Multi-objective optimal design of hybrid renewable energy systems using PSO-simulation based approach

Recently, the increasing energy demand has caused dramatic consumption of fossil fuels and unavoidable raising energy prices. Moreover, environmental effect of fossil fuel led to the need of using renewable energy (RE) to meet the rising energy demand. Unpredictability and the high cost of the renewable energy technologies are the main challenges of renewable energy usage. In this context, the integration of renewable energy sources to meet the energy demand of a given area is a promising scenario to overcome the RE challenges. In this study, a novel approach is proposed for optimal design of hybrid renewable energy systems (HRES) including various generators and storage devices. The ε-constraint method has been applied to minimize simultaneously the total cost of the system, unmet load, and fuel emission. A particle swarm optimization (PSO)-simulation based approach has been used to tackle the multi-objective optimization problem. The proposed approach has been tested on a case study of an HRES system that includes wind turbine, photovoltaic (PV) panels, diesel generator, batteries, fuel cell (FC), electrolyzer and hydrogen tank. Finally, a sensitivity analysis study is performed to study the sensibility of different parameters to the developed model.     

生物质能汽车的动力系统技术

能源和环境问题成为本世纪世界各国共同面临的两个重大问题。寻找新的"清洁代用燃料"是人类的必然选择。生物质能源是一种可作为车辆发动机燃料的新型清洁低廉的可再生能源,因此研究和开发生物质能汽车动力系统技术有利于改变我国能源消费结构、维护国家能源安全和环境保护。介绍了生物质燃料汽车动力系统技术,主要包括固体燃料裂解气化技术、气体燃料净化技术以及使用燃气式发动机技术等。为研究和开发使用生物质燃料汽车提供了一定的指导和参考信息,为其今后的深入研究提供了一定的参考。     

Turkey's Renewable Energy Facilities in the Near Future

In this work, renewable energy facilities of Turkey were investigated. Electricity is mainly produced by thermal power plants, consuming coal, lignite, natural gas, fuel oil and geothermal energy, and hydro power plants in Turkey. Turkey has no large oil and gas reserves. The main indigenous energy resources are lignite, hydro and biomass. Turkey has to adopt new, long-term energy strategies to reduce the share of fossil fuels in primary energy consumption. For these reasons, the development and use of renewable energy sources and technologies are increasingly becoming vital for sustainable economic development of Turkey. The most significant developments in renewable production are observed hydropower and geothermal energy production. Renewable electricity facilities mainly include electricity from biomass, hydropower, geothermal, and wind and solar energy sources. Biomass cogeneration is a promising method for production bioelectricity.     

Current utilization and future prospects of emerging renewable energy applications in Canada

Canada has vast renewable energy resources due to its extensive geography and traditionally they have played an important role, particularly prior to the turn of the 20th century. Public interest in new renewable energy technologies (RETs) emerged and grew during the oil shocks of the 1970s and early 1980s. Even though many Canadian provinces had been deriving most of their electricity from hydroelectric power, the first oil crises of the 1970s ignited a strong interest in all forms of renewable energy. Though Canada has huge prospects for low-impact RETs, it is falling behind most industrialized nations in the expansion of these technologies due to a lack of supporting market structures and the absence of appropriate government policies and initiatives. This review focuses on only applications of low-impact emerging RETs that refer to wind, solar, small hydro, geothermal, marine and modern biomass energy. Today, these technologies are mostly in the dissemination, demonstration and early stage of commercialization phase in Canada and currently they contribute less than 1% of the total primary energy consumption. It is evident from the past experience of Europe and Japan that environmentally benign RETs can contribute significantly toward Canada’s Kyoto target of reducing greenhouse gas emissions by displacing the use of conventional fossil fuels, and help Canada take an essential step toward a sustainable energy future. In this paper, the current energy utilization scenario of Canada has been analyzed and an array of emerging RET applications has been presented under the category of: (i) green power technologies; (ii) green heat technologies; and (iii) green fuel technologies.     

Real-time energy management in an off-grid smart home: Flexible demand side control with electric vehicle and green hydrogen production

A real-time energy management system for an off-grid smart home is presented in this paper. The primary energy sources for the system are wind turbine and photovoltaics, with a fuel cell serving as a supporting energy source. Surplus power is used to generate hydrogen through an electrolyzer. Data on renewable energy and load demand is gathered from a real smart home located in the Yildiz Technical University Smart Home Laboratory. The aim of the study is to reduce hydrogen consumption and effectively utilize surplus renewable energy by managing controllable loads with fuzzy logic controller, all while maintaining the user's comfort level. Load shifting and tuning are used to increase the demand supplied by renewable energy sources by 10.8% and 13.65% from wind turbines and photovoltaics, respectively. As a result, annual hydrogen consumption is reduced by 7.03%, and the average annual efficiency of the fuel cell increases by 4.6%     

Renewable energy market conditions and barriers in Turkey

Decentralized wind, hydropower, biogas and biomass, geothermal, solar thermal and solar electricity energy systems are the most commonly found renewable energy technologies promoted for rural energy supply within sustainable developments programs. They are, therefore, seen to have a central place in the practice of sustainable development and in allowing less development countries to bypass the environmentally damaging fossil fuel intensive paths made by industrialized countries. On the political front, many less development countries are critical of pressure on them to adopt environmental energy technologies.Turkey is situated the meeting point of three continents (Asia, Europe and Africa) and stands as a bridge between Asia and Europe. The country is located in southeastern Europe and southwestern Asia. As Turkey’s economy has expanded in recent years, the consumption of primary energy has increased. Presently in order to increase the energy production from domestic energy resources, decrease the use of fossil fuels as well as reduce of green house gas emissions different renewable energy sources are used for energy production in Turkey. The share of energy production from renewable energy sources has increased during the last 10 years. Turkey must import most of the energy to meet her needs. Turkey also has a large potential for renewable energies. The lack of knowledge about renewable energy technologies by most policy-makers, potential consumers, and energy firm managers has played against renewable energy developments. The paper presents renewable energy used in Turkey and Europe Union and evaluation of the market conditions and barriers of renewable energy use in Turkey.     

Tidal current energy resource assessment in Ireland: Current status and future update

Interest in renewable energy in Ireland has increased continually over the past decade. This interest is due primarily to security of supply issues and the effects of climate change. Ireland imports over 90% of its primary energy consumption, mostly in the form of fossil fuels. The exploitation of Ireland's vast indigenous renewable energy resources is required in order to reduce this over-dependence on fossil fuel imports to meet energy demand. Various targets have been set by the Irish government to incorporate renewable energy technologies into Ireland's energy market. As a result of these targets, the development in wind energy has increased substantially over the past decade; however this method of energy extraction is intermittent and unpredictable. Ireland has an excellent tidal current energy resource and the use of this resource will assist in the development of a sustainable energy future. Energy extraction using tidal current energy technologies offers a vast and predictable energy resource. This paper reviews the currently accepted tidal current energy resource assessment for Ireland. This assessment was compiled by Sustainable Energy Ireland in a report in 2004. The assessment employed a 2-dimensional numerical model of the tidal current velocities around Ireland, and from this numerical model the theoretical tidal current energy resource was identified. With the introduction of constraints and limitations, the technical, practical, accessible and viable tidal current energy resources were obtained. The paper discusses why the assessment needs updating including the effect on the assessment of the current stage of development of tidal current turbines and their deployment technology.     

Behavioural responses to photovoltaic systems in the UK domestic sector

Microgeneration—the generation of electricity and/or heat within the home—has recently become a notable addition to UK energy policy debates. Specifically research has suggested that, as well as providing renewable energy, these technologies might encourage changes in household energy consumption. The research presented here investigates this ‘double-dividend’ effect using PV households in the UK. It is shown that the installation of PV encouraged households to reduce their overall electricity consumption by approximately 6% and shift demand to times of peak generation. From a household perspective, system performance monitors had the most notable influence on these behavioural responses; however evolving industry arrangements for metering and microgeneration tariffs will be central in determining the future role of consumers. The paper therefore concludes that the full benefits of microgeneration can only be realised if informed households are integrated within supportive industry and government frameworks.     

Solid oxide fuel cell technology for sustainable development in China: An over-view

Fuel cell technology motivates a variety of benefits, which are barely offered by other energy technologies. The fuel cell can be obtained through natural resources—biomass, coal and water, which are abundant in China. More importantly, most of these are sustainable and realize ecological circulation. Being blessed with a source of renewable energy, fuel cell technology is favorably promoted in China. Simultaneously, fuel cell technology offers China great opportunities to meet the energy consumption demand for its sustainable development. In this proposed method, useful results of leading research in solid oxide fuel cell relevant research in China are reviewed and the hybrid system based fuel cell technology is particularly detailed. Additionally, the effects of some important renewable energy parameters, future challenges and constructive recommendations for China's energy technology are suggested.     

The achievement,significance and future prospect of China's renewable energy initiative

China's high-speed economic growth and ambitious urbanization depend heavily on the massive consumption of fossil fuel. However, the over-dependence on the depleting fossil fuels causes severe environmental problems, making China the largest energy consumer and the biggest CO₂ emitter in the world. Faced with significant challenges in terms of managing its environment and moving forward with the concept of sustainable economic development, the Chinese government plans to move away from fossil fuels and rely on renewables such as hydropower, wind power, solar power, biomass power and nuclear power. In this paper, the current status of China's renewable energy deployment and the ongoing development projects are summarized and discussed. Most recent developments of major renewable energy sources are clearly reviewed. Additionally, the renewable energy development policies including laws and regulations, economic encouragement, technical research and development are also summarized. This study showcases China's achievements in exploiting its abundant domestic renewable energy sources to meet the future energy demand and reducing carbon emissions. To move toward a low carbon society, technological progress and policy improvements are needed for improving grid access (wind), securing nuclear fuel supplies and managing safety protocols (nuclear), integrating supply chains to achieve indigenous manufacture of technologies across supply chains (solar). Beyond that, a preliminary prediction of the development of China's future renewable energy developments, and proposes targeted countermeasures and suggestions are proposed. The proposal involves developing smart-grid system, investing on renewable energy research, improving the feed-in tariff system and clarifying the subsidy system.     

An investigation into the current utilisation and prospective of renewable energy resources and technologies in Libya

With the increase in energy demand and the international drive to reduce carbon emission from fossil fuel, there has been a drive in many oil-rich countries to diversify their energy portfolio and resources. Libya is currently interested in utilising its renewable energy resources in order to reduce the financial and energy dependency on oil reserves. This paper investigates the current utilisation and the future of renewable energy in Libya. Interviews have been conducted with managers, consultants and decision makers from different government organisations including energy policy makers, energy generation companies and major energy consumers. The results indicate that Libya is rich in renewable energy resources but in urgent need of a more comprehensive energy strategy and detailed implementation including reasonable financial and educational investment in the renewable energy sector.     

An overview of the environmental,economic, and material developments of the solar and wind sources coupled with the energy storage systems

There is a constant growth in energy consumption and consequently energy generation around the world. During the recent decades, renewable energy sources took heed of scientists and policy makers as a remedy for substituting traditional sources. Wind and photovoltaic (PV) are the least reliable sources because of their dependence on wind speed and irradiance and therefore their intermittent nature. Energy storage systems are usually coupled with these sources to increase the reliability of the hybrid system. Environmental effects are one of the biggest concerns associated with the renewable energy sources. This study summarizes the last and most important environmental and economic analysis of a grid‐connected hybrid network consisting of wind turbine, PV panels, and energy storage systems. Focusing on environmental aspects, this paper reviews land efficiency, shaded analysis of wind turbines and PV panels, greenhouse gas emission, wastes of wind turbine and PV panels' components, fossil fuel consumption, wildlife, sensitive ecosystems, health benefits, and so on. A cost analysis of the energy generated by a hybrid system has been discussed. Furthermore, this study reviews the latest technologies for materials that have been used for solar PV manufacturing. This paper can help to make a right decision considering all aspects of installing a hybrid system. Copyright © 2017 John Wiley & Sons, Ltd.     

A review on energy scenario and sustainable energy in Indonesia

The global energy consumption is likely to grow faster than the population growth. The fuel consumption was growing from 6630 million tons of oil equivalents (Mtoe) in 1980 to 11,163 Mtoe in 2009. This projected consumption will increase 1.5% per year until 2030 and reach 16,900 Mtoe and the main drivers of this growth are mostly developing countries in Asia. Indonesia is one of the developing countries and energy supply is an important factor for all-around development. The country's energy consumption still depends on non-renewable energy such as crude oil, coal and natural gas as sources of energy. Utilization of fossil fuel continuously contributes to huge amount of greenhouse gases emission that leads to climate change. Facing such an unfavorable situation, the government of Indonesia prioritizes on energy supply securities by diversification of energy resources. The energy mixes in Indonesia based on five main resources; these are crude oil, natural gas, coal, hydropower, and renewable energy. Although the country encourages utilizing renewable energy, the contribution is only around 3%. Considering natural condition and geography, this country is blessed with great potential of renewable energy such as solar energy, wind energy, micro hydro and biomass energy. Noting the potential of renewable and sustainable energy resources in the country, the government must pay more attention on how to utilize it. Many efforts have been done to promote renewable energy such as to create energy policy and regulations, yet it still did not give any satisfactory result. Government, non-government agencies and the public should take a more proactive step to promote and use renewable energy in order to achieve the secure and environmentally sustainable energy resources.     

Impacts of CO2 emission constraints on technology selection and energy resources for power generation in Bangladesh

This paper examines the impacts of CO₂ emission reduction target and carbon tax on future technologies selection and energy use in Bangladesh power sector during 2005–2035. The analyses are based on a long-term energy system model of Bangladesh using the MARKAL framework. The analysis shows that Bangladesh will not be able to meet the future energy demand without importing energy. However, alternative policies on CO₂ emission constraints reduce the burden of imported fuel, improve energy security and reduce environmental impacts. The results show that the introduction of the CO₂ emission reduction targets and carbon taxes directly affect the shift of technologies from high carbon content fossil-based to low carbon content fossil-based and clean renewable energy-based technologies compared to the base scenario. With the cumulative CO₂ emission reduction target of 10–20% and carbon tax of 2500 Taka/ton, the cumulative net energy imports during 2005–2035 would be reduced in the range of 39–65% and 37%, respectively, compared to the base scenario emission level. The total primary energy requirement would be reduced in the range of 4.5–22.3% in the CO₂ emission reduction targets and carbon tax 2500 Taka/ton scenarios and the primary energy supply system would be diversified compared to the base scenario.     

A figure of merit assessment of the routes to hydrogen

The efficient use of primary energy sources, which can be used for hydrogen production, is addressed by a consideration of four key measures, which reflect the ability of different sources and processing routes to meet underlying needs and the practical demands of energy on a large scale. The measures considered are carbon dioxide emission reduction, primary energy availability, land use implications and hydrogen production costs. Fourteen pathways to hydrogen are considered involving fossil fuels and nuclear energy as well as the range of renewable sources, and including additional strategies for carbon sequestration.The overall comparison of routes, based on simple figures-of-merit, shows a clear division between those using renewable energies and those associated with the traditional ‘high energy density’ primary sources. Emerging from the work is a clearer view of the implications of following a particular production path, the limitations of certain technologies and the research challenges which must be met in addressing future fuel options and global warming.     

Quantification of provincial-level carbon emissions from energy consumption in China

Greenhouse gas emission inventories are useful tools for monitoring air quality and assisting local policy development. This article estimates CO₂ emission inventories from energy consumption and carbon intensities of provinces and municipalities in Mainland China in 1990, 1995, 2000, and 2005–2008 using the IPCC mass balance approach. Results show that China's coal-based energy structure and unique economic development have heavily impacted CO₂ emissions. Fortunately, although coal consumption has increased to over 70% of all fuel use, the share of CO₂ emissions from coal has gradually decreased due to energy consumption restructuring. The switch from coal-dominance to cleaner, renewable energies (wind, solar, natural gas, nuclear power, geothermal, biomass energy) will undoubtedly reduce CO₂ emissions in China. Results also indicate that carbon intensity has improved steadily, as China's economic development introduces new technologies intended to minimize environmental pollution and destruction. Our results suggest that China's CO₂ emissions may not be as high as expected in future, and will gradually lessen.     

Surface reflectance and conversion efficiency dependence of technologies for mitigating global warming

A means of assessing the relative impact of different renewable energy technologies on global warming has been developed. All power plants emit thermal energy to the atmosphere. Fossil fuel power plants also emit CO₂ which accumulates in the atmosphere and provides an indirect increase in global warming via the greenhouse effect. A fossil fuel power plant may operate for some time before the global warming due to its CO₂ emission exceeds the warming due to its direct heat emission. When a renewable energy power plant is deployed instead of a fossil fuel power plant there may be a significant time delay before the direct global warming effect is less than the combined direct and indirect global warming effect from an equivalent output coal fired plant – the “business as usual” case. Simple expressions are derived to calculate global temperature change as a function of ground reflectance and conversion efficiency for various types of fossil fuelled and renewable energy power plants. These expressions are used to assess the global warming mitigation potential of some proposed Australian renewable energy projects. The application of the expressions is extended to evaluate the deployment in Australia of current and new geo-engineering and carbon sequestration solutions to mitigate global warming. Principal findings are that warming mitigation depends strongly on the solar to electric conversion efficiency of renewable technologies, geo-engineering projects may offer more economic mitigation than renewable energy projects and the mitigation potential of reforestation projects depends strongly on the location of the projects.     

利用EGR技术降低涡轮增压柴油机排气污染的研究

以一台增压柴油机为研究对象设计了一套带有文曲利管的并联EGR系统,该系统可以在较小地损失充气效率的情况下,将排气较为容易的引入到进气管,并与之混合,使混合气的静压力在扩压管中得到最大程度的恢复,通过试验找出了达到Tier3排放法规要求的各工况下所需的EGR率,以及各工况下EGR率与NOx、烟度、油耗的关系,得到了各工况下兼顾满足NOx、油耗、颗粒排放等指标的EGR率范围,并研究了冷却EGR对NOx排放的影响,EGR经过冷却后降低NOx的效果更加明显,这些研究成果具有重要的工程应用价值.     

An integrated system framework for fuel cell-based distributed green energy applications

The environmental pollution and diminishing conventional fuel sources and global warming problems make it more attractive for considering renewables as alternative energy sources, such as solar, wind and micro hydro, etc. Recent advances in hydrogen and fuel cell technologies further facilitate these energy options to supply electrical power to various communities. Hydrogen fuel cell systems coupled with renewable energy sources stand out as a promising solution. This paper presents an integrated system framework for fuel cell-based distributed energy applications. Five components are included in this framework: a physical energy system application, a virtual simulation model, a distributed coordination and control, a human system interface and a database. The integrated system framework provides a means to optimize system design, evaluate its performance and balance supplies and demands in a hydrogen assisted renewable energy application. It can either be applied to a distributed energy node that fulfills a local energy demand or to an energy-network that coordinates distributed energy nodes in a region, such as a hydrogen highway. The proposed system framework has been applied in the first phase of our multi-phases project to investigate and analyze the feasibility and suitability of hydrogen fuel assisted renewable power for a remote community. Through integration with an available renewable energy profile database, the developed system efficiently assists in selecting, integrating, and evaluating different system configurations and various operational scenarios at the application site. The simulation results provide a solid basis for the next phase of our demonstration projects.     

Status,challenges and opportunities of dual fuel hybrid approaches-a review

Consumers conventionally adopt diesel generation to meet the energy needs where the grid connection is unreliable or unavailable. While electrification has provided these communities a variety of economic and social opportunities, diesel consumption has resulted in adverse costs and environmental pollution. Two technologies available to reduce the expense and emissions of diesel fuel reliance include dual fuel or hybrid diesel applications. The dual-fuel approach involves a supplementary gas fuel charge in support of reduced diesel fuel consumption. Hybrid applications involve the integration of renewable generation to displace diesel fuel consumption. This paper reviews the potential for hybrid dual-fuel applications, identifying engine flexibility as a major integration barrier. In comparing the flexibility of various dual-fuel technologies to operate dynamically, this paper presents a critical review across hydrogen, liquified petroleum gas (LPG), natural gas (NG) and blended hydrogen and NG derivatives. The results identify a range of approaches able to improve engine flexibility and thus reduce the cost and carbon intensity of diesel-fired internal combustion engines. At low load conditions, while NG and LPG exhibit similar performance, the use of hydrogen and hydrogen blends provide improved engine performance and response. Unfortunately, given the current cost of hydrogen fuel, significant commercial barriers exist to the adoption of hydrogen or hydrogen blended fuels. Despite this, this review indicates the potential of hydrogen-NG blends to offer additional flexibility in comparison to alternative dual-fuel technologies. This position is furthered considering near term cost targets associated with the development of a global green hydrogen industry, coupled with its ability to serve as a demand-side management approach within isolated power systems, one of the multiple future research themes.