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Eastern Renewable Generation Integration Study

The Eastern Renewable Generation Integration Study (ERGIS) is a multi­year U.S. Department of Energyfunded research project designed to simulate operations of the largest power system in the world with high

penetrations of wind and solar generation. The study will inform critical questions on how system operations

could be impacted by various wind and solar deployment strategies and operational paradigms. It is the first

study to simulate the entire Eastern Interconnection and Hydro­Québec with hourly day­ahead unit

commitment, 5­minute real­time dispatch, and a nodal DC­power flow. NREL staff developed new modeling

capabilities to study the system at this resolution and fidelity and applied advanced computational techniques

to the problem.

Map of the Eastern Interconnection as simulated in 2026.

ERGIS is a follow­on study to the Eastern Wind Integration and Transmission Study, the Western Wind and

Solar Integration Study Phase 1, and other analyses. These studies showed that the variability and uncertainty

of wind and solar power at high penetration levels require new ways of planning and operating electric power

systems. However, new questions are being posed about future regulatory, market, and environmental

policies; the siting and timing of new nonrenewable generation and transmission; and even load profiles with

embedded and distributed generation. ERGIS will address these follow­up questions and place additional

emphasis on the question of how to plan and operate the Eastern Interconnection in the face of generation

and transmission uncertainty.

One way to bound this uncertainty in the analytical environment is to evaluate more than one possible future

scenario. Another way is to test system robustness with a sensitivity analysis to key input parameters. This

study will do both. ERGIS developed four study scenarios with the assistance of a technical review committee.

This panel of industry experts is composed of individuals from every Regional Transmission Organization,

several utilities, trade associations, and government agencies. The Current Variable Generation (VG) and

State Renewable Portfolio Standard (RPS) scenarios provide insights into low penetrations of renewables. The

Current VG case includes all wind and solar generation physically connected to the Eastern Interconnection in

the year 2012. The State RPS scenario builds out wind and solar generation to existing State RPS

requirements and interconnection queues as of 2012. This scenario has a penetration of about 12% on an

energy basis. The two 30% scenarios book­end two approaches to reaching 30% penetration, on an energy

basis. The Regional 30% scenario features 10% solar and 20% wind penetration. In the National 30%

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scenario, the solar penetration is 5% and the wind is 25%. The Regional 30% scenario is a logical extension

of existing State RPS strategies and forces wind and solar generation to be built within each of the ERGIS

regions. The National 30% scenario chooses the best resources in the interconnection to meet the 30% target

and would be akin to an RPS implemented over the entire U.S. portion of the Eastern Interconnection.

Four ERGIS study scenarios.

ERGIS will evaluate the impact of various operating practices on production costs, curtailment, unit starts and

stops, and emissions. In specific, ERGIS will evaluate the impacts of greater inter­regional cooperation, new

reserve products, and intra­day unit commitment to provide operational flexibility.

Both statistical analysis and grid operation simulations with an Eastern Interconnection transmission system

model will be performed to inform these questions. Final results are expected in the winter of 2015.

For more information, view this presentation.

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Eastern Wind Integration and Transmission Study

NREL researchers initiated the Eastern Wind Integration and Transmission Study to examine the operational

impact of 20%–30% wind energy penetration on the power system of the Eastern Interconnect of the United

States. This study was a response to questions about wind energy and transmission development posed by

utilities, regional transmission operators, and planning organizations.

The Eastern Wind Integration and Transmission Study addressed these questions:

How do local wind resources compare with higher capacity­factor wind power that requires more

transmission?

How does geographic diversity of wind reduce wind integration costs?

How do offshore and onshore wind power compare?

What transmission is needed to facilitate higher penetrations of wind power?
What is the role and value of wind forecasting?

How are wind integration costs spread over large market footprints and regions?

What additional operating reserves are needed for large wind power deployments?

A key task of the Eastern Wind Integration and Transmission Study was the development of a dataset of three

years of modeled time series of wind speed and power output that was used to model the impacts of wind

energy.

A technical review committee composed of regional and national experts on wind generation and power

systems analysis guided and reviewed the study by providing feedback on key assumptions, methodology,

and preliminary results.

The Eastern Wind Integration and Transmission Study was completed in 2010.

For More Information

For more information about the Eastern Renewable Generation Integration Study and the Eastern Wind

Integration and Transmission Study, see the following resources. Additional publications can be found in the

NREL Publications Database.

Eastern Wind Integration and Transmission Study

This study answers questions about technical issues related to a 20%–30% wind energy scenario in the

Eastern Interconnection.

Eastern Wind Integration and Transmission Study: Executive Summary and Project Overview

Eastern Wind Dataset

Access to and information about the eastern wind dataset, including details about the methodology used

to develop the accuracy of the data, site selection, power output, and forecasts.

Development of Eastern Regional Wind Resource and Wind Plant Output Datasets

The project provided wind resource inputs to the Eastern Wind Integration and Transmission Study.

Solar Power Data for Integration Studies

The Solar Power Data for Integration Studies consist of one year (2006) of 5­minute solar power and

hourly day­ahead forecasts for approximately 6,000 simulated PV plants.

Contact

Aaron Bloom

720­402­2065

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Content Last Updated: May 27, 2015

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