Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
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More positively, reservoirs resulting from dams can be valuable recreation areas,
and dams assist in flood control efforts, thereby preventing economic hardship and loss of
life.
Many environmental groups object to the broad definition of hydroelectric
resources as renewable. Numerous classification systems for hydro have developed in an
attempt to distinguish “renewable” projects. Generally this distinction is based on size,
although “low-impact,” low-head, and run-of-river plants are also often labeled
renewable. Incremental hydro, which generally does not alter water flows any more than
the existing hydro project, may also qualify as renewable.
Kauai Outlook
Hydroelectric generation is a fully commercial technology that already makes a
significant contribution to the electric supply on Kauai. Hydro resources on Kauai are
very good with consistently large rainfall and sharp elevation changes on many parts of
the island. On the other hand, Hawaiian stream flows vary considerably throughout the
year, making hydro an intermittent, “as available” resource.
There has been considerable opposition to new hydro development on the island
in the past 20 years. Several proposed projects, such as a project diverting the Hanalei
River, have been strongly opposed by local residents forcing project developers to
eventually abandon plans. However, with the recent increase in fossil fuel prices, there
appears to be new interest in hydro development on the island, particularly projects
involving upgrades to existing plants and addition of generation to agricultural irrigation
systems. Such projects have little new impact on important watersheds and would
presumably encounter less opposition than past proposals.
It is difficult to develop a precise estimate of the developable hydro potential on
the island due to the large variety of different schemes and the environmental and
institutional obstacles facing many projects. A recently released broad survey of United
States hydro potential performed by INEEL includes estimates of the cost and
performance of new and upgrade hydro projects on Kauai. 34 The INEEL database was
developed based on information from projects identified and proposed in the past.
Although development of all of these sites is highly unlikely, the INEEL projects provide
one view of the developable potential for hydro generation on the island. The total
potential identified is about 60 MW producing 320 GWh annually. This could be viewed
as an upper bound for the hydro potential on the island. See Table 3-19 for a list of the
projects.
34 Idaho National Engineering and Environmental Laboratory, “Hydropower Equipment Refurbishment or
Replacement: Generation Increases and Associated Costs,” 2003.
21 March 2005 3-45 Black & Veatch