Solar Energy

Photovoltaic Panels

•	The sun’s energy can be harnessed with solar technologies to create heat and electricity
•	Installing a solar water heater is one of the best ways a homeowner can reduce utility bills, save energy and protect the environment
•	Photovoltaic technology, also known as PV, uses solar energy to produce electricity. Many businesses and homes in Hawaii are adding PV arrays
•	Concentrated solar power includes technologies are in various states of development that could provide a significant amount of electricity, heat, hot water and air conditioning.

Solar water heating

With our clear, sunny skies, Hawaii has the most successful solar water heating program in the country. An energy efficiency rebate in addition to state and federal tax credits make solar water heating one of the smartest ways to improve a home.

Some quick facts about solar water heating in Hawaii.

• There are an estimated 85,000 residential solar water heating systems statewide
• One in four single-family homes in Hawaii has a solar water heater

Homeowners who install solar water heating systems can get help with cash rebates provided by the Hawaii Energy Efficiency Program. The rebates, along with state and federal tax credits, can dramatically lower costs.

The typical household can save nearly $15 per person per month (or $600 per year for a family of four) on the home electric bill after installing solar water heating. The typical installation cost can be recovered in three to four years. After that, the savings all go right to the family budget.

Through a partnership between Hawaiian Electric and the City & County of Honolulu, a Solar Roofs Initiative offers zero-interest or low-interest loans for solar water heating installation to assist families with low to moderate income and owners who rent a majority of their units to low income families.

Photovoltaic electricity

Photovoltaic (PV) or solar electricity uses cells made from semi-conducting silicon material to turn sunlight directly into electricity. Though costs are high, technology is advancing rapidly and roofing that includes photovoltaic cells and other advances are in the research and development stage.

PV is becoming more popular. At present, on Oahu, PV systems have exceeded two megawatts of total capacity, and that number is growing. Hawaiian Electric, in partnership with Hoku Scientific, is installing a photovoltaic system at the Ward Avenue facility to gain experience with the technology and better advise customers on its use.

A program called net energy metering allows homes and business that produce more renewable electricity than they use to export surplus power to the grid for retail credit to offset their bills. Most net metering customers have PV arrays but it is also available for small-scale wind, hydro and biomass systems. Net energy metering is intended to encourage use of renewable energy by residences and small businesses.

Learn more about net energy metering.

For more information on photovoltaic energy, contact:

Hawaii Solar Energy Association
P.O. Box 37070
Honolulu, Hawaii 96837
Tel: (808) 521 9085
Fax: (808) 847 4938

Or for more information, click here.

Concentrating solar power

Concentrating solar technologies utilizing focused sunlight to produce electricity (with photovoltaics) or heat – including parabolic trough and dish or a central receiver -- are in various stages of development.

Parabolic troughs focus the sun's energy through long rectangular, curved mirrors. The mirrors follow the sun, focusing sunlight on a pipe running down the center of the trough containing oil. The heated oil can be used to produce electricity, air conditioning or drinking water from sea water. Parabolic trough systems have been reliably operating in the U.S. for over 22 years.

Concentrating photovoltaic systems use lenses to concentrate sunlight on high efficiency photovoltaic cells to produce electricity gaining higher efficiencies.

Parabolic dish systems use reflectors arranged in a dish-type pattern to focus concentrated sunlight onto a receiver located at the focal point of the dish. The sunlight heats a working fluid such as hydrogen or helium in a reciprocating engine to produce mechanical power which is then converted to electricity by a generator.

Central receiver systems, or power towers, use hundreds of mirrors called heliostats to track the sun and focus concentrated solar energy on a tower-mounted heat exchanger. The concentrated solar radiation heats water, or a molten salt that transfers heat to water, to produce steam for a conventional steam turbine cycle. Two central receiver systems were operated in the U.S. in the late 1980s and 1990s.

For more information on concentrating solar power, click here or here.

Learn more about a local company pioneering concentrating solar power.

Future Solar Projects.

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