Kauai Island Utility Cooperative On Track for Renewables Goal of 50% by 2022

Kauai co-op’s latest renewable growth figures pave the way for its ambitious renewable goal.
Published: Tue 16 Feb 2016

Over a year ago we reviewed Hawaii’s ambitious renewable plans and so far, the state has shown the world some impressive figures. [Hawaii – An Energy Future Based on Renewables And Smart Grid] [Hawaii Looks To 100% Renewables].

Hawaii’s impressive renewables figures

Last year it was evident that the state meant business as more than 18% of electricity used by customers came from renewable sources- this figure exceeded the state goal of 15% by 2015. Now, Kauai Island Utility Cooperative (KIUC) is boasting that 90%-plus of its electricity came from renewables on four separate occasions during the month of January:

  • Jan. 13: Total of 61 minutes at or above 90% renewables with 59MW of demand and an average resource mix of 71% solar, 8% hydro, 11% biomass, 10% diesel;

  • Jan. 16: Total of 34 minutes at or above 90% renewables with 57MW of demand and an average resource mix of 73% solar, 8% hydro, 9% biomass, 10% diesel; 

  • Jan. 17: Total of 34 minutes at or above 90% renewables with 53MW of demand and an average resource mix of 72% solar, 8% hydro, 10% biomass and 10% diesel;

  • Jan. 18: Total of 5 minutes at or above 90% renewables with 58MW of demand and an average resource mix of 77% solar, 6% hydro, 7% biomass and 10% diesel.


In addition to its baseload capacities of 8% biomass, 7% hydroelectric and ramping diesel generation, KIUC achieved up to 77% solar in its power mix. This is a record since this is the most solar to ever be integrated by a US utility.

KIUC’s average energy mix in 2015 was 38% renewables and 62% diesel fuel generation. Its rooftop solar generation is growing at a steady pace and it has two utility-scale solar installations, five hydroelectric facilities and a newly operational biomass plant that burns albizia wood chips.

The 77% solar that drove the renewables total over 90% was only achieved for short intervals, the longest being 61 minutes on January 13, according to KIUC spokesperson Jim Kelly. On an average day in January, solar was about 62% of the utility’s generation, making renewables 77% of its power mix.

Based on these figures, the co-op is likely to achieve 50% of its power from renewable resources in seven years.

Fine turning renewables integration

According to Mr Kelly, the recently-added biomass plant was critical to integrating the high levels of solar as it provides a stable source of renewable generation.

In order to integrate the escalating solar levels, KIUC upgraded its conventional diesel generators so they can be more responsive to solar variability. In addition to this, air permits were modified to enable generators to run at below 50% loads, generator governors were tuned to ramp faster, relay protection and load shed schemes were redesigned and solar inverters and battery inverters were adjusted to ride through wider frequency and voltage excursions.

“Being an engineer in the control room is a lot more challenging than it was six months ago… it is a real team effort to keep it in balance,” explained Mr Kelly.

The major increase in renewables has forced Hawaii’s utilities to install energy storage solutions in order to deal with the sudden changes in availability of these variable natural energy resources. [ Hawaii Calls for Large-Scale Energy Storage.]

At European Utility Week 2015, Hawaii’s experience around storage solutions was discussed at length [Tackling Grid Challenges with Energy Storage: The Hawaiian Experience]

A cleaner and more energy efficient Hawaii

Hawaii’s electric companies plan to have more than 65% renewable energy generation capacity by 2030. High electricity tariffs, as a result of costly oil generation and diesel imports, is driving this move to cleaner energy.

The state is certainly rich in natural resources. Hawaii has one of the most diverse renewable energy portfolios in the country, including solar, wind, geothermal, biomass, biofuel, and hydroelectric sources of power. Ocean power is also a promising option for the future.[ Azura Starts Producing Wave Power Off Hawaii]

In addition to the state’s plans to develop a cleaner energy future, there is also a strategy in place to improve energy efficiency levels [Incentivizing Energy Efficiency – Hawaii Opens Auction Bidding].

While Hawaii has a long way to go to reach 100% renewables as a state, the intentions are good and the short term goals seem attainable. The potential is certainly there and we will be watching this state with a keen eye.