Integrating Variable Renewable Energy into the Grid: Key Issues and Emerging Solutions
Fact Sheets
Greening the Grid seeks to provide concise yet comprehensive information on important grid integration topics. Click the links below to download fact sheets that overview these issues.
Please check this website frequently, as we are adding new fact sheets. Additionally, if you would like to request a new fact sheet on a topic not represented below, please contact us.
Cross-Border Power Trade to Support Resilience
Cross-border power trade can support public interest goals such as better grid resilience, increased energy access, economic development, and other power sector improvements. This fact sheet explains how cross-border trade can be a potential technical solution to support resilience. Ensuring systems are designed to enhance power sector resilience across countries can be challenging and complex, but also highly beneficial. Resilient cross-border power trade can be enabled by key approaches and actions presented in this fact sheet.
Power System Planning: Advancements in Capacity Expansion Modeling
An electricity capacity expansion model (CEM) is a tool or suite of tools used in long-term planning studies for the power sector. CEMs are used to identify the least-cost mix of power system resources, taking into consideration new policies, technologies, demand projections, and other factors. CEM analysis can be an important tool in developing power sector master plans or integrated resource plans. Low-cost clean energy, storage, and demandside management technologies, along with low-cost computing have improved the quality and complexity of CEM analysis. This fact sheet summarizes eight key advancements in the CEM process: Increased temporal resolution Increased geographic resolution Representing RE resource variability Energy storage technologies Demand response, electric vehicle, and distributed energy resource representation Climate change impacts Technologies for deep decarbonization Linkages across energy sectors
Grid-Scale Battery Storage: Frequently Asked Questions
Battery storage is a technology that enables power system operators and utilities to store energy for later use. A battery energy storage system (BESS) is an electrochemical device that charges (or collects energy) from the grid or a power plant and then discharges that energy at a later time to provide electricity or other grid services when needed. Several battery chemistries are available or under investigation for grid-scale applications, including lithium-ion, lead-acid, redox flow, and molten salt (including sodium-based chemistries). Battery chemistries differ in key technical characteristics, and each battery has unique advantages and disadvantages.
Wind and Solar on the Power Grid: Myths and Misperceptions (Spanish)
Spanish-language myths fact sheet.
Integrating Variable Renewable Energy Into the Grid: Key Issues (Spanish)
Spanish-language key issues fact sheet.
Forecasting Wind and Solar Generation (Spanish)
Spanish-language forecasting fact sheet.
Designing Wind and Solar Power Purchase Agreements to Support Grid Integration
Power purchase agreements (PPAs) represent one of many institutional tools that power systems can use to improve grid services from variable renewable energy (VRE) generators. This fact sheet introduces the concept of PPAs for VRE generators and provides a brief summary of key PPA components that can facilitate VRE generators to enhance grid stability and serve as a source of power system flexibility.
Renewable Energy Zones
Achieving clean energy goals may require new investments in transmission, especially if planners anticipate economic growth and increased demand for electricity. The renewable energy zone (REZ) transmission planning process can help policymakers ensure their infrastructure investments achieve national goals in the most economical manner.
Grid-Integrated Distributed Solar: Addressing Challenges for Operations and Planning
Distributed, grid-connected photovoltaic (PV) solar power poses a unique set of benefits and challenges. This brief overviews common technical impacts of PV on electric distribution systems and utility operations (as distinct from other utility concerns such as tariffs, rates, and billing), as well as emerging strategies for successfully managing some of the priority issues.
Forecasting Wind and Solar Generation
Forecasting is a crucial and cost-effective tool for integratingvariable renewable energy (VRE)resources such as wind and solar into power systems. This fact sheet reviews the key terms and methods for operational forecasting of variable renewable energy generation.
Grid Integration Studies: Data Requirements
This fact sheet review the data needed to undertake different types of grid integration studies.
Grid Integration Studies: Advancing Clean Energy Planning and Deployment
A grid integration study is an analytical framework used to evaluate a power system with high penetration levels of variable renewable energy (VRE). A grid integration study simulates the operation of the power system under different VRE scenarios, identifying reliability constraints and evaluating the cost of actions to alleviate those constraints. These VRE scenarios establish where, how much, and over what timeframe to build generation and transmission capacity, ideally capturing the spatial diversity benefits of wind and solar resources. The results help build confidence among policymakers, system operators, and investors to move forward with plans to increase the amount of VRE on the grid. High quality data are critical to robust and reliable grid integration studies.
The Role of Demand Response and Storage
Affordably integrating high levels of variable renewable energy (VRE) sources such as wind and solar requires a flexible grid. Storage and demand response provide means to better align wind and solar power supply with electricity demand patterns: storage shifts the timing of supply, and demand response shifts the timing of demand.
Methods for Procuring Power System Flexibility
This fact sheet reviews administrative and market-based mechanisms for procuring a cost effective mix of flexible resources needed to ensure system reliability and adequacy.
Sources of Operational Flexibility
Operational flexibility refers to the ability of a power system to respond to changes in electricity demand and generation. Flexibility is particularly important for power systems that integrate high levels of solar and wind, whose power outputs can be variable and uncertain, creating a fluctuating supply.
Balancing Area Coordination: Efficiently Integrating Renewable Energy into the Grid
Coordinating balancing area operation can promote more cost and resource efficient integration of variable renewable energy (VRE), such as wind and solar, into power systems. This efficiency is achieved by sharing or coordinating balancing resources and operating reserves across larger geographic boundaries.
Using Wind and Solar to Reliably Meet Electricity Demand
An important aspect of power system planning is ensuring that adequate generation capacity exists to meet electricity demand during all hours of the year. Mechanical failures, planned maintenance, or lack of on-demand generating resources (especially for variable renewable resources) may leave a power system with insufficient capacity to meet demand. Grid planners project future peak demand patterns and estimate the relative contribution of each generator towards achieving a reliable supply of energy. When generating during peak demand periods, variable renewable energy (VRE) such as wind or solar PV provides capacity value to the system. By providing capacity value, VRE can help to defer capital investments in traditional generation and transmission infrastructure.
Scaling Up Renewable Energy Generation: Aligning Targets and Incentives With Grid Integration Considerations
Countries around the world have established ambitious targets for increasing the contribution of renewable energy toward meeting their national energy demand. At low penetrations of wind and solar (e.g., below 5%–10% of annual electric demand), impacts to the power system are likely to be minimal. However, as the proportion of variable renewable energy (VRE) connected to the grid increases, power system planners will increasingly need to evaluate and manage the impact of increased variability and uncertainty on system operations. They will also need to ensure that the policy and regulatory environment offers sufficient certainty and revenue streams to encourage investment in new VRE generation. To address these needs, power system planners can take several steps to align targets and incentives with grid integration considerations.
The Evolution of Power System Planning with High Levels of Variable Renewable Generation
Power system planning methods and processes can evolve to address the unique characteristics of variable renewable energy (VRE). This brief presents an overview of the analyses involved in traditional power system planning, and describes the changes required to plan for higher levels of VRE integration.
Wind and Solar on the Power Grid: Myths and Misperceptions
Wind and solar are inherently more variable and uncertain than the traditional dispatchable thermal and hydro generators that have historically provided a majority of grid-supplied electricity. The unique characteristics of variable renewable energy (VRE) resources have resulted in many misperceptions regarding their contribution to a low-cost and reliable power grid.
Integrating Variable Renewable Energy Into the Grid: Key Issues
To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost effectiveness of incorporating VRE into the power system while maintaining or increasing system stability and reliability.