Integrating Variable Renewable Energy into the Grid: Key Issues and Emerging Solutions
Forecasting folder
Photovoltaic and Solar Forecasting
This report discusses the links between weather forecasts and photovoltaic (PV) output, as well as the various methods for conducting forecasting. Also included is an example of “upscaling” in which representative systems are used to develop a forecast for a larger pool of systems. The authors also analyze the accuracy of tools and present a survey of tools used worldwide.
A Review of Wind Power Forecasting Models
This review examines several wind power forecasting models, including Wind Power Management System, Wind Power Prediction Took, Prediktor, ARMINES, and Previento. These models use physical, statistical, and hybrid methodologies. The authors examine the accuracy of the models and possible causes of error.
A Survey on Wind Power Ramp Forecasting
This report examines wind forecasting of wind ramp events and possible metrics to evaluate ramps. The authors compare existing methodologies, including event detection and regression, to assess such ramps and find that additional work is needed to develop forecasting methodologies that are more accurate.
Variable Renewable Energy Forecasting – Integration into Electricity Grids and Markets – A Best Practice Guide
This report provides a brief overview of emerging best practices and state-of-the-art methods for variable RE forecasting. The authors differentiate between shortest term (0 – 6 hours), short term (6 – 48 hours) and medium-term (2 – 10 days) applications for solar and wind power forecasting. Topics covered include forecasting techniques (including data requirements, numerical prediction models, conversion of meteorological forecasts to power generation forecasts, ensemble forecasting, forecasting power plant outages and curtailments), forecast accuracy, and various approaches to RE forecasting. Chapter 3 provides examples of how systems around the world are approaching RE forecasting, with examples from Europe, the United States, India, South Africa, Brazil and Uruguay. Additionally, the report discusses general concepts for integrating RE forecasting into system operations.
The Value of Improved Short-Term Wind Power Forecasting
This report quantifies the value of improved short-term wind power forecasting in the California Independent System Operator market and estimates savings from regulation and flex reserves, as well as production savings. The authors examine both low wind (8% penetration) and high wind (25% penetration) scenarios. Cost savings are estimated to be USD 1.27 to 17.1 million for flex reserves, USD 0.917 to 12.7 million for regulation reserves, and USD 2.87 to 116 million for production costs.
A Review of Variable Generation Forecasting in the West
Based on a series of interviews with thirteen operating entities in the Western Interconnection of the United States, this report summarizes practices, lessons learned, and priorities related to the implementation of wind and solar forecasting. The operating entities provided insights regarding cost assignment, forecasting accuracy and uses, data collection, curtailment and outages, probabilistic forecasting, distributed solar production, control room integration, and staff training, among other topics.
PJM Renewable Integration Study: Task Report: Review of Industry Practice and Experience in the Integration of Wind and Solar Generation
This report describes the state-of-the-art with respect to variable generation integration, mostly focused on the United States but also providing a few international examples where particularly relevant. The report is predominantly based on an extensive literature review with input from General Electric (GE) and PJM. Pages 97–119 focus on forecasting.
Wind Energy Forecasting: A Collaboration of the National Center for Atmospheric Research (NCAR) and Xcel Energy
This report summarizes Xcel Energy’s forecasting program for its Colorado service area. Xcel began partnering with the National Center for Atmospheric Research (NCAR) in 2008 to develop a new forecasting system. The report overviews the wind forecasting system, data acquisition, models, power conversion and outputs, results of the program and ongoing work.
Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations
This framework was developed to incorporate uncertainties associated with wind and demand forecast errors, unpredicted ramps, and forced generation disconnections into the energy management system (EMS) as well as generation dispatch and commitment applications.
Variable Generation Power Forecasting for Operations
The North American Electric Reliability Council (NERC) examines best practices for variable RE generation forecasting. The authors suggest using forecasts across timeframes and as close to real-time as is possible. The report focuses on forecasts from real-time to the coming 48-hours and how the forecasts can be best communicated to and utilized by system operators.
Model Wind Power Purchase Agreement
Xcel Energy, a vertically integrated utility located in the United States, is a pioneer in incorporating state-of-the-art wind forecasting into system operations. Xcel Energy’s Model Wind Power Purchase Agreement (PPA) provides an example of a mechanism that enables the system operator to collect forecasting data (e.g., meteorological data, real-time power potential, and forecasted turbine availability) from wind power generators. Sections of the Model Wind PPA that relate specifically to data collection for forecasting include Article 10 (“Operations and Maintenance”) and Exhibit H, which includes a data list and protocols for automatic generation control for wind generators. In addition to forecasting considerations, the Model Wind PPA also includes provisions related to compensation for wind generators when Xcel Energy curtails wind output.
FERC Order No. 764
The Federal Energy Regulatory Commission of the U.S. (FERC) Order No. 764 is an example of a regulation that reduces barriers for variable RE by requiring transmission providers to offer sub-hourly transmission scheduling for their customers. The Order also requires new interconnection requests from customers with large variable RE to provide meteorological and forced outage data to transmission providers, in those cases where the provider conducts variable RE forecasting.
FERC Order 764 and the Integration of Renewable Generation
This report summarizes the key changes to power system planning and operations that FERC Order 764 encourages. The authors outline the reasons why traditional electricity scheduling practices may lead to system inefficiencies in the presence of variable RE generation. While compliance costs for renewable energy producers are expected to be minimal, the report estimates that complete compliance by regional transmission operators and independent system operators will take many years to achieve due to challenges associated with cost allocation.
MISO Dispatchable Intermittent Resource Implementation Guide
In 2010, the United States’ Midcontinent Independent System Operator (MISO) began a process to work with stakeholders to design a new market mechanism that utilizes the benefits of wind energy and reduces the relevance of the non-dispatchability of the technology. This guide outlines MISO's approach to wind forecasting and practices to improve ramping capabilities.
Xcel CO Model PPA Wind and Solar 2017
Copy of the model PPA Xcel used for solar and wind in Colorado for 2017. Contains provisions for remuneration after curtailment, telemetry requirements and more.