Integrated energy systems based on cascade utilization of energy

Focusing on the traditional principle of physical energy utilization, new integration concepts for combined cooling, heating and power (CCHP) system were identified, and corresponding systems were investigated. Furthermore, the principle of cascade utilization of both chemical and physical energy in energy systems with the integration of chemical processes and thermal cycles was introduced, along with a general equation describing the interrelationship among energy levels of substance, Gibbs free energy of chemical reaction and physical energy. On the basis of this principle, a polygeneration system for power and liquid fuel (methanol) production has been presented and investigated. This system innovatively integrates a fresh gas preparation subsystem without composition adjustment process (NA) and a methanol synthesis subsystem with partial-recycle scheme (PR). Meanwhile, a multi-functional energy system (MES) that consumes coal and natural gas as fuels simultaneously, and co-generates methanol and power, has been presented. In the MES, coal and natural gas are utilized synthetically based on the method of dual-fuel reforming, which integrates methane/steam reforming and coal combustion. Compared with conventional energy systems that do not consider cascade utilization of chemical energy, both of these systems provide superior performance, whose energy saving ratio can be as high as 10%–15%. With special attention paid to chemical energy utilization, the integration features of these two systems have been revealed, and the important role that the principle of cascade utilization of both chemical and physical energy plays in system integration has been identified.     

Research,development and the prospect of combined cooling,heating, and power systems

The development of a combined cooling, heating, and power (CCHP) system in China is presented in this paper. The key scientific problems of a distributed energy system and the integration principles of a CCHP system are also pointed out. Moreover, two corresponding CCHP systems: one with the complementarities of fossil fuels energy and renewable energy, and the other integrated with desalination technology, are investigated. With special attention to thermal energy utilization, the integrating characteristics of these systems are likewise revealed, and the important role that the principle of cascade utilization of physical energy plays in system integration is identified. We have found that the energy-saving ratio of the integrated CCHP systems can be as high as 30%, and as such, the innovative CCHP systems suitable for China's sustainable development are also recommended.     

Sustainable development of energy systems for western China

The distribution of energy and industry in China is extremely uneven. The western region is rich in energy resources but relatively economically backward, while the eastern region, particularly, the southeast coastal area, is an industrially-developed area but is short of energy resources. On the basis of such a situation, this paper recommends the sustainable development of energy systems for the western region. The specific innovative energy systems adopted here can convert the western region's fossil fuels to alternative fuels and electricity with higher efficiency, lower investment cost, and less impact upon the environment. As one of such innovative energy systems, the MES (multi-functional energy system) can achieve 10–14% in the energy conservation ratio, 4–8% reduction of investment cost, and a 10–37% decrease of main pollutants. Moreover, its adoption will increase the income and accelerate the development of the energy industry in the western region, as well as meet the energy demand of the eastern region. The analysis in this paper presents a feasible energy road map for the rapid yet sustainable development of China's western region.     

新能源制氢在传统炼化企业的应用

  目的  化石燃料和新能源电力在使用和发展中面临着问题与挑战。为解决传统炼化企业依赖化石燃料制氢中的碳排放问题,和新能源电力发展中的波动性问题提供建议,有必要对氢气制备技术的应用与发展,和传统炼化企业的氢气网络状况进行梳理。  方法  调研了氢气制备技术的应用与发展,尤其关注了关键技术电解水制氢技术的应用发展;分氢制备、氢使用、氢纯化三部分对传统炼化企业的氢气网络进行了深入剖析。  结果  通过总结,提出通过电解水制氢技术将富余的新能源电力与传统炼化企业氢网络相结合的设想。在传统炼化企业附近布置新能源电给,不但可以供炼厂日常用电,还可将因波动性大而无法直接利用的弃电部分,直接通过电解水制氢技术,制氢供传统炼化企业使用,有效降低传统炼化企业的碳排放强度。  结论  要解决化石燃料使用中的碳排放问题与新能源电力使用中波动性高的问题,实现新能源制氢在传统炼化企业的应用,还面临着诸多挑战。     

A discussion on recent developments in Turkey's emerging solar power market

Market reform, energy security and environmental protection are three primary energy policy goals of Turkish government. Although Turkey's abundant solar energy resources can directly address the government's energy policy goals, Turkey has not utilized solar power yet. Utilization of country's huge solar energy potential would decrease dependence on imported fossil fuels and contribute to fulfill environmental commitments. However, lack of regulatory and financial support for the development of solar power has considerably delayed the utilization of country's huge solar potential. The government has taken only modest steps to promote investment in solar power until the end of 2010 when a new feed-in tariff policy was adapted. Turkey's solar energy potential, PV technology status and prospect for concentrating solar power in Turkey have been explored in a number of studies; yet literature dealing with recent policy developments, associated investment environment and opportunities for solar power investors are limited. The aim of this paper is to set out the latest legal framework for investment in Turkey's emerging solar power market and to provide some guidelines to potential investors who appreciated country's huge solar energy potential.     

我国发展智能电网初探

智能电网对推动社会经济发展具有战略意义。我国发展的是坚强智能电网,具有坚强可靠、经济高效、清洁环保、透明开放、友好互动的特点。建设智能电网具有良好的社会效益和经济效益,可以调整我国区域能源不平衡的问题,为我国能源结构调整提供支持,促进各种电网相关技术全面升级,加速产业结构调整,实现对化石能源的替代。同时可以降低电网企业的运营及建设成本,减少发电装机投资和发电环节运营成本。坚强智能电网所使用的特高压输电具有远距离、大容量和低损耗的优势。预计到2020年,建设运行智能电网实现的节能量相当于减少社会能源投入约1392亿元,并可实现减排二氧化碳约13.8×108t。我国已在与智能电网发展相关的清洁能源技术、电网储能技术、输配电技术、用电技术、信息通信技术及标准与规范等方面取得了一定的技术成果,但仍面临许多问题。需要政府在重大科技项目立项、电网项目核准、电价、资金政策和标准制定方面给予支持;并应尽快启动智能电网框架设计,建立完善标准规范体系;政府应根据电力市场的垄断状况,制定出适合我国智能电网发展的投资及控股制度。     

Sustainable energy: A review of gasification technologies

Biomass has been widely recognized as a clean and renewable energy source, with increasing potential to replace conventional fossil fuels in the energy market. The abundance of biomass ranks it as the third energy resource after oil and coal. The reduction of imported forms of energy, and the conservation of the limited supply of fossil fuels, depends upon the utilization of all other available fuel energy sources. Energy conversion systems based on the use of biomass are of particular interest to scientists because of their potential to reduce global CO₂ emissions. With these considerations, gasification methods come to the forefront of biomass-to-energy conversions for a number of reasons. Primarily, gasification is more advantageous because of the conversion of biomass into a combustible gas, making it a more efficient process than other thermochemical processes. Biomass gasification has been studied widely as an efficient and sustainable technology for the generation of heat, production of hydrogen and ethanol, and power generation. Renewable energy can have a significant positive impact for developing countries. In rural areas, particularly in remote locations, transmission and distribution of energy generated from fossil fuels can be difficult and expensive, a challenge that renewable energy can attempt to correct by facilitating economic and social development in communities. This paper aims to take stock of the latest technologies for gasification.     

A review: Energy recovery in batch processes

The implementation of batch processing has increased due to its intrinsic flexibility and adaptability. These are essential characteristics when it comes to producing high-value added materials such as agrochemicals, pharmaceuticals, specialty chemicals…the demand for which has grown in recent decades.Although industrial processes are highly diverse, a common feature to all is that they utilize fossil fuels as the energy source. The reliance on fossil fuels as a primary source of energy generates a negative impact on the environment. The implantation of renewable energies and efficient usage of energy has thus become crucial. Improving energy use could be achieved through advancements in plant machinery and the use of methodologies such as ‘process integration’.Process integration can be described as system oriented methods that could be used during the design and retrofit of industrial processes in order to obtain an optimal utilization of resources. The methods have traditionally focused on an efficient energy use, although recently process integration techniques cover other areas such as efficient use of raw materials, emission reduction and process operations. Energy integration tries to reach the optimization of heat, power, fuel and utilities.The consideration of energy integration complicates the process design and the generation of batch process design alternatives, so what is now required is the proposal and development of different approaches and methods oriented towards recovering energy in this kind of industrial process. Improving energy end-use efficiency will make it possible to reduce dependence on energy imports and bring about innovation and competitiveness.The aim of this work is report the main contributions that have been carried out in order to attain energy integration in batch processes, as well as different examples of applications that have shown the possibilities offered by the developed tools.     

世界促进风电产业发展最新动向

近年来可再生能源发电发展迅速,其中风力发电表现尤为突出.在一些风电先行国家的推动下,风电机组大型化取得长足进展,单机容量从亚兆瓦级迅速提升到兆瓦级,研制中的10MW级风电机组即将问世.机组的大型化提高了风电的经济性和竞争力.风机设备利用率将由目前的25％左右提高至2015年的28％,同时投资成本将大幅下降,按照GWEC的高增长方案预测,投资成本将由2009年的1350欧元/kW降至2030年的1093欧元/kW.鉴于风力发电的间歇性和随机性,蓄电技术成为大量引入可再生能源的有效手段,美欧日等都投入专项经费支持蓄电技术的研究开发.IEA最近在报告中指出,与热电联产组合的方式可大幅扩大可再生能源的利用,其重点在于热供应.智能电网将成为解决风电大规模接入和输送问题的根本途径,它将使电力系统整体利用效率大大提高,有利于抑制发电厂的化石燃料消费.我国在智能电网方面已取得了一定成果,但仍面临许多问题.各国政府的可再生能源电力收购政策促进了风电产业的发展,其中德国的风电收购政策值得我国借鉴.     

On the wind energy in Turkey

Increase in negative effects of fossil fuels on the environment has forced many countries, including Turkey, to use renewable energy sources. Today, clean, domestic and renewable energy is commonly accepted as the key for future life, not only for Turkey but also for the world. As wind energy is an alternative clean energy source compared to the fossil fuels that pollute the atmosphere, systems that convert wind energy to electricity have developed rapidly. Turkey is an energy importing country, more than half of the energy requirement has been supplied by imports. Turkey's domestic fossil fuel resources are extremely limited. In addition, Turkey's geographical location has several advantages for extensive use of wind power. In this context, renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development and environmental pollution prevention in Turkey. Since wind energy will be used more and more in the future, its current potential, usage, and assessment in Turkey is the focus of the present study. The paper not only presents a review of the potential and utilization of the wind power in Turkey but also provides some guidelines for policy makers.     

Environmental and energy life cycle analyses of passenger vehicle systems using fossil fuel-derived hydrogen

Hydrogen energy utilization is expected due to its environmental and energy efficiencies. However, many issues remain to be solved in the social implementation of hydrogen energy through water electrolysis. This analyzes and compares the energy consumption and GHG emissions of fossil fuel-derived hydrogen and gasoline energy systems over their entire life cycle. The results demonstrate that for similar vehicle weights, the hydrogen energy system consumes 1.8 MJ/km less energy and emits 0.15 kg-CO 2 eq./km fewer GHG emissions than those of the gasoline energy system. Hydrogen derived from fossil fuels may contribute to future energy systems due to its stable energy supply and economic efficiency. Lowering the power source carbon content also improved the environmental and energy efficiencies of hydrogen energy derived from fossil fuels.     

Role of optimal transmission switching in accommodating renewable energy in deep peak regulation-enabled power systems

Due to the shortage of fossil energy and the pollution caused by combustion of fossil fuels, the proportion of renewable energy in power systems is gradually increasing across the world. Accordingly, the capacity of power systems to accommodate renewable energy must be improved. However, integration of a large amount of renewable energy into power grids may result in network congestion. Hence, in this study, optimal transmission switching (OTS) is considered as an important method of accommodating renewable energy. It is incorporated into the operation of a power grid along with deep peak regulation of thermal power units, forming an interactive mode of coordinated operation of source and network. A stochastic unit commitment model considering deep peak regulation and OTS is established, and the role of OTS in promoting the accommodation of renewable energy is analyzed quantitatively. The results of case studies involving the IEEE 30-bus system demonstrate that OTS can enable utilization of the potential of deep peak regulation and facilitate the accommodation of renewable energy.     

Direct air capture from demonstration to commercialization stage: A bibliometric analysis

Concerns related to increasing CO₂ emission and its effects on global warming and climate change have been increased with increasing the global consumption of fossil fuels. One solution to respond to this challenge is the development and utilization of carbon capturing and storage technologies. Among different carbon capturing technologies, direct air capture (DAC) reduces CO₂ emissions from air. While the technology readiness level (TRL) of DAC is in the demonstration stage, identifying the commercialization research gaps and possible opportunities can help with diffusion and adoption of the technology. This research uses a knowledge discovery in research databases, based on bibliometric analysis and data mining, to understand DAC research and development's current status and future. Then, we identify the critical areas of the research gap for commercialization. The bibliometric analysis results show that DAC has not yet reached its maturity level compared with other carbon capture technologies (CCTs). However, there are different opportunities for the development of this technology. The results indicate that (a) new systematic designs, improvement in nano-catalysts, increase in the capturing capacity, (b) economic and investment improvements in combination with the environmental assessment of the optimized DAC technology, (c) assessment of future prospects, (d) integration with alternative energy supply sources especially renewable energy to respond to the required energy and process integration with current carbon emitted processes, (e) technology demonstration and readiness assessment, and (f) policy and uncertainty analysis of the market are the key areas that should be investigated for the success of this technology in the competitive market.     

The thermodynamic effect of thermal energy storage on compressed air energy storage system

With the increasing penetration of renewable energy into energy market, it is urgent to solve the problem of fluctuations of renewable energy sources (RES). Energy storage technology is regarded as one method to cope with the unstable nature of RES. One of these technologies is compressed air energy storage (CAES), which is a modification of the basic gas turbine technology. Electric power supplied by CAES can meet peak-load requirement of electric utility systems. Because there is heat waste in the existing CAES systems during compression process, fossil fuels are used to improve the expansion work to generate peak power. In order to avoid the use of fuels and keep high efficiency of system, CAES system with thermal energy storage (TES) is designed to capture and reuse the compressed air heat. This paper uses a thermodynamic model of a CAES system with TES to analyze the effect of TES on system efficiency. Besides, this paper evaluates the influence of temperature and pressure on the utilization of heat in TES. Results show that even when power efficiency reaches maximum, there is still a proportion of thermal energy left in TES for other use. Meanwhile, the utilization of heat in TES can be affected by pressure in the air storage chamber. With appropriate selection of pressure limits, the utilization of compressed air heat can be optimized.     

Techno-economic analysis of a local district heating plant under fuel flexibility and performance

Brovst is a small district in Denmark. This paper analyses the use of local renewable resources in the district heating systems of Brovst. The present use of fossil fuels in the Brovst district heating plant (DHP) represents an increasing environmental and climate-related load. Therefore, an investigation has been made to reduce the use of fossil fuels for district heating system and make use of the local renewable resources (biogas, solar, and heat pump) for district heating purposes. In this article, the techno-economic assessment is achieved through the development of a suite of models that are combined to give cost and performance data for this district heating system. Local fuels have been analyzed for different perspectives to find the way to optimize the whole integrated system in accordance with fuel availability and cost. This paper represents the energy system analysis mode, energyPRO, which has been used to analyze the integration of a large-scale energy system into the domestic district heating system. A model of the current work on the basis of information from the Brovst plant (using fossil fuel) is established and named as a reference option. Then, four other options are calculated using the same procedure according to the use of various local renewable fuels known as “biogas option,” “solar option,” “heat pump option,” and “imported heat option.” A comparison has been made between the reference option and other options. The greatest reduction in heat cost is obtained from the biogas option by replacing a new engine, where 66 % of the current fuel is substituted with biogas.     

Hydrogen versus synthetic fossil fuels

The fuels most considered for the post petroleum and natural gas era, hydrogen (gaseous and liquid) and synthetic fluid fossil fuels, have been compared by taking into account production costs, utilization efficiencies and environmental effects. Three different cost bases have been used for hydrogen depending on the primary energy sources used in its production. The results show that hydrogen is a much more cost effective energy carrier than synthetic fossil fuels. In addition to its environmental and efficiency benefits, hydrogen causes resource conservation, savings in transportation and capital investment, and reduction in inflation.     

世界主要国家应对气候变化政策分析与启示

美国、欧盟、澳大利亚、日本等主要温室气体排放国家或地区为了应对气候变化,都制定了各自的温室气体排放控制目标。为了实现减排目标,各国（或地区）分别制定了应对全球气候变化的法律法规,建立了应对气候变化的碳排放交易体系,实施了各种气候变化税收政策。各国加大资金投入研究开发减缓气候变化的低碳技术,普遍对可再生能源的开发利用颁布了政策法令并建立气候变化资金。世界各主要国家或地区的应对气候变化的政策对完善我国气候变化政策框架体系有一定的启示。我国应加快建立温室气体统计制度,通过技术进步与财税政策促进节能降耗,大力发展可再生能源,降低对化石能源的依赖,建立应对气候变化专项科学基金和低碳技术基金。     

新能源系统中双储能耦合燃煤机组的应用策略研究

  目的  随着新能源电力消费比例不断提高,燃煤机组耦合双储能技术的能源系统发展受到广泛关注。  方法  文章基于能源系统组成、储能技术特性、项目示范情况以及技术瓶颈等方面的分析,针对风电、光伏嵌入下双储能技术耦合燃煤机组参与电力系统调峰应用开展了运行控制策略研究。  结果  双储能技术耦合燃煤机组可通过不同的结构组成、运行策略优化有效解决新能源系统运行稳定性、能源高效利用以及技术经济性等问题,但目前尚未到实现大规模商业化应用阶段。  结论  双储能耦合燃煤机组在新能源系统中的推广应用,需要对双储能技术的策略优化及储能技术本身的发展突破方面不断开展工作。     

对我国风电发展战略的冷思考

我国风电发展迅速,计划2010年风电装机容量要达到3500×10^4kW,2020年达到1.5×10^8kW。据IEA预测,2030年世界能源供应仍以化石能源为主,其比重由2006年的80.8%下降到80.4%;2030年世界发电能源结构也以化石能源发电为主,其比重由2006年的74%下降到73%。中国到21世纪中叶传统化石能源仍将居绝对优势地位。因此在可再生能源和新能源的开发过程中,不要急于求成,片面追求能源和电源结构优化不可取。我国未来要依靠核电和新能源发电,但需要通过对其技术经济的进一步研究,才能确定主要靠核电还是风电、太阳能发电或生物质能发电。目前我国风电发展的主要问题是对风电的技术要求起点低,技术路线不对,从国外引进了落后的风电技术。为了我国风电的健康发展,必须加快风电合理利用的研究,包括风电储能和风电直接利用的研究。     

A review: Exergy analysis of PEM and PEM fuel cell based CHP systems

In recent years, growing attention has been given to new alternative energy sources and exergy analysis since fossil fuels cause emissions that have some negative impacts on earth such as global warming, greenhouse effect etc. New power generation systems have been developed in order to reduce or eliminate these impacts as possible. So that, new alternative energy systems have been taken place instead of fossil fuel based systems with nearly zero emission levels. One of them is solid polymer electrolyte or proton exchange membrane (PEM) fuel cell. Although it has significant advantages, there are some disadvantages such as cost, and hydrogen is not a fuel that can be easily obtained. For these reasons, efficiency of a PEM fuel cell has a great significance. Energy efficiency of a system is the most important parameter for utilization. But, energy analysis does not always show the capacity to do work potential of energy of a system. Exergy analysis must be investigated for a system in order to see available work of the system. Because of disadvantages of the PEM fuel cell, exergy analysis has quite importance. In this paper PEM fuel cell and exergy analysis of PEM fuel cell are combined and investigated. A detailed review of the past and recent research activities has been documented. The review focuses on exergy analysis of both PEM fuel cells and PEM based combined heat and power (CHP) systems at different operating parameters. It is concluded that there are a lot of parameters which effects the exergy efficiencies of systems.