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New England Wind Integration Study: Need to prepare grid operations

Currently New England has only a small amount of wind on the grid—about
270 megawatts (MW), with most of that developed in just the last two or three years—but projects in ISO New England’s generation interconnection queue would add more than 2,800 MW of wind to a system that currently has a total capacity of about 32,600 MW.

Public policy drivers behind the development of wind include the New England states’ renewable portfolio standards (RPS) and environmental initiatives such as the Regional Greenhouse Gas Initiative (RGGI). The states’ RPSs and related goals, combined, call for renewable energy and energy efficiency to meet 30% of New England’s projected 2020 electricity demand.

With those facts as a backdrop, ISO New England initiated a comprehensive study in 2009 to determine how large amounts of wind energy could be integrated into New England’s power system operations without affecting reliability. With wind’s variability and the difficulty of predicting when it will pick up or subside, the ISO, as the system operator, is at risk of committing either more generation than is needed to be sure demand will be met or not enough generation to compensate for lower wind output than expected.

Wind zones and demand centersISO New England commissioned GE Energy Applications and Systems Engineering and its project partners, EnerNex and
AWS Truepower, to conduct the New England Wind Integration Study (NEWIS) published this month. The project was overseen for ISO New England by John Norden, currently Director of Operations, but until recently he served as Manager of Renewable Resource Integration. He was assisted by William Henson, Senior Renewable Resource Engineer.

"This study provides a wealth of data on a variety of wind integration scenarios for market participants, policymakers and other stakeholders," said Gordon van Welie, President and CEO of ISO New England. "It provides some encouraging findings, most prominently that the region has an abundance of excellent wind resources and that the power system could conceivably integrate up to 24% of its energy from wind in 2020 if certain conditions are met. Those conditions include transmission investment to deliver the energy to demand centers, increases in operating reserves and regulation, and ensuring a flexible fleet of conventional resources to balance the variability of wind."

Study Scope

NEWIS is a technical analysis of the impacts of large-scale wind development on power system operations. The 400-page report is not a blueprint for wind-farm development in New England, and it’s not a transmission planning study.

The analysis explored the impact of differing levels of hypothetical wind development, including different onshore and offshore geographic configurations, on power system operations. The placement of these hypothetical wind farms avoided sensitive environmental and cultural areas such as the Appalachian and Long trails and urban areas.

NEWIS looked at these five wind build-out scenarios.

To conduct the study, GE Energy time-synchronized more than 26,000 hours of both wind and demand data from 2004 through 2006 in New England, and projected those patterns onto the forecasted load levels and patterns in 2020.

Key Findings

Applying the resulting data to the five different scenarios led to some interesting findings on the effects of higher levels of wind on the operation of the power system:

  • If certain conditions are met, New England could integrate up to 24% of the energy used in 2020 from wind. Those conditions include retention of all the resources on the system now and all the resources secured through 2011-2012 in the Forward Capacity Market;
    more regulation and reserves; and significant expansion of the region’s high-voltage transmission system.
  • When available to provide energy, wind generation could reduce use of oil- and natural-gas-fired power plants. The energy from wind would primarily affect natural gas plants because they are often the marginal units dispatched to meet demand. The study also showed that large-scale wind development would almost fully reduce the use of oil-fired power plants.
  • The region needs to maintain a power system with flexible resources to manage wind’s variability. Flexible resources are those that can provide regulation in response to signals every four seconds from the ISO, or can provide reserves that can be available quickly in the event of an unexpected outage. Natural gas generators tend to have those characteristics.
  • New England’s wind patterns offer high productivity—capacity factors and capacity values—particularly offshore. Capacity factor tells how much wind a resource can generate in a year compared to its nameplate rating. Capacity values represent the output of wind power during times of system need such as peak load hours, expressed as a percentage of nameplate capacity.
  • More accurate wind forecasting will be needed to ensure the right amount of resources is committed in the day-ahead and hour-ahead.

NEWIS concluded that some areas require further study. These include:

  • Refining the conceptual transmission overlays developed initially for the New England Governors’ technical analysis to determine if the hypothetical transmission expansion scenarios are viable.
  • Studying the region’s ability to maintain an adequate fleet of flexible resources, assuming wind energy will reduce the use of natural gas-fired generation.
  • Evaluating the flexibility of demand response resources to help manage the variability of wind generation.
  • Incorporating actual wind data into system operations analysis.

ISO New England and its stakeholders will review the report’s findings and recommendations, and any proposals for market or operating procedure changes will go through New England’s comprehensive stakeholder process.

Learn More

On December 15, ISO New England held a media briefing to discuss the findings of the study. The presentations and remarks given by van Welie and Norden are available on the ISO’s website.