Preparation of hydrogen from metals and water without CO2 emissions

Considering the high calorific value and low-carbon characteristics of hydrogen energy, it will play an important role in replacing fossil energy sources. The production of hydrogen from renewable energy sources for electricity generation and electrolysis of water is an important process to obtain green hydrogen compared with classic low-carbon hydrogen production methods. However, the challenges in this process include the high cost of liquefied hydrogen and the difficulty of storing hydrogen on a large scale. In this paper, we propose a new route for hydrogen storage in metals, namely, electricity generation from renewable energy sources, electrolysis to obtain metals, and subsequent hydrogen production from metals and water. Metal monomers facilitate large-scale and long-term storage and transportation, and metals can be used as large-scale hydrogen storage carriers in the future. In this technical route, the reaction between metal and water for hydrogen production is an important link. In this paper, we systematically summarize the research progress, development trend, and challenges in the field of metal to hydrogen production. This study aim to aid in the development of this field.     

Brazilian energy policies side-effects on CO2 emissions reduction

This study focuses on some of the programs and measures Brazil has undertaken over the past two or three decades in order to mitigate economic or environmental problems, which have also had positive effects on the reduction of the country's carbon dioxide emissions. Results show that, in the year 2000 alone, some 11% in CO₂ emissions from energy use in Brazil have been reduced compared to what would have been emitted that year had the actions reviewed here not been implemented in good time. As these actions have not been motivated as a strategy to curb global climate change, if their benefits related to avoided carbon emissions are not fully appraised in the near future, chances are that these policies may be discontinued. For instance, in the case of the business-as-usual scenario drawn up by the Ministry of Mines and Energy in 2001, the discontinuity of the policies analyzed here would result in CO₂ emissions 20% higher by 2020, compared to what would happen were these policies kept over the long term. Therefore, the perspective presented here spotlights some of the hidden benefits of the programs and measures underway in the country, justifying their continuation or even intensification.     

Analysis of CO2 emissions reduction in the Malaysian transportation sector: An optimisation approach

The demand for transport services is expected to rise, causing the CO₂ emissions level to increase as well. In Malaysia, the transportation sector accounts for 28% of total CO₂ emissions, of which 85% comes from road transport. By 2020, Malaysia is targeting a reduction in CO₂ emissions intensity by up to 40% and in this effort the role of road transport is paramount. This paper attempts to investigate effective policy options that can assist Malaysia in reducing the CO₂ emissions level. An Optimisation model is developed to estimate the potential CO₂ emissions mitigation strategies for road transport by minimising the CO₂ emissions under the constraint of fuel cost and demand travel. Several mitigation strategies have been applied to analyse the effect of CO₂ emissions reduction potential. The results demonstrate that removal of fuel price subsidies can result in reductions of up to 652 ktonnes of fuel consumption and CO₂ emissions can be decreased by 6.55%, which would enable Malaysia to hit its target by 2020. CO₂ emissions can be reduced significantly, up to 20%, by employing a combination of mitigation policies in Malaysia. This suggests that appropriate mitigation policies can assist the country in its quest to achieve the CO₂ emissions reduction target.     

渗滤液流失造成的MSW填埋气潜能减量

中国城市生活垃圾(MSW)中易生物降解的有机质能产生大量可造成有机污染的渗滤液,这些渗滤液的流失对填埋垃圾的产气能力会产生不利影响,为了确定损失的这部分渗滤液的产气能力,对模拟填埋100 d的处于酸化阶段的渗滤液实施了70d的厌氧消化试验.试验过程中对渗滤液的产气量、甲烷含量、产沼气潜能、pH变化规律及COD去除率做了监测研究.结果表明,渗滤液沼气累积产量为34.55 ml/ml,甲烷浓度为65.0%,渗滤液产甲烷潜能为22.46 ml/g;pH值在开始两天下降至6.7,并在产气阶段逐渐上升到8.3;渗滤液的COD去除率为83.8%.基于对模拟填埋渗滤液的沼气潜能研究,一个开始填埋100d后的中国MSW填埋场流失的填埋气潜能已达到11.5%.     

Indian fertilizer industry: assessment of potential energy demand and CO2 emissions

Fertilizer industry is one of the largest energy consumers in India with a share of nearly 15% in total industrial energy consumption. Amongst two types of fertilizers produced in India (nitrogenous (N) and phosphatic (P₂O₅)), nearly 90% energy is consumed by the nitrogenous fertilizer in the form of fuel and feed stock. Based on the future demand projections for fertilizers in India, an attempt has been made in this paper to estimate future energy demand and CO₂ emissions from the industry. © 1998 John Wiley & Sons, Ltd.     

Participation in GVCs and CO2 emissions

This paper attempts to explore the determinants of CO₂ emissions in the context of international trade. While there exist studies that examine the roles of horizontal specialization and inter-industry trade transactions, little previous research attention has been paid to the roles of vertical specialization and intra-industry trade transactions in affecting CO₂ emissions. To fill the knowledge gap, this study uses the panel data of 62 countries and regions for the period of 1995–2011 to estimate the effect of participation in global value chains (GVCs) on per capita CO₂ emissions. Major findings include: (1) The relationship between participation degrees in GVCs and per capita CO₂ emissions is found to be inversely U-shaped at the aggregate economy-level and for most individual industries; (2) Per capita GDP shows an N-shaped relationship with per capita CO₂ emissions; and (3) Benign drivers of CO₂ emissions include R&D, energy conservation, and population control. It can be concluded that countries with low GDP or GVC participation degrees are expected to experience worsening CO₂ emissions in the short or even medium run. This trend, however, can be moderated or even reversed with more R&D investments.     

Assessment of CO2 emission reduction and identification of CDM potential in a township

This paper presents the theoretical investigation of CDM opportunity in a township at Jaipur, India. The purpose of study is to identify and analyze the various opportunities viz., installation of solar water heater, energy efficient lighting, energy efficient air conditioners, and energy efficient submersible water pumps in desert coolers and thus achieve a considerable (65.7?%) reduction in GHG emissions. Out of the various opportunities considered, the retrofitting with solar water heater can be recommended for CDM. Though, the retrofitting with energy efficient lighting, energy efficient air conditioners and energy efficient submersible water pumps in desert coolers claimed CO₂ emission reduction of 104.84, 25.92, and 36.94?tons per annum, respectively, but the only opportunity which got through CDM was retrofitting with solar water heater claiming 115.70?tCO₂ (100?%) emission reductions per annum which could result into net earnings of 115.70 CERs. The simple and discounted payback period for all four project activities are also calculated with and without CDM and tax benefits.     

Decomposing the change of CO2 emissions: A joint production theoretical approach

This paper presents an alternative decomposition method to explore the driving forces of change in carbon emissions by using distance functions estimated by data envelopment analysis. The proposed approach can isolate the effects of changes in GDP composition and energy supply composition on the change of carbon emissions. In addition, it is capable of identifying the effects of changes in different input ratios, which may be very important if there are substitution effects among different inputs. Moreover, the proposed model can measure the effects of changes in good and bad output technical efficiencies. Consequently, this decomposition technique allows a change of carbon emissions to be decomposed into contributions from ten factors, which provides more insights for policy makers. We apply this model to decompose carbon emissions in 25 OECD counties and China. For the sample countries as a whole, the empirical results indicate that the economic growth is the crucial driver to carbon emissions increase, while the changes in GDP composition and capital–energy ratio are two main drivers to carbon emissions reduction. In particular, we discuss in detail the driving forces of China's carbon emissions change in order to propose some valuable policy implications for China from an international perspective.     

Syngas production by electrocatalytic reduction of CO2 using Ag-decorated TiO2 nanotubes

Huge efforts have been done in the last years on electrochemical and photoelectrochemical reduction of CO₂ to offer a sustainable route to recycle CO₂. A promising route is to electrochemically reduce CO₂ into CO which, by combination with hydrogen, can be used as a feedstock to different added-value products or fuels. Herein, perpendicular oriented TiO₂ nanotubes (NTs) on the electrode plate were grown by anodic oxidation of titanium substrate and then decorated by a low loading of silver nanoparticles deposited by sputtering (i.e. Ag/TiO₂ NTs). Due to their quasi one-dimensional arrangement, TiO₂ NTs are able to provide higher surface area for Ag adhesion and superior electron transport properties than other Ti substrates (e.g. Ti foil and TiO₂ nanoparticles), as confirmed by electrochemical (CV, EIS, electrochemical active surface area) and chemical/morphological analysis (FESEM, TEM, EDS). These characteristics together with the role of the TiO₂ NTs to enhance the stability of CO₂^·- intermediate formed due to titania redox couple (Ti^IV/Ti^III) lead to an improvement of the CO production in the Ag/TiO₂ NTs electrodes. Particular attention has been devoted to reduce the loading of noble metal in the electrode(14.5 %w/%w) and to increase the catalysts active surface area in order to decrease the required overpotential.     

Temporal changes in China's production and consumption-based CO2 emissions and the factors contributing to changes

As the largest carbon emitter in the world, China is actively promoting carbon emission reduction and low-carbon sustainable development. To better formulate low-carbon transformation measures, we calculated and compared China's production-based carbon emissions (PD-CEs) and consumption-based carbon emissions (CD-CEs) from 2000 to 2014 based on the Multi-Regional Input–Output tables. We also performed a structural decomposition analysis (SDA) to investigate the factors contributing to changes in China's PD-CEs and CD-CEs. The study's findings are as follows: First, China's PD-CEs are continually larger than its CD-CEs, such that China is a net exporter of emissions. However, China's exported emissions and net exported emissions peaked at 2200 and 1786 Mt., respectively, as of 2007. In 2014, China's net exported emissions were 1371 Mt., down 23.25% compared with 2007. Second, China's PD-CEs mainly serve the domestic final demand, and China's CD-CEs are mainly emitted at home. Production and supply of electric power, steam and hot water is the biggest contributor to China's PD-CEs while Construction the largest contributor to China's CD-CEs. Third, the SDA results show that China's PD-CEs and CD-CEs mainly grew due to changes in China's final demand volume. The significant restraint to the growth of China's PD-CEs and CD-CEs is the effect of changes in the domestic emission intensity. Changes in China's ties with other economies have an important impact on China's carbon emissions. Developing economies are replacing developed economies as major destinations for China's emissions export. Fourth, the growth rate of China's PD-CEs and CD-CEs significantly slowed down and the factors contributing to the changes in China's PD-CEs and PD-CEs have changed after China's economy entered the new normal.     

Optimal reductions in CO2 emissions.

Current optimizing climate-economy models use CO2 uptake functions that greatly underestimate both peak atmospheric CO2 concentrations and the time horizon of elevated CO2. As a result these models underestimate potential global warming damages. Here, a more realistic, but practical, carbon cycle parameterization is developed that can be incorporated within an optimizing climate-economy model framework. This method is utilized in conjunction with the DICE model (Nordhaus, 1994) to estimate optimal reductions in CO2 emissions. The results are shown to be extremely sensitive to the pore rate of time preference, rho. For rho=3% (Nordhaus' preferred value), our model predicts an optimal CO2 emission reduction of 13% by the year 2045, as compared to 11% in the original DICE model. But, for rho=0% the optimal emissions reduction rises to 79% in the year 2045 and to 97% by the year 2200. We argue that energy policy should be guided by the rho=0% results for both economic and ethical reasons. A steady-state analysis performed using the DICE model supports the argument that large fractional reductions in CO2 emissions should be undertaken.     

CO2 emissions and reduction potential in China’s chemical industry

GHG (Increasing greenhouse gas) emissions in China imposes enormous pressure on China’s government and society. The increasing GHG trend is primarily driven by the fast expansion of high energy-intensive sectors including the chemical industry. This study investigates energy consumption and CO₂ emissions in the processes of chemical production in China through calculating the amounts of CO₂ emissions and estimating the reduction potential in the near future. The research is based on a two-level perspective which treats the entire industry as Level one and six key sub-sectors as Level two, including coal-based ammonia, calcium carbide, caustic soda, coal-based methanol, sodium carbonate, and yellow phosphorus. These two levels are used in order to address the complexity caused by the fact that there are more than 40 thousand chemical products in this industry and the performance levels of the technologies employed are extremely uneven. Three scenarios with different technological improvements are defined to estimate the emissions of the six sub-sectors and analyze the implied reduction potential in the near future. The results highlight the pivotal role that regulation and policy administration could play in controlling the CO₂ emissions by promoting average technology performances in this industry.     

Scenario analysis on CO2 emissions reduction potential in China''s electricity sector

With the approach of the year 2012, a new round of international negotiations has energized the entire climate change community. With this, analyses on sector-based emissions reduction and mitigation options will provide the necessary information to form the debate. In order to assess the CO₂ emissions reduction potential of China's electricity sector, this research employs three scenarios based on the “long-range energy alternative planning system” (LEAP) model to simulate the different development paths in this sector. The baseline scenario, the current policy scenario, and the new policy scenario seek to gradually increase the extent of industrial restructuring and technical advancement. Results imply that energy consumption and CO₂ emission in China's electricity sector will rise rapidly in all scenarios until 2030—triple or quadruple the 2000 level; however, through structural adjustment in China's electricity sector, and through implementing technical mitigation measures, various degrees of abatement can be achieved. These reductions range from 85 to 350 million tons CO₂ per year—figures that correspond to different degrees of cost and investment. Demand side management and circulating fluidized bed combustion (CFBC) (ranked in order) are employed prior to use to realize emissions reduction, followed by supercritical plants and the renovation of conventional thermal power plants. In the long term, nuclear and hydropower will play the dominant role in contributing to emissions reduction. It is also suggested that a “self-restraint” reduction commitment should be employed to help contribute to the reduction of emission intensity, an avenue that is more practical for China in light of its current development phase. Setting the year 2000 as the base year, the intensity reduction target could possibly range from 4.2% to 19.4%, dependent on the implementation effectiveness of various mitigation options.     

The effect of CO2 emissions and economic performance on hydrogen-based renewable production in 35 European Countries

This study applies the OLS and panel data approach to estimate the influence of variables such as greenhouse gas emissions, per capita income, the scale of labor force input, the portion of added value in manufacturing industry and government mechanism on hydrogen-based renewable production in 35 European countries. The empirical results show that the nation's economic input and its income level have a positive effect on hydrogen-based renewable energy, which indicated that the economic growth has promoted living standards, inspired environmental awareness, and influenced the use of alternative energy and renewable energy. Moreover, the empirical results also show that deepening democracy (government mechanism) has a positive impact on hydrogen-based renewable energy in OECD countries, but the impact on non-OECD countries is not clear.     

Size distribution of national CO2 emissions

We examine the size distribution of national carbon dioxide (CO₂) emissions on a sample of 210 countries and territories for the period 2000–2010. We employ lognormal, double Pareto-lognormal, lognormal-upper tail Pareto, and Pareto tails-lognormal distributions to estimate CO₂ size distribution. The analysis demonstrates that the lognormal-Pareto composite distributions generally fit the size distribution of CO₂ emissions better than the lognormal distribution. The parametric analysis reveals that the upper-tail of CO₂ emissions is characterized by Zipf's law. The power law in the upper-tail implies that large countries emit much of the CO₂. When controlling for population, Zipf's law no longer holds, but per capita CO₂ emissions still exhibit a strong Pareto upper tail.     

Scenario analysis on CO2 emissions reduction potential in China's iron and steel industry

The international climate community has begun to assess a range of possible options for strengthening the international climate change effort after 2012. Analysis of the potential for sector-based emissions reduction and relevant mitigation options will provide the necessary background information for the debate. In order to assess the CO₂ abatement potential of China's steel industry, a model was developed using LEAP software to generate 3 different CO₂ emission scenarios for the industry from 2000 to 2030. The abatement potentials of different scenarios were compared, and their respective feasibilities were assessed according to the cost information. High priority abatement measures were then identified. The results show that the average CO₂ abatement per year in the Recent Policy scenario and in the New Policy scenario, compared with the reference scenario, are 51 and 107 million tons, respectively. The corresponding total incremental costs are 9.34 and 80.95 billion dollars. It is concluded that there is great potential for CO₂ abatement in China's steel industry. Adjusting the structure of the industry and technological advancement will play an important role in emissions reduction. Successful implementation of current sustainable development policies and measures will result in CO₂ abatement at a low cost. However, to achieve higher levels of abatement, the cost will increase dramatically. In the near future, specific energy conservation technologies such as dry coke quenching, exhaust gas and heat recovery equipment will be of great significance. However, taking a long term perspective, emissions reduction will rely more on the adjustment of production processes and the application of more modern large scale plants. Advanced blast furnace technology will inevitably play an important role.     

CO2 emissions from aluminium manufacturing in India

Aluminium manufacturing is highly energy-intensive and a large contributor of CO₂. The emissions per tonne of aluminium manufacturing in India have been estimated. Demand for aluminium and associated CO₂ emissions have been projected for the industry as a whole for the years 2001/02 and 2006/07. The reduction potential in CO₂ emissions through energy-conservation measures has been assessed.     

Short-rotation forestry of birch,maple, poplar and willow in Flanders (Belgium) II. Energy production and CO2 emission reduction potential

Belgium, being an EU country, has committed itself to a 7.5% reduction of greenhouse gas emissions during the first commitment period of the Kyoto Protocol. Within this framework, the Flemish government aims at reaching a share of 6% of renewable electricity in the total electricity production by 2010. In this work, the biomass production of birch, maple, poplar and willow in a short-rotation forestry (SRF) plantation after a 4-year growth period served as the base to calculate the amount of (electrical) energy that could be produced by this type of bioenergy crop in Flanders. The maximum amount of electricity that could be provided by SRF biomass was estimated at 72.9 GWh_e year⁻¹, which only accounts for 0.16% of the total electricity production in this region. Although the energy output was rather low, the bioenergy production process under consideration appeared to be more energy efficient than energy production processes based on fossil fuels. The high efficiency of birch compared to the other species was mainly due to the high calorific value of the birch wood. The maximum CO₂ emission reduction potential of SRF plantations in Flanders was estimated at only 0.09% of the total annual CO₂ emission. The most interesting application of SRF in Flanders seemed to be the establishment of small-scale plantations, linked to a local combined heat and power plant. These plantations could be established on marginal arable soils or on polluted sites, and they could be of importance in the densely populated area of Flanders because of other environmental benefits, among which their function as (temporary) habitat for many species.     

Wind power and CO2 emissions in the Irish market

This paper presents an empirical analysis of the displacement of CO₂ emissions associated with wind generation in the Irish electricity market between December 2013 and May 2017. We find that the average marginal effect of an additional MWh of wind generation corresponds to a reduction in CO₂ emissions of 0.401 tonnes in Ireland (All-Island system) and 0.459 tonnes when accounting also for the emissions offset in Great Britain. We also find that, for each given demand level, the amount of emissions displaced by wind varies with the wind level. In particular, overall the amount of total (domestic plus external) CO₂ emissions offset by a MWh of wind generation increases as the wind generation level increases, a result which suggests that as wind generation capacity increases the effectiveness of wind in displacing CO₂ may be retained. However, when accounting exclusively for the effects of wind generation on domestic emissions, we observe that the effectiveness of wind in displacing emissions may decrease as the amount of wind generation increases further. As the effects of CO₂ as a GHG are independent of the location where it is emitted, our work also highlights that accounting for reductions in emissions due to a reduction of imports from, or an increase in exports to, interconnected markets is crucial in this type of analysis due to the potential for underestimating the effects of wind on emissions savings when only national emissions are accounted for. The Irish government has a target for 40% of total electricity generation to be produced by renewable energy sources by 2020 which, according to institutional reports, may entail an additional 25% to 35% increase in wind generation capacity from the present levels. Accordingly, our findings are particularly relevant for policy making since they do not support one of the arguments against further investment in wind, namely that the corresponding environmental benefits in the form of emissions savings are reduced.