Operating Impact and Integration Study Users Group Scope

Background: The questions most often asked today by those responsible for integrating wind plants into the conventional electricity system are related to the capacity value of wind plants and the impact of wind plants on the short term planning and operation of the system. This is due to the variability in the output of the wind plant, which is driven by the wind, as compared to conventional plants, which are controlled by system operators. Those utilities that have not yet experienced the competitive markets brought about by restructuring view the world through vertically integrated utility eyes, while those operating in competitive markets may be thinking more in terms of the ancillary services that must be provided to accommodate this new form of generation.

UWIG sponsored the first comprehensive study of the cost of ancillary services associated with the operating impacts of wind plants on time scales up to and including unit commitment, i.e. from regulating duty on the order of seconds, to hourly scheduling up to a week in advance. Even so, this study was only able to look at a single snapshot for a single system. Significant sensitivity study needs to be carried out to understand how the costs change with wind penetration level, generation mix, and fuel cost. Additional studies of this issue have been undertaken both domestically and internationally, and the results are of great interest to the wind and utility communities. The outcome of these studies and similar efforts undertaken in the next few years will play a significant role in the rate of adoption of wind technology in this country and abroad. A concerted effort is needed to gather, distill, and disseminate the results of this work and pursue it to the next level.

Scope: The scope of the user group will cover the following areas:

A. Cost of ancillary services for wind plants

  • Modeling tools and methods

    • - Utility planning and operating models
    - Wind models
  • Study assumptions and results
  • Study comparisons and limitations
  • Operating experience

B. Capacity value for wind plants

  • Modeling tools and methods

    • - Utility planning and operating models
    - Wind models
  • Study assumptions and results
  • Study comparisons and limitations
  • Operating experience

C. Wind/hydro integration

  • Modeling tools and methods

    • - Utility planning and operating models
    - Wind models
  • Study assumptions and results
  • Study comparisons and limitations
  • Operating experience

Within the topic of Modeling Tools and Methods, the topic of wind plant output models is quite important and deserving of additional attention. For each of the time frames of interest, appropriate models are needed for the traditional time series simulation methods used for utility system analysis. In addition to the time series models appropriate for individual wind plants, methods are needed to aggregate the output of multiple wind plants across a broad geographical region. Methods suitable for intra-state as well as inter-state models are required. In the longer term, both diurnal and seasonal variations must be represented. Means of extrapolating existing time series wind plant output data are required, as well as means of converting single anemometer data to aggregated wind plant output data. Ultimately, simplified application examples should be produced for those actually performing integration studies. This User Group will follow and report on models and methods as they emerge, and will foster their development and refinement to the extent desired by members and allowed by resources available to the Group.

Communication and Education: User Group results will be made available by the following methods:

  • Tech Briefs for each area
  • Fact Sheets for individual topics or studies
  • Bibliography with links
  • Technical sessions at UWIG meetings
  • Seminars
  • Participation in industry meetings

User Group Startup: Numerous methods and studies in the areas above have already been identified or performed. Significant value can be obtained by analyzing, condensing, and summarizing the existing work to provide guidance for new entrants to the field, as well as help determine the areas needing more attention in the future. We would like to begin by identifying user group members who would like to make a contribution by providing material that can be analyzed and summarized by others, as well as members who would like to actively participate in performing the work themselves. We especially encourage the participation of planners who can contribute knowledge and experience with utility planning and operating models and study results.

NREL Participation: The NREL has a substantial ongoing program in the integration study area. Active contributions in the area of wind plant output modeling will be provided by Yih-huei Wan; in the area of wind plant operating impact analysis, by Brian Parsons and Michael Milligan; in the area of capacity value by Michael Milligan; and in wind/hydro integration by Tom Acker.

Work to be included in User Group Scope:

Operating Impacts:

Domestic

UWIG/Xcel Phase 1
Xcel Phase 2
HECO IGAP
Great River Energy
We Energies
NYSERDA
BPA
PacifiCorp
Avista
SPS
CEC
AREVA simulator
Wind plant output modeling

International

NORDEL/ELTRA
Ireland
England
Cyprus

Capacity Value:

CEC
Xcel Phase 2
NYSERDA
PJM
SPP

Wind/Hydro Integration:

IEA Annex
Colorado River/Arizona Power Authority analysis
Upper Missouri study
Grant County Case Study

For more information, please send e-mail to info@uwig.org

 

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