Oahu power utilizes less than 2% renewables.
It has the highest reliability: HECO SAIF in 2009 was 1.1%, Maui power utilizes about 17% renewables (wind and biomass).
It has the middle reliability: MECO SAIF in 2009 was 1.6%, Hawaii power utilizes about 33% renewables (geothermal, wind, hydro).
It has the lowest reliability: HELCO SAIF in 2009 was 3.1%, where, SAIF is System Average Interruption Frequency (0% is best)
HELCO reported that 20,660 customer interruptions (16% of all interruptions) were related to Independent Power Producer (non-HELCO Generation) sources.
In 2009, Hamakua Energy Partners (HEP) and Pakini Nui Windfarm were the non-HELCO generation sources that caused customer interruptions. Geothermal did not have any negative effect on HELCO’s SAIF.
The lesson here is that unless the right renewable energy sources are selected, reliability in the provision of power will deteriorate.