Solar-assisted hydrogen production from natural gas with low CO2 emissions

1998 ◽  
pp. 503-512
Author(s):  
Robert Williams ◽  
Brian Wells
Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper two methodologies, able to avoid CO2 dispersion in atmosphere, have been analyzed: • treating exhaust gases in order to remove, liquefy and store the produced carbon dioxide; • de-carbonizing fossil fuels before using them in the combustion in order to inhibit completely carbon dioxide production. These methodologies have been implemented in advanced power plants based on gas turbine: a combined cycle power plant (CC), fed by natural gas, and an integrated gasification combined cycle (IGCC), fed by coal. The exhaust gas treatment is based on a chemical process of absorption, while the fossil fuel decarbonization is based on partial oxidation of methane, steam methane reforming and coal gasification. These systems require material and energetic integrations with the power sections and so the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above mentioned reference plants. An efficiency decrease and an increase in the cost of electricity have been obtained when power plants are equipped with systems able to reduce CO2 emissions. However, in order to obtain low CO2 emissions when coal is used, the coal decarbonization must be implemented: in this case it is possible to attain a global efficiency of about 38%, a specific emission of 0.1117 kg/kWh and an increase of kWh cost of about 32%. Vice versa, in order to obtain low CO2 emissions when natural gas is used, the exhaust gas treatment must be implemented: in this case it is possible to attain a global efficiency of about 50.7%, a specific emission of 0.0391 kg/kWh and an increase of kWh cost of about 15%. The clean use of coal seems to have good potential because it allows low energy penalizations (about 7.5 percentage points) and economic increases of about 32%. Because of the great availability, the homogeneous distribution and the low cost of this fuel, these results seem to be very interesting especially in the viewpoint of a transition towards the “hydrogen economy”, based, at least in the medium term, on fossil fuels.


2021 ◽  
Vol 13 (15) ◽  
pp. 8237
Author(s):  
István Árpád ◽  
Judit T. Kiss ◽  
Gábor Bellér ◽  
Dénes Kocsis

The regulation of vehicular CO2 emissions determines the permissible emissions of vehicles in units of g CO2/km. However, these values only partially provide adequate information because they characterize only the vehicle but not the emission of the associated energy supply technology system. The energy needed for the motion of vehicles is generated in several ways by the energy industry, depending on how the vehicles are driven. These methods of energy generation consist of different series of energy source conversions, where the last technological step is the vehicle itself, and the result is the motion. In addition, sustainability characterization of vehicles cannot be determined by the vehicle’s CO2 emissions alone because it is a more complex notion. The new approach investigates the entire energy technology system associated with the generation of motion, which of course includes the vehicle. The total CO2 emissions and the resulting energy efficiency have been determined. For this, it was necessary to systematize (collect) the energy supply technology lines of the vehicles. The emission results are not given in g CO2/km but in g CO2/J, which is defined in the paper. This new method is complementary to the European Union regulative one, but it allows more complex evaluations of sustainability. The calculations were performed based on Hungarian data. Finally, using the resulting energy efficiency values, the emission results were evaluated by constructing a sustainability matrix similar to the risk matrix. If only the vehicle is investigated, low CO2 emissions can be achieved with vehicles using internal combustion engines. However, taking into consideration present technologies, in terms of sustainability, the spread of electric-only vehicles using renewable energies can result in improvement in the future. This proposal was supported by the combined analysis of the energy-specific CO2 emissions and the energy efficiency of vehicles with different power-driven systems.


Author(s):  
Tomiwa Sunday Adebayo ◽  
Abraham Ayobamiji Awosusi ◽  
Seun Damola Oladipupo ◽  
Ephraim Bonah Agyekum ◽  
Arunkumar Jayakumar ◽  
...  

Despite the drive for increased environmental protection and the achievement of the Sustainable Development Goals (SDGs), coal, oil, and natural gas use continues to dominate Japan’s energy mix. In light of this issue, this research assessed the position of natural gas, oil, and coal energy use in Japan’s environmental mitigation efforts from the perspective of sustainable development with respect to economic growth between 1965 and 2019. In this regard, the study employs Bayer and Hanck cointegration, fully modified Ordinary Least Square (FMOLS), and dynamic ordinary least square (DOLS) to investigate these interconnections. The empirical findings from this study revealed that the utilization of natural gas, oil, and coal energy reduces the sustainability of the environment with oil consumption having the most significant impact. Furthermore, the study validates the environmental Kuznets curve (EKC) hypothesis in Japan. The outcomes of the Gradual shift causality showed that CO2 emissions can predict economic growth, while oil, coal, and energy consumption can predict CO2 emissions in Japan. Given Japan’s ongoing energy crisis, this innovative analysis provides valuable policy insights to stakeholders and authorities in the nation’s energy sector.


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