Peak Shaving Strategy of Concentrating Solar Power Generation Based on Multi-Time-Scale and Considering Demand Response

According to the multi-time-scale characteristics of power generation and demand-side response(DR)resources,as well as the improvement of prediction accuracy along with the approaching operating point,a rolling peak shaving optimization model consisting of three different time scales has been proposed.The proposed peak shaving optimization model considers not only the generation resources of two different response speeds but also the two different DR resources and determines each unit combination,generation power,and demand response strategy on different time scales so as to participate in the peaking of the power system by taking full advantage of the fast response characteristics of the concentrating solar power(CSP).At the same time,in order to improve the accuracy of the scheduling results,the combination of the day-ahead peak shaving phase with scenario-based stochastic programming can further reduce the influence of wind power prediction errors on scheduling results.The testing results have shown that by optimizing the allocation of scheduling resources in each phase,it can effectively reduce the number of starts and stops of thermal power units and improve the economic efficiency of system operation.The spinning reserve capacity is reduced,and the effectiveness of the peak shaving strategy is verified.

Site Ranking and Potential Assessment for Concentrating Solar Power in West Africa

Access to electricity is poor in the Economic Community of West African States (ECOWAS). Concentrating Solar Power (CSP) presents better opportunities for increasing access to electricity and for diversifying sources of energy in the ECOWAS region;however, to date, except for Burkina Faso, no site evaluation pertaining to the region has ever been performed for CSP. This study provides potential assessment and site ranking for large-scale CSP projects in the ECOWAS region. It computes the nominal potential power and gives the corresponding energy yield with many scenarios. By considering only 1% of the suitable land area with daily DNI greater or equal to 5 kWh/m2, a land slope less or equal to 5% and distance to transmission line not more than 100 km, the study showed, for example, that West Africa has a potential nominal capacity of 21.3 GW for parabolic trough technology.

Full scale experimental study of a small natural draft dry cooling tower for concentrating solar thermal power plant

Concentrating solar thermal power system can provide low carbon,renewable energy resources in countries or regions with strong solar irradiation.For this kind of power plant which is likely to be located in the arid area,natural draft dry cooling tower is a promising choice.To develop the experimental studies on small cooling tower,a 20 m high natural draft dry cooling tower with fully instrumented measurement system was established by the Queensland Geothermal Energy Centre of Excellence.The performance of this cooling tower was measured with the constant heat input of 600 kW and 840 kW and with ambient temperature ranging from 20 ℃ to 32 ℃.The cooling tower numerical model was refined and validated with the experimental data.The model of 1 MW concentrating solar thermal supercritical CO2 power cycle was developed and integrated with the cooling tower model.The influences of changing ambient temperature and the performance of the cooling tower on efficiency of the power system were simulated.The differences of the mechanism of the ambient temperature effect on Rankine cycle and supercritical CO2 Brayton cycle were analysed and discussed.

Energy and Exergy Analysis of a New Small Concentrating Solar Power Plant

A new small concentrating solar power plant which is suitable for urban area is presented, and a theoretical framework for the energy and exergy analysis in the overall power plant is also constructed. The framework can be used to evaluate the energy and exergy losses in each component. Furthermore, the energy and exergy efficiencies have also been computed and compared for the individual components as well as for the overall plant.

Research progress on protective coatings against molten nitrate salts for thermal energy storage in concentrating solar power plants

Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten salt technology for thermal energy storage(TES) has further contributed to the growth of CSP plants;however, the corrosive nature of molten salts poses challenges to the durability of container materials, necessitating innovative corrosion mitigation strategies.This review summarizes scientific advancements in high-temperature anticorrosion coatings for molten nitrate salts, highlighting the key challenges and future trends.It also explores various coating types, including metallic, ceramic, and carbon-based coatings, and compares different coating deposition methods.This review emphasizes the need for durable coatings that meet long-term performance requirements and regulatory limitations, with an emphasis on carbon-based coatings and emerging nanomaterials.A combination of multiple coatings is required to achieve desirable anticorrosion properties while addressing material compatibility and cost considerations.The overall goal is to advance the manufacturing, assembly, and performance of CSP systems for increased efficiency, reliability, and durability in various applications.

Concentrating Solar Power in Europe, the Middle East and North Africa： Achieving Its Potential

CSP （concentrating solar power） is a commercially available renewable energy technology capable of harnessing the immense solar resource in southern Europe, the MENA region （Middle East and North Africa）, and elsewhere. This paper summarises the findings of a study by the European Academies Science Advisory Council which has examined the current status and development challenges of CSP, and consequently has evaluated the potential contribution of CSP in Europe and the MENA region to 2050. It identifies the actions that will be required by scientists, engineers, policy makers, politicians, business and investors alike, to enable this vast solar resource to make a major contribution to establishing a sustainable energy system. The study concludes that cost reductions of 50%-60% in CSP electricity may reasonably be expected in the next 10-15 years, enabling the technology to be cost competitive with fossil-fired power generation at some point between 2020 and 2030. Incorporation of storage delivers added value in enabling CSP to deliver dispatchable power. Incentive schemes will be needed in Europe and MENA countries to enable this point to be achieved. Such schemes should reflect the true value of electricity to the grid, effectively drive research and development, and ensure transparency of performance and cost data.

Progress in Research and Development of Molten Chloride Salt Technology for Next Generation Concentrated Solar Power Plants

Concentrated solar power(CSP)plants with thermal energy storage(TES)system are emerging as one kind of the most promising power plants in the future renewable energy system,since they can supply dispatchable and low-cost electricity with abundant but intermittent solar energy.In order to significantly reduce the levelized cost of electricity(LCOE)of the present commercial CSP plants,the next generation CSP technology with higher process temperature and energy efficiency is being developed.The TES system in the next generation CSP plants works with new TES materials at higher temperatures(>565℃)compared to that with the commercial nitrate salt mixtures.This paper reviews recent progressin research and development of the next generation CSP and TES technology.Emphasis is given on theadvanced'TES technology based on molten chloride salt mixtures such as MgCl_(2)/NaCl/KCl which hassimilar thermo-physical properties as the commercial nitrate salt mixtures,higher thermal stability(>800℃),and lower costs(<0.35USD·kg^(-1)).Recent progress in the selection/optimization of chloridesalts,determination of molten chloride salt properties,and corrosion control of construction materials(eg.,alloys)in molten chlorides is reviewed.

High-temperature Thermal Properties and Wear Behavior of Basalt as Heat Storage Material for Concentrated Solar Power Plants

The microstructures,components,thermal stability,specific heat capacity and thermal conductivity of basalt sample were studied.Besides,as a comprehensive result of thermal expansion and contraction process,both the friction coefficient and wear rate of the basalt sample were also characterized.Our results indicate that basalt is an excellent candidate to be used as thermal energy storage material for concentrated solar power plants,and also provide a strategy for solar energy utilization in volcanic area with excellent geographical environment.

Application of Model Predictive Control Based on Kalman Filter in Solar Collector Field of Solar Thermal Power Generation

There are two prominent features in the process of temperature control in solar collector field.Firstly,the dynamic model of solar collector field is nonlinear and complex,which needs to be simplified.Secondly,there are a lot of random and uncontrollable,measurable and unmeasurable disturbances in solar collector field.This paper uses Taylor formula and difference approximation method to design a dynamic matrix predictive control(DMC)by linearizing and discretizing the dynamic model of the solar collector field.In addition,the purpose of controlling the stability of the outlet solar field salt temperature is achieved by adjusting the mass flow of molten salt.In order to further improve the ability of the system to suppress unmeasured disturbances,a steady-state Kalman filter is designed to estimate state variables,so that the system has better stability and robustness.The simulation verification results show that the DMC control system based on Kamlan filtering has better control effect than the traditional DMC control system.In the case of large fluctuations in solar radiation intensity and consideration of undetectable interference,the overshoot of the system is reduced by 4%and the rise time remains unchanged.

Multi-aiming Strategy Design for Quadruple Prism Shaped Central Receiver in Solar Power Tower System

For solar power tower technology, the improvement of interception efficiency of heliostat field and the extension of central receiver U+02BC s life time are two technical difficulties. To the receiver, higher interception efficiency means more thermal shocks and stronger stresses of high temperatures mainly contribute to the reduction of receiver's life time. To address these problems, a semi-random distribution strategy is proposed to select the best aiming point of the heliostat, and the distribution of onedimensional array arranged on the centerline of the receiver is carried out for further optimization. It is shown by simulation that through our optimization the temperature distribution on the receiver surface becomes much more uniform while maintaining acceptable interception efficiency. © 2017 Chinese Association of Automation.

Demonstration of Pilot Scale Large Aperture Parabolic Trough Organic Rankine Cycle Solar Thermal Power Plant in Louisiana

During the calendar year of 2012 the University of Louisiana at Lafayette in conjunction with CLECO Power LLC (CLECO) has constructed and commissioned a pilot scale parabolic trough solar thermal power plant for the first time in Louisiana. The large aperture trough (LAT) solar collectors were provided by Gossamer Space Frames and are coupled with an organic Rankine cycle (ORC) power block provided by ElectraTherm, Inc. for study of the feasibility of cost-effective commercial scale solar thermal power production in Louisiana. Supported by CLECO and providing power to the existing CLECO grid, the implementation of state-of-the-industry collector frames, mirrors, trackers, and ORC power block is studied under various local weather conditions which present varied operating regimes from existing solar thermal installations. The solar collectors provide a design output of 650 kWth and preliminary actual performance data from the system level is presented. The optimal size, configuration and location for such a plant in the given solar resource region are being studied in conjunction with CLECO’s search for optimal renewable energy solutions for the region. The pilot scale size of the facility and implementation of the simpler ORC allow remote operation of the facility and flexibility in operating parameters for optimization studies. The construction of the facility was supported by the Louisiana Department of Natural Resources, the U.S. Department of Energy, and CLECO. The continued operation of the plant is supported by CLECO Power LLC and the University of Louisiana at Lafayette.

Determination of Suitable Sites for Establishment of Large-Scale Concentrated Solar Power Plants in Kenya

The demand for energy in Kenya, especially for electricity, is increasing rapidly due to population growth, decentralization of governance, and technological and industrial development. Hydroelectricity, the core source of power, has proved unreliable due to the rapid climate change. In response, the country has ventured into other renewable sources to counter the issues posed by the alternative nonrenewable sources such as unreliability, high costs, and environmental degradation as seen with the use of diesel and kerosene. The purpose of this research is to determine the viability of setting up a large-scale concentrated solar power plantation in Kenya that will assist in stabilizing Kenya’s energy demand and supply as well as increase its affordability. The project is divided into three phases. The first phase conducts an overlay analysis to determine the Kenya’s solar energy potential. The results show that the northern region has the highest potential. The second step involves the creation of an exclusion mask which eliminates the unsuitable land forms and Land Use Land Cover. Based on the results, the best ten sites are situated in Turkana and Marsabit counties. The final phase involves the evaluation of the potential capacity of power that could be generated per square kilometer. The study finds out that the potential varies based on the technologies: parabolic trough, linear Fresnel reflector, or dish systems.

Assessment of Hybrid Concentrated Solar Power-Biomass Plant Generation Potential in Sahel: Case Study of Senegal

Concentrating Solar Power (CSP) is non-existent in Sahel. Such a situation arises from the high investment costs required by these energy infrastructures and from a lack of information on the identification of suitable sites to accommodate them. Conversely, CSP-biomass plants due to lower investment may be an option for CSP penetration in Sahel where Direct Normal Irradiation (DNI) is between 1400 kWh/m2/year and 2000 kWh/m2/year and significant biomass potential. This work presents the results of an identification of suitable sites for hybrid CSP-Biomass in the Sahel, case study of Senegal, taking into account the Direct Normal Irradiation, the availability of water, space and biomass potential. The identified sites have a DNI > 1600 kWh/m2/year. The biogas production capacity is equivalent to 5,096,563 m3/year. The quantity of Typha Australis, invasive plant in Senegal river valley available is estimated at more than 3 million tons. The capacity of electrical energy in this zone is estimated at 6.89 GWe for an installation surface estimated at 275.61 km2. The establishment of CSP/hybrid plants can also contribute to combat the proliferation of Typha Australis.

Preliminary Design Study on Concentrated Solar Power PVRs to Operate with RCBC

Parabolic through concentrators and parabolic dish concentrators followed by a PVR （pressurized volumetric receiver） are proposed, studying the performance behavior of a RCBC （regenerative closed Brayton cycle） operating with helium or hydrogen. A pressurized gas such as helium circulates along the volumetric receiver, capturing the concentrated thermal solar energy to be further converted into electric power via a thermal cycle. The overall efficiency of the plant has been computed under variable parameters to determine the operating conditions for which efficiency and specific power are acceptable. As consequence of the proposed analysis, it is concluded that direct coupling between volumetric receivers and thermal engines renders high efficiency while avoiding an intermediate heat transfer medium.

Overview of Concentrated Solar Power

CSP （concentrated solar power） has been viewed as the technology that if properly developed could lead to a large scale conversion of solar energy into electricity. CSP is a type of solar energy converter that is classified as thermal converter because the output power produced is a function of the operating temperature. The main components of a CSP plant are the solar field which is made up of the heliostat arrays, the receiver tower, the heat transfer fluid, the molten salt thermal energy storage tanks and the power conversion unit, which is made up of the turbine and the generator. The main advantage of CSP is that of a cheap thermal storage （i.e., molten salt storage） which makes it possible to dispatch power at a cost comparable to the grid electricity. Simulations run with the SAM （systems advisory model） developed by NREL （National Renewable Energy Laboratory） showed that CSP is capable of delivering electricity at the cost of 17UScents per kWh for the 30-year life of the plant. The main disadvantage of CSP however, is that of low efficiency （8%-16%）. There are ongoing research works to improve the efficiency of the CSP. One way to improve the efficiency is to increase the operating temperature of the system. In this paper, the authors discussed different modules of the CSP plant and suggested ways to improve on the conversion efficiencies of individual modules. Finally, an overall systems performance simulation is carried using SAM and the simulation results show that electricity can be produced using CSP at the cost of RI.05 per kWh.

含聚合CSP和深度调峰火电机组的电力系统分布鲁棒机会约束优化调度方法

随着“双碳”目标不断推进,可再生能源的装机容量和发电占比不断增加。然而,以风电、光伏为代表的可再生能源所固有的不确定性和波动性,使得以火电机组深度调峰为主的传统运行方式的经济性难以得到保障。针对上述问题,提出一种含聚合光热发电(Concentrating Solar Power,CSP)和深度调峰火电机组的电力系统分布鲁棒机会约束优化调度方法。首先,分析火电机组的基本调峰和深度调峰能力,构建考虑火电机组进行基本调峰或深度调峰成本的深度调峰模型。其次,分析光热电站启动时的热量传递过程,构建考虑启动热量约束的CSP模型。在此基础上,采用基于数据驱动的分布鲁棒机会约束描述可再生能源出力的不确定性,构建以火电机组发电成本、购售电成本和储能使用成本之和最小为优化目标的调度模型。最后,以改进的IEEE 30节点系统为例验证了所提方法具有较好的经济性和鲁棒性。

光热发电储能熔盐研究进展

光热发电是极具发展前景的可再生能源技术,不仅可实现电力能源的梯次利用,还能与风电、光电等互补运行。基于国内外对光热发电技术的研究,本文综述了光热发电用储能熔盐的研究进展。熔盐是光热发电热能存储系统中理想的传储能介质,具有高热容量、高导热性和低黏度等优异的热物理性质。熔盐储能具有储能容量大、储存周期长和成本低等优点,在光热发电、熔盐反应堆、供暖和余热回收等领域广泛应用。本文首先介绍了光热发电技术的优势和发展,接着归纳总结了光热发电用储能熔盐的主要特性和发展,并对新开发配比的熔盐以及熔盐纳米流体热物理性质进行了阐述,最后总结和展望了下一代光热发电储能熔盐的发展。期望了解光热发电储能熔盐的技术发展,为下一代热能传储系统的设计、制造和运行维护提供参考。

考虑风电与光热电站参与能量-调频辅助服务市场的联合投标策略

针对高比例新能源接入电网导致电网调频需求增大的困局,提出风电和光热电站联合参与能量-调频市场的系统架构。为保证日前投标计划的精准执行,引入偏差惩罚机制,并考虑风电、光照幅度及市场价格的不确定性因素,以联合系统总收益最大为目标,提出基于鲁棒优化的日前-实时两阶段最优投标策略,通过仿真验证,证明了相比于风电、光热电站单独投标,联合投标可通过光热电站灵活的调节特性平抑风电波动造成的投标偏差惩罚,提升联合系统的整体收益。最后,分析不同能量和调频市场价格对联合系统投标收益的影响。

风电–CSP联合发电系统优化运行研究

为了抑制风电波动,减少弃风量,考虑到配备储热的太阳能热发电(concentrated solar power,CSP)系统具有可调度性,提出了一种风电—CSP联合发电系统。该系统由风电子系统、CSP子系统及电加热(electric heater,EH)子系统组成。其中,EH子系统的主要作用是将弃风电能转化为热能,并将热能送入CSP储热子系统(thermal energy storage,TES),既为弃风利用提供一条有效途径,又为CSP增加一个热源,使系统的可调度性和灵活性进一步提高。针对该联合系统,以最小化系统输出负荷与计划负荷间的偏差和最大化能源利用率为目标,建立了其混合整数规划调度模型。以未加EH子系统的风电–CSP联合发电系统为参照,通过案例对比研究了在晴天及部分阴云天气下系统的特性。结果显示该联合系统可更好地跟踪计划负荷,有效降低风电弃风量,为CSP储热子系统提供更多的热能,使系统具有更高的灵活性和可调度性。

双级聚光集热的槽式太阳能热发电系统研究

为了提高槽式光热发电系统的性能,通过高、低聚光比镜场的耦合布置,辅以两种传热介质的搭配,建立了双级聚光集热的槽式太阳能热发电系统模型,与传统槽式光热发电系统展开对比,得到了双级系统集热、换热性能提升的机理和系统关键过程[火用]损失减小的原因。对双级系统进行能量分析和[火用]分析,展示了双级系统中的能量和[火用]流动情况,揭示了在镜场侧和动力侧的各项能量和[火用]损失的分布规律。结果表明:双级聚光集热系统中镜场的耦合布置有效地提高了系统的集热性能,两种传热介质的协同搭配改善了系统的换热性能。损失分布方面,光学损失仍是导致系统集热损失的重要因素,同时光热转化过程的不可逆损失在[火用]损失中占比较大,具有较大的提升潜力。双级系统的热效率可达到27.35%,[火用]效率达到28.84%,相较于传统单聚光比、单介质的槽式太阳能热发电系统,热效率和[火用]效率均可提升0.9%~1.5%,相同发电量下可节省镜场面积4%~6%。研究为槽式太阳能热发电系统提出了改进策略,为进一步优化研究提供了一定的理论依据。