 5% of its primary energy and 6% of its electricity to pump, convey, treat, distribute, heat, and recondition water in the US public water supply. Allocating this energy towards water has contributed to a national public water distribution system that is considered among the best in the world, providing its users with a clean and reliable water supply. This water supply, treated to stringent water standards defined by the Environmental Protection Agency’s Safe Drinking Water Act, has been critical to the health and livelihood of United States’ citizens. However, this energy-expenditure comes at an environmental cost, since the majority of water-related energy is derived from burning fossil fuels. Fossil-fuel combustion emits carbon-dioxide, a greenhouse gas that has become of concern in recent years because of its connection to anthropogenic climate change. The amount of carbon-dioxide that is emitted from fossil-fuel combustion is principally a function of the quantity and type of fuel that is burned for energy. This first-order analysis quantifying national water-related carbon dioxide emissions is the second in a series of several analyses by the authors, quantifying the energy and greenhouse emissions embedded in the US public water supply. Results indicate that water withdrawal, conveyance, treatment, distribution, end-use preparation, and wastewater treatment produces approximately 301 million metric tonnes of CO2 emissions annually. This quantity is 5.1% of total US CO2 emissions in 2009, which is approximately equal to emissions from the gasoline consumed by one-quarter of the US passenger fleet in the same year. Considering that the emissions associated with water for industrial, municipal and self-supplied sectors (such as agriculture) were not included in this analysis, the actual quantity of carbon emissions released as a result of water-related activities is likely to be higher. Consequently, identifying efficiency measures and conservation schemes to reduce the amount of water-related energy consumed in the US might be significant in achieving future greenhouse gas emission reduction goals.

Assessing the constraint of the CO2 monitoring mission on fossil fuel emissions from power plants and a city in a regional carbon cycle fossil fuel data assimilation system

2021 ◽  
Author(s):  
Thomas Kaminski ◽  
Marko Scholze ◽  
Peter Rayner ◽  
Sander Houweling ◽  
Michael Voßbeck ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Power Plants ◽  
Fossil Fuel ◽  
Spatial Scales ◽  
The Other ◽  
Model Parameters ◽  
Atmospheric Measurements ◽  
Co2 Monitoring ◽  
The Impact ◽  
Fossil Fuel Emissions

&lt;p&gt;The Paris Agreement foresees to establish a transparency framework that builds upon inventory-based national greenhouse gas emission reports, complemented by independent emission estimates derived from atmospheric measurements through inverse modelling. The capability of such a Monitoring and Verification Support (MVS) capacity to constrain fossil fuel emissions to a sufficient extent has not yet been assessed. The CO2 Monitoring Mission (CO2M), planned as a constellation of satellites measuring column-integrated atmospheric CO2 concentration (XCO2), is expected to become a key component of an MVS capacity.&amp;#160;&lt;/p&gt;&lt;p&gt;Here we present a CCFFDAS that operates at the resolution of the CO2M sensor, i.e. 2km by 2km, over a 200 km by 200 km region around Berlin. It combines models of sectorial fossil fuel CO2 emissions and biospheric fluxes with the Community Multiscale Air Quality model (coupled to a model of the plume rise from large power plants) as observation operator for XCO2 and tropospheric column NO2 measurements. Inflow from the domain boundaries is treated as extra unknown to be solved for by the CCFFDAS, which also includes prior information on the process model parameters. We discuss the sensitivities (Jacobian matrix) of simulated XCO2 and NO2 troposheric columns with respect to a) emissions from power plants, b) emissions from the surface and c) the lateral inflow and quantify the respective contributions to the observed signal. The Jacobian representation of the complete modelling chain allows us to evaluate data sets of simulated random and systematic CO2M errors in terms of posterior uncertainties in sectorial fossil fuel emissions. We provide assessments of XCO2 alone and in combination with NO2 on the posterior uncertainty in sectorial fossil fuel emissions for two 1-day study periods, one in winter and one in summer. We quantify the added value of the observations for emissions at a single point, at the 2km by 2km scale, at the scale of Berlin districts, and for &amp;#160;Berlin and further cities in our domain. This means the assessments include temporal and spatial scales typically not covered by inventories. Further, we quantify the effect of better information of atmospheric aerosol, provided by a multi-angular polarimeter (MAP) onboard CO2M, on the posterior uncertainties.&lt;/p&gt;&lt;p&gt;The assessments differentiate the fossil fuel CO2 emissions into two sectors, an energy generation sector (power plants) and the complement, which we call &amp;#8220;other sector&amp;#8221;. We find that XCO2 measurements alone provide a powerful constraint on emissions from larger power plants and a constraint on emissions from the other sector that increases when aggregated to larger spatial scales. The MAP improves the impact of the CO2M measurements for all power plants and for the other sector on all spatial scales. Over our study domain, the impact of the MAP is particularly high in winter. NO2 measurements provide a powerful additional constraint on the emissions from power plants and from the other sector.&lt;/p&gt;

Urban fossil fuel CO2 emissions from space: lessons learned from the OCO missions

2020 ◽  
Author(s):  
Thomas Lauvaux ◽  
Sha Feng ◽  
Ruixue Lei ◽  
Tomohiro Oda ◽  
Alexandre Danjou ◽  
...  
Keyword(s):  
Los Angeles ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Power Plants ◽  
Fossil Fuel ◽  
Urban Environments ◽  
Lessons Learned ◽  
Atmospheric Measurements ◽  
Gas Emissions ◽  
Fossil Fuel Emissions

&lt;p&gt;Pledges from nations and cities to reduce their carbon footprints have reinforced the needs for accurate and transparent reporting of fossil fuel emissions at various scales, with the ultimate goal of the establishments of carbon stocktake as defined by the Paris Agreement. But the assessment of anthropogenic emissions results primarily in collecting socio-economic indicators and emission factors, hence difficult to evaluate, track, or compare without a more standardized and robust methodology. Atmospheric measurements of greenhouse gases are of particular interests by offering an independent and global source of information thanks to satellite platforms observing continuously the atmospheric content of the major gases responsible for human-induced climate change. &lt;br&gt;&lt;br&gt;Based on lessons learned from the NASA Orbiting Carbon Observatory (OCO)-2 mission, we present the potential of satellite-based approaches to monitor greenhouse gas emissions from large metropolitan areas across the world (Riyadh, Lahore, Los Angeles). After exploring the technical aspects and challenges of the approach, potential aerosol contamination (CALIPSO), and model requirements, we introduce the upcoming capabilities from the follow-up mission, OCO-3, dedicated in part to urban emissions with the Snapshot Area Mapping mode, the first imagery of atmospheric CO2 concentrations for hundreds of targeted cities and power plants. Early snapshots are examined with high-resolution simulations over a handful of cities. The ongoing development of assimilation systems to inform policy makers about current trends and inter-annual variations is presented and discussed. We finally examine the potential roles and objectives of satellite missions by exploring recent trends in fossil fuel emissions along with proxies of air quality (MODIS) as a unique opportunity to track not only greenhouse gas emissions but more generally the evolution of urban environments.&lt;/p&gt;

Performance Influences of Hydrogen Enriched Fuel on Heavy-Duty Gas Turbines in Combined Cycle Power Plants

2015 ◽  
Author(s):  
Carl Georg Seydel
Keyword(s):  
Renewable Energy ◽  
Natural Gas ◽  
Fuel Consumption ◽  
Co2 Emissions ◽  
Power Plants ◽  
Fossil Fuel ◽  
Electricity Demand ◽  
Combined Cycle ◽  
Fossil Fuel Consumption ◽  
High Flexibility

In order to meet the ambitious reduction targets for future CO2 emissions and fossil fuel consumption, the extension of renewable power systems is mandatory. One main issue is the fluctuating and unpredictable availability of renewable energy. With a higher portion of renewable energy, a secure electricity supply becomes more challenging. On days with high electricity demand but low availability of renewable energy, fossil back up power plants with high flexibility and efficiency are needed. Most applicable for this requirements are combined cycle power plants, which provide both high flexibility and efficiency. On the other hand potential renewable energy is wasted during days with low electricity demand but high available renewable energy, because electricity cannot be stored yet economically in such vast amounts. In order to use the available renewable energy more efficiently, hydrogen could be produced via electrolysis during phases of surplus available renewable energy. The hydrogen serves as a high density energy storage, which can be used as an alternative fuel in combined cycle power plants for a highly efficient reconversion into electricity if necessary. In this study it is analyzed how the usage of hydrogen as the burner fuel will influence the performance of combined cycle power plants. Therefore the on- and off-design performance of a state of the art combined cycle power plant will be calculated at different ratios of hydrogen mixtures with natural gas. The thermodynamic calculations are made with the performance software GTlab of the German Aerospace Center. Furthermore the natural gas and CO2 savings for different hydrogen ratios will be quantified. The results show that the usage of hydrogen enriched fuel increases the combined cycle efficiency and power output. Accordingly a considerable reduction in CO2 emissions and fossil fuel consumption is possible.

scholarly journals Non-deforestation fire vs. fossil fuel combustion: the source of CO<sub>2</sub> emissions affects the global carbon cycle and climate responses

2016 ◽  
Vol 13 (7) ◽  
pp. 2137-2149 ◽  
Author(s):  
Jean-Sébastien Landry ◽  
H. Damon Matthews
Keyword(s):  
Carbon Cycle ◽  
Co2 Emissions ◽  
Fossil Fuel ◽  
Fire Regime ◽  
Terrestrial Ecosystems ◽  
Global Carbon Cycle ◽  
Fuel Combustion ◽  
Atmospheric Co2 ◽  
Fossil Fuel Combustion ◽  
Global Carbon

Abstract. Non-deforestation fire – i.e., fire that is typically followed by the recovery of natural vegetation – is arguably the most influential disturbance in terrestrial ecosystems, thereby playing a major role in carbon exchanges and affecting many climatic processes. The radiative effect from a given atmospheric CO2 perturbation is the same for fire and fossil fuel combustion. However, major differences exist per unit of CO2 emitted between the effects of non-deforestation fire vs. fossil fuel combustion on the global carbon cycle and climate, because (1) fossil fuel combustion implies a net transfer of carbon from geological reservoirs to the atmospheric, oceanic, and terrestrial pools, whereas fire occurring in terrestrial ecosystems does not; (2) the average lifetime of the atmospheric CO2 increase is longer when originating from fossil fuel combustion compared to fire, due to the strong vegetation regrowth following fire disturbances in terrestrial ecosystems; and (3) other impacts, for example on land surface albedo, also differ between fire and fossil fuel combustion. The main purpose of this study is to illustrate the consequences from these fundamental differences between fossil fuel combustion and non-deforestation fires using 1000-year simulations of a coupled climate–carbon model with interactive vegetation. We assessed emissions from both pulse and stable fire regime changes, considering both the gross (carbon released from combustion) and net (fire-caused change in land carbon, also accounting for vegetation decomposition and regrowth, as well as climate–carbon feedbacks) fire CO2 emissions. In all cases, we found substantial differences from equivalent amounts of emissions produced by fossil fuel combustion. These findings suggest that side-by-side comparisons of non-deforestation fire and fossil fuel CO2 emissions – implicitly implying that they have similar effects per unit of CO2 emitted – should therefore be avoided, particularly when these comparisons involve gross fire emissions, because the reservoirs from which these emissions are drawn have very different residence times (millions of years for fossil fuel; years to centuries for vegetation and soil–litter). Our results also support the notion that most net emissions occur relatively soon after fire regime shifts and then progressively approach zero. Overall, our study calls for the explicit representation of fire activity as a valuable step to foster a more accurate understanding of its impacts on global carbon cycling and temperature, as opposed to conceiving fire effects as congruent with the consequences from fossil fuel combustion.

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