Oahu Wind Integration Study - Hawaii Natural Energy Institute ...

advanced capabilities can contribute towards on-line reserve requirements and potentially
increase total wind energy that can be accepted by the system.
This study did not perform extensive analysis on strategies to mitigate variability that utilize
energy storage because of constraints on the study's resources and timeline. While energy
storage can be used to help mitigate the variability and uncertainty of wind power in the HECO
system, the cost and benefit of energy storage would need to be explicitly compared against
alternate technologies and strategies that were considered in this study. This type of comparative
benefit-cost analysis was beyond the scope of the current study.
Under the scenarios considered in this study, the team did conclude that energy storage is not
necessary to manage the variability of the wind plants if the present ramp rate capabilities of the
HECO thermal units are increased to the ramp rates proposed by HECO. This conclusion is
sensitive to the underlying assumptions in the scenarios analyzed in the study. Each of the
scenarios consists of a specific generation mix, wind plant sizes and locations, and assumed
performance capabilities of the Energy Management System, thermal units, and wind plants. As
the Oahu power system evolves, it may be necessary for HECO to reconsider the strategies and
technologies to enable high levels of wind power, and/or consider alternate strategies to help
enable the levels of wind power considered in this study.
1.8. Recommendations
This study shows that it is operationally feasible for the Oahu system to accommodate the wind
projects and supply more than 25% of the island’s energy from the 500 MW of wind power and
100 MW of solar PV projects, if the following strategies are incorporated:
1.8.1. Operating Strategies
• Incorporate state-of-the-art wind power forecasting into the unit commitment process and
account for the availability of wind plants in this forecast,
• Increase the up-reserve requirement to help manage sub-hourly wind variability and
uncertainty in wind power forecasts,
• Continuously monitor wind power variability and wind power forecast accuracy to
improve above estimates and operating strategies,
• Implement severe weather monitoring to ensure adequate unit commitment during
periods of higher wind power variability,
• Evaluate the effectiveness of including other resources capable of contributing to upreserve,
such as fast-starting thermal units and load control programs,
• Continuously monitor and report fast-start capacity and load control available to enhance
real-time system operation during wind variability, wind uncertainty, and other events,
• Implement a down-reserve requirement based on feasible loss-of-load events and the
anticipated system response to the event,
• Once the wind plants are in operation, further refine the down-reserve requirement based
on actual wind plant over-frequency performance during loss-of-load events,
• Integrate wind power measurements, automatic wind curtailment, and wind curtailment
allocation in system operating practices.
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