Capacity demand analysis of energy storage in the sending-side of a power grid for accommodating large-scale renewables

我国新能源富集的"三北地区"弃风弃光现象严重,同时储能技术发展已逐步接近规模化应用水平。该文在分析影响新能源消纳问题的电网结构特性、储能技术应用发展方向与技术水平的基础上,基于电网可最大释放的新能源发电空间约束建立了以缩减弃风率与弃光率为目标的储能系统功率与容量配置的数学模型,结合储能投资成本与提升新能源消纳收益构成的投资收益比评估约束指标,提出了满足新能源消纳性能/投资成本比较优的储能容量需求计算方法,探索了储能提升新能源消纳能力的技术与经济可行性分析思路。以消纳风电和光伏为主的两省级电网为例,讨论了储能在送端电网中促进风电和光伏消纳应用中的作用及经济适用性,验证了该新能源消纳方案的可行性。     

Intermittently renewable energy,optimal capacity mix and prices in a deregulated electricity market

This paper assesses the effect of intermittently renewable energy on generation capacity mix and market prices. We consider two generating technologies: (1) conventional fossil-fueled technology such as combined cycle gas turbine (CCGT), and (2) sunshine-dependent renewable technology such as photovoltaic cells (PV). In the first stage of the model (game), when only the probability distribution functions of future daily electricity demand and sunshine are known, producers maximize their expected profits by determining the CCGT and PV capacity to be constructed. In the second stage, once daily demand and sunshine conditions become known, each producer selects the daily production by each technology, taking the capacities of both technologies as given, and subject to the availability of the PV capacity, which can be used only if the sun is shining. Using real-world data for Israel, we confirm that the introduction of PV technology amplifies price volatility. A large reduction in PV capacity cost increases PV adoption but may also raise the average price. Thus, when considering the promotion of renewable energy to reduce CO₂ emissions, regulators should assess the behavior of the electricity market, particularly with respect to characteristics of renewable technologies and demand and supply uncertainties.     

Modeling,control and simulation of a photovoltaic /hydrogen/ supercapacitor hybrid power generation system for grid-connected applications

Hybrid renewable energy systems (HRES) should be designed appropriately with an adequate combination of different renewable sources and various energy storage methods to overcome the problem of intermittency of renewable energy resources. Focusing on the inevitable impact on the grid caused by strong randomicity and apparent intermittency of photovoltaic (PV) generation system, modeling and control strategy of pure green and grid-friendly hybrid power generation system based on hydrogen energy storage and supercapacitor (SC) is proposed in this paper. Aiming at smoothing grid-connected power fluctuations of PV and meeting load demand, the alkaline electrolyzer (AE) and proton exchange membrane fuel cell (PEMFC) and SC are connected to DC bus of photovoltaic grid-connected generation system. Through coordinated control and power management of PV, AE, PEMFC and SC, hybrid power generation system friendliness and active grid-connection are realized. The validity and correctness of modeling and control strategies referred in this paper are verified through simulation results based on PSCAD/EMTDC software platform.     

Scalable methodology for the photovoltaic solar energy potential assessment based on available roof surface area: Application to Piedmont Region (Italy)

During the last few years the photovoltaic energy market has seen an outstanding growth. According to the new directive on renewable energies of the European Commission (2009/28/EC), the European Union should reach a 20% share of the total energy consumption from renewable sources by 2020. The national overall targets impose for Italy a 17% renewable share: in case of failure the gap would be filled by importation of renewable energy from non-UE countries. The ambitious national targets and thus the continuously increasing interest on renewable fuels, require simple but reliable methods for the energy potential assessment over large-scale territories. Considering roof-top integrated PV systems, the assessment of the PV energy potential passes through the evaluation of the roof surface area available for installations. In the present paper a methodology for estimating the PV solar energy potential is presented, together with its application to Piedmont Region (North-Western Italy). The roof area suitable for solar applications, is calculated through the analysis of available GIS data. The solar radiation maps are taken from the database of the Joint Research Centre of the European Commission. Different solar energy exploitation scenarios are proposed with the relative perspective results and confidence interval. Further developments and applications of the presented methodology are finally discussed.     

Assessment of Korean customers’ willingness to pay with RPS

To increase the use of renewable energy, the Korean government will introduce the Renewable Portfolio Standard (RPS) in 2012. The RPS places responsibility for extra renewable energy costs on the consumers and allows price competition among different renewable sources. Accordingly, this study analyzes through the contingent valuation (CV) the willingness of Korean households to pay more for electricity generated by wind, photovoltaic (PV), and hydropower. Our empirical results show that, although the willingness to pay (or WTP) was highest for wind power and lowest for hydropower, the differences in WTP among the renewable sources were statistically insignificant. This suggests that Korean consumers prefer a renewable portfolio that minimizes power supply costs.The average WTP for all three energy types was KRW 1562.7 (USD 1.350) per month per household, which was approximately 3.7% of the average monthly electricity bill in 2010. This amount represents only 58.2% of what the Korean government allocated in its budget to the new and renewable energy dissemination program in 2010. Thus, our results imply that the promotion of the new and renewable energy dissemination program may be difficult only with the WTP for electricity generated from renewable sources. Specifically, the mean WTP will not support the set-aside dissemination capacity for PV after 2014.     

构建适应可再生能源资源特点的新型电力体系

从节能减排、重构能源供应体系出发,阐述了可再生能源在未来能源体系中的作用,分析了可再生能源发展面临的主要制约因素,提出构建适应可再生能源资源特点的新型电力系统主要措施,强调构建新型电力系统既要保障电力系统的安全可靠运行,又要充分发挥可再生新能源清洁环保的作用,推动能源体系由以石化能源为主向以可再生能源为主的转变。     

太阳能光伏发电技术及其应用

随着现代工业的发展,全球能源危机和大气污染问题日益突出,太阳能作为理想的可再生能源受到了许多国家的重视。目前太阳能光伏发电技术正在迅速发展,应用的规模和范围也在不断地扩大,已成为当今世界新能源发电领域的一个研究热点。本文在介绍太阳能光伏发电基本原理的基础上,详细阐述了太阳能光伏发电的相关重要技术,论述了太阳能光伏发电技术的主要应用方式和应用领域,并分析了太阳能光伏发电技术的应用前景。     

Parameter study for dimensioning of a PV optimized hydrogen supply plant

Green hydrogen produced from intermittent renewable energy sources is a key component on the way to a carbon neutral planet. In order to achieve the most sustainable, efficient and cost-effective solutions, it is necessary to match the dimensioning of the renewable energy source, the capacity of the hydrogen production and the size of the hydrogen storage to the hydrogen demand of the application.For optimized dimensioning of a PV powered hydrogen production system, fulfilling a specific hydrogen demand, a detailed plant simulation model has been developed. In this study the model was used to conduct a parameter study to optimize a plant that should serve 5 hydrogen fuel cell buses with a daily hydrogen demand of 90 kg overall with photovoltaics (PV) as renewable energy source. Furthermore, the influence of the parameters PV system size, electrolyser capacity and hydrogen storage size on the hydrogen production costs and other key indicators is investigated. The plant primarily uses the PV produced energy but can also use grid energy for production.The results show that the most cost-efficient design primarily depends on the grid electricity price that is available to supplement the PV system if necessary. Higher grid electricity prices make it economically sensible to invest into higher hydrogen production and storage capacity. For a grid electricity price of 200 €/MWh the most cost-efficient design was found to be a plant with a 2000 kWp PV system, an electrolyser with 360 kW capacity and a hydrogen storage of 575 kg.     

Technico-economic analysis of off grid solar PV/Fuel cell energy system for residential community in desert region

A technico-economic analysis based on integrated modeling, simulation, and optimization approach is used in this study to design an off grid hybrid solar PV/Fuel Cell power system. The main objective is to optimize the design and develop dispatch control strategies of the standalone hybrid renewable power system to meet the desired electric load of a residential community located in a desert region. The effects of temperature and dust accumulation on the solar PV panels on the design and performance of the hybrid power system in a desert region is investigated. The goal of the proposed off-grid hybrid renewable energy system is to increase the penetration of renewable energy in the energy mix, reduce the greenhouse gas emissions from fossil fuel combustion, and lower the cost of energy from the power systems. Simulation, modeling, optimization and dispatch control strategies were used in this study to determine the performance and the cost of the proposed hybrid renewable power system. The simulation results show that the distributed power generation using solar PV and Fuel Cell energy systems integrated with an electrolyzer for hydrogen production and using cycle charging dispatch control strategy (the fuel cell will operate to meet the AC primary load and the surplus of electrical power is used to run the electrolyzer) offers the best performance. The hybrid power system was designed to meet the energy demand of 4500 kWh/day of the residential community (150 houses). The total power production from the distributed hybrid energy system was 52% from the solar PV, and 48% from the fuel cell. From the total electricity generated from the photovoltaic hydrogen fuel cell hybrid system, 80.70% is used to meet all the AC load of the residential community with negligible unmet AC primary load (0.08%), 14.08% is the input DC power for the electrolyzer for hydrogen production, 3.30% are the losses in the DC/AC inverter, and 1.84% is the excess power (dumped energy). The proposed off-grid hybrid renewable power system has 40.2% renewable fraction, is economically viable with a levelized cost of energy of 145 $/MWh and is environmentally friendly (zero carbon dioxide emissions during the electricity generation from the solar PV and Fuel Cell hybrid power system).     

分布式光伏发电与能源可持续利用

为了应对世界不可再生能源资源日益匮乏的现状,可再生能源已经得到了长足的发展,而分布式光伏发电已成为当今世界最有希望的可再生能源资源之一。近期国务院能源局、国家发改委、国家财政部下发多个支持发展该项项目的文件,全国各地积极响应,已经出现不少成功案例。在对国内外分布式光伏发电发展历程调研的基础上,对发展分布式光伏发电提出一些建议。     

Alternatives to grid extension for rural electrification: Decentralized renewable energy technologies in Vietnam

This paper examines the economic viability of stand-alone, household-sized renewable energy technologies, namely wind generator and solar PV for application in remote and rural areas of Vietnam. Three reference technologies are chosen. These are two solar PV systems of 130 and 100 Wp for solar conditions in the North and the South, respectively, and one 150 W wind turbine. It is found for all regions that levelized costs of PV energy are lower than the cost of energy from gasoline gen-set, and are cost-competitive with grid extension, especially for areas with low load density and low number of households to be electrified. Regarding wind energy, the viability is dependent on the location due to the wide variation of wind resource to topography. However, in locations with proper resources, wind energy is even more cost-competitive than solar PV. Thus, the use of either wind generator or solar PV is economically feasible in rural villages and remote areas of Vietnam. Policy recommendations for promoting the market development of renewable energy technologies are discussed in the final section of the paper.     

Evaluating the potential of small-scale renewable energy options to meet rural livelihoods needs: A GIS- and lifecycle cost-based assessment of Western China's options

The economics and livelihoods impacts of stand-alone, small-scale (less than 2 kW) renewable energy technologies for rural electrification are assessed using a representative sample of 531 rural households in three provinces of Western China. Over 20 small wind, photovoltaic (PV) and wind–PV hybrid configurations were evaluated for their potential to meet local electricity needs. The assessment integrates lifecycle costing and geographic information system (GIS) methods in order to provide a comprehensive resource, economic, technological and livelihoods assessment. The results of the analysis indicate that off-grid renewable energy technologies can provide cost-effective and reliable alternatives to conventional generator sets in addressing rural livelihoods energy requirements. Findings also demonstrate the existence of a sizeable market potential for stand-alone renewable energy systems in Western China. In support of market development for these technologies, policy recommendations are provided.     

Renewable power for China: Past,present, and future

This paper briefly examines the history, status, policy situation, development issues, and prospects for key renewable power technologies in China. The country has become a global leader in wind turbine and solar photovoltaic (PV) production, and leads the world in total power capacity from renewable energy. Policy frameworks have matured and evolved since the landmark 2005 Renewable Energy Law, updated in 2009. China’s 2020 renewable energy target is similar to that of the EU. However, China continues to face many challenges in technology development, grid-integration, and policy frameworks. These include training, research and development, wind turbine operating experience and performance, transmission constraints, grid interconnection time lags, resource assessments, power grid integration on large scales, and continued policy development and adjustment. Wind and solar PV targets for 2020 will likely be satisfied early, although domestic demand for solar PV remains weak and the pathways toward incorporating distributed and building-integrated solar PV are uncertain. Prospects for biomass power are limited by resource constraints. Other technologies such as concentrating solar thermal power, ocean energy, and electricity storage require greater attention.     

欧盟可再生能源发展形势和2020年发展战略目标分析

2010年,欧盟可再生能源发展呈现出新的形势:一方面,风电满足了欧盟5.3%的电力需求,已经开始发挥替代能源的战略作用;另一方面,光伏发电新增装机容量首次超过风电,显示出分布式光伏发电的巨大优势。在欧盟可再生能源"20-20-20"发展目标的基础上,欧盟各成员国相继制定了具有法律效力的国家可再生能源行动方案,规定了各国在不同时期的可再生能源的发展目标和实现路径。     

力促大规模非水可再生能源发展

综述了我国能源与电力可持续发展的现状和未来,着重阐述了风力发电、光伏发电、太阳能热发电等可再生能源发电发展的主要特点和问题,最后建议加快规划与部署建设以可再生能源为主体的综合能源基地,积极构建我国能源可持续发展体系。     

加快发展河北省太阳能光热发电的建议和对策

太阳能作为一种可再生的新能源,越来越引起人们的关注。我国每年太阳能资源理论储量折合标准煤达17000亿t,而包括风能、水能、生物质能、地热能在内的其它所有可再生能源折合标准煤不到60亿t,太阳能利用潜力巨大。太阳能发电主要有光伏发电和光热发电。太阳能光热发电比光伏发电具有更多的优势。阐述了太阳能光热发电的国内外发展现状,分析了河北省太阳能的资源潜力,并提出了河北省发展太阳能光热发电的建议和对策.     

Research on Hybrid Renewable Energy Systems with Fault Detection Technology

Early and accurate fault detection and diagnosis for renewable energy systems can increase their safety and ensure the continuity of their service. This paper presents a comprehensive review of different fault detection and diagnosis methods for hybrid renewable energy systems consisting of a wind turbine power generator, a PV （photovoltaic） array, a PEM （polymer electrolyte membrane） fuel cell and a battery storage system. The need of batteries to store the generated power from the solar panel, wind turbine or PEM fuel cell is also emphasized. Finally, an overview of the current methods used in the diagnosing of the lead-acid battery degradation is given.     

Renewable power for China: Past, present, and future

This paper briefly examines the history, status, policy situation, development issues, and prospects for key renewable power technologies in China. The country has become a global leader in wind turbine and solar photovoltaic (PV) production, and leads the world in total power capacity from renewable energy. Policy frameworks have matured and evolved since the landmark 2005 Renewable Energy Law, updated in 2009. China’s 2020 renewable energy target is similar to that of the EU. However, China continues to face many challenges in technology development, grid-integration, and policy frameworks. These include training, research and development, wind turbine operating experience and performance, transmission constraints, grid interconnection time lags, resource assessments, power grid integration on large scales, and continued policy development and adjustment. Wind and solar PV targets for 2020 will likely be satisfied early, although domestic demand for solar PV remains weak and the pathways toward incorporating distributed and building-integrated solar PV are uncertain. Prospects for biomass power are limited by resource constraints. Other technologies such as concentrating solar thermal power, ocean energy, and electricity storage require greater attention.     

Domestic integration of micro-renewable electricity generation in Ireland – The current status and economic reality

The utilisation of renewable energy resources for power generation is extremely important for Ireland due to the lack of indigenous fossil fuel resources. A micro-wind turbine is by far the most commonly used grid-connected micro-renewable electricity generation system for domestic applications in Ireland, followed by solar PV. Unfortunately, neither a single micro-wind turbine nor a single solar PV system can provide a continuous power supply due to variations in weather and climate conditions. The coupling of these two systems however can improve the power supply reliability by using the complementary characteristics of wind and solar energy. In this paper, a micro-renewable electricity-generation-system integration technique, tailored for applications in Ireland but generally applicable, is presented. Net present value is the parameter used to identify the optimal system. The optimal system can be a mono system, formed from a single micro-wind turbine or a single solar PV system, or a hybrid system formed from a combination of both. A renewable energy requirement is a constraint used in the integration to eliminate systems that cannot provide sufficient energy from renewable energy resources. The integration technique is applied to find the optimal system, under current Irish conditions, that can be formed from six sample micro-wind turbines and/or solar PV systems assembled from three sample solar PV modules. The analyses show that, with a 50% renewable energy requirement, the optimal system is a mono system containing a 2.4 kW micro-wind turbine; however, critically, the system is not economically viable. Four parameter studies assessing the effect of household electrical load, imported electricity price, exported electricity tariff and wind speed have also been conducted. From these studies it is seen that the most effective way to improve the financial performance of all systems is to offer a higher exported electricity tariff; installing a mono/hybrid system containing a micro-wind turbine in a location with a good wind resource can also have a significant effect.     

中国可再生能源发展进入阶段转换期

本世纪前10年,中国可再生能源采取开放型发展模式,凭借风电产业"以市场换技术"的战略及光伏产业"两头在外"的发展模式,加之国内政策的大力扶持,连续3年保持全球风电第一大国地位,2011年中国光伏电池产量占到全球产量的56.5%,光伏组件出口量占当年全球新增光伏装机容量的54.6%。然而自2010年末起,中国可再生能源产业频繁遭遇国外"双反"制裁,正面临"保护难"和"出口难"的两难困境,"以市场换技术"战略难以为继,"两头在外"的发展模式也走到了尽头。开放式的发展模式已不适合产业的进一步发展,中国可再生能源产业开始步入主要依靠国内市场、依靠自主创新的内向化发展新阶段。中国的可再生能源市场前景广阔,国内市场足以支撑产业的发展。虽然国外企业在技术水平方面领先于中国企业,但由于技术边界效应的存在,中国企业在国内市场上还是有优势的。新阶段中国的产业政策应该转向大力开发国内市场,将补贴产品的生产和贸易环节改为补贴生产要素,并加大对可再生能源消费端的补贴。同时,要加快提升企业自主创新能力和产业技术水平。