Energy efficiency and renewable energy are the best known pieces of Hawaii's clean energy future puzzle. But there are technologies that displace the use of oil that are also part of the effort to end Hawaii's near total dependence on imported fossil fuel.
Solar Water Heating
Solar water heating, a solar thermal technology, uses heat from the sun to produce hot water. It is one of the most effective ways people who live in single-family homes or small apartment buildings can reduce their electric bills. With rebates and tax credits, the up front cost of a typical solar water heating system can be paid off through the electricity saving in roughly four years in most homes. Before home owners consider adding a solar photovoltaic system, they should reduce their electricity demand as much as possible with steps like adding solar water heating.
From 1996-2009, Hawaiian Electric, Maui Electric and Hawaii Electric Light Company administered energy efficiency programs, including a very successful solar water heating rebate program. Cash rebates were offered to homeowners to help defray the installation costs of a solar water heating system. As part of the program, Hawaiian Electric maintained a list of approved solar water heating installers and conducted a 100-point inspection after the solar water heaters were installed. Customers who also qualified for State and Federal tax credits were able to dramatically lower solar water heating installation costs.
The program was one of the largest and most successful solar water heating programs in the nation. By 2009, the Hawaiian Electric companies achieved a milestone 50,000 solar water heating installations. Combined with previously installed solar systems, the total statewide in 2009 was more than 80,000, making Hawaii a national leader with an estimated one out of three single-family homes equipped with solar water heating.
The utilities’ solar water heating program reduced the demand for electricity by 111,328,000 kilowatt-hours annually (the equivalent of the estimated annual electric usage of more than 14,000 households), avoided the use of 210,000 barrels of oil annually and reduced carbon dioxide emissions – a major contributor to global warming – by 116,000 tons annually.
In 2009 the solar water heating program was transitioned to a Public Benefits Fund administrator selected by the Hawaii Public Utilities Commission. Information about approved installers and rebates are now available at www.hawaiienergy.com.
Starting in 2010, a new law requires all new homes to be equipped with solar water heating as original equipment.
Deep, cold seawater can be used to cool buildings, offsetting the electricity needed for air conditioning
A proven technology available right away
As of 2011, the company had leased land for a cooling station and making preparations to begin construction on the system.
Seawater air conditioning does not create energy. It reduces the electricity needed to cool buildings by using a clean, renewable technology. It is our most immediate opportunity to take advantage of the ocean’s energy potential.
Conventional air conditioning systems consume four to 12 times more electricity than equivalent seawater A/C systems.
Honolulu Seawater Air Conditioning, LLC, is currently developing a 25,000-ton seawater air conditioning system for downtown Honolulu.
Hawaiian Electric is among the companies that have committed to use seawater A/C at its headquarters building at 900 Richards Street.
How does it work?
Cold seawater is pumped from deep offshore to a cooling station located near the buildings. There the cold sea water chills fresh water. The system is designed to prevent sea water from mixing with fresh water.
The chilled freshwater is then pumped through a loop system to buildings that will use the chilled water for cooling. The slightly warmed sea water is returned to the ocean at a level where it will match the ambient temperature of the water.
Possible areas for expansion include Waikiki, Kapolei, Kaka'ako and the University of Hawaii at Manoa. A modified system using deep well water is already in use at the University of Hawaii John A. Burns School of Medicine in Kaka'ako, reducing the electric use for A/C in that complex by about 25%.
Seawater A/C systems provide numerous environmental, economic development and customer benefits.
reduces electrical usage with a renewable resource significantly
reduces use of ozone-depleting chlorofluorocarbon (CFC) refrigerants
reduces reliance on fossil fuels and emission of greenhouse gases
uses less potable water and discards less toxic water to sewers
price-competitive service with stable energy cost to consumer
model of sustainability with fuel dollars staying in the local economy
eliminates the need for chillers or cooling towers
saves space in the mechanical room
equipment built to last 75 to 100 years is easy to operate and maintain