Hawaii's proposed 400 MW Interisland Wind project, which would bring wind power from Molokai and Lanai to Oahu, could reliably supply more than 25% of Oahu's projected electricity demand when combined with solar power, according to the Oahu Wind Integration Study (OWIS).
The OWIS studied what the impact would have on the Oahu grid of a total of 500 MW of wind energy and a nominal 100 MW of solar power, though a good deal more utility-scale and customer-sited solar power is expected in Oahu.
The study found that the 500 MW of wind and 100 MW of solar power could eliminate the need to burn approximately 2.8 million barrels of low-sulfur fuel oil and 132,000 tons of coal each year while maintaining system reliability, if a number of recommendations are incorporated, including the following:
– Provide state-of-the-art wind power forecasting to help anticipate the amount of power that will be available from wind;
– Increase power reserves (the amount of power that can be called upon from operating generators) to help manage wind variability and uncertainty in wind power forecasts;
– Reduce minimum stable operating power of baseload generating units to provide more power reserves;
– Increase ramp rates of Hawaiian Electric Co.'s thermal generating units;
– Implement severe weather monitoring to ensure adequate power generation is available during periods of higher wind power variability; and
– Evaluate other resources capable of contributing reserve, such as fast-starting thermal generating units and load control programs.
The study notes that ensuring reliability will require further studies, upgrades to existing and new infrastructure, as well as specific requirements on the wind farms to be connected to the Oahu system.
With these and other proposed changes, the technical analysis suggests, Oahu can accommodate increased wind and solar projects with minimal limits on output of renewable resources.
‘The findings of this study show it is feasible to integrate large-scale wind and solar projects on Oahu but also have value beyond Hawaii,’ says Rick Rocheleau, director of the Hawaii Natural Energy Institute (HNEI). ‘Both large mainland utilities and relatively small and/or isolated grids that wish to integrate significant amounts of renewable energy while maintaining reliability for their customers can learn from this study.’
The OWIS was conducted by the HNEI, GE and Hawaiian Electric. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) assembled a technical review committee with representatives of industry and academia, which met throughout the project to review findings. NREL also contracted the private firm AWS Truepower to develop wind and solar power profiles that were used in the study.
SOURCE: Hawaiian Electric Co.