Oahu Wind Integration and Transmission Study
NREL's Wind Systems Integration team participated in the Oahu Wind Integration and Transmission Study (OWITS) to examine grid and transmission integration of renewables as part of the Hawaii Clean Energy Initiative's Energy Agreement. The Energy Agreement includes a commitment to integrate up to 400 megawatts (MW) of offshore wind energy from Molokai or Lanai and transmit it to Oahu via undersea cable systems (the "Big Wind" projects).
The Hawaii Clean Energy Initiative also includes an aggressive mandate for the state of Hawaii to generate 40% of its energy from renewable resources by 2030. The "Big Wind" element is a significant part of the 40% renewable energy goal.
The goal of the OWITS is to help stakeholders, especially the utilities and the state, to 1) understand the costs and operating impacts of significant amounts of wind power—up to 400 MW offshore and 100 MW on island—on their island grids, and 2) plan for future transmission.
The scope of the OWITS includes the following:
- Identifying the technical requirements and configuration for an undersea inter-island cable to transmit electricity from large wind plants to Oahu;
- Identifying the ancillary services and potential mitigation measures to offset the variable nature of planned wind generation;
- Evaluating potential modifications to the utilities' existing generating units to offset the variable nature of wind energy; and
- Changing some of the utilities' operational practices and procedures, including an evaluation of the potential benefits of wind forecasting, that are required to operate the island grids with inter-island wind integration.
Main Tasks
NREL's Wind Systems Integration staff provided support in these areas.
- Wind Resource Modeling:
- Develop modeled time-series wind speed datasets for the wind integration study area.
- Develop modeled time-series power outputs for up to 400 MW of wind from Molokai and/or Lanai and 100 MW of wind from Oahu as well as 100 MW of PV on Oahu.
- Transmission Analysis:
- Develop technical analysis of undersea cable using HVDC technology.
- Analyze different undersea cable analysis for different wind scenarios.
- Integration Analysis:
- Evaluate operating and reliability impacts of high penetration wind scenarios.
- Identify issues for wind integration.
- Identify how other generation sources are affected.
The Oahu Wind Integration and Transmission Study was sponsored by the Hawaiian Electric Company; the state of Hawaii Department of Business, Economic Development, and Tourism; and the U.S. Department of Energy.
Technical Review Committee
A technical review committee consisting of regional, national, and international technical experts with experience in power systems, renewable energy, direct-current (DC) cable systems, island grids, and wind integration guided and reviewed the study. The technical review committee provided feedback on key assumptions, methods, and preliminary results.
More Information
Oahu Wind Integration and Transmission Study (OWITS): Hawaiian Islands Transmission Interconnection Project. (February 2011). Woodford, D.
Phase 2 Report: Oahu Wind Integration and Transmission Study (OWITS): Hawaiian Islands Transmission Interconnection Project. (February 2011). Woodford, D.
Oahu Wind Integration And Transmission Study: Summary Report. (November 2010).
Development of Regional Wind Resource and Wind Plant Output Datasets for the Hawaiian Islands. (July 2010).
