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As the world No.1 emitter of carbon dioxide (CO2), China has made up its mind to act on climate change. After trials in six pilot regions- Shenzhen, Shanghai, Beijing, Guangdong, Tianjin, Hubei, and Chongqing- a nationwide ETS has been established and implemented in line with the Thirteenth Five-Year Plan period (2016–2020). This paper simulates the effect of a national ETS in China using GTAP 9.1 database and a revised GTAP-E model. The simulation results show that the ETS is very effective in emissions reduction but will cause a mild economic contraction. At the sectoral level, the energy and resource sectors and energy intensive sectors are to be hit hard while most other sectors are affected negatively but insignificantly. [ABSTRACT FROM AUTHOR]

In the field of embedded systems, energy efficiency is a critical requirement, particularly for battery-powered devices. RISC-V processors have gained popularity due to their flexibility and open-source nature, making them an attractive choice for embedded applications. However, not all RISC-V processors are equally energy-efficient, and evaluating their performance in specific use cases is essential. This paper presents RisCO2, an RISC-V implementation optimized for energy efficiency. It evaluates its performance compared to other RISC-V processors in terms of resource utilization and energy consumption in a signal processing application for nondispersive infrared (NDIR) CO2 sensors.The processors were implemented in the PULPino SoC and synthesized using Vivado IDE. RisCO2 is based on the RV32E_Zfinx instruction set and was designed from scratch by the authors specifically for low-power signal demodulation in CO2 NDIR sensors. The other processors are Ri5cy, Micro-riscy, and Zero-riscy, developed by the PULP team, and CV32E40P (derived from Ri5cy) from the OpenHW Group, all of them widely used in the RISC-V community. Our experiments showed that RisCO2 had the lowest energy consumption among the five processors, with a 53.5% reduction in energy consumption compared to CV32E40P and a 94.8% reduction compared to Micro-riscy. Additionally, RisCO2 had the lowest FPGA resource utilization compared to the best-performing processors, CV32E40P and Ri5cy, with a 46.1% and a 59% reduction in LUTs, respectively. Our findings suggest that RisCO2 is a highly energy-efficient RISC-V processor for NDIR CO2 sensors that require signal demodulation to enhance the accuracy of the measurements. The results also highlight the importance of evaluating processors in specific use cases to identify the most energy-efficient option. This paper provides valuable insights for designers of energy-efficient embedded systems using RISC-V processors. [ABSTRACT FROM AUTHOR]

The utilization of geological formations, distinguished by natural porosity and permeability and protected by low-permeability caprock, has emerged as an effective strategy for carbon dioxide (CO2) storage. This method significantly contributes to mitigating anthropogenic greenhouse gas emissions and addressing the challenges of climate change. Recent research has unveiled the potential of CO2 to enhance geothermal heat energy extraction in geothermal reservoirs by acting as a subsurface heat exchange fluid. This review paper explores the viability of CO2 in augmenting geothermal heat energy extraction, comparing it to conventional water-based geothermal systems. Special emphasis is placed on CO2 plume geothermal (CPG) systems, characterized by rapid deployment and long-term utilization of geothermal energy resources. With the overarching objective of establishing net-zero energy communities, the analysis of such systems offers a comprehensive understanding of their features, providing a fresh perspective on extracted energy within the context of energy supply in integrated, sustainable energy in built systems. Notably, these systems demonstrate efficacy in meeting the power requirements of an energy community, spanning both distinct heating and electricity needs. However, the key challenge lies in selecting suitable locations. This scientific review aims to comprehend the characteristics of CPG under specific temperature and pressure conditions while optimizing subsurface permeability. This insight is pivotal for identifying future locations for CPG operations with the intent of powering small energy communities. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to strengthen research concerning the impact of climate change on China's water resources, in order to avoid extreme weather events such as regional rainstorms and floods affecting the stable supply of energy and electricity. The goal is to reorganize energy industry allocation to make China's energy the most efficient, which would thus help achieve sustainable development goals. The biggest contribution and of this paper is not only to enlarge the scale and take into account the sustainable aspects, but also to consider climate change factors that have been ignored in the past as exogenous variables. For the first time, we take stock of the optimal allocation of new and tradition energy sources and carbon dioxide. This study uses the Dynamic ZSG-DDF model with exogenous variables and undesirable outputs to find a way to redistribute carbon dioxide, new energy, and tradition energy from different provinces on the premise of maximizing efficiency, thus achieving the goal of reducing carbon and saving the earth. The research results show that the energy efficiency of tradition energy is higher than that of new energy in various provinces. At the same time, the China government must comprehensively review the quota targets of new energy, tradition energy, and carbon dioxide (CO2) in each province as quickly as possible. Currently, the quotas of various provinces are seriously misplaced, and 26 provinces in total have great room for improvement. [ABSTRACT FROM AUTHOR]

The article discusses a study on the metabolic model of glacial-interglacial energy supply to the upper ocean. It mentions the application of a two-state two-box ocean model for simulating carbon dioxide signal during the glacial-interglacial changes in the earth system. It also notes that the capability of the model to reproduce long-term oscillations and identify the planet's metabolic rate with net autotrophic primary production in the ocean.

In this paper, an innovative multi-phase strategy is developed and numerically tested to optimize CO2 utilization and storage in an oil reservoir to support low carbon transition. In the first phase, the water-alternating-gas (WAG) injection is conducted to simultaneously store CO2 and produce crude oil in the reservoir from the respective injection and production wells. In the second phase, the injection and production wells are both shut in for some time to allow CO2 and water to be stratigraphically separated. In the third phase, CO2 is injected from the upper part of the reservoir above the separated water layer to displace water downwards, while fluids continue to be produced in the water-dominated zone from the lower part of the production well. Lastly, the production well is finally shut in when the produced gas–water ratio (GWR) reaches 95%, but CO2 injection is kept until the reservoir pressure is close to the fracture pressure of its caprocks. The numerical simulations show that implementing the proposed multi-phase strategy doubles CO2 storage in comparison to applying the WAG injection alone. In particular, 80% of the increased CO2 is stored in the third phase due to the optimized perforation. In addition, the CO2 injection rate in the last phase does not appear to affect the amount of CO2 storage, while a higher CO2 injection rate can reduce the CO2 injection time and accelerate the CO2 storage process. In the proposed strategy, we assume that the geothermal energy resources from the produced fluids can be utilized to offset some energy needs for the operation. The analysis of energy gain and consumption from the simulation found that at the early stage of the CO2-WAG phase, the energy gain mostly comes from the produced oil. At the late stage of the CO2-WAG phase and the subsequent phases, there is very little or even no energy gain from the produced oil. However, the geothermal energy of the produced water and CO2 substantially compensate for the energy loss due to decreasing oil production. As a result, a net energy gain can be achieved from the proposed multi-phase strategy when geothermal energy extraction is incorporated. The new multi-phase strategy and numerical simulation provide insights for practical energy transition and CO2 storage by converting a "to be depleted" oil reservoir to a CO2 storage site and a geothermal energy producer while enhancing oil recovery. [ABSTRACT FROM AUTHOR]

Due to the depletion of fossil resources and the increase in carbon dioxide emissions, renewable energy systems (RESs) such as photovoltaic (PV) and wind generator (WG) have become an active player in power systems (PSs). In Japan, diesel generators (DGs) are the means of power generation in most isolated islands. Therefore, the introduction of RESs into these islands is of great importance. However, due to the uncertainty of RESs, battery energy storage systems (BESSs), fuel cells (FCs) and exploiting the electric vehicles (EVs) owned by customers are expected as vital power sources for the next generation. Moreover, demand response programs are utilized in this paper. As a result of reforming PSs in recent years, transactions on power markets have also been increasing in Japan. The Japan electric power exchange provides day-ahead market, intraday hour-ahead market, and forward market. It is expected that these markets make it possible to deal with uncertainties related to the generated power fluctuation. This paper presents the optimal operation method for multi-area PSs consisting of DG, PV, WG, BESS and FC by using chance-constrained programming. The proposed method has achieved reduction of the total operational cost of the multi-area small power systems by using FC, household EVs and two power markets. [ABSTRACT FROM AUTHOR]

Generated electricity from renewable sources such as solar panels and wind turbines is considered, until now, as clean and nonpolluting energy. However, these systems are responsible and directly tied to greenhouse gases (GHG) emissions when considering their different steps of manufacturing, transportation, operation, maintenance, and decommissioning. This paper describes a new sizing optimization methodology of a stand-alone hybrid Photovoltaic/Wind/Battery system, minimizing the Levelized Cost of Energy (LCOE), the Loss of Power Supply Probability (LPSP), and the Equivalent Carbon Dioxide (CO2-eq) life cycle emission. An elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to solve this constrained nonlinear multi-objective optimization problem taking the expected photovoltaic peak power, wind turbine output power, batteries' energy capacity as decision variables and embodied carbon dioxide per unit of electricity consumed as a constraint. Different combinations of PV/Wind/Battery systems are optimized and compared to identify the cost-effective, reliable, and environmentally friendly optimal architecture. Finally, a sensitivity analysis is applied to the proposed algorithm; only the batteries' state of charge (SOC) setpoint is considered to examine its impact on the system sizing procedure. The proposed algorithm is used for optimal planning of a stand-alone hybrid renewable power system expected to be installed in Borj Cedria Science and Technology Park (latitude = 36.71ºN, longitude = 10.42ºE). Simulation results proved the effectiveness of the proposed method to achieve economic, energetic, and environmental objectives. [ABSTRACT FROM AUTHOR]

Renewable-energy-based microgrids (MGs) are being advocated around the world in response to increasing energy demand, high levels of greenhouse gas (GHG) emissions, energy losses, and the depletion of conventional energy resources. However, the high investment cost of the MGs besides the low selling price of the energy to the main grid are two main challenges to realize the MGs in developing countries such as Iran. For this reason, the government should define some incentive policies to attract investor attention to MGs. This paper aims to develop a framework for the optimal planning of a renewable energy-based MG considering the incentive policies. To investigate the effect of the incentive policies on the planning formulation, three different policies are introduced in a pilot system in Iran. The minimum penetration rates of the RESs in the MG to receive the government incentive are defined as 20% and 40% in two different scenarios. The results show that the proposed incentive policies reduce the MG's total net present cost (NPC) and the amount of carbon dioxide (CO2) emissions. The maximum NPC and CO2 reduction in comparison with the base case (with incentive policies) are 22.87% and 56.13%, respectively. The simulations are conducted using the hybrid optimization model for electric renewables (HOMER) software. [ABSTRACT FROM AUTHOR]

The acceleration of distributed energy resources and carbon pricing policies have compelled utilities to act and to prioritize carbon-constrained infrastructure augmentation in their capital programs. To implement various carbon emission reduction policies, power system transmission planning has become more challenging. The existing energy system will face massive retirement of coal-fired power plants (CFPPs), large scale integration of renewable energy and network expansion. In this paper, an electricity network planning and transformation roadmap, which has two milestones, is put forward. In the first stage, a mathematical model is proposed based on the average cost of carbon emission reduction to realize the cooperation of CFPPs retirement and renewable energy investment. It can help the network carry out the transition from a fossil-fuel dominated system to a low-carbon oriented system. Because of the promising prospect of power-to-gas (P2G) technology, in the second milestone, a method based on carbon emission flow (CEF) is employed to help the power-to-gas stations (P2GSes) to select the construction site and capacity. The gas network constraints are modeled to guarantee that P2GSes can work smoothly without energy flow congestion in both electricity and gas networks. According to the simulation results in case studies, our method can reach the emission reduction target more economically and effectively, and the P2GSes can produce and absorb clean energy. [ABSTRACT FROM AUTHOR]

Carbon financing policies such as emission trading have been used to assist in emission mitigation worldwide. As energy end-users/consumers are the underlying driver of emissions, it would be difficult to effectively mitigate carbon emissions by creating an emission trading market without active end-users’ involvement. In electricity markets, demand side management (DSM) in the smart grid can manage demands in response to power supply conditions and influence end-users to contribute to improving both network efficiency and economic efficiency. However, it is a relatively new topic to study the environmental benefits of DSM. This paper proposes a two-stage scheduling model to comprehensively investigate the environmental benefits of consumers participating in both electricity and carbon emission trading markets through active DSM. A developed zero sum gains-data envelopment analysis (ZSG-DEA) model based multi-criteria allocation scheme for emission allocation is employed. Meanwhile, the carbon emission flow model (CEF) is applied to track the “virtual” carbon flow accompanying power flow. According to case studies on the IEEE 24-bus system and IEEE 118-bus system, the proposed model can effectively achieve carbon emission mitigation and provide consumers extra environmental benefits in some scenarios. This model can be an important guide for governments to establish emission trading schemes. [ABSTRACT FROM AUTHOR]

In this paper, one of the ways to reduce carbon dioxide (CO2) emissions into the atmosphere through the use of various types of solar power plants (SES) was considered. The paper provides an overview of the energy resources that currently exist in the Republic of Cuba, as well as the new investments made by the country in order to introduce a more extensive use of the renewable energy sources. The paper also describes the benefits of renewable energy that help to reduce the CO2 emissions into the environment. [ABSTRACT FROM AUTHOR]

Energy supply in Germany is subject to a profound change. The present paper addresses the German potential of storing excess energy from renewable power sources in the geological subsurface. Wind and solar electricity can be transformed into hydrogen, and with carbon dioxide subsequently into methane. When needed, electricity is regained in a gas turbine power plant combusting the methane. Here, we are taking into account the actual German storage capacity for natural gas and show that the outlined technology is ready for operation and economically competitive. The current potential for combined storage of methane and carbon dioxide allows to store around 80 TWh renewable excess energy. This is far more than required to date and estimated to provide the entire coverage in 2050. [ABSTRACT FROM AUTHOR]

For a smart grid system operating with clustered generating units, the challenge usually lies in the optimal scheduling of energy resources. Thus, the improvement of a unit commitment problem gains importance in the present power network. In this paper, a novel probability algorithm is proposed for solving the unit commitment problem, in which five separate units from a four-cluster group are operated for one day. This is done with the aim of optimizing the characteristics such as optional units, generation, operating, and marginal cost. Being a multi-objective function, the other factors such as cost response, unit commitment of supply clustering units, clustering of combined operational units, and CO2 emissions are also included. For this study, an RLC load is mathematically modeled in the cluster system, whereas the Unit Control is provided by a Converter and Battery Management Unit. The clustering model developed along with the Unit demand aims to increase the optional units (from 20 to 100 units), decrease the average demand (from 99 to 93 percentage), and lower the generating and marginal costs (from Rs.23,881 to Rs.21,079, Rs.43,082 to Rs.42,111, Rs.71,162 to Rs.64,955, Rs.83,169 to Rs.81,694, Rs.104,104 to Rs.102,928). The suggested algorithm is simulated for a comprehensive smart grid system and the response for marginal cost, CO2 emissions are obtained. In comparison to conventional schemes, the results of the proposed optimization approach show a reduction in the Carbon dioxide emission (in the range of 100 to 400 kg) and in the losses after adding working units with cluster spans of 0.5 to 1.5 kW. [ABSTRACT FROM AUTHOR]

The current conventional approach to determining the primary energy associated with non-combustible renewable energy (RE) sources such as wind energy and hydro power is to equate the electricity generated from these sources with the primary energy supply. This paper compares this with an approach that was formerly used by the IEA, in which the primary energy equivalent attributed to renewable energy was equated with the fossil fuel energy it displaces. Difficulties with implementing this approach in a meaningful way for international comparisons lead to most international organisations abandoning the primary energy equivalent methodology. It has recently re-emerged in prominence however, as efforts grow to develop baseline procedures for quantifying the greenhouse gas (GHG) emissions avoided by renewable energy within the context of the Kyoto Protocol credit trading mechanisms. This paper discusses the primary energy equivalent approach and in particular the distinctions between displacing fossil fuel energy in existing plant or in new plant. The approach is then extended provide insight into future primary energy displacement by renewable energy and to quantify the amount of CO 2 emissions avoided by renewable energy. The usefulness of this approach in quantifying the benefits of renewable energy is also discussed in an energy policy context, with regard to increasing security of energy supply as well as reducing energy-related GHG (and other) emissions. The approach is applied in a national context and Ireland is case study country selected for this research. The choice of Ireland is interesting in two respects. The first relates to the high proportion of electricity only fossil fuel plants in Ireland resulting in a significant variation between primary energy and primary energy equivalent. The second concerns Ireland's poor performance to date in limiting GHG emissions in line with its Kyoto target and points to the need for techniques to quantify the potential contribution of renewable energy in achieving the target set. [ABSTRACT FROM AUTHOR]

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The credible sources of fossil energy efficiently are a vital cause of economic growth and considerable influence on adequate security. Whereas radiant energy positively enhances or ostensibly promotes socio-economic stability and the controlled environment. The fossil energy sources supply has become progressively stern in China and reconnoitering the beta decoupling relationships between CO2 emissions, GDP, energy consumption, electricity consumption, value-added industries, and population. The results will be favorable for illustrative the security of the valuable resources. This study adopts the extended stochastic model (STIRPAT) with Beta Decoupling Techniques (BDT). This modern technique merely employs the decoupling situation by the alpha and beta effects from 1989 to 2018 and calculates the % change in CO2 emissions by GDP growth and energy consumption. The estimated results represent negative and economic growth depends on coal and natural gas. First, CO2 emissions annually increasing cause of rapid growth, energy consumption, and electricity production, and the structural contradiction of energy remained static. Second, the Value-added industries estimated that CO2 emissions reduce by primary industries. Third, the decoupling states of CO2 emissions and population show an inverse relationship. This paper tentatively suggests China is sustainable, naturally strengthens energy output, transmutes the energy consumption structure, and advances development policies under environmental circumstances. [ABSTRACT FROM AUTHOR]

In order to achieve sustainable development goals, modern power systems need to achieve a low-carbon transition. Retirement and replacement of aging coal-fired power plants (CFPP) is the major part of electricity network transition. However, the sudden retirement of large aging CFPP could lead to power supply or reserve shortages and generally, it takes several years to complete the replacement process. This paper proposes a low-carbon electricity network transition model, helping to plan aging CFPP retirement and renewable power plants installation as well as network augmentation. The trade-off decisions are found among three conflicting objectives including cost, risk and carbon emission. Moreover, the carbon emission flow (CEF) model is applied in the planning process to calculate carbon emissions from the demand side, in order to assess the efficacy of the low-carbon transition. A relatively new multi-objective natural aggregation algorithm (MONAA) is introduced and applied to find the optimal solution. The proposed model is verified on a modified IEEE 24-bus RTS system and a modified IEEE 118-bus system. According to the numerical results, the proposed model can achieve carbon mitigation, cost and risk benefits and provide a roadmap to guide the energy network transformation towards a low-carbon economy. [ABSTRACT FROM AUTHOR]

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Synergistic governance of emission reduction between pollutants and CO2 (hereinafter referred to as synergistic governance) reflects China's proactive response to climate change and will become a central task in China's environmental governance over the next decade and beyond. Given this, this paper aims to systematically understand why synergistic governance is possible and what China has achieved in synergistic governance. In order to achieve these aims, this paper constructs a scientific indicator system based on synergistic governance theory and applies the composite system synergy model to assess the level of synergistic governance in China. The results show that China has made great progress in synergistic governance in the past decade, achieving a leaping development from mild non-synergy to moderate synergy. The achievement mainly comes from the efforts of nearly 1/3 of Chinese provinces in advancing synergistic governance, and the improvement direction of synergistic governance in these provinces is consistent with the national level, jumping from mild non-synergy to moderate synergy. However, the level of synergistic governance in some provinces has decreased rather than increased. It is worth noting that the widening gap in the level of synergistic governance within China's regions may become a vital factor that hinders the sustainable promotion of synergistic governance. This paper clarifies the operational logic of synergistic governance and provides a comprehensive evaluation method, which is beneficial to provide some references for other countries that intend to work on synergistic governance. • Theoretical explanation on synergistic governance from resource flow and energy flow. • A composite system synergy model for the synergistic governance is developed. • Spatial-temporal evolution of synergistic governance in Chinese regions is analyzed. • Widening differences will constrain the sustainability of synergistic governance. [ABSTRACT FROM AUTHOR]

The objective of this study is to perform an analysis to determine the most suitable type of wind turbine that can be installed at a specific location for electricity generation, using annual measurements of wind characteristics and meteorological parameters. Wind potential analysis has shown that the analyzed location is suitable for the development of a wind farm. The analysis was carried out for six different types of wind turbines, with a power ranging from 1.5 to 3.0 MW and a hub height set at 80 m. Wind power potential was assessed using the Weibull analysis. The values of the scale coefficient c were determined, and a large monthly variation was observed, with values ranging from 1.92 to 8.36 m/s and an annual value of 4.95 m/s. Monthly values for the shape coefficient k varied between 0.86 and 1.53, with an annual value of 1.07. Additionally, the capacity factor of the turbines was determined, ranging from 17.75 to 22.22%. The Vestas turbine, with a nominal power of 2 MW and a capacity factor of 22.22%, proved to be the most efficient wind turbine for the specific conditions of the location. The quantity of greenhouse gas emissions that will be reduced if this type of turbine is implemented was also calculated, considering the average CO2 emission intensity factor (kg CO2/kWh) of the national electricity system. [ABSTRACT FROM AUTHOR]

Microalgae are one of the most promising feedstocks for biodiesel production due to their high lipid content and easy farming. However, the extraction of lipids from microalgae is energy intensive and costly and involves the use of toxic organic solvents. Compared with organic solvent extraction, supercritical CO2 (SCCO2) has demonstrated advantages through lower toxicity and no solvent-liquid separation. Due to the nonpolar nature of SCCO2, polar organic solvents such as methanol may need to be added as a modifier in order to increase the extraction ability of SCCO2. In this paper, pilot scale lipid extraction using SCCO2 was studied on two microalgae species: Spirulina sp. and Schizochytrium sp. For each species, SCCO2 extraction was conducted on 200 g of biomass for 6 h. Methanol was added as a cosolvent in the extraction process based on a volume ratio of 4%. The results showed that adding methanol in SCCO2 increased the lipid extraction yield significantly for both species. Under an operating pressure of 4000 psi, the lipid extraction yields for Spirulina sp. and Schizochytrium sp. were increased by 80% and 72%, respectively. It was also found that a stepwise addition of methanol was more effective than a one-time addition. In comparison with Soxhlet extraction using methylene chloride/methanol (2:1, v/v), the methanol-SCCO2 extraction demonstrated its high effectiveness for lipid extraction. In addition, the methanol-SCCO2 system showed a high lipid extraction yield after increasing biomass loading fivefold, indicating good potential for scaling up this method. Finally, a kinetic study of the SCCO2 extraction process was conducted, and the results showed that methanol concentration in SCCO2 has the strongest influence on the lipid extraction yield. [ABSTRACT FROM AUTHOR]

Integrated energy systems (IESs) have attracted increasing attention in recent years due to the high energy efficiency and low emission of carbon dioxide. To deal with the limitation of single IES, distributed energy networks consisting of multi-IESs are proposed to improve the complementarity of both the energy supply and the demand. This paper mainly focuses on the day-ahead energy management of the whole energy network for the economic operation of the system, following which, a cooperative game is formulated to determine the optimal strategy of each IES to minimize the coalition daily cost. Meanwhile, an allocation mechanism is designed from the perspective of probability to allocate coalition cost to each IES. According to the results of the numerical study, the proposed approach can improve the economic performance of both the energy network and the individual IES by interchanging electrical and thermal energies in the network. [ABSTRACT FROM AUTHOR]

With the increasing use of renewable energy resources for the power grid, the need for long-term storage technologies, such as power-to-gas systems, is growing. Biomethanation provides the opportunity to store energy in the form of the natural gas-equivalent biomethane. This study investigates a novel plug flow reactor that employs a helical static mixer for the biological methanation of hydrogen and carbon dioxide. In tests, the reactor achieved an average methane production rate of 2.5 L C H 4 L R ∗ d (methane production [LCH4] per liter of reactor volume [LR] per day [d]) with a maximum methane content of 94%. It demonstrated good flexibilization properties, as repeated 12 h downtimes did not negatively impact the process. The genera Methanothermobacter and Methanobacterium were predominant during the initial phase, along with volatile organic acid-producing, hydrogenotrophic, and proteolytic bacteria. The average ratio of volatile organic acid to total inorganic carbon increased to 0.52 ± 0.04, while the pH remained stable at an average of pH 8.1 ± 0.25 from day 32 to 98, spanning stable and flexible operation modes. This study contributes to the development of efficient flexible biological methanation systems for sustainable energy storage and management. [ABSTRACT FROM AUTHOR]

The proposed transition to hydrogen is aimed at resolving global issues, such as petroleum scarcity and CO2 emissions, so it is sensible to look at this transition at a global level. In this paper, we present a model, named the World Hydrogen Transition Model (WHTM), that seeks to achieve two goals: 1) a projection of requirements for worldwide automobile travel measured in vehicle-kilometers traveled through the end of the 21st century, and 2) a prediction of hydrogen and underlying energy resource requirements based on different scenarios for improvement in vehicle efficiency, introduction of fuel cell vehicles, and introduction of hydrogen produced from non-fossil resources. The model includes industrializing and less developed as well as industrialized countries. Results from the model suggest that, for a range of likely scenarios, energy consumption for automobile travel will be as great or greater than current levels. However, if the transition to hydrogen fuel cell vehicles can be carried out successfully in the middle of the century, and is then followed by a transition to hydrogen from non-fossil resources, total petroleum consumption and CO2 emissions from the automobile sector could be greatly reduced compared to current levels, thereby making motorized personal transportation more sustainable. Applicability to other emerging zero-carbon vehicle options, such as plug-in hybrid electric vehicles (PHEVs), is also discussed. [ABSTRACT FROM AUTHOR]

A strategic land-use-transport interaction model is used to investigate the impacts of policies in technology, infrastructure, pricing and regulation under different assumptions about energy supply. Six scenarios have been defined, analysing three policy strategies in two different contexts of energy supply—A, generally accepted energy supply forecast and B, worst-case energy supply forecast (scarcity of energy). Policies include: business as usual; investment in infrastructure and technology; and a demand regulation based approach involving changes in taxation and tolls. The paper assesses the impact and robustness of each policy against assumptions about future oil supply/demand. Our results demonstrate three key issues. First, scarcity of oil will accelerate the development and take-up of alternative fuel technologies; second, investment in alternative technologies alone will alleviate the impact of local emissions and reduce energy consumption per kilometre travelled but will only reduce yearly carbon dioxide (CO2) emissions after a time lag of about 15 years; so that, third, some form of regulation of demand will be necessary to reduce total emissions and externalities caused by congestion. Research is required to define the necessary level of regulation in combination with technology investments. However, we suggest that a policy involving improvements in infrastructure coupled with investments in fuel technology and differentiated fuel taxes will be required in the future. [ABSTRACT FROM AUTHOR]

The paper analyses the discourse on global environmental change in Iceland in official reports and newspaper discussions around the turn of the millennium. Three competing discursive positions were found. First, Iceland can provide clean energy for the world so that aluminium smelters do not need to burn as much fossil fuels as they would have to do otherwise. Second, Iceland is responsible to the world for the protection of its environment because Icelanders have a unique land to protect – the largest unpopulated and untouched area in western Europe. Third, Iceland can help the world by contributing its vast land areas to grow grass and forests and fix carbon dioxide, in part because some of these areas are especially well suited to soil reclamation and afforestation. The study focuses on the use of nationalistic arguments for the global role and responsibility of Iceland in environmental matters. [ABSTRACT FROM AUTHOR]

This paper discusses reduction in specific CO[sub 2] emissions, industry efforts to promote use of natural gas, expanded nuclear generation, and research and development (R&D) works on improving efficiency of fossil plants. It also discusses feasibility of HVdc interconnected power systems for environmental protection, development of hydropower, and specific possible developments in Siberia and Russia to the year 2030. The paper first discusses the main features of Asia's power sector. It examines how Asia will account for half of global generation expansion, where most of this expansion will be dominated by coal-firing power stations. It examines power in Japan: measures for environmental issues and related R&D. A reduction in specific CO[sub 2] emissions (kg-C/kWh) exceeding 30% has been achieved over the past 20 years as a result of expanded use of nuclear power generation and industry efforts to promote the use of liquefied natural gas. Discussed is Japan's target for CO[sub 2] reduction in the year 2010 of 6% below the level of 1990. The paper goes on to focus on prospects for development of power generation in East Russia. Current state of generating capacity of East Russia, prerequisites for prospective power development, and prospects for development are examined. Finally, future electric power development in China is reviewed. A feasibility study for interconnection of the eastern area of the Eurasian continent for around the year 2020 is then discussed. [ABSTRACT FROM AUTHOR]

Power cycles running on carbon dioxide at supercritical pressure and temperature were introduced in the late ninety-sixties but, after a warm welcome to the theoretical performance announced, they were later abandoned in favour of standard combustion gas turbines. Nevertheless, the technology was brought forward about a decade ago and has since captured significant attention from the scientific and industrial community. The number of publications has risen exponentially and there are several experimental projects under development today. The performances of these cycles have been deeply analysed in literature, proving to be theoretically competitive. This paper reviews all the works published in the topic to date. Different cycle concepts (stand-alone and in combination with other cycles using the same or different technologies), layouts, fuels, applications (power only or combined heat and power) and operating conditions are reviewed and categorised according to the configuration of the cycle. This latter feature is thought to be an interesting added value of this paper since, rather than just listing the past work in the area of sCO 2 power cycles, it also organises the numerous cycles in different categories and provides a comparison of the claimed performance of each one of them. This comparison between the performances of the various configurations is based on the values declared in the original papers and thus applies to very different boundary conditions. Obviously, this great heterogeneity of the available data (in particular the temperatures and pressures considered) makes it impossible to establish a fair comparison between the configurations reviewed. Therefore, a future study seems to be mandatory where the performances of all cycles should be compared for the same set of operating conditions. [ABSTRACT FROM AUTHOR]

In this paper, the significance of CO 2 -free hydrogen is discussed using a long-term global energy system. The energy demand–supply system including CO 2 -free hydrogen was assumed, though there are still large uncertainties as to whether a global CO 2 -free hydrogen energy system will be deployed. System analysis was conducted using the global and long-term intertemporal optimization energy model GRAPE under severe CO 2 emission constraints. Applied global CO 2 constraints for 2050 were a 50% reduction from 1990 levels. CO 2 constraints accounting for Intended Nationally Determined Contributions (INDCs) in each region were also considered. A variety of energy resources and technologies were considered in this model. Hydrogen can be produced from low-grade coal or natural gas with CO 2 capture and electricity from renewable energy. The hydrogen CIF (cost, insurance, and freight) price for Japan was about 3.2 cents/MJ in 2030. Hydrogen demand technologies considered in this paper are hydrogen-fired power plants, direct combustion, combined heat and power (fuel cells, gas engines, and gas turbines), fuel cell vehicles, and hydrogen internal combustion engine vehicles. The majority of CO 2 -free hydrogen was deployed in the transportation sector. CO 2 -free hydrogen was utilized in the power sector, where deployment of other zero emission technology has some constraints. From an economic viewpoint, CO 2 -free hydrogen can reduce the global energy system cost. From the viewpoint of a localized region, such as Japan, deployment of CO 2 -free hydrogen can improve energy security and environmental indicators. [ABSTRACT FROM AUTHOR]

This paper explores the viability of relying on wind power to replace upwards of 60% of electricity generation in Alberta that would be lost if coal-fired generation is phased out. Using hourly wind data from 17 locations across Alberta, we are able to simulate the potential wind power output available to the Alberta grid when modern, 3.5 MW-capacity wind turbines are spread across the province. Using wind regimes for the years 2006 through 2015, we find that available wind power is less than 60% of installed capacity 98% of the time, and below 30% of capacity 74% of the time. There is only a small amount of correlation between wind speeds at different locations, but yet it remains necessary to rely on fossil fuel generation. Then, based on the results from a grid allocation model, we find that CO2 emissions can be reduced by about 30%, but only through a combination of investment in wind energy and reliance on purchases of hydropower from British Columbia. Only if nuclear energy is permitted into the generation mix would Alberta be able to meet its CO2-emissions reduction target in the electricity sector. With nuclear power, emissions can be reduced by upwards of 85%. [ABSTRACT FROM AUTHOR]

In this paper, a combined cooling, heating and power system based on diesel-fueled chemical looping hydrogen generation and solid oxide fuel cell, and with CO 2 capture was established. The system can achieve efficient power generation while separating CO 2 without energy consumption, and effectively avoid the carbon deposition problem. Aspen software is used to simulate the process of the system, and FORTRAN program is used to calculate, through the thermodynamic analysis model, the unique performance change law of the new system using diesel is obtained, and thermodynamic analysis is performed on the system at last. The results show that the power efficiency of the new system is 54.1%, while the exergy efficiency and fuel energy saving ratio can reach 53%. At the same time, the influence of fuel flow and fuel utilization factor on the system performance does not continue to increase or decrease, and the system performance parameters will have a peak value with the change of pressure. The results not only provide a theoretical basis for the future construction of new diesel-fueled energy supply system, but also provide a new idea for the optimization scheme of energy-saving system and carbon recovery. • Propose a new type of SOFC–CCHP system with diesel reforming by CLHG to produce hydrogen as fuel. • The new system can avoid the carbon deposition and separate CO 2 without energy consumption. • Established the thermal analysis models obtaining the unique performance change law of the integrated system. [ABSTRACT FROM AUTHOR]

Cloud computing provides online services to users from anywhere in a pay‐as‐you‐go basis. This leads to the construction of different forms of data centers around the world, which usually consumes huge amount of energy and produce pollution (heat and carbon dioxide footprint). Many efforts have focused on managing cloud resources to decrease their energy consumption. Since servers are the highest energy consumers in data centers, most researchers have focused on optimizing their energy consumption while other resources such as network devices and cooling systems have received less attention. In this paper, we propose a network‐aware virtual machine (VM) relocation algorithm, which optimizes the distribution of the VMs running on the data center in order to conserve energy in both servers and network devices (switches). The proposed technique targets the communicated VMs and places them closer to each other. This would reduce the traffic overhead between any communicating VMs so that fewer network devices are involved in the communication process. This also increases the VMs consolidation to some servers while leaving other servers idle. Switching off the idle servers and network devices would significantly reduce the total energy consumed by the data center. The proposed algorithm is evaluated using simulation and the performance of the proposed algorithm is compared against different previously proposed algorithms in the literature. Performance metrics used are the energy consumed by the host and by the network switches, the service level agreement violations, and the number of VM migrations. The impact of different packet sizes, the efficiency of switching the network elements to sleep mode, and the impact of resource homogeneity and heterogeneity are also studied and discussed. Simulation results show that the proposed algorithm outperforms the existing algorithms in terms of all evaluation metrics. [ABSTRACT FROM AUTHOR]

Abstract: India’s aspiration for economic growth has consequences for energy growth and CO2 emissions. This paper examines India’s need for energy with 20 year perspectives. From an earlier paper by K. Parikh et al. (2009), demand scenario are examined from the supply perspectives ranging from coal, hydrocarbon, nuclear, hydrogen, hydro and other renewable etc. None of these are substantial and India will have to rely on imports. The need for energy has to be reduced by a drive for energy efficiency and renewable energy. Government programmes for the above are also commented upon. Though India’s CO2 emissions are unlikely to grow very much due to energy scarcity and energy mix the article examines the potential to reduce CO2 emissions and the associated costs involved in various options. It finds that 30% reduction in CO2 emissions by 2030 is feasible but would involve additional costs. The most promising option is to reduce energy demand by various measures to increase energy use efficiency in production and consumption. [Copyright &y& Elsevier]

Biofuels are fuels produced from biomass, mostly in liquid form, within a time frame sufficiently short to consider that their feedstock (biomass) can be renewed, contrarily to fossil fuels. This paper reviews the current and future biofuel technologies, and their development impacts (including on the climate) within given policy and economic frameworks. Current technologies make it possible to provide first generation biodiesel, ethanol or biogas to the transport sector to be blended with fossil fuels. Still under-development 2nd generation biofuels from lignocellulose should be available on the market by 2020. Research is active on the improvement of their conversion efficiency. A ten-fold increase compared with current cost-effective capacities would make them highly competitive. Within bioenergy policies, emphasis has been put on biofuels for transportation as this sector is fast-growing and represents a major source of anthropogenic greenhouse gas emissions. Compared with fossil fuels, biofuel combustion can emit less greenhouse gases throughout their life cycle, considering that part of the emitted CO2 returns to the atmosphere where it was fixed from by photosynthesis in the first place. Life cycle assessment (LCA) is commonly used to assess the potential environmental impacts of biofuel chains, notably the impact on global warming. This tool, whose holistic nature is fundamental to avoid pollution trade-offs, is a standardised methodology that should make comparisons between biofuel and fossil fuel chains objective and thorough. However, it is a complex and time-consuming process, which requires lots of data, and whose methodology is still lacking harmonisation. Hence the life-cycle performances of biofuel chains vary widely in the literature. Furthermore, LCA is a site- and time-independent tool that cannot take into account the spatial and temporal dimensions of emissions, and can hardly serve as a decision-making tool either at local or regional levels. Focusing on greenhouse gases, emission factors used in LCAs give a rough estimate of the potential average emissions on a national level. However, they do not take into account the types of crop, soil or management practices, for instance. Modelling the impact of local factors on the determinism of greenhouse gas emissions can provide better estimates for LCA on the local level, which would be the relevant scale and degree of reliability for decision-making purposes. Nevertheless, a deeper understanding of the processes involved, most notably NO emissions, is still needed to definitely improve the accuracy of LCA. Perennial crops are a promising option for biofuels, due to their rapid and efficient use of nitrogen, and their limited farming operations. However, the main overall limiting factor to biofuel development will ultimately be land availability. Given the available land areas, population growth rate and consumption behaviours, it would be possible to reach by 2030 a global 10% biofuel share in the transport sector, contributing to lower global greenhouse gas emissions by up to 1 GtCO eq · year (IEA, 2006), provided that harmonised policies ensure that sustainability criteria for the production systems are respected worldwide. Furthermore, policies should also be more integrative across sectors, so that changes in energy efficiency, the automotive sector and global consumption patterns converge towards drastic reduction of the pressure on resources. Indeed, neither biofuels nor other energy source or carriers are likely to mitigate the impacts of anthropogenic pressure on resources in a range that would compensate for this pressure growth. Hence, the first step is to reduce this pressure by starting from the variable that drives it up, i.e. anthropic consumptions. [ABSTRACT FROM AUTHOR]

Abstract The Renewable energy power generation capacity has been rapidly increasing in China recently. Meanwhile, the contradiction between power supply and demand is becoming increasingly more prominent due to the intermittence of renewable energies. On the other hand, on the mitigation of carbon dioxide (CO 2) emissions in China needs immediate attention. Power-to-Gas (PtG), a chemical energy storage technology, can convert surplus electricity into combustible gases. Subsurface energy storage can meet the requirements of long term storage with its large capacity. This paper provides a discussion of the entire PtG energy storage technology process and the current research progress. Based on the comparative study of different geological storage schemes for synthetic methane, their respective research progress and limitations are noted. In addition, a full investigation of the distribution and implementation of global PtG and CO 2 capture and storage (CCS) demonstration projects is performed. Subsequently, the opportunities and challenges of the development of this technology in China are discussed based on techno-economic and ecological effects analysis. While PtG is expected to be a revolutionary technology that will replace traditional power systems, the main issues of site selection, energy efficiency and the economy still need to be adequately addressed. Additionally, based on the comprehensive discussion of the results of the analysis, power-to-gas and subsurface energy storage implementation strategies, as well as outlook in China are presented. Graphical abstract fx1 Highlights • The entire process of power-to-gas (PtG) and subsurface energy storage is reviewed in detail. • A comparative analysis of gas storage in the same or different formations. • Opportunities and challenges for China based on techno-economic and ecological effects analysis. • Power-to-gas implementation strategies and outlook for China. [ABSTRACT FROM AUTHOR]

Abstract: Fossil fuel based power generation is and will still be the back bone of our world economy, albeit such form of power generation significantly contributes to global CO2 emissions. Solar energy is a clean, environmental friendly energy source for power generation, however solar photovoltaic electricity generation is not practical for large commercial scales due to its cost and high-tech nature. Solar thermal is another way to use solar energy to generate power. Many attempts to establish solar (solo) thermal power stations have been practiced all over the world. Although there are some advantages in solo solar thermal power systems, the efficiencies and costs of these systems are not so attractive. Alternately by modifying, if possible, the existing coal-fired power stations to generate green sustainable power, a much more efficient means of power generation can be reached. This paper presents the concept of solar aided power generation in conventional coal-fired power stations, i.e., integrating solar (thermal) energy into conventional fossil fuelled power generation cycles (termed as solar aided thermal power). The solar aided power generation (SAPG) concept has technically been derived to use the strong points of the two technologies (traditional regenerative Rankine cycle with relatively higher efficiency and solar heating at relatively low temperature range). The SAPG does not only contribute to increase the efficiencies of the conventional power station and reduce its emission of the greenhouse gases, but also provides a better way to use solar heat to generate the power. This paper presents the advantages of the SAPG at conceptual level. [Copyright &y& Elsevier]

Abstract: This paper explores the integration and evaluation of a power plant with a CaO-based CO2 capture system. There is a great amount of recoverable heat in the CaO-based CO2 capture process. Five cases for the possible integration of a 600MW power plant with CaO-based CO2 capture process are considered in this paper. When the system is configured so that recovered heat is used to replace part of the boiler heat load (Case 2), modelling not only shows that this is the system recovering the most heat of 1008.8MW but also results in the system with the lowest net power output of 446MW and the second lowest of efficiency of 34.1%. It is indicated that system performance depends both on the amount of heat recovery and the type of heat utilization. When the system is configured so that a 400MW power plant is built using the recovered heat (Case 4), modelling shows that this is the system with the most net power output of 846MW, the highest efficiency of 36.8%, the lowest cost of electricity of 54.3€/MWh and the lowest cost of CO2 avoided of 28.9€/tCO2. This new built steam cycle will not affect the operation of the reference plant which vents its CO2 to the atmosphere, highly reducing the connection between the CO2 capture process and the reference plant which vents its CO2 to the atmosphere. The average cost of electricity and the cost of CO2 avoided of the five cases are about 58.9€/kWh and 35.9€/tCO2, respectively. [Copyright &y& Elsevier]

Abstract: Optimization of combined cooling, heating, and power (CCHP) systems operation commonly focuses only on energy cost. Different algorithms have been developed to attain optimal utilization of CCHP units by minimizing the energy cost in CCHP systems operation. However, other outcomes resulting from CCHP operation such as primary energy consumption and emission of pollutants should also be considered during CCHP systems evaluation as one would expect these outcomes can be subject to regulation. This paper presents an optimization of the operation of CCHP systems for different climate conditions based on operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE) using an optimal energy dispatch algorithm. The results for the selected cities demonstrate that in general there is not a common trend among the three optimization modes presented in this paper since optimizing one parameter may reduce or increase the other two parameters. The only cities that show reduction of PEC while also reducing the CDE are Columbus, MS; Minneapolis, MN; and Miami, FL. For these cities the operational cost always increases when compared to the reference case consisting of using a vapor/compression cycle for cooling and natural gas for heating. On the other hand, for San Francisco and Boston, CCHP systems increase the CDE. In general, if CCHP systems increase the cost of operation, as long as energy savings and reduction of emissions are guaranteed, the implementation of these systems should be considered. [Copyright &y& Elsevier]

It is widely recognised that for the foreseeable future coal will remain an important energy source for generation of electric power in many areas of the world. However, it will be essential to develop generation technologies that include the capture and storage of emissions such as CO2 to combat the harmful effects of climate change. The key to the successful implementation of advanced generation technologies, the ultimate aim of which is the zero emission power plant, depends heavily on the availability of suitable materials. In this paper, the requirements for materials with improved high temperature performance will be considered in the context of three types of power generation system being developed to operate with greatly reduced emissions and with high levels of efficiency. The limitations of existing materials will be outlined and the need for materials with higher temperature capabilities and good fabricability will be discussed. [ABSTRACT FROM AUTHOR]

ALSTOM Power Service delivers solutions not only to recover degradation, but also to increase the performance and efficiency of the installed global power generation fleet. Such performance improvements also reduce greenhouse gases, particularly CO2 emissions. The mechanisms of the Kyoto Protocol promote the implementation of CO2-reducing state-of-the-art technologies to developing and emerging economies. Having installed the world's largest power generation fleet, ALSTOM wants to make use of the Clean Development Mechanism (CDM) to make technology implementation economically attractive for non-Annex I countries. This paper gives an overview and outlook for environmental mechanisms and technologies, the value proposition and some experience in pioneering a CDM project with a gas turbine upgrade in a non-Annex I country. It is shown that in a crediting period of 10 years 3 million tons of CO2eq can be saved on a mid-sized power plant. Assuming a price of € 8 per ton of CO2eq for Certified Emission Reductions this would lead to an annual revenue of 20 % of the initial implementation cost, representing a very attractive business case for the plant operator. The described CDM application can be a decisive factor for proceeding with a fuel switch or an upgrade. The revenues earned from emission trading enables the plant operator to make the investment to reduce Kyoto-relevant emissions. [ABSTRACT FROM AUTHOR]

This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO2 analysis results provide useful data for policy discussions regarding an efficient and lowcarbon energy mix. The EPR is the amount of electrical energy produced for the lifetime of the power plant divided by the total amount of energy required to procure and transport the materials, build, operate, and decommission the power plants. The CO2 analysis for each power plant was calculated from the life-cycle energy input data. A previous study also analyzed coal and nuclear fission power plants. At the time of that study, two of the three wind systems had less than a full year of generation data to project the life-cycle energy production. This study updates the analysis of three wind systems with an additional four to eight years of operating data. The EPR for the utility-scale wind systems ranges from a low of 11 for a two-turbine system in Wisconsin to 28 for a 143-turbine system in southwestern Minnesota. The EPR is 11 for coal, 25 for fission with gas centrifuge enriched uranium and 7 for gaseous diffusion enriched uranium. The normalized CO2 emissions, in tonnes of CO2 per GWeh, ranges from 14 to 33 for the wind systems, 974 for coal, and 10 and 34 for nuclear fission using gas centrifuge and gaseous diffusion enriched uranium, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a regionally disaggregated global energy model treating energy and CO2 transportation in detail is used to examine a cost-effective pattern for their interregional transportation over the 21st century under the CO2 stabilization target of 550 ppm. Also, we assess future perspectives for the hydrogen economy in such a scenario. The results show that as major petroleum and gas supplies shift to unconventional resources along the second half of this century due to resource depletion, the Middle East loses its importance as a petroleum and gas exporter and the global patterns of their transportation change significantly. We then show that while hydrogen's competitiveness decreases due to the detailed treatment of energy and CO2 transportation, biomass- derived Fischer­Tropsch (FT) fuels become attractive because their production facilitates a wide diffusion of CO2-neutral energy carriers by considerably reducing the transportation cost. FT fuels are produced in regions rich in forest resources and then transported on a large scale by tanker. By contrast, hydrogen is produced mainly at the center of its consumption regions using domestic feedstock, and its interregional delivery, which is done only by pipeline, plays a marginal role due to its high transportation cost. It is confirmed that such a hydrogen supply structure offers energy security benefits. Finally, we show that the regional distribution of CO2 storage capacity is a major determinant of the pattern of hydrogen transportation around 2100, because all the CO2 generated from hydrogen production is required to be captured for sequestration in that period and because interregional CO2 transportation is hardly chosen for economic reasons. [ABSTRACT FROM AUTHOR]

A new policy approach is needed to deliver carbon dioxide savings in the UK; this paper proposes carbon rationing for personal energy use. Current policies are extremely unlikely to result in sufficient savings to meet the 2010 national reduction target. Indeed, when international air travel emissions are included, carbon equivalent emissions have not actually fallen since 1990. In the domestic sector, energy efficiency is expected to deliver significant carbon savings, but data from recent decades show this to be a triumph of hope over experience. Instead carbon rations for personal transport and household energy use are suggested. Rations would be equal, tradable, mandatory and would decrease year-on-year. The aim would be to make guaranteed carbon savings in an egalitarian way. Practical details of rationing are outlined and concerns about its effects are debated. Finally, it is concluded that rationing has great potential to enable the UK, and other countries, to meet their carbon saving targets. [ABSTRACT FROM AUTHOR]

In order to achieve efficient utilization of solar energy resources, this study combines the trans-critical organic Rankine cycle (ORC) power cycle (TORC) with the trans-critical CO2 refrigeration cycle (TCO2). Additionally, a comprehensive three-level index decision evaluation system is developed based on system safety and environmental protection, thermodynamics, and techno-economic performance. The evaluation focuses on typical medium- and high-temperature solar energy applications and considers six organic working gases. The evaluation results demonstrate that the R600 + CO2 solution outperformed the others. This solution achieved a maximum net output power (Pnet) of 1531.31 kW and 2306.43 kW, a maximum coefficient of performance (COP) of 3.16, a predicted payback period of 2.651 years and 2.033 years, and a benefit–investment ratio of 4.533 and 5.773. [ABSTRACT FROM AUTHOR]

The Chinese Government just released its Energy Revolution Strategy (2016–2030) as an official policy response to President Xi Jinping’s urge. Withdraw of the US from Paris Climate Agreement has turned the global focus on if China can comply with its climate change commitments. The purpose of this paper is to conduct a comprehensive assessment on this utterly important question. We find that the 2030 Strategy is consistent with the GDP CO 2 intensity target but cannot deliver CO 2 peak earlier than 2030. We also explore the possibility for China to realize leapfrog in energy efficiency and contribute more to global society in CO 2 emissions abatement. Given China’s economic restructuring potential, continuous efforts in energy efficiency could lead to much lower primary energy demand than the Strategy proposed and thus peak energy-related CO 2 emissions around 2020. It can also make China a new champion in the world with highest energy efficiency level at comparable income level during the economic development process. A much lower primary energy demand can also facilitate China’s non-fossil primary energy share target and the low-carbon power system transition. [ABSTRACT FROM AUTHOR]

Building occupancy information could aid energy preservation while simultaneously maintaining the end-user comfort level. Energy conservation becomes essential since energy resources are scarce and human dependency on appliances is only exponentially increasing. While intrusive sensors (i.e., cameras and microphones) can raise privacy concerns, this paper presents an innovative non-intrusive occupancy detection approach using environmental sensor data (e.g., temperature, humidity, carbon dioxide (CO 2), and light sensors). The proposed scheme transforms multivariate time-series data into images for better encoding and extracting relevant features. The utilized image transformation method is based on data normalization and matrix conversion. Precisely, by representing time-series in 2D space, an encoding kernel can move in two directions while it can move only in one direction when applied to a 1D signal. Moreover, machine learning (ML) and deep learning (DL) techniques are utilized to classify occupancy patterns. Several simulations are used to evaluate the approach; mainly, we investigated pre-trained and custom convolutional neural network (CNN) models. The latter attained an accuracy of 99.00%. Additionally, pixel data are extracted from the generated images and subjected to traditional ML methods. Throughout the numerous comparison settings, it was observed that the latter strategy provided the optimal balance of 99.42% accuracy performance and minimal training time across the occupancy datasets. • Exhaustive literature review on occupancy detection schemes based on sensor data. • Image transformation technique based on data normalization and matrix conversion. • Assessing a variety of pre-trained and custom CNN models to predict occupancy status. • Pixel extraction to gather values and integrate them with conventional ML algorithms. [ABSTRACT FROM AUTHOR]

Energy is the driver in the economic development of any country. However, most of the developing countries do not have sufficient oil reserves to cater to their energy requirement and depend upon oil producing countries. The perturbations in the crude oil price and adverse environmental impacts from fossil fuel usage are the biggest concern. Therefore, developing countries have started investing heavily in solar and wind power and are considering hydrogen as a future energy resource. However, to tap the potential of hydrogen as a fuel, an entirely new infrastructure will be needed for transporting, storing and dispensing it safely, which would be expensive. In the transportation sector, a liquid alternate to fossil fuels will be highly desirable as the existing infrastructure can be used with minor modifications. Among the possible liquid fuels, methanol is very promising. Methanol is a single carbon atom compound and can be produced from wide variety of sources such as natural gas, coal and biomass. The properties of methanol are conducive for use in gasoline engines since it has high octane number and flame speed. Other possible uses of methanol are: as a cooking fuel in rural areas and as a fuel for running the fuel cells. The present study reviews the limitations in the hydrogen economy and why moving toward methanol economy is more beneficial. [ABSTRACT FROM AUTHOR]