Stabilize CO2 Emissions Research Articles

Current-Voltage (i-V) characteristics of electrolyte-supported (NiO-YSZ/NiO-SDC/ScSZ/LSCF-GDC/LSCF) solid oxide electrolysis cell during CO2/H2O co-electrolysis

Solid oxide electrolysis cells (SOECs) stabilize CO2 emissions by converting CO2/H2O into synfuel. Current-Voltage (i-V) characteristics of an electrolyte-supported button cell (NiO-YSZ/NiO-SDC/ScSZ/LSCF-GDC/LSCF) were measured as a function of temperature, water vapor concentration, and CO2 gas concentrations. The cell microstructure was characterized by the Field Emission Scanning Electron Microscope (FE-SEM). FE-SEM micrographs depict that the electrolyte layer is relatively dense, and porous fuel and air electrode layers are well adhered to the electrolyte. The i-V curves were obtained at a scan rate of 0.02 Vs−1 from 0.3 to 1.5 V. Electrolysis current density increases as the temperature increases. SOEC performance increases, but SOFC performance decreases with increased water vapor concentration. Electrolysis current densities decrease as the CO2 concentration increases. The i-V characteristics show only ohmic polarization under fuel-lean and fuel-rich conditions. At optimal conditions, current density values at 800 °C/1.5 V are -174, -187, and -195 mA cm−2 for 5 %H2O, 30 %CO2, and 30 %CO2/5 %H2O co-electrolysis. At 800 °C, open-circuit voltage (OCV) values for H2O, CO2, and co-electrolysis are 0.906, 0.891, and 0.885 V, respectively. The electrolysis area-specific resistances (ASRs) give information on the reduction of CO2 or H2O, forming CO or H2, respectively. At optimal conditions, ASR values are 3.43, 3.29, and 3.18 Ω cm2 for H2O, CO2, and co-electrolysis, respectively. Co-electrolysis has a lower ASR value than pure H2O and CO2 electrolysis, indicating that H2O and CO2 are involved in the electrochemical processes.

Achieving decent living standards in emerging economies challenges national mitigation goals for CO2 emissions

Emerging economies, low- and middle-income countries experiencing rapid population and GDP growth, face the challenge of improving their living standards while stabilizing CO2 emissions to meet net-zero goals. In this study, we quantify the CO2 emissions required for achieving decent living standards (DLS) in emerging economies. The results show that, compared to other regions, achieving DLS in emerging Asian and African economies will result in more additional CO2 emissions, particularly in the DLS indicators of Mobility and Electricity. Achievement of DLS in emerging economies will result in 8.6 Gt of additional CO2 emissions, which should not jeopardize global climate targets. However, a concerning trend arises as more than half of the emerging economies (62 out of 121) will face substantial challenges in aligning their expected emission growth for achieving DLS with their national emission mitigation targets.

Neural-network-based estimation of regional-scale anthropogenic CO<sub>2</sub> emissions using an Orbiting Carbon Observatory-2 (OCO-2) dataset over East and West Asia

Abstract. Atmospheric carbon dioxide (CO2) is the most significant greenhouse gas, and its concentration is continuously increasing, mainly as a consequence of anthropogenic activities. Accurate quantification of CO2 is critical for addressing the global challenge of climate change and for designing mitigation strategies aimed at stabilizing CO2 emissions. Satellites provide the most effective way to monitor the concentration of CO2 in the atmosphere. In this study, we utilized the concentration of the column-averaged dry-air mole fraction of CO2, i.e., XCO2 retrieved from a CO2 monitoring satellite, the Orbiting Carbon Observatory-2 (OCO-2), and the net primary productivity (NPP) provided by the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate the anthropogenic CO2 emissions using the Generalized Regression Neural Network (GRNN) over East and West Asia. OCO-2 XCO2, MODIS NPP, and the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) CO2 emission datasets for a period of 5 years (2015–2019) were used in this study. The annual XCO2 anomalies were calculated from the OCO-2 retrievals for each year to remove the larger background CO2 concentrations and seasonal variability. The XCO2 anomaly, NPP, and ODIAC emission datasets from 2015 to 2018 were then used to train the GRNN model, and, finally, the anthropogenic CO2 emissions were estimated for 2019 based on the NPP and XCO2 anomalies derived for the same year. The estimated and the ODIAC CO2 emissions were compared, and the results showed good agreement in terms of spatial distribution. The CO2 emissions were estimated separately over East and West Asia. In addition, correlations between the ODIAC emissions and XCO2 anomalies were also determined separately for East and West Asia, and East Asia exhibited relatively better results. The results showed that satellite-based XCO2 retrievals can be used to estimate the regional-scale anthropogenic CO2 emissions, and the accuracy of the results can be enhanced by further improvement of the GRNN model with the addition of more CO2 emission and concentration datasets.

BIOACTIVE DEVICES AS SELF-SUFFICIENT SYSTEMS FOR ENERGY PRODUCTION IN ARCHITECTURE

ABSTRACT Using bioenergy systems in architecture provides energy by means of negative emissions technologies (NETs). It plays an important role in stabilizing CO2 emissions at low levels. This depends on options of low life cycle emissions (for instance, a sustainable use of biomass residues), and on outcomes that are site-specific and rely on efficient integrated systems that convert biomass into bioenergy. The objective of this study is to develop self-sufficient systems that generate bioelectricity and offer safety, electricity generation efficiency, cost-effectiveness, waste treatment, integration in domestic use, ease of use, reproducibility and availability. The study also intends to elaborate a general design method of embedding and utilizing microorganisms into architectural elements to achieve design ecology, introducing a multidisciplinary research application through a design theory aspect. The study is based on previous experimental work conducted by the authors. Microbial fuel cell technology was applied to exploit the natural potential of a fungal strain that was identified and optimized to be implemented in microbial fuel cells (MFCs) to generate electricity. The outcomes were included in the self-sufficient cluster design that meets the aforementioned conditions. The novelty of this study is the direct use of a bioreactor of MFCs in a design application for bioelectricity production. It aims to reduce the currently high global CO2 emissions that come from the energy supply sector (47%) and from the building sector (3%), as well as to eliminate the need for large-scale infrastructure intervention. This self-sufficient bio-electricity cluster therefore outweighs other abiotic renewable energy resources such as solar energy or wind power.

The strategy of a low-carbon economy based on the STIRPAT and SD models

With the rapid development of certain nations' economies, CO2 emissions have become a major concern worldwide. Controlling and stabilizing CO2 emissions is the primary goal of a low carbon society. The STIRPAT model aims to find the driving forces that contribute to carbon emissions, while the SD model is one of the decision-making tools used to analyze complex urban environmental issues. This paper combined these two models and effectively identified the key driving forces of CO2 emissions at the scale of Wanquan town. These driving forces included the population, the urbanization level, the per capita GDP, the industrial structure, and the energy intensity. The contribution degrees of the driving forces to the change in CO2 emissions from the STIRPAT model suggested that population growth is the key driving factor, while industrial structures and affluence followed closely. A low carbon development pattern was also established by applying the STIRPAT and SD models together. Using the dynamic simulation of the SD model, an optimal scenario was selected under different development levels and the CO2 emissions were 72,868t and 78,699t in 2015 and 2020, respectively. A stable population growth, moderate industrialization and urbanization level, reasonable industrial structure, and low energy consumption are the regional development priorities for energy saving and emission reduction.

Microbial fixation of CO2 in water bodies and in drylands to combat climate change, soil loss and desertification

The growing concern for the increase of the global warming effects due to anthropogenic activities raises the challenge of finding novel technological approaches to stabilize CO2 emissions in the atmosphere and counteract impinging interconnected issues such as desertification and loss of biodiversity. Biological-CO2 mitigation, triggered through biological fixation, is considered a promising and eco-sustainable method, mostly owing to its downstream benefits that can be exploited. Microorganisms such as cyanobacteria, green algae and some autotrophic bacteria could potentially fix CO2 more efficiently than higher plants, due to their faster growth. Some examples of the potential of biological-CO2 mitigation are reported and discussed in this paper. In arid and semiarid environments, soil carbon sequestration (CO2 fixation) by cyanobacteria and biological soil crusts is considered an eco-friendly and natural process to increase soil C content and a viable pathway to soil restoration after one disturbance event. Another way for biological-CO2 mitigation intensively studied in the last few years is related to the possibility to perform carbon dioxide sequestration using microalgae, obtaining at the same time bioproducts of industrial interest. Another possibility under study is the exploitation of specific chemotrophic bacteria, such as Ralstonia eutropha (or picketii) and related organisms, for CO2 fixation coupled with the production chemicals such as polyhydroxyalkanoates (PHAs). In spite of the potential of these processes, multiple factors still have to be optimized for maximum rate of CO2 fixation by these microorganisms. The optimization of culture conditions, including the optimal concentration of CO2 in the provided gas, the use of metabolic engineering and of dual purpose systems for the treatment of wastewater and production of biofuels and high value products within a biorefinery concept, the design of photobioreactors in the case of phototrophs are some of the issues that, among others, have to be addressed and tested for cost-effective CO2 sequestration.

Will technological progress be sufficient to stabilize CO2 emissions from air transport in the mid-term?

This article investigates whether anticipated technological progress can be expected to offset the CO2 emissions resulting from rapid air traffic growth. Global aviation CO2 emissions projections are examined for eight geographical zones until 2025. Air traffic flows are forecast using a dynamic panel-data econometric model, and then converted into corresponding quantities of air traffic CO2 emissions using specific hypotheses and energy factors. None of our nine scenarios appears compatible with the objective of 450ppm CO2-eq. recommended by the Intergovernmental Panel on Climate Change. Nor is any compatible with the Panel’s aim of limiting global warming to 3.2°C.

The Effect of Carbon Taxes on Energy Use by the Manufacturing Sector of Taiwan

This study evaluates the possible impact of carbon taxes on the most important sector of a newly industrialized economy. Changes in the energy consumption pattern and the resulting carbon dioxide emissions are analyzed for the entire manufacturing sector as well as four energy-intensive industries of Taiwan. A carbon tax is imposed as a predetermined, fixed tax on each type of energy according to its carbon content. Simulations are performed, using atwo-stage translog price model, for a reference case and for four different levels of carbon taxes.The results indicate that a high tax is expected to stabilize CO2 emissions to the 1990 level by the year 2005 while maintaining a 5% growth rate in the manufacturing sector. Reductions in energy consumptionand CO2 emissions resulting from such taxes are substantial, and are sensitive to the tax level. Prices of energy aggregates increase due to a carbon tax and are directly related to the increase in the level of the carbon tax. Industries react differently to the tax in choosing their energy mix. Specifically, a decrease in the share allocated to coal inputs and an increase in the shares of oil, natural gas, and noncarbon energy inputs in its energy mix is observed in the electricity generation sector.

Global warming: least-cost electricity planning to meet CO2 emissions limits

This paper explores least-cost strategies for reducing CO2 emissions from the electric power industry. It uses an economic-engineering model for electric generation capacity expansion to investigate expansion plans which meet alternative CO2 emissions constraints in the lowest cost. The model selects the mix of various energy technologies, which are either presently in use or will possibly be in use in the future, to meet a specific carbon emissions limit and, furthermore, estimates the optimal tax required to achieve the least-cost strategy for reducing emissions to the desired level. Using Greece as a case study, the study suggests that to stabilize CO2 emissions at their 1990 level by the year 2005 and thereafter, the industry should move away from lignite generation to hydro and renewables and to coal or lignite technologies with CO2 removal capabilities. An optimal tax of $105 per ton of carbon is required to achieve this target in the lowest cost. © 1998 John Wiley & Sons, Ltd.

CO2-stabilization may be a ‘no-regrets’ policy

Restricting CO2 emissions requires changing today's consumption pattern away from energy and emission intensive commodities towards cleaner goods. The cost of stabilizing CO2 emissions at the 1990 level by the year 2000, say, as compared to a business-as-usual trend, is estimated by several researchers to be on the order of 1% of GNP. We will argue that the cost may be overestimated because of a too simple model describing the working of the economic system and the evaluation of welfare. We demonstrate that by expanding a model to include the actual tax system and negative externalities, the cost to present generations from restricting emissions by a CO2 tax may be negative. That is, some reduction may actually correspond to a ‘no-regrets’ policy. The reasons are inefficiencies in today's tax system and non-optimal handling of negative externalities. Our analysis suggests that a CO2 tax and reduced emissions will lessen such inefficiencies.

96/05536 Global warming policy, energy, and the Chinese economy

Abstract China is the world's largest user of coal and therefore a major generator of greenhouse gases. This paper addresses the issue of whether the country can reconfigure its energy structure without hindering its future economic development. We construct a dynamic linear programming model of the Chinese economy and use it to simulate five alternative strategies to stabilize CO2 emissions at 20% of projected year 2000 baseline levels. Our results, under more optimistic assumptions, indicate this goal can be achieved with no growth penalty. However, if major technological changes relating to energy conservation and coal displacement, as well as vastly increasing availabilities of clean fuels, are not forthcoming, China could suffer a significant decline in its rate of economic growth.

Klimaschutz im Alleingang – der richtige Weg für die Schweiz?

This paper discusses two aspects of the economic effects of curtailing carbon dioxide emissions in Switzerland, that is in a small and open economy. First, using a Computable General Equilibrium is the most adequate methodological approach to evaluate the economic impact of cutting back CO2 emissions. Second, reducing Swiss CO2 emissions has only a negligible effect on the global CO2 concentration, but affects the Swiss economy significantly. Hence, it seems reasonable to stabilize CO2 emissions in Switzerland on the 1985 level and to enforce international agreements and monetary compensations for cutting CO2 emissions in countries contributing most to the greenhouse effect.

Optimizing Tax Strategies to Reduce Greenhouse Gases Without Curtailing Growth

Increasing federal gasoline taxes is one of the policy options available for reducing gasoline consumption and the resulting carbon dioxide (CO2) emissions that contribute to global warming. At the request of the U.S. Environmental Protection Agency (EPA), DRI/McGraw-Hill (DRI) estimated the levels of gasoline tax that would be necessary to stabilize CO2 emissions from the light-vehicle fleet over a 20-year period, and the economic impacts of such a tax. Three options for utilizing the revenues generated are examined: a reduction of the federal budget deficit, a reduction in personal and corporate income taxes, and a reduction in the employer-paid portion of payroll taxes. Each option would yield markedly different levels of economic performance: while the first two options would result in reductions in economic growth, the third option (a reduction in the employer-paid portion of payroll taxes) would result in relatively slight negative economic impacts in the short term and positive economic impacts in the long term.