On four occasions in January 2016, Kaua‘i Island Utility Cooperative (KIUC) used a variety of renewable resources to generate 90% of the Hawaiian island’s electricity.
- In January, renewable resources met an average of 77% of KIUC’s energy demand during the peak solar hours, spiking to 90% on four separate days:
- Wednesday, January 13: 61 minutes at or above 90% renewables with 59 MW of demand
- Saturday, January 16: 34 minutes at or above 90% renewables with 57 MW of demand
- Sunday, January 17: 34 minutes at or above 90% renewables with 53 MW of demand
- Monday, January 18: 5 minutes at or above 90% renewables with 58 MW of demand
- KIUC used a combination of solar (52.6 MW), biomass (7.2 MW), and hydro (9.1 MW) resources to hit the milestone
- By comparison, Germany—a leader in renewable generation—peaked at 83% renewable generation in August 2015
- On an annual basis, renewable resources account for 38% of KIUC’s generation, up from 8% in 2010; KIUC’s strategic plan calls for renewables to account for 50% of generation by 2023
- Key operational changes that allow high penetrations of renewables include:
- Upgrading diesel generators to be more responsive to solar variability
- Adjusting generator governors to ramp faster
- Redesigning relay protection and load shed schemes
- Setting solar and battery invertors to ride through frequency and voltage events
KIUC has proven the ability to manage an electric system that incorporates 38% renewables and peaks up to 90% renewable. Even more impressive, KIUC has accomplished this without the benefit of an interconnection to a large electric grid (e.g., Germany or mainland United States).
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