Energy storage systems (ESSs) are enabling technologies for well-established and new applications such as power peak shaving, electric vehicles, integration of renewable energies, etc. This paper presents a review of ESSs for transport and grid applications, covering several aspects as the storage technology, the main applications, and the power converters used to operate some of the energy storage technologies. Special attention is given to the different applications, providing a deep description of the system and addressing the most suitable storage technology. The main objective of this paper is to introduce the subject and to give an updated reference to nonspecialist, academic, and engineers in the field of power electronics.

Energy Storage Systems for Transport and Grid Applications

Energy storage for mitigating the variability of renewable electricity sources: An updated review

Energy storage: Applications and challenges

Vehicle-to-grid (V2G) has been proposed as a way to increase the adoption rate of electric vehicles (EVs). Unidirectional V2G is especially attractive because it requires little if any additional infrastructure other than communication between the EV and an aggregator. The aggregator in turn combines the capacity of many EVs to bid into energy markets. In this work an algorithm for unidirectional regulation is developed for use by an aggregator. Several smart charging algorithms are used to set the point about which the rate of charge varies while performing regulation. An aggregator profit maximization algorithm is formulated with optional system load and price constraints analogous to the smart charging algorithms. Simulations on a hypothetical group of 10 000 commuter EVs in the Pacific Northwest verify that the optimal algorithms increase aggregator profits while reducing system load impacts and customer costs.

Optimal Charging Strategies for Unidirectional Vehicle-to-Grid

The paper analyzes the impact of integrating wind generation on the regulation and load following requirements of the California Independent System Operator (CAISO). These requirements are simulated and compared for the study cases with and without wind generation impacts included into the study for the years 2006 and 2010. Regulation and load following models were built based on hour-ahead and five-minute ahead load and wind generation forecasts. In 2006, the CAISO system peaked at 50 270 MW. Wind generation (at the installed capacity of 2600 MW) had limited impact on the requirement of load following and regulation in the CAISO Balancing Authority. However, in 2010 (with an expected installed capacity of approximately 6700 MW), this impact will significantly increase. The results provide very useful information for the CAISO to adjust its scheduling and real-time dispatch systems to reliably accommodate future wind generation additions within the CAISO Balancing Authority.

/pdf/operational-impacts-of-wind-generation-on-california-power-4ensdj5ovs.pdf

Operational Impacts of Wind Generation on California Power Systems

Energy produced by intermittent renewable resources is sharply increasing in the United States. At high penetration levels, volatility of wind power production could cause additional problems for the power system balancing functions such as regulation. This paper reports some partial results of a project work, recently conducted by the Pacific Northwest National Laboratory (PNNL) for Bonneville Power Administration (BPA). The project proposes to mitigate additional intermittency with the help of Wide Area Energy Management System (WAEMS) that would provide a two-way simultaneous regulation service for the BPA and California ISO systems by using a large energy storage facility. The paper evaluates several utility-scale energy storage technology options for their usage as regulation resources. The regulation service requires a participating resource to quickly vary its power output following the rapidly and frequently changing regulation signal. Several energy storage options have been analyzed based on thirteen selection criteria. The evaluation process resulted in the selection of flywheels, pumped hydro electric power (or conventional hydro electric power) plant and sodium sulfur or nickel cadmium batteries as candidate technologies for the WAEMS project. A cost benefit analysis should be conducted to narrow the choice to one technology.

On the use of energy storage technologies for regulation services in electric power systems with significant penetration of wind energy

Wind power is growing in a very fast pace as an alternative generating resource. As the ratio of wind power over total system capacity increases, the impact of wind on various system aspects becomes significant. This paper presents a methodology to study the future impact of wind on BPA power system ancillary services including load following and regulation. Existing approaches for similar analysis include dispatch model simulation and standard deviation evaluation. The methodology proposed in this paper uses historical data and stochastic processes to simulate the load balancing processes in BPA power system. Then capacity, ramp rate and ramp duration characteristics are extracted from the simulation results, and load following and regulation requirements are calculated accordingly. It mimics the actual power system operations therefore the results can be more realistic yet the approach is convenient to perform. Further, the ramp rate and ramp duration data obtained from the analysis can be used to evaluate generator response or maneuverability and energy requirement, respectively, additional to the capacity requirement.

The future impact of wind on BPA power system ancillary services

This report provides key information concerning the German experience with integrating of 25 gigawatts of wind and 7 gigawatts of solar power capacity and mitigating its impacts on the electric power system. The report has been prepared based on information provided by the Amprion GmbH and 50Hertz Transmission GmbH managers and engineers to the Bonneville Power Administration (BPA) and Pacific Northwest National Laboratory representatives during their visit to Germany in October 2009. The trip and this report have been sponsored by the BPA Technology Innovation office. Learning from the German experience could help the Bonneville Power Administration engineers to compare and evaluate potential new solutions for managing higher penetrations of wind energy resources in their control area. A broader dissemination of this experience will benefit wind and solar resource integration efforts in the United States.

/pdf/large-scale-wind-and-solar-integration-in-germany-150g49qb17.pdf

Large Scale Wind and Solar Integration in Germany

This paper presents a methodology for the prediction of power system balancing requirement and the probability of tail event (large imbalance between generation and load). Maintaining sufficient balancing reserves to match the difference between hourly generation schedule and real-time variable load and intermittent resources becomes more and more challenging with the increasing penetration of intermittent energy sources. The presented methodology uses yearly distributions and hourly distributions of balancing requirement and tail events to provide a high level look at the issue and warn system operators of those hours when problems are most likely to occur. For real-time prediction, a Bayes net model is constructed to model the statistical relationships between system imbalance and forecast errors, generation schedule control errors and other influential factors. The methodology will be able to provide reference information to system operators in determining the sufficiency of system balancing reserve and taking appropriate control actions.

Prediction of power system balancing requirement and tail event

-This paper describes a control algorithm for a Wide Area Energy Storage and Management System (WAEMS). The WAEMS is designed to meet the demand for fast, accurate and reliable regulation services in multiarea power systems with a significant share of wind power and other intermittent generation. The means are utilization of flywheel energy storage units, hydro power generation, and energy exchange among the participating control areas. The objective of the control algorithm is to respond to the control signals from the different system operators, whilst optimizing the hydro power plant operation by reducing the tear and wear on the mechanical parts and improving the energy efficiency of the plant. The performance of the WAEMS is simulated using a mathematical model, including hydro power plant and flywheel energy storage models. ACE measurements from the California ISO and Bonneville Power Administration control areas are used as control signals to the WAEMS. Simulations demonstrate excellent regulation response and break-through results in terms of improved hydro power plant operation.

/pdf/coordinated-multi-objective-control-of-regulating-resources-46qo0r14lh.pdf

J. Pease

Papers

On the use of energy storage technologies for regulation services in electric power systems with significant penetration of wind energy

The future impact of wind on BPA power system ancillary services

Large Scale Wind and Solar Integration in Germany

Prediction of power system balancing requirement and tail event

Coordinated Multi-Objective Control of Regulating Resources in Multi-Area Power Systems with Large Penetration of Wind Power Generation