Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments 3.0 Renewable Energy Technology Options
Environmental Impacts
Dissolved minerals and hazardous non-condensable gases in geothermal fluids
can be an environmental concern if not handled correctly (fluid reinjection addresses
many concerns). Geothermal power plants with modern emission control technologies
have minimal environmental impact. They emit less than 0.2 percent of the carbon
dioxide, less than 1 percent of the sulfur dioxide and less than 0.1 percent of the
particulates of the cleanest fossil fuel plant.
There is the potential for geothermal production to cause ground subsidence. This
is rare in dry steam resources, but possible in liquid-dominated fields. However, carefully
applied reinjection techniques can effectively mitigate this risk.
Kauai Outlook
The prospects for geothermal electricity production on Kauai are poor. In 1995
and 1996 the US Geological Survey (USGS) drilled six groundwater monitoring wells
near Lihue that ranged from 800 to 1,150 feet in depth. The results from these
monitoring stations yielded water temperatures ranging from 24-27ºC (75-80ºF),
practically identical to those in non-geothermal regions of Hawaii. 45 To fully assess the
island’s geothermal potential, further drilling and investigation would be required.
Geothermal resources that might be discovered would likely be more suitable for
geothermal heat pumps for building space conditioning and direct heating applications
than electricity production.
While several of the other Hawaiian Islands have very promising geothermal
potential, as the oldest geological island of the archipelago, Kauai has relatively little to
no geothermal activity. While all of the Hawaiian Islands were formed by volcanic
activity that took place deep in the Pacific Ocean along tectonic boundaries, the islands
formed in a southeastward direction; making Ni’ihau and Kauai the oldest of the islands.
This being the case, any significant geothermal activity on the island ceased millions of
years ago. As such, there are no promising conventional geothermal resources suitable
for power production in Kauai.
3.10 Multi-Fuel Generation Technologies
There are a number of energy conversion technologies that could be used to
generate power from conventional and renewable fuels. This section provides a
description of each of these technologies, and the outlook for their future implementation.
45 GeothermEx, Inc., "Update of the Statewide Geothermal Resource Assessment of Hawaii", available at
http://www.hawaii.gov/dbedt/ert/geothermal/geothermex2000.pdf, June 2000.
21 March 2005 3-76 Black & Veatch