Solar energy uses radiation from the sun for heating or electricity generation. “Passive” solar heating utilizes building design and construction to minimize the use of heating fuel. Passive solar design employs windows, thermal mass, and proper insulation to enable a building itself to function as a solar collector. For example, by orienting windows to the south, the sun’s energy is transferred into the building through natural processes of conduction, convection, and radiation. “Active” solar heating systems use pumps or fans to circulate heat (water or air) to a point of use, such as a domestic hot water tank. Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. Indirect-circulation systems are the best type of water heating system for Alaska. They work by pumping an intermediary heat-transfer fluid through the solar collectors, which then circulates through a heat exchanger and warms the potable hot water held in a tank. In warmer climates, the water is pumped directly through the solar collectors without an intermediary fluid. Despite short winter days, solar water heaters can be used about 9 months out of the year in Alaska, making them one of the most practical applications of solar energy for domestic use.
Photovoltaic (PV), or solar-electric panels, are used to generate electricity from the sun. They are commonly used to power homes or communities that are “off the grid”, or not connected to an electric utility’s power grid. Increased worldwide demand and larger scale production of panel components have cut solar panel costs by 80% over the last five years. Another emerging technology in solar electricity generation is concentrated solar power, which uses mirrors to concentrate sunlight onto receivers that collect the solar energy and heat thermal oil. That thermal energy is then used to produce electricity via a heat exchanger that vaporizes water to drive a steam turbine. Since 2007, the 64 MW Nevada Solar One project has used concentrated solar power to generate electricity at $0.15 – $0.17 per kWh. While this rate is more expensive than fossil-fuel derived power in the area, long-term contracts help to reduce rates over time while providing clean energy to America’s southwest.
Solar energy in Alaska
Although Alaska’s northern location presents the challenge of having minimal solar energy during the long winter when energy demand is greatest, solar energy fulfills an important role in space heating and off-grid power generation. The largest amount of solar-electric generation in Alaska comes from the Golden Valley Electric Association’s Sustainable Natural Alternatives Program (SNAP). Members of the electrical coop install their own renewable energy producing systems, the vast majority of which are solar. Non-producing members can choose to donate to an escrow account to support such renewable energy development. The donations are used to pay the producers of the renewable energy. Launched in 2005, the SNAP program is available to systems with a generation capacity of 25 kW or less. GVEA also operates a solar thermal hot water heating system at the Denali Education Center in Denali National Park. The project consists of 36 flat panel solar thermal collectors that offset electricity and propane required to heat water for 13 cabins and other buildings at the facility, saving Denali Education Center about $7,000 annually. To date this is the only solar thermal project funded through the Alaska Renewable Energy Fund.
In addition to solar thermal, some Alaskan communities are starting to incorporate solar PV to offset their fuel consumption. In 2012 Alaska Village Electric Cooperative installed a 10kW solar PV system in the village of Kaltag (pop. 190) to reduce the community’s use of diesel fuel at the local powerhouse. In its first year of operation the solar array produced about 8,200 kWh, saving Kaltag residents over $1,700 in diesel fuel for FY13. To date this is the only solar PV system that has been funded through the Alaska Renewable Energy Fund.
Who we are
Renewable Energy Alaska Project is a coalition of energy stakeholders working to facilitate the development of renewable energy in Alaska through collaboration, education, training, and advocacy.