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Methods for Procuring Power System Flexibility. 
English (PDF).

Ancillary Services folder

Flexibility Options in Electricity Systems
This filmed presentation summarizes a 2014 report from Ecofys. The first half of the video discusses the grid operation challenges that arise with high penetrations of variable RE. The second half of the video describes the various technical, regulatory, and market options for improving flexibility of the grid over the short-, medium-, and long-term. The Ecofys report includes factsheets on the following topics: Active Power Control (pg. 19), Demand Management in Industrial Installations and in Services and Households (pgs. 21-22), Electric Vehicles (pg. 23), Compressed Air Storage (pg. 27), Fly Wheels (pg. 28), and Batteries (pg. 29).
Effective Ancillary Services Market Designs on High Wind Power Penetration Systems
Ancillary service market designs may require changes in systems with greater penetration of variable RE, particularly wind. This paper explores design considerations that take into account economics and engineering. The authors examine current market design, services pricing and cost allocation, changes to existing designs, and the potential for new designs. The report focuses on load following, frequency response, inertial response, and reactive power/voltage control.
Ancillary Service and Balancing Authority Area Solutions to Integrate Variable Generation
This report explores how various balancing areas in North America provide ancillary services and addresses regulatory institutional practices for maintaining system integrity. The report surveys different practices that balancing areas use to plan for and manage the provision of ancillary services and makes recommendations related to enlarging and/or increasing the coordination among balancing areas to provide ancillary services. The authors seek to clarify the balancing area rules that each entity much follow, and how the many balancing areas in North America can operate in a homogenous way to address ancillary service requirements for variable RE generation.
Active Power Control from Wind Power: Bridging the Gaps
This report examines the three forms of active power controls that wind may be able to support, including synthetic inertial control, primary frequency control, and automatic generation control regulation. These controls contribute ancillary services to the power system. The study analyzes millisecond timeframes to characterize the impact of using wind to provide active power controls on the lifetimes of large wind plants as well as on the broader power system. The authors explore the implications of active power controls on economics and power system engineering control design. They conclude that wind may earn additional revenue and reduce production costs to consumers by providing power control services, and that market design, reliability criteria, and engineering design will impact future opportunities for wind generators to provide these services.
Ancillary services in Spain: Dealing with High Penetration of RES
This document includes a summary of the Spanish power system schedule (page 5) and electricity price stacks with ancillary services broken out (page 13). The report also includes a chart showing the impact of wind on primary, secondary, tertiary, and supplemental reserves (page 27). Also included is a description of Spain’s RE generation control center.
Operating Reserves and Variable Generation: A comprehensive review of current strategies, studies, and fundamental research on the impact that increased penetration of variable renewable generation has on power system operating reserves
This report first provides a characterization of the various types of reserves, followed by a summary of how reserves are applied internationally currently, and how reserves could be managed in the future. The purpose of the assessment is to understand differences and commonalities between practices and to suggest options for improved practices, especially under higher variable RE penetration scenarios.
PJM Renewable Integration Study: Task Report: Review of Industry Practice and Experience in the Integration of Wind and Solar Generation
This report describes state-of-the-art practices with respect to variable generation integration. The report is predominantly based on an extensive literature review and includes highlights of ancillary service requirements for distributed generation in Germany and Spain. Pages 167 – 177 contain information on regional ancillary service practices in the United States.
Staff Paper on Introduction of Ancillary Services to Indian Electricity Market
This discussion paper from the India's Central Energy Regulatory Commission examines the impetus for developing an ancillary services market and focuses on the services of frequency support, voltage control, and black start. The report also explores challenges for developing an ancillary services market and is the first step in a stakeholder engagement process intended to inform any regulatory actions taken by the commission.
ERCOT Concept Paper: Future Ancillary Services in ERCOT
The Electricity Reliability Council of Texas (ERCOT), a U.S. independent system operator with relatively high wind penetration is exploring new possibilities for its ancillary services planning and procurement processes. This analysis is intended to inform potential market redesigns that take into account an evolving resource mix (including higher levels of variable RE) in an effort to better address the challenges of these new resources, and to better utilize existing and new resources. This report focuses on frequency control and does not address emergency response service, voltage support, reliability must-run, and black-start.
Eastern Wind Integration and Transmission Study
This study summarizes the results of an in-depth modeling of the U.S. Eastern Interconnection, wind integration study, and transmission analysis. The study examines various technical issues under a 20% wind integration scenario. Section 5 examines power system regulation and balancing, and Section 6 explores impacts on systems operation. The report assesses ancillary services that provide both spinning and nonspinning reserves and offer frequency response, balancing, and system security.
Flexible Ramping Product
In 2011, the California Independent System Operator (CAISO) began a stakeholder engagement process to develop a market-based ramping product. The stakeholder engagement process will also help inform how ramping costs could be allocated to generation and demand. The CAISO website includes information on the initiative status, current meetings, and tariff and policy development.
FERC Order 784: Third-Party Provision of Ancillary Services; Accounting and Financial Reporting for New Electric Storage Technologies
FERC Order 784 is a final rule from the United States Department of Energy’s Federal Energy Regulatory Commission (FERC) that outlines revisions to its regulations to foster competition and transparency in ancillary services markets. The revision affects market-based rate regulations, ancillary services requirements under the pro forma open-access transmission tariff (OATT), and accounting and reporting requirements. The changes proposed also modify the accounting regulations to increase transparency for energy storage facilities.
Economic Grid Support Services by Wind and Solar PV: a Review of System Needs, Technology Options, Economic Benefits and Suitable Market Mechanisms
The REserviceS paper explores the changing needs for Grid Support Services (GSS), also known as Ancillary Services, in European energy markets. These energy markets are increasingly characterized by fewer fossil fuel generators, the traditional providers of GSS, and larger numbers of decentralized renewable energy plants, many of which are connected at low and medium voltage levels. Some of the specific recommendations the paper makes include: 1) Decreasing gate closures and increasing cross border integration in day-ahead and intra-day energy markets so producers have more opportunities to trade imbalances; 2) Minimizing uncompensated ancillary service provision and procuring such services through competitive processes such as markets or auctions where possible; 3) Allowing for provision of ancillary services from aggregated portfolios of renewable energy services to decrease uncertainty and forecasting errors; 4) Incorporating the spatial distribution of resources when procuring ancillary services at the distribution level to reduce inefficiencies; and 5) Formulating of technical requirements for extremely fast frequency control for future power systems with low inertia.
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