A review on compressed air energy storage - a pathway for smart grid and polygeneration

The increase in energy demand and reduction in resources for conventional energy production along with various environmental impacts, promote the use of renewable energy for electricity generation and other energy-need applications around the world. Wind power has emerged as the biggest renewable energy source in the world, whose potential, when employed properly serves to provide the best power output. In order to achieve self-sustenance in energy supply and to match the critical needs of impoverished and developing regions, wind power has proven to be the best solution. However, wind power is intermittent and unstable in nature and hence creates lot of grid integration and power fluctuation issues, which ultimately disturbs the stability of the grid. In such cases, energy storage technologies are highly essential and researchers turned their attention to find efficient ways of storing energy to achieve maximum utilization. The use of batteries to store wind energy is very expensive and not practical for wind applications. Compressed Air Energy Storage (CAES) is found to be a viable solution to store energy generated from wind and other renewable energy systems. A detailed review on various aspects of a CAES system has been made and presented in this paper which includes the thermodynamic analysis, modeling and simulation analysis, experimental investigation, various control strategies, some case studies and economic evaluation with the role of energy storage towards smart grid and poly-generation

Wind Power

This book is the result of inspirations and contributions from many researchers of different fields. A wide verity of research results are merged together to make this book useful for students and researchers who will take contribution for further development of the existing technology. I hope you will enjoy the book, so that my effort to bringing it together for you will be successful. In my capacity, as the Editor of this book, I would like to thanks and appreciate the chapter authors, who ensured the quality of the material as well as submitting their best works. Most of the results presented in to the book have already been published on international journals and appreciated in many international conferences

Feasibility study of a hybrid wind turbine system - integration with compressed air energy storage

The paper presents a new hybrid wind turbine system that is formed by a direct mechanical shaft connection of the wind turbine with an air expander, which converts stored compressed air energy to mechanical energy. A power split device is designed to synthesize the power delivered by the wind turbine and the air expander. The study is conducted to understand the relationship between the power delivered wind and compressed air energy. A small scale hybrid wind turbine system is mathematically modelled, analyzed and verified using a laboratory experimental test rig. By utilizing the compressed air energy storage, it is shown that the hybrid wind turbine system can provide smooth power output under wind speed variations. Such a direct connection structure reduces the overall system costs by using one generator instead of two. The study demonstrates the benefit of improved efficiency brought to the turbine operation by the hybridization of wind energy and the stored energy

Hybrid-Microgrid Planning, Sizing and Optimization for an Industrial Demand in Pakistan

Industrial sector is of great significance for the economic growth of every country. The energy crisis in Pakistan has become the prime stumbling block in the economic development of the country. There are many industrial processes that need uninterrupted supply; even a trivial outage can cost millions of dollars. The main cause of "load shedding" in Pakistan is that it produces a major portion of its energy from fossil fuels, whose price and demand is constantly increasing. Most of the customers at industrial and commercial level use Diesel Generator (DiG) as a reliable alternative source of electrical power when grid supply is unavailable. The use of DiG during loading shedding hours would increase the Cost of Energy (COE) per kWh and also enhance environmental emissions. Pakistan has a wide range of renewable power sources like bioenergy, wind, solar, hydel, geothermal etc. The distinct emphasis on the implementation of an industrial microgrid in Faisalabad, Pakistan has been specified in this paper. The prospective benefits of the microgrid fall into three major kinds: cost reduction, fuel saving, and improved environmental emissions. The optimized objective of this work is to maximize these benefits. Moreover while designing the hybrid microgrid system it encounters many design challenges like sizing of the components, system feasibility, COE, system reliability etc. This study contributes to the ongoing studies about hybrid microgrid system and draws attention to the optimal design and sizing considering several techno-economic factors including Net Present Cost (NPC), COE, supply reliability, capacity shortage constraint, battery state of charge (SOC), dispatch strategy, PV power generation and PV array tracking systems. Different cases are studied; microgrid sizing, techno-economic exploration, sensitivity analysis and environmental effects are addressed using (Hybrid Optimization Model for Electric Renewables) HOMER. The results show that COE and environmental emissions have been significantly reduced for the proposed system

Feasibility study of a simulation software tool development for dynamic modelling and transient control of adiabatic compressed air energy storage with its electrical power system applications

The field of large-scale electrical energy storage is growing rapidly in both academia and industry, which has driven a fast increase in the research and development on adiabatic compressed air energy storage. The significant challenge of adiabatic compressed air energy storage with its thermal energy storage is in the complexity of the system dynamic characteristics arising from the multi-physical (pneumatic, thermal, mechanical and electrical) processes. This has led to a strong demand for simulation software tools specifically for dynamic modelling and transient control of relevant multi-scale components, subsystems and whole systems with different configurations. The paper presents a feasibility study of a simulation tool development implemented by the University of Warwick Engineering team to achieve this purpose. The developed tool includes a range of validated simulation models from the fields of pneumatics, thermodynamics, heat transfer, electrical machines and power grids. The structure of the developed tool is introduced and a component library is built up on the Matlab/Simulink platform. The mathematical descriptions of key components are presented, which precedes a presentation of four case studies of different applications. The case studies demonstrate that the simulation software tool can be used for dynamic modelling of multi-scale adiabatic compressed air energy storage components and systems, real performance analysis, dynamic control strategy implementation and feasibility studies of applications of adiabatic compressed air energy storage integrated with power grids. The paper concludes that the continued development and use of such a tool is both feasible and valuable

Modeling and Optimization of Renewable Energy Systems

This book includes solar energy, wind energy, hybrid systems, biofuels, energy management and efficiency, optimization of renewable energy systems and much more. Subsequently, the book presents the physical and technical principles of promising ways of utilizing renewable energies. The authors provide the important data and parameter sets for the major possibilities of renewable energies utilization which allow an economic and environmental assessment. Such an assessment enables us to judge the chances and limits of the multiple options utilizing renewable energy sources. It will provide useful insights in the modeling and optimization of different renewable systems. The primary target audience for the book includes students, researchers, and people working on renewable energy systems

Improving data center efficiency through smart grid integration and intelligent analytics

The ever-increasing growth of the demand in IT computing, storage and large-scale cloud services leads to the proliferation of data centers that consist of (tens of) thousands of servers. As a result, data centers are now among the largest electricity consumers worldwide. Data center energy and resource efficiency has started to receive significant attention due to its economical, environmental, and performance impacts. In tandem, facing increasing challenges in stabilizing the power grids due to growing needs of intermittent renewable energy integration, power market operators have started to offer a number of demand response (DR) opportunities for energy consumers (such as data centers) to receive credits by modulating their power consumption dynamically following specific requirements. This dissertation claims that data centers have strong capabilities to emerge as major enablers of substantial electricity integration from renewables. The participation of data centers into emerging DR, such as regulation service reserves (RSRs), enables the growth of the data center in a sustainable, environmentally neutral, or even beneficial way, while also significantly reducing data center electricity costs. In this dissertation, we first model data center participation in DR, and then propose runtime policies to dynamically modulate data center power in response to independent system operator (ISO) requests, leveraging advanced server power and workload management techniques. We also propose energy and reserve bidding strategies to minimize the data center energy cost. Our results demonstrate that a typical data center can achieve up to 44% monetary savings in its electricity cost with RSR provision, dramatically surpassing savings achieved by traditional energy management strategies. In addition, we investigate the capabilities and benefits of various types of energy storage devices (ESDs) in DR. Finally, we demonstrate RSR provision in practice on a real server. In addition to its contributions on improving data center energy efficiency, this dissertation also proposes a novel method to address data center management efficiency. We propose an intelligent system analytics approach, "discovery by example", which leverages fingerprinting and machine learning methods to automatically discover software and system changes. Our approach eases runtime data center introspection and reduces the cost of system management.2018-11-04T00:00:00

Design and optimization of a small compressed air energy storage system for isolated applications

In this study, a variety of practical and theoretical CAES systems are reviewed in order to show the current status of the available CAES systems. Then a small scale compressed air energy storage for small isolated wind based hybrid energy system is introduced and discussed. In order to develop a cost-effective renewable based hybrid energy system, this research investigates the optimization of each component of the system from the wind turbine to the load to deliver the required energy in the most efficient way. After finding the general control strategy for energy harvesting from the wind, the control strategy based on predictive initial working condition of the air vane motor is investigated through practical tests. A control path is developed using the implemented air motor steady state operation based on its manufacturer datasheet, and it is used to supply a fixed amount of power to the grid. A new criterion for evaluation of different energy storage system with identical power rating and storage capacity is proposed and examined during a case study and the performance of pumped hydro, battery and compressed air energy systems are compared based on the total shortage time and total fuel consumption of backup diesel generators. The Monte Carlo simulation was used in order to regenerate the wind speed data with 10 minute resolution to represent more accurate variable wind speed. The proposed Harvested Energy Index (HEI) showed the ability of energy storage systems with low efficiency in utilizing excess wind energy and reach their storage capacity. Based on the obtained results, a novel general control concept for such systems is proposed and its steady state simulation results are discussed

Battery Energy Storage System: A Financial Analysis for Microgrids

Renewable Energy Sources are becoming more popular mostly due to their reduced carbon footprint. One major issue that keeps them from becoming more popular is their output variability. Energy Storage Systems have been gaining a lot of “traction” into the power grid since they can address that variability and make RES more controllable. In this thesis, various Energy Storage Systems are introduced, while Battery Energy Storage Systems and their various technologies are studied in more detail. BESS are commonly used in supporting Photovoltaic Power Plants, as they provide the convenience of a shared DC bus. This thesis also includes an overview in solar energy technologies in order to assess the complexities of solar energy harvesting, through a PPP. A mathematical approach that quantifies the financial and operational impacts of a BESS is developed. Specifically, two test cases are investigated: intermittency mitigation of a PPP using a BESS and optimal scheduling of microgrid with BESS. The former problem is formulated as a Mixed Integer Linear Programming problem while the latter is formulated as a Linear Programming problem. Both algorithms provide accurate solutions while achieving optimality. The study concludes with a financial model for the optimal operation of an advanced lead-acid BESS and the outcome is analyzed

Direct Connection of Supercapacitor-Battery Hybrid Storage System to the Grid-tied Photovoltaic System

IEEE Penetration rate of grid-connected photovoltaic (PV) generation to the existing utility grid is rapidly increasing over the years. Since the power generated from PV systems fluctuate according to the weather condition, e.g., cloud passing, this can significantly disturb the stability of a weak utility grid. The integration of energy storage devices and its ramp-rate control technique are required to reduce the impact of PV systems output fluctuations and augment the stability of the utility grid. In this paper, ramp-rate control is applied to the direct connection of energy storage devices in PV generation system configuration. The direct connection of supercapacitors string and battery combination scheme is proposed to reduce the number of power converters so that the efficiency of the system is increased. In this work, the PV system output is controlled by directly control the energy storage system (ESS) to limit the changing rate of PV output to desired ramp-rate value. Hence, reducing the battery charge/discharge cycles and extending the expected lifetime of the ESS. The performance of the proposed direct connection scheme of ESS and its ramp-rate control strategy is verified using a 1-kW PV system prototype