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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 overviewing these issues.

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Integrating Variable Renewable Energy Into the Grid: Key Issues

Grid integration is the practice of developing efficient ways to deliver variable renewable energy to the grid. This fact sheet provides a brief contextual introduction to key grid integration issues, which are explored in more detail in the other fact sheet and toolkit topics.

En Español: click here for a Spanish-language version of this Fact Sheet


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 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. This fact sheet describes several steps power system planners can take to align targets and incentives with grid integration considerations.


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, such as wind and solar, into power systems. This fact sheet describes approaches power systems can take to share or coordinate 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. Grid planners project future peak demand patterns and estimate the relative contribution of each generator towards achieving a reliable supply of energy. This fact sheet discusses how variable renewable energy such as wind or solar PV provides capacity value to the system and overviews approaches to calculating capacity value.


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. This fact sheet overviews common sources of flexibility to enable the integration of variable renewable energy.

Methods for Procuring Power System Flexibility

Flexibility is a prized characteristic in power systems with significant variable renewable energy . How this flexibility is procured is strongly shaped by the regulatory context. 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.

The Role of Storage and Demand Response

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. This fact sheet overviews the benefits, tradeoffs, and analysis challenges associated with employing demand response and storage to increase the penetration of variable renewable energy.


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. This fact sheet summarizes three types of grid integration studies and overviews the process of conducting a grid integration study.


Grid Integration Studies: Data Requirements

This fact sheet describes the types of data that are critical to developing robust and reliable grid integration studies.


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  resources have resulted in many misperceptions regarding their contribution to a low-cost and reliable power grid. This fact sheet provides information to combat common grid integration myths and misperceptions.

Forecasting Wind and Solar Generation

Forecasting is a crucial and cost effective tool for integrating variable renewable energy (VRE) resources such as wind and solar into power systems. By integrating VRE forecasts into system operations, power system operators can anticipate up- and down-ramps in VRE generation in order to cost-effectively balance load and generation in intra-day and day-ahead scheduling. This leads to reduced fuel costs, improved system reliability, and minimized curtailment of renewable resources.

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 fact sheet 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.


Renewable Energy Zones: Delivering Clean Power to Meet Demand

The Renewable Energy Zone (REZ) concept has emerged as a transmission planning tool to help scale up the penetration of solar, wind, and other resources on the power system. This fact sheet describes the REZ concept and its potential benefits, outlines the process for implementing a REZ, and provides an illustrative example of a successful REZ process.


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.


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

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