Linking renewables and fossil fuels with carbon capture via energy storage for a sustainable energy future

Renewable energy sources and low-carbon power generation systems with carbon capture and storage (CCS) are expected to be key contributors towards the decarbonisation of the energy sector and to ensure sustainable energy supply in the future. However, the variable nature of wind and solar power generation systems may affect the operation of the electricity system grid. Deployment of energy storage is expected to increase grid stability and renewable energy utilisation. The power sector of the future, therefore, needs to seek a synergy between renewable energy sources and low-carbon fossil fuel power generation. This can be achieved via wide deployment of CCS linked with energy storage. Interestingly, recent progress in both the CCS and energy storage fields reveals that technologies such as calcium looping are technically viable and promising options in both cases. Novel integrated systems can be achieved by integrating these applications into CCS with inherent energy storage capacity, as well as linking other CCS technologies with renewable energy sources via energy storage technologies, which will maximise the profit from electricity production, mitigate efficiency and economic penalties related to CCS, and improve renewable energy utilisation.     

Concentrating solar power for seawater desalination in the Middle East and North Africa

The paper presents a long-term scenario for the demand of freshwater in the Middle East and North Africa (MENA) and shows how it may be covered by a better use of the existing renewable water sources and by sea water desalination powered with solar energy. Growth of population and economy, increasing urbanization and industrialization, and the rather limited natural resources of potable water in MENA are leading to serious deficits of freshwater in many parts of MENA. Modern infrastructure for water distribution, enhanced efficiency of use and better water management are to be established as soon as possible. However, even the change to best practice would leave considerable deficits, which are poorly covered by over-exploiting groundwater resources. Increased use of desalted seawater is therefore unavoidable in order to maintain a reasonable level of water supply. The desalination of seawater based on fossil fuels is neither sustainable nor economically feasible in a long-term perspective, as fuels are increasingly becoming expensive and scarce. Concentrating solar power (CSP) offers a sustainable alternative to fossil fuels for large scale seawater desalination. CSP can help to solve the problem, but market introduction must start immediately in order to achieve the necessary freshwater production rates in time.     

Solar thermal desalination technologies

The use of solar energy in thermal desalination processes is one of the most promising applications of the renewable energies. Solar desalination can either be direct; use solar energy to produce distillate directly in the solar collector, or indirect; combining conventional desalination techniques, such as multistage flash desalination (MSF), vapor compression (VC), reverse osmosis (RO), membrane distillation (MD) and electrodialysis, with solar collectors for heat generation. Direct solar desalination compared with the indirect technologies requires large land areas and has a relatively low productivity. It is however competitive to the indirect desalination plants in small-scale production due to its relatively low cost and simplicity. This paper describes several desalination technologies in commercial and pilot stages of development. The primary focus is on those technologies suitable for use in remote areas, especially those which could be integrated into solar thermal energy systems.     

三效管式海水淡化装置产水性能实验研究

研制了一种三效管式海水淡化装置,对其进行了定功率和太阳能加热运行实验研究,分析了该淡化装置的产水性能及影响因素。定功率实验研究表明,当淡化装置加热功率为300 W时,其性能系数最高达约1.32,提升淡化装置蒸发传热,同时降低热量耗散(辐射耗散和对流耗散),加大装置冷凝温差可以提升淡化装置性能。太阳能加热实验结果表明,淡化装置的产水性能受太阳辐射值、太阳能集热系统效率、热源稳定性、环境温度与风速等多种因素影响,特别是热源稳定性对装置性能有较大影响。     

Water desalination: An imperative measure for water security in Egypt

Water Desalination is an indispensable industry for the most of the Arab countries. In the last four decades, the number and capacities of desalination units have increased dramatically (45% Multi-Stage Flash (MSF) and 42% Reverse Osmosis (RO) of world capacity); especially in the Gulf States. Almost all available conventional water resources in Egypt - represented by the Nile water, renewable groundwater, and some scant annual precipitation- have been exhausted. Further development measures require review of current water allocations in order to raise efficiencies and protect against pollution, in addition to exploring new options of non-conventional water resources to narrow the gap between water supply and demand. These measures are the pillars of Egypt's integrated water policy and have been clearly postulated in its National Water Resources Plan 2017. The objective of this paper is to study and investigate water desalination as a solution for water scarcity in Egypt. Moreover, the present work demonstrates the significance of seawater desalination for national development in Egypt. At present, Egypt is encouraging, not only the public sector but also the private sector, to apply modern technologies for desalination, which historically started with Distillation then Electrodyalisis and followed by RO. The great achievements in desalination technology have now moved the costs for desalting in many applications from the realm of "expensive" to "competitive". Current technology is feasible for tourist villages in the north coast and the Red Sea, due to its far distances from conventional sources that makes the cost of water conveyance very high and subject to pollution problems. The results indicated that, in spite of research and developments, still the energy requirement and membrane know-how are limiting factors. Thus, Egypt's future vision is non-traditional in the field of desalination. It is based on a real breakthrough towards the use of renewable energy, namely, solar energy to be harnessed for operating high compression pumps needed for reverse osmosis modular systems. The reasons are obvious, since Egypt has great potential of brackish water wells, immense amounts of solar radiation in remote areas and future integrated development projects are located at a distance from the Nile water. This trend is what Egypt is focusing on as a prospective future for wide applications of desalination. Finally, this research concluded that, the water desalination as a conventional water resource should be considered as an imperative measure for water security in Egypt. The future use of such resource for different purposes will largely depend on the rate of improvement in the technologies used for desalination and the cost of needed power.     

Glasses for solar energy conversion systems

Solar technologies are projected to increase tremendously over the next 10 years. Glasses are playing an important role as transparent materials of photovoltaic (PV) cells and concentrating solar power (CSP) systems. Glasses are materials of short energy payback time and environmental compatibility suitable for sustainable energy concepts. The paper reviews recent solar applications. Surface structuring and coating of glasses are shown to improve energy efficiency for solar conversion systems substantially. Encapsulated glass-to-glass PV modules and solar photocatalytic glass surfaces are identified as elements of a green architecture combining renewable power generating and destruction of air pollutants of urban environments. Emerging solar technologies for power generation, including transparent PV modules, solar chimney and thermoelectric systems may become significant areas of future solar glass applications.     

Solar desalination with a humidification-dehumidification technique — a comprehensive technical review

Major desalination processes consume a large amount of energy derived from oil and natural gas as heat and electricity. Solar desalination, although researched for over two decades, has only recently emerged as a promising renewable energy-powered technology for producing fresh water. Solar desalination based on the humidification-dehumidification cycle presents the best method of solar desalination due to overall high-energy efficiency. This paper provides a comprehensive technical review of solar desalination with a multi-effect cycle providing a better understanding of the process. Discussion on methods to improve system performance and efficiency paves the way towards possible commercialisation of such units in the future.     

Design and simulation of a novel solar photovoltaic system assisted single-slope solar still distillation unit

Water is an essential component of our lives. Conventional seawater desalination, based on fossil fuel energy, is primary in meeting freshwater demands. Thus, solar desalination still emerged as an alternative technology that employs environmentally friendly renewable energy. Here, we aim to design and simulate a novel hybrid solar photovoltaic (PV) system coupled with a single-slope solar still unit for freshwater production. Various design techniques were utilized to fine-tune the model towards producing 3–4.6 kg/m² · day of distillate water, thereby calculating the design aspects such as tank size, energy, and cost. The results revealed that a conventional solar desalination system had 22% lower efficiency than the proposed novel still distillation unit assisted with a solar PV system (connected to a heating element). The maximum efficiency of 45% has been recorded at the peak solar insolation due to the combination of the solar PV system. According to our design constraints, only a 3 m² basin area was required to achieve a productivity of ${\mathit{P}}_{\mathit{st}}$ = 1–5 kg/day. Design analysis showed that the total capital cost of a conventional still can be significantly reduced from 2600 to 1500 $/unit with PV system integration at the specified productivity and optimal solar radiation of ~17 MJ/m² · day at peak time (02.00 PM). This work paves the way towards maximizing solar energy utilization from PV integration with solar desalination to achieve high freshwater productivity in single-basin solar still systems.     

Design, simulation and economic analysis of a stand-alone reverse osmosis desalination unit powered by wind turbines and photovoltaics

The fresh water shortage is a significant problem in many areas of the world such as deserts, rural areas, Mediterranean countries and islands. However, renewable energy potential in these areas is usually high using solar and wind energy. A desalination unit powered by renewable energy sources is a promising solution for this problem. This paper presents the design of a stand-alone hybrid wind-PV system to power a seawater reverse osmosis desalination unit, with energy recovery using a simplified spreadsheet model. A daily and monthly simulation and economic analysis were also performed. The calculated fresh water production cost was 5.2 ?/m³, and the realized energy saving was up to 48% when a pressure-exchanger-type energy recovery unit is considered.     

Renewable energy desalination plants for the Greek islands—technical and economic considerations

For the majority of the Greek islands, water resources are quite restricted, limiting the economic development of the local societies. To face increased potable water requirements, more than 2,500,000 m of clean water is transferred annually to these islands at a cost approaching the value of 7 /m³ On the other hand, the final cost of the locally produced water from renewable energy sources (RES) based desalination plants is expected to be quite lower than this value. The main purpose of the present study is to examine the economic viability of several representative desalination plant configurations based on the available renewable energy sources using an integrated cost-benefit analysis. In the proposed analysis all the cost parameters of the problem are taken into consideration, including the capital cost of the desalination plant, the annual maintenance and operation cost, the energy consumption cost, the local economy annual capital cost index and the corresponding inflation rate. The calculation results obtained definitely support the utilization of RES-based desalination plants as the most promising and sustainable method to satisfy the fresh, potable water demands of the small- to medium-sized Greek islands at a minimal cost, without disregarding the considerable environmental and macro-economic benefits.     

Comparison of solar thermal technologies for applications in seawater desalination

This paper deals with a global analysis of the use of solar energy in seawater distillation under Spanish climatic conditions. Static solar technologies as well as one-axis sun tracking were compared. Different temperature ranges of the thermal energy supply required for a desalination process were considered. At each temperature range, suitable solar collectors were compared in some aspects as: (1) fresh water production from a given desalination plant; (2) attainable fresh water production if a heat pump is coupled to the solar desalination system; (3) area of solar collector required for equivalent energy production. Results showed that direct steam generation (DSG) parabolic troughs are a promising technology for solar-assisted seawater desalination.     

新型闭式太阳能海水淡化装置及其性能模拟

本文提出了一种闭式海水淡化装置,阐述了系统的工作原理,建立了相应的数学模型。就冷却水流量、海水喷淋量、集热器面积、蒸发器尺寸等因素对系统淡水产量的影响情况进行了计算机模拟,根据实验测得的气象数据对一天内系统淡水产量随时间变化情况进行了模拟,并根据典型的月平均日气象数据对系统一年内每个月的系统性能进行了分析。分析表明,不计系统夜间运行时的淡水产量,在西安地区系统淡水产量可以达到4.6kg/d.m2。     

二硫化钼作为海水淡化材料的研究进展

海水淡化是从丰富的海水资源中提取清洁淡水的技术,是解决淡水资源短缺的重要途径。传统的海水淡化技术在实际应用中已经暴露出高成本、高能耗和低效率等缺点,因此开发海水淡化新兴技术及材料成为研究重点。二硫化钼（MoS₂）是典型层状过渡金属硫化物,因其化学稳定、吸光能力优异等优点,在海水淡化领域具有极大的应用前景。作为一种高效环保的海水淡化材料,MoS₂及其复合材料在改善传统脱盐工艺和发展新兴脱盐技术中已得到广泛研究。本文主要论述和分析MoS₂基材料在电容去离子、膜脱盐及太阳能脱盐等海水淡化应用中的研究进展以及在工业化应用中面临的挑战,并展望其今后在脱盐领域的发展方向。     

碳中和目标下的光伏发电技术

化石能源燃烧发电过程是我国CO₂排放的主要来源之一。在碳中和、碳达峰的“双碳”目标下,大力发展可再生能源等低碳或零碳能源体系,构建以新能源为主体的新型电力系统,成为能源领域技术变革的战略方向,其中光伏发电是公认的我国未来可再生能源发电的主要方式之一。本文重点对我国光伏发电的开发现状、存在问题、关键技术、未来趋势及发展策略等进行简要论述,分别对晶硅太阳能电池、薄膜太阳能电池（硅基、砷化镓、铜铟镓硒、碲化镉）、钙钛矿太阳能电池、其他新型太阳能电池（有机、染料敏化、量子点）等关键技术进行了详细论述,以期为我国光伏发电产业的快速发展及高效安全的清洁能源新体系构建提供方向引导。     

太阳能膜蒸馏系统进展与展望

海水淡化技术可有效解决现有的淡水资源短缺等问题,但受限于高成本、高能耗、低热效率等因素,传统海水淡化工艺难以进一步推广。近年来,太阳能海水淡化作为一种高效低廉的海水淡化技术正逐渐进入人们的视野,其中,太阳能膜蒸馏技术更是凭借着适用范围广、蒸发效率高、能耗低、成本低廉等诸多优点为众多学者所青睐。各国学者从宏观的系统结构到微观的光热材料等方面展开了大量的工作。但由于膜蒸馏固有的温度极化以及膜污染等问题,太阳能膜蒸馏技术仍然处于发展瓶颈中。本文按照太阳能引入膜蒸馏装置位置的不同,对现有的诸多太阳能膜蒸馏系统进行分类,并针对各类太阳能膜蒸馏系统的发展现状和技术瓶颈进行详细阐述。探讨了当前太阳能膜蒸馏技术的局限性及未来的挑战,以期为太阳能膜蒸馏系统的进一步发展及应用提供参考。     

Adhesive technology and sustainability

After considering problems associated with reconciling sustainability with a commitment to growth, the major environmental impacts of adhesive technology are discussed.Most adhesives come from fossil fuel sources, but many adhesive types can be produced from renewable resources either by traditional or newly developed routes. Significant energy usage in production and processing make energy conservation and renewable energy generation relevant to adhesive technology. Considerable improvements have been made by the replacement of volatile organic compounds in pretreatments and as solvents by aqueous systems, and more remains to be done.It is important to consider the total environmental impact of the engineering context in which the adhesive is to be used: adhesive technology may give improved engineering efficiency in the traditional sense of the term, and also lower environmental impact.     

Solar desalination with a humidification-dehumidification cycle: mathematical modeling of the unit

Solar desalination is gradually emerging as a successful renewable energy source of producing fresh water. Solar Multi-Effect Humidification (MEH) units based on the humidification-dehumidification principle are considered as the most viable among solar desalination units. A simulation study of these units leads to a better understanding of the performance of such type of desalination units. This study therefore focuses on studying and analysing the effects and performance of various components involved in the process along with the study of the effect of water feed flow rate on the desalination production. To our knowledge, there is no such comprehensive model available in the literature. This study could lead a step further in the commercialisation of solar desalination units based on the humidification-dehumidification principle.     

Current research trends and prospects among the various materials and designs used in lithium-based batteries

Increasing energy consumption, shortages of fossil fuels, and concerns about the environmental impact of energy use, especially emissions of carbon dioxide, give fresh impetus to the development of renewable energy sources. With the advent of renewable energy, it is now indispensable that efficient energy storage systems have to be developed. One of the most promising storage systems to be employed in stationary energy storage applications are lithium-based batteries (LIB), mainly due to their high energy density, high power, and nearly 100 % efficiency. Within the scope of this paper, we carry out a patent search using the patent database PatBase^® to assess the development status of LIB technology. The analysis of the generated patent sample reveals disproportionately high growth rates in LIB patent applications over the last years compared to other selected energy-related technologies. Breaking down patent application growth by the different components of LIB shows the principal drivers of growth. The purpose of this paper is to provide current research trends and prospects for the main LIB materials and designs.     

Crisp and fuzzy integer programming models for optimal carbon sequestration retrofit in the power sector

Carbon capture and storage (CCS) is one of the interim technologies to mitigate greenhouse gas emissions from stationary sources such as power plant and large industrial facilities. CCS allows for continued utilization of fossil fuels (e.g. coal, natural gas and oil), which are still relatively inexpensive and reliable in comparison to inherently low-carbon renewable resources (e.g. wind, solar etc.). On the other hand, retrofitting power plants for carbon capture (CC) entails major capital costs as well as reduction of thermal efficiency and power output. This paper presents integer programming optimization models for planning the retrofit of power plants at the regional, sectoral or national level. In addition to the base case (i.e., non-fuzzy or crisp) formulation, two fuzzy extensions are given to account for the inherent conflict between environmental and economic goals, as well as parametric uncertainties pertaining to the emerging CC technologies. Case studies are shown to illustrate the modeling approach.     

碳达峰与碳中和目标下PEM电解水制氢研究进展

氢能作为重要的能源载体，燃烧过程绿色无污染，能够助力碳达峰和碳中和目标实现。本文通过对比化石能源制氢、工业副产气制氢、电解水制氢等方式，分析各制氢方式的优缺点，阐述了质子交换膜（PEM）电解水制氢与可再生能源结合的重要意义。之后从PEM电解槽内部结构和可再生能源电解水制氢两个方面展开综述，详细介绍了PEM电解槽双极板、催化剂、扩散层、质子交换膜研究进展、存在的主要问题和未来发展方向。文中通过分析我国太阳能、风能分布特征，总结可再生能源利用存在的问题，从研究现状和产业发展的角度介绍了太阳能制氢、风电制氢、可再生能源多能互补制氢的发展。最后对可再生能源PEM电解水制氢的未来发展方向进行了展望，期望为可再生能源PEM电解水制氢的发展提供借鉴和参考。