Hawaii Solar and Wind Integration Studies
NREL's Hawaii Solar Integration Study and Oahu Wind Integration and Transmission Study investigated the effects of high penetrations of renewables on island grids.
Hawaii Solar Integration Study
The Hawaii Solar Integration Study was a detailed technical examination of the effects of high penetrations of solar and wind energy on the operations of the electric grids of two Hawaiian Islands: Maui and Oahu. Carried out under the auspices of the Hawaii Clean Energy Initiative, the study was sponsored by the Hawaii Natural Energy Institute, the U.S. Department of Energy, and the Hawaiian Electric Company.
Unlike mainland power grids, island power grids are self-contained and isolated, so they have no neighboring grids to turn to for support if they are pushed beyond their normal operating limits. The Hawaiian Islands also rely heavily on oil and oil products to fuel their power plants, which results in high electricity costs that help make renewable energy economically competitive.
Maui and Oahu already have significant wind and solar power feeding their electric grids, but the utilities on each island wanted to know how their grids will operate with more renewable energy. Some of this will be under utility control in the form of centralized, utility-owned solar power plants, but much of the solar power will be distributed throughout the island on homes and businesses—outside of the utility's control.
The study included detailed computer modeling and simulations of the generation and transmission systems on each island to examine how future scenarios of high penetrations of solar and wind power will affect generator operations under normal system configurations. The distribution-level impacts were not assessed in this study. For cases in which the generator deviated from its preferred operating parameters, potential mitigation strategies were proposed and modeled.
For more information about the Hawaii Solar Integration Study, see the Executive Summary.
Oahu Wind Integration and Transmission Study
The Oahu Wind Integration and Transmission Study examined the integration of renewable energy as part of the Hawaii Clean Energy Initiative's Energy Agreement. The 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 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 wind projects are a significant part of the 40% renewable energy goal.
The goal of the Oahu Wind Integration and Transmission Study was to help stakeholders, especially utilities and the state, 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 plan for future transmission.
The scope of the study included:
- Identifying the technical requirements and configuration for an undersea interisland 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
- Changing some of the utilities' operational practices and procedures required to operate the island grids with interisland wind integration.
A technical review committee of regional, national, and international technical experts with experience in electric power systems, renewable energy, direct-current cable systems, island grids, and wind integration guided and reviewed the study and provided feedback on key assumptions, methods, and preliminary results.
The Oahu Wind Integration and Transmission Study was sponsored by the Hawaiian Electric Companies; the State of Hawaii Department of Business, Economic Development, and Tourism; and the U.S. Department of Energy. The project team consisted of NREL, General Electric, Hawaii Natural Energy Institute, and Hawaiian Electric.