基于CRPS的整县光伏虚拟电厂动态电价机制研究

在“双碳”目标要求下,采用“1+X”开发模式的整县光伏在运行方式上可以视作为由分布式光伏聚合而成的电源型虚拟电厂。然而,现行分布式光伏固定上网电价制度无法有效鼓励社会资本或用户将其所投建的分布式光伏交由整县光伏运营商托管,即聚合而成虚拟电厂统一运行管理。基于此,将电价与出力预测误差相结合,建立基于CRPS光伏出力预测评分体系的整县光伏虚拟电厂动态电价机制,并以某采用“1+X”模式开发的整县光伏虚拟电厂为例开展电价仿真。算例结果表明,该虚拟电厂电价机制能够激励分布式光伏发电商加入整县光伏虚拟电厂,也能激励其提高自身的预测水平。     

基于改进引力搜索算法的电力市场环境下可再生能源竞标消纳优化

为解决新能源参与电力市场竞标、促进新能源消纳的问题,文章提出了基于改进引力搜索算法的电力市场环境下可再生能源竞标消纳优化模型。建立了风电、光伏机组出力模型,确定了风电光伏不确定出力场景削减。针对可再生能源竞标消纳模型建立了出清电价模型,确定了交易双方利润模型,并针对交易过程中的不确定概率进行了分析。提出了采用改进引力搜索算法联合模式搜索算法对出清电价模型进行求解。最后通过仿真分析,说明了所提方法的有效性。     

基于MIV-PSO-BPNN的光伏出力短期预测

针对高比例光伏接入电网时,光伏出力的波动性会严重影响电力系统稳定运行的问题提出一种基于平均影响值与改进粒子群优化神经网络的组合式光伏出力短期预测模型。首先,采用直接预测法,选取总辐射量、直接辐射量、散射量、相对湿度、气温、风速和降雨量7个影响光伏出力的因素,构建MIV-PSO-BPNN模型,基于Rapid Miner数据挖掘得出降雨量对光伏出力平均影响值为0.0099,影响较小,不作为模型输入变量。然后,用改进PSO优化算法对BPNN的权值与阈值进行优化。最后,利用上海浦东国际机场T2-2光伏电站数据进行验证,结果表明MIV-PSO-BPNN模型对光伏出力预测有效,在实际中有一定应用价值。     

云团移动对光伏电站出力特性及系统调频的影响

云团移动会造成大规模光伏系统出力的大幅度波动,并影响区域电网频率的稳定性。基于此,文章提出了地基云图和中尺度数值天气预报模式相结合的修正预测方法,并利用该方法来分析云团的移动特性及其对太阳辐照度衰减情况的影响,得到光伏电站出力的波动幅度和爬坡速率。在此基础上,分析了光伏电站出力波动对区域电力系统调频情况的影响。研究结果表明,该预测方法能够较为准确地预测云团移动情况下太阳辐照度和光伏电站的发电功率,并确定了当区域电网中,光伏发电装机容量与常规发电机组装机容量的比值小于常规机组爬坡率与光伏发电爬坡率之比时,区域电力系统的调频能力能够应对云团移动情况下光伏发电功率波动引起的区域电网频率的变化。     

基于动态负荷特性的家用光伏发电系统经济性评价

以家用光伏发电系统为研究对象,基于用户侧动态负荷特性与供给侧光伏发电出力特性的耦合解析,根据分布式光伏系统"自用为主、余电上网"的应用原则,构建家用分布式光伏发电系统经济性评价模型。应用该模型,以上海某家用光伏发电系统为例,分析其运行特性、经济性能及其影响因素。研究结果表明,现行政策下家用光伏发电系统的动态投资回收年限为12.4 a;在中国,促进光伏产业发展最实际、最有效的政策是提高上网电价。     

中国光伏发电平价上网分析

随着光伏电站投资成本与度电成本的不断下降,光伏发电成本已逐步逼近燃煤发电成本。针对不同太阳能资源状况、不同光伏电站投资成本水平下的光伏发电最低上网电价,以及我国不同地区光伏发电平价上网的可能性进行了测算分析,得出以下结论:在我国,若不考虑"弃光"问题,太阳能资源丰富、燃煤标杆上网电价高的地区可以实现光伏发电平价上网,甚至可以实现光伏发电上网电价低于燃煤标杆上网电价;太阳能资源丰富、燃煤标杆上网电价低的地区,或太阳能资源差、燃煤标杆上网电价高的地区,在控制好光伏电站投资成本的前提下,有希望实现光伏发电平价上网;而太阳能资源差、燃煤标杆上网电价低的地区,要实现光伏发电平价上网则较为困难。期望该研究结果可为相关政策的制定及项目决策提供依据。     

发电市场竞价模式研究

发电市场竞价模式是电力市场中实现电力资源优化配置的重要因素之一。叙述了有限电量、两部制电价和差价合约3种发电市场竞价的基本运营模式、适用条件以及上网竞价原理和竞价流程。     

考虑时段耦合的带有蓄电池的用户光伏系统优化运行研究

考虑到光伏出力、负荷变化以及电价都有明显的以一天为周期的变化规律,建立以天为一个运行优化周期,一天内又可分为任意多个时段的带有时段耦合的配蓄电池的用户光伏系统的运行优化模型。该模型在整个优化周期表现为非线性模型或分段线性模型,通过控制变量分拆的方法将其改造为等价全局线性模型,以便运用高效快捷的线性规划单纯形算法对其求解。与非线性模型在相同条件下进行比较,该模型不仅可在分时电价、实时电价下得出最佳运行方案,更重要的是在运算时间上也有极强优势,所以不但可用于日前优化方案的制定,也可用超短时优化方案的制定。最后在某省现行分时电价下应用该模型预测了蓄电池配在光伏系统中可实现盈利的折旧费或投资成本。     

含光热-光伏联合发电的电力系统随机生产模拟研究

针对光伏发电出力的随机性和时序性等不确定因素,提出了基于稀疏卷积递推间隔-频率曲线法的电力系统随机生产模拟方法。将间隔-频率曲线法和稀疏卷积递推法相结合,评估光伏发电接入对电力系统经济性和可靠性的影响。首先,利用间隔-频率曲线法对原始负荷和光伏出力的时变特性进行分析,并通过计算获得短时间内的净负荷曲线以及净负荷的累计概率、频率分布;然后,采用稀疏卷积递推法将净负荷曲线与发电机组的故障转移过程相结合,依次控制发电机组的运行,完成相应的卷积运算,并结合计算结果求得光热-光伏联合发电接入后电力系统的可靠性指标和生产成本;最后,基于EPRI 36发电系统的仿真结果,发现光热-光伏联合发电对电力系统有一定的容量可信度,因此可替代一定的常规机组,提高电力系统的可靠性和经济效益,这也验证了文章所提方法的正确性和有效性。     

计入峰谷分时上网电价的天然气发电竞争力分析

针对当前天然气发电燃料成本高、天然气供应不足而导致上网电价水平偏高,难以与煤电竞价的问题,提出考虑在发电侧实施峰谷分时上网电价机制,鼓励燃气电厂提高峰时段的上网电量,同时制定计入峰谷分时电价补贴标准来提高天然气发电的市场竞争力。算例结果表明,该措施明显提高了天然气发电的经济优势、气价的承受能力、与煤电平等竞价上网的竟争力。     

Design of the incentive mechanism in electricity auction market based on the signaling game theory

At present, designing a proper bidding mechanism to decrease the generators' market power is considered to be one of the key approaches to deepen the reform of the electricity market. Based on the signaling game theory, the paper analyzes the main electricity bidding mechanisms in the electricity auction markets and considers the degree of information disturbance as an important factor for evaluating bidding mechanisms. Under the above studies, an incentive electricity bidding mechanism defined as the Generator Semi-randomized Matching (GSM) mechanism is proposed. In order to verify the new bidding mechanism, this paper uses the Swarm platform to develop a simulation model based on the multi-agents. In the simulation model, the generators and purchasers use the partly superior study strategy to adjust their price and their electricity quantity. Then, the paper examines a simulation experiment of the GSM bidding mechanism and compares it to a simulation of the High-Low Matching (HLM) bidding mechanism. According to the simulation results, several conclusions can be drawn when comparing the proposed GSM bidding mechanism to the equilibrium state of HLM: the clearing price decreases, the total transaction volume increases, the profits of electricity generators decreases, and the overall benefits of purchasers increases.     

An auction story: How simple bids struggle with uncertainty

Short-term electricity markets are key to an efficient production by generation units. We develop a two-period model to assess different bidding formats to determine for each bidding format the optimal bidding strategy of competitive generators facing price-uncertainty. We compare the results for simple bidding, block bidding and multi-part bidding. We find that even under optimal simple and block bidding, generators face the risk of ex-post suboptimal solutions, whereas in multi-part bidding these do not occur. This points to efficiency gains of multi-part bidding in the presence of uncertainty in electricity markets.     

Techno-economic analysis of the integration of hydrogen energy technologies in renewable energy-based stand-alone power systems

A large number of stand-alone power systems that are based on fossil fuel or renewable energy (RE) based, are installed all over Europe. Such systems, often comprising photovoltaics (PV) and/or diesel generators provide power to communities or technical installations, which do not have access to the local or national electricity grid. The replacement of conventional technologies such as diesel generators and/or batteries with hydrogen technologies, including fuel cells in an existing PV-diesel stand-alone power system providing electricity to a remote community was simulated and optimised, using the hybrid optimisation model for electric renewables (HOMER) simulation tool. A techno-economic analysis of the existing hybrid stand-alone power system and the optimised hydrogen-based system was also conducted. The results of the analyses showed that the replacement of fossil fuel based gensets with hydrogen technologies is technically feasible, but still not economically viable, unless significant reductions in the cost of hydrogen technologies are made in the future.     

基于SQP法的电厂日前合约市场报价策略研究

在电力市场环境下,发电企业为了追求经济效益的最大化,必须在优化机组负荷分配的基础上掌握企业运行成本,并在电力市场上报出具有竞争力的上网电价。针对日前市场的特殊性,并建立了机组经济性曲线拟合的数学模型和基于序列二次规划法(SQP法)的机组负荷优化分配模型,指出了完全成本加成法的报价方法。用算例验证了一个发电企业在4个时段日前市场负荷的耗量成本。     

Economic evaluation of a stand-alone residential photovoltaic power system in Bangladesh

The economics of stand-alone photovoltaic power system is studied to test its feasibility in remote and rural areas of Bangladesh and to compare renewable generators with non-renewable generators. The life cycle cost of these generators are determined using the method of net present value analysis. It is found that the life cycle cost of this experimental PV system is Tk. 43.40/kWh for one family (US $1.00 = Bangladeshi taka Tk.50.00). The life cycle cost for grid electricity is Tk. 20.00/kWh and Tk. 7.75/kWh for generation of fuel costs of Tk. 6.80/kWh and Tk. 0.47/kWh respectively. For a village 1 km away from the distribution line, this cost becomes Tk. 125.00/kWh for a family. For petrol generator life cycle cost is Tk. 50.00/kWh at fuel price of Tk. 22.00 per litre. For diesel generator life cycle cost is found to be Tk. 46.10/kWh at fuel cost of Tk. 15.00 per litre. It is observed that the life cycle cost of one unit of energy from grids that are 1 km away from a village is much higher than the cost of energy from a PV system. Thus, the use of PV system is economically feasible in rural villages and remote areas of Bangladesh, where grid electricity is not available.     

Optimal operation of microgrid using hybrid differential evolution and harmony search algorithm

This paper proposes the generation scheduling approach for a microgrid comprised of conventional generators, wind energy generators, solar photovoltaic (PV) systems, battery storage, and electric vehicles. The electrical vehicles (EVs) play two different roles: as load demands during charging, and as storage units to supply energy to remaining load demands in the MG when they are plugged into the microgrid (MG). Wind and solar PV powers are intermittent in nature; hence by including the battery storage and EVs, the MG becomes more stable. Here, the total cost objective is minimized considering the cost of conventional generators, wind generators, solar PV systems and EVs. The proposed optimal scheduling problem is solved using the hybrid differential evolution and harmony search (hybrid DE-HS) algorithm including the wind energy generators and solar PV system along with the battery storage and EVs. Moreover, it requires the least investment.     

Analysis of grid connected solar PV system in the southeastern part of Bangladesh

Bangladesh is a potential site of implementing renewable energy system to reduce the severe power crisis throughout the year. According to this, Chittagong is the southeastern part of Bangladesh is also a potential site for implementing renewable energy system such as grid-connected photovoltaic (PV) system. Financial viability and green-house gas emission reduction of solar PV as an electricity generation source are assessed for 500 kW grid connected solar PV system at University of Chittagong, Chittagong. Homer simulation software and monthly average solar radiation data from NASA is used for this task. In the proposed system monthly electricity generation varies between 82.65 MW h and 60.3 MW h throughout the year with a mean value of 68.25 MW h depending on the monthly highest and lowest solar radiation data. It is found that per unit electricity production cost is US$ 0.20 based on project lifetime 25 years. The IRR, equity payback and benefit-cost ratio shows favorable condition for development of the proposed solar PV system in this site. A minimum 664 tones of green-house gas emissions can be reduced annually utilizing the proposed system.     

Assessing the potential of concentrating solar photovoltaic generation in Brazil with satellite-derived direct normal irradiation

With the declining costs of flat plate and concentrating photovoltaic (PV) systems, solar PV generation in many sunny regions in Brazil will eventually become cost competitive with conventional and centralized power generation. Detailed knowledge of the local solar radiation resource becomes critical in assisting on the choice of the technology most suited for large-scale solar electricity generation. When assessing the energy generation potential of non-concentrating, fixed flat plate versus concentrating PV, sites with high levels of direct normal irradiation (DNI) can result in cost-competitive electricity generation with the use of high concentrating photovoltaic systems (HCPV). In large countries, where the transmission and distribution infrastructure costs and associated losses typical of centralized generation must be taken into account, the distributed nature of solar radiation should be perceived as a valuable asset. In this work we assess the potential of HCPV energy generation using satellite-derived DNI data for Brazil, a large and sunny country with a continental surface of 8.5 million km². The methodology used in the study involved the analysis of global horizontal, latitude-tilt, and direct normal solar irradiation data resulting from the Solar and Wind Energy Resource Assessment (SWERA) Project, and an estimate of the resulting electricity production potential, based on a review of HCPV generators operating at other sites. The satellite-derived solar irradiation data, with 10 km × 10 km spatial resolution, were analysed over the whole country, in order to identify the regions where HCPV might present a considerable advantage over fixed plate PV on an annual energy generation basis. Our results show that there is a considerable fraction of the national territory where the direct normal solar irradiation resource is up to 20% higher than the latitude-tilt irradiation availability. Furthermore, these sites are located in the most industrially-developed region of the country, and indicate that with the declining costs of this technology, distributed multi-megawatt HCPV can be a good choice of technology for solar energy generation at these sites in the near future.     

计及机组爬坡速率约束的发电报价策略

从发电机组自身的成本特性和技术约束出发,建立了多个时段内考虑机组启停约束和爬坡约束时的最优报价策略模型,并采用动态规划算法进行了仿真分析。结果表明,该模型与方法能为发电商提供最优的、实用的报价方案。     

Assessing the technical and economic performance of building integrated photovoltaics and their value to the GCC society

This paper assesses the technical and economic performance of PV technology integrated into residential buildings in the Gulf Cooperation Council (GCC) countries. It highlights the value of PV electricity for the GCC society from the perspective of consumers, utilities and environment. Through a systematic modelling analysis it is shown that the efficiency of PV system drops by 4–6% due to high range of module temperature and also a change in power output due to high ambient temperatures. Consequently, the outputs of horizontal and vertical PV modules are found to be less than estimates based on standard test conditions. Economically, this study shows that building integrated photovoltaic (BIPV) systems are not viable in GCC countries and cannot compete with conventional electricity sources on a unit cost basis. From a society point of view, however, the integration of PV technology into buildings would have several benefits for the GCC countries, including: first, savings in capital cost due to central power plants and transmission and distribution processes; second, an increase in the exported oil and natural gas used for electricity generation; and third, a reduction in the CO₂ emissions from conventional power plants. When these considerations are taken into account then BIPV should become a feasible technology in GCC countries.