中国农村民居屋顶分布式光伏发电的发展潜力分析

农村社区有充足的空间和较大的能源消费，应在实现碳达峰、碳中和的能源转型中发挥重要作用，然而许多关于能源转型的预测分析都未给予农村社区足够的关注。分析了中国大陆农村人口、家庭户数及能源消费的基本情况，从各具特色的农村民居出发，归纳了中国农村民居屋顶的主要类型，推算出农村民居屋顶面积的基本量；然后以此为基础，探讨了影响农村民居屋顶分布式光伏发电系统应用的主要因素，包括：屋顶基本形式、屋顶大小、屋顶强度、阴影、坡屋顶平面的倾斜度、屋顶平面的方位角、屋顶面积的可利用性等；并分别针对基本情景和积极情景，对中国农村民居屋顶分布式光伏发电系统的装机容量潜力和发电量，以及由此带来的环境效益和经济效益进行了预测，以说明发展农村民居屋顶分布式光伏发电可以在促进中国能源转型和助推乡村振兴方面发挥作用。结果表明：基本情景下，中国农村民居屋顶分布式光伏发电的装机容量潜力为348 GW；积极情景下，装机容量潜力为696 GW。     

光伏发电系统节能减排效果模糊评价

火电机组发电能量利用率较低且污染量较大,在一定程度上不符合当前的双碳目标。为此,增加低能耗、低污染的以光伏等清洁能源为主要发电来源的新型电力系统,有助于节能减排和双碳目标的实现。为了评估新型电力系统节能减排效果,以光伏发电系统为研究对象,在双碳目标背景下,提出基于模糊数学理论的新型电力系统节能减排效果评价方法。分析光伏发电系统节能减排效果的影响因素,确定光伏发电系统节能减排效果评价体系的构建原则;利用模糊数学理论,识别节能减排效果评估对象;通过聚类处理节能减排效果评估的影响因素,构建了光伏发电系统节能减排效果评价体系,实现了光伏发电系统节能减排效果的评价。以某省2019—2021年光伏企业节能减排效果评价的指标数据作为案例数据进行应用分析。结果表明,文中方法在评价光伏发电系统节能减排效果时,可以将评价误差控制在-0.24%～-1.80%,提高了光伏发电系统节能减排效果评价精度。     

光储一体化的屋顶分布式光伏电站的设计与建设

光伏发电是清洁安全的可再生能源发电技术,利用厂房、仓库屋顶建设分布式光伏电站,可不占用土地资源,再配备储能系统,可稳定电能质量,降低用户用电成本,是屋顶分布式光伏电站的一大发展方向。以某工厂的光储一体化的屋顶分布式光伏电站的设计与建设为例,分析了此类光伏电站的设计、接入电网方式及运行效果,以期为该类光伏电站的建设提供参考。     

光伏产业发展迎来提速期

在环保压力、节能减排的大背景下,以光伏为主的新能源产业快速发展。国家在政策面上十分给力,国家能源局下发的《2015年光伏发电建设实施方案》中,提出全年新增光伏建设目标为17.8GW,屋顶分布式光伏发电及全部自发自用地面分布式光伏发电项目将不限制建设规模。业内人士指出,随着行业的发展,未来5~10年将是整个光伏发电走向     

基于城乡低碳发展的屋顶分布式光伏电站建设问题探讨

屋顶分布式光伏发电是一种利用建筑物屋顶空间进行光伏发电的新型绿色能源技术,具备节约土地资源、减少线损、提高能源利用率和可持续性等诸多优势,与集中式光伏发电相比,其更适合在城乡规划中推广应用。从城乡规划角度出发,基于城乡低碳发展路径,系统分析了屋顶分布式光伏发电在提高城乡能源供给安全性、促进绿色低碳转型、改善环境质量和促进社会经济发展等方面的作用和影响,深入探讨了屋顶分布式光伏电站在建设过程中面临的屋顶资源获取、电网接入和消纳、政策支持和市场推广等难题和挑战,并提出了相应的对策和建议。     

新供给模式下城市建筑屋顶光伏发电的利用潜力分析

为了提高城市建筑屋顶光伏发电系统的利用价值和经济效益,从不同的用户侧角度分析,利用k均值聚类的方法得到了不同类型城市建筑的用电特征,并与软件模拟得到的典型屋顶光伏发电系统的发电特征结合进行了匹配分析,提出了"在居住建筑的屋顶安装光伏发电系统,为周围办公建筑供电"的模式。以上海市10个区域为例,结合模拟退火算法,计算得到经济效益最大、利用价值最高时,某特定区域城市建筑屋顶用于安装光伏发电系统的理论最佳面积比例。本研究结果可为未来城市屋顶光伏发电系统的规划和设计提供新的思路。     

“整县推进”模式下屋顶分布式光伏发电项目的典型设计方案和设计要点探讨

“整县推进”屋顶分布式光伏开发模式下,屋顶分布式光伏发电设计方案中的光伏组件、逆变器的选择及布置形式,接入电网模式的选择是关键。首先介绍了“整县推进”模式下屋顶分布式光伏发电的4种典型应用场景,并详细阐述了建设场址选择原则、主要设备的选型原则、发电量分析原则、接入电网设计原则,以及智慧光伏运维方案;然后结合实际工程中的设计实践,总结了屋顶分布式光伏发电项目设计要点,给出了整套设计方案,以期助力屋顶分布式光伏发电的大力发展。     

可再生能源与核电减排二氧化碳经济性分析

大量的二氧化碳排放推动了全球气候变暖。我国从2008年起已成为全球最大的二氧化碳排放国,约占全球排放总量的1/5。电力行业是二氧化碳排放大户,每年的排放量接近我国排放总量的一半,而且主要来自燃煤发电。目前核电、水电、风电和太阳能光伏等清洁能源发电均能实现二氧化碳的近零排放。为此,国家提出了到2020年、2030年非化石能源占一次能源消费比重分别达到15%和20%的目标。采用技术经济评价方法对水电、风电、太阳能光伏发电和核电减排二氧化碳的经济性进行定量分析。分析结果表明,单从减排二氧化碳的经济性看,水电最好,其次为核电,再次是风电和太阳能光伏。如果以水电为基准,核电减排1t二氧化碳的费用是水电的1.24倍,风电减排1t二氧化碳的费用是水电的1.88倍,太阳能光伏减排1t二氧化碳的费用是水电的3.37倍。如果从减排效果看,核电最强。为了降低我国二氧化碳排放量,必须大力发展可再生能源发电和核电,同时发展坚强智能电网和远距离输电技术,加强节能减排发电调度,避免或减少弃水、弃风、弃光现象的发生。     

海南召开太阳能发电应用技术推广场会

海南省大力推广节能减排的太阳能发电技术,年内将至少新增50 MW屋顶光伏电站,促进海南光伏产业链的发展。3月16日,海南省工信厅召开了太阳能发电技术推广现场会。本次会议主要推广太阳能发电原理和建筑闲置屋顶太阳能发电系统的安装技术,现场参观     

国家体育馆首用太阳能发电

国家体育馆建设100kW太阳能光伏电站示范项目已经批准正式启动，这是我国第一个和体育场馆结合的太阳能发电系统。该系统将安装在体育馆南侧的玻璃幕墙上，每年可发电9．7万kWh，按设计寿命25年计算，寿命期内共产生约243万kWh的电能，作为一种清洁的可再生能源，与火力发电相比，相当于累计节约标准煤约952t，减排421tCO2、19tSO2、12t粉尘和251t灰渣。由于该光伏发电系统已并入电网，不需要蓄电池储能装置，相对于独立运行的光伏系统，提高了发电效率。     

Multi-objective optimal allocation strategy for the energy internet in Huangpu District,Guangzhou, China

To improve the overall efficiency of the energy system, the basic structure for the energy internet of coordination and optimization of “generation-grid-load-storage” of Huangpu District, Guangzhou, China is designed, while the arrangement for the output of centralized and distributed energy module and energy storage are proposed. Taking economic benefit maximization, environmental benefit maximization and energy efficiency maximization as sub-objectives, the mathematical model of multi-objective optimal allocation and operation strategy of the energy internet is established considering supply-demand balance constraints, equipment characteristic constraints, operation mode constraints, and energy conditions constraints. The calculation results show that without considering the outsourced electricity, the balanced strategy, the economic development strategy, the environmental protection strategy, and the energy efficiency strategy are obtained by calculation, which are all superior to the traditional energy supply strategy. Moreover, considering the outsourced electricity, the proportion of outsourced electricity to total electricity is 19.8%, which is the system optimization of the energy internet under certain power demand. Compared with other strategies without outsourced electricity, the outsourced electricity strategy can have a certain emission reduction effect, but at the same time reduce the economic benefit. Furthermore, the huge difference in demand for thermal and cooling load between industrial and commercial areas results in the installed capacity of gas distributed energy stations in industrial areas being nearly twice as large as that in commercial areas. The distributed photovoltaic power generation is allocated according to the proportion of the installed roof areas of photovoltaic power generation system in residential, industrial, and commercial areas.     

Synergistic planning of an integrated energy system containing hydrogen storage with the coupled use of electric-thermal energy

Regional integrated energy systems (RIES) can economically and efficiently use regional renewable energy resources, of which energy storage is an important means to solve the uncertainty of renewable energy output, but traditional electrochemical energy storage is only single electrical energy storage, and the energy efficiency level is low. Hydrogen energy storage has the advantages of large energy storage capacity, long storage time, clean and pollution-free, and can realize the synergistic and efficient utilization of electricity and thermal power. Based on this, this paper proposes a synergistic planning method for an integrated energy system with hydrogen storage taking into account the coupled use of electric-thermal energy, which effectively reduces the system carbon emission and improves the comprehensive energy efficiency level. Firstly, this paper constructs an electric-thermal coupling model of the hydrogen energy storage unit and proposes an optimization strategy for the integrated energy system containing hydrogen storage taking into account the utilization of electricity and thermal power. Secondly, a planning optimization model with the lowest economy and carbon emission and the highest comprehensive energy efficiency was constructed. Third, the CSPO-GE optimization algorithm is proposed for solving the problem, which significantly improves the solution efficiency. Finally, a planning optimization simulation of RIES for a residential community W in northern China verifies the effectiveness of the model and method proposed in this paper. The comparative analysis of the three schemes shows that compared with the integrated energy system with conventional electrochemical energy storage and heat storage tank as the main form of energy storage and the integrated energy system with only hydrogen storage, the integrated energy system with hydrogen storage and heat storage tank can reduce carbon emissions by 43.8% and 7.61%, respectively, and improve the integrated energy efficiency level by 337.14% and 14.44%.     

Overview of energy storage systems for storing electricity from renewable energy sources in Saudi Arabia

Renewable power (photovoltaic, solar thermal or wind) is inherently intermittent and fluctuating. If renewable power has to become a major source of base-load dispatchable power, electricity storage systems of multi-MW capacity and multi-hours duration are indispensable. An overview of the advanced energy storage systems to store electrical energy generated by renewable energy sources is presented along with climatic conditions and supply demand situation of power in Saudi Arabia. Based on the review, battery features needed for the storage of electricity generated from renewable energy sources are: low cost, high efficiency, long cycle life, mature technology, withstand high ambient temperatures, large power and energy capacities and environmentally benign. Although there are various commercially available electrical energy storage systems (EESS), no single storage system meets all the requirements for an ideal EESS. Each EESS has a suitable application range.     

A combined wind and hydro power system

A high degree of coverage of electricity demand by wind energy conversion is possible only with access to energy storage. For regions with both hydro and wind resources, the hydro power system and the wind power system may complement each other and alleviate the need for any other energy storage. Scandinavia is such a region, and this article uses a simulation model to assess the conditions under which all the electricity needs of Norway and Denmark could be satisfied by a combination of the existing Norwegian hydro power system with a hypothetical all wind-based Danish power system.     

Design and analysis of a solar tower power plant integrated with thermal energy storage system for cogeneration

In the current study, a solar tower–based energy system integrated with a thermal energy storage option is offered to supply both the electricity and freshwater through distillation and reverse osmosis technologies. A high‐temperature thermal energy storage subsystem using molten salt is considered for the effective and efficient operation of the integrated system. The molten salt is heated up to 565°C through passing the solar tower. The thermal energy storage tanks are designed to store heat up to 12 hours. The temperature variations in the storage tanks are studied and compared accordingly for evaluation. The effect of operating temperatures on the freshwater production and overall system efficiency is determined. About 24.46 MW electricity is generated in the steam turbine under sunny conditions. Furthermore, the storage subsystem stores heat during sunny hours to utilize later in cloudy hours and night time. The produced power decreases to 20.17 MW in discharging hours due to temperature decrease in the tank. The electricity generated by the system is then used to produce freshwater through the reverse osmosis units and also to supply electricity for the residential use. A total flowrate of 240.02 kg/s freshwater is obtained by distillation and reverse osmosis subsystems.     

Integration of large-scale hydrogen storages in a low-carbon electricity generation system

This study investigates the overall feasibility of large energy storages with hydrogen as energy carrier onsite with a pre-combustion carbon capture and storage coal gasification plant and assesses the general impacts of such a backup installation on an electricity generation system with high wind power portion. The developed system plant configuration consists of four main units namely the gasification unit, main power unit, backup power unit including hydrogen storage and ancillary power unit. Findings show that integrating a backup storage in solid or gaseous hydrogen storage configuration allows to store excessive energy under high renewable power output or low demand and to make use of the stored energy to compensate low renewable output or high power demand. The study concludes that the developed system configuration reaches much higher load factors and efficiency levels than a plant configuration without backup storage, which simply increases its power unit capacity to meet the electricity demand. Also from an economical point of view, the suggested system configurations are capable to achieve lower electricity generation costs.     

Thermodynamic analysis of a transcritical CO2 power cycle driven by solar energy with liquified natural gas as its heat sink

This paper proposes a transcritical CO₂ power cycle driven by solar energy while utilizing the cold heat rejection to an liquified natural gas (LNG) evaporation system. In order to ensure a continuous and stable operation for the system, a thermal storage system is introduced to store the collected solar energy and to provide stable power output when solar radiation is insufficient. A mathematical model is developed to simulate the solar-driven transcritical CO₂ power cycle under steady-state conditions, and a modified system efficiency is defined to better evaluate the cycle performance over a period of time. The thermodynamic analysis focuses on the effects of some key parameters, including the turbine inlet pressure, the turbine inlet temperature and the condensation temperature, on the system performance. Results indicate that the net power output mainly depends on the solar radiation over a day, yet the system is still capable of generating electricity long after sunset by virtue of the thermal storage tank. An optimum turbine inlet pressure exists under given conditions where the net power output and the system efficiency both reach maximum values. The net power output and the system efficiency are less sensitive to the change in the turbine inlet temperature, but the condensation temperature exerts a significant influence on the system performance. The surface area of heat exchangers increases with the rise in the turbine inlet temperature, while changes in the turbine inlet pressure have no significant impact on the heat exchanging area under the given conditions.     

Life-cycle energy efficiency estimation of large-scale ammonia fuel energy storage system

本文讨论了氨作为燃料使用会具备与传统化石燃料显著不同的环境效益,并进一步探讨了氨作为储能介质的特点,包括储能密度和规模大、受地理条件约束小、便于运输存储等。本文还针对目前的合成氨路线从理论分析和工业实际两个方面对合成效率进行了估算和评价。针对目前国内核能、风能、太阳能等清洁能源电力的低谷或弃电问题,建议采用以制氨的方式存储或外运,以便于在电力不足时将其用于发电。建议并评估了几条基于制氨并发电的路线,并基于现有氨燃料的发电效率计算了各路线在全生命周期内的总储能效率（25%～40%）和以电换电的效率[2.5～4.0(度/10度）]。     

Simulation of high temperature thermal energy storage system based on coupled metal hydrides for solar driven steam power plants

Concentrating solar power plants can achieve low cost and efficient renewable electricity production if equipped with adequate thermal energy storage systems. Metal hydride based thermal energy storage systems are appealing candidates due to their demonstrated potential for very high volumetric energy densities, high exergetic efficiencies, and low costs. The feasibility and performance of a thermal energy storage system based on NaMgH₂F hydride paired with TiCr_1.6Mn_0.2 is examined, discussing its integration with a solar-driven ultra-supercritical steam power plant. The simulated storage system is based on a laboratory-scale experimental apparatus. It is analyzed using a detailed transport model accounting for the thermochemical hydrogen absorption and desorption reactions, including kinetics expressions adequate for the current metal hydride system. The results show that the proposed metal hydride pair can suitably be integrated with a high temperature steam power plant. The thermal energy storage system achieves output energy densities of 226 kWh/m³, 9 times the DOE SunShot target, with moderate temperature and pressure swings. In addition, simulations indicate that there is significant scope for performance improvement via heat-transfer enhancement strategies.     

The economic feasibility study of a 100-MW Power-to-Gas plant

Power-to-Gas (PtG) is a grid-scale energy storage technology by which electricity is converted into gas fuel as an energy carrier. PtG utilizes surplus renewable electricity to generate hydrogen from Solid-Oxide-Cell, and the hydrogen is then combined with CO₂ in the Sabatier process to produce the methane. The transportation of methane is mature and energy-efficient within the existing natural gas pipeline or town gas network. Additionally, it is ideal to make use of the reverse function of SOC, the Solid-Oxide-Fuel-Cell, to generate electricity when the grid is weak in power. This study estimated the cost of building a hypothetical 100-MW PtG power plant with energy storage and power generation capabilities. The emphasis is on the effects of SOC cost, fuel cost and capacity factor to the Levelized Cost of Energy of the PtG plant. The net present value of the plant is analyzed to estimate the lowest affordable contract price to secure a positive present value. Besides, the plant payback period and CO₂ emission are estimated.