Energy technologies that use the sun’s radiation directly are referred to as solar energy technologies. These may be employed to heat or light living space directly, to supply energy to a heat storage system for later use, or to generate electricity.
Two major factors should be considered when employing solar energy in Alaska: the abundance of sunlight when the energy is needed and the cost of other forms of energy. Technologies other than solar must carry the load during the dark times of the year in Alaska. For this reason, the addition of a solar auxiliary system will not reduce the capital cost of a primary heating or electrical system. Primary systems must be designed to operate for months without benefit of significant solar input.
Solar Technology in Alaska
Active systems hold the most promise for Alaskan applications. These are systems that can store energy for longer periods of time or be incorporated as auxiliary energy sources into existing energy systems. Active systems also lend themselves to being controlled automatically. Because of the seasonal nature of the solar resource in Alaska, passive solar designs yield only modest benefits, since they cannot store solar energy for an extended period of time. Passive solar lighting systems use sunlight only during the daylight hours. Passive heat systems are generally effective for some hours (in some cases a few days) after collecting solar energy, and they often require active participation in the building operation.
Active solar systems most suitable for Alaska are photovoltaic systems and solar hot water systems. Except for specific niche applications, it is unlikely that photovoltaic electrical generation is suitable for reducing the cost of electricity in Alaska. Grid-connected photovoltaic systems offer the most economical means of generating electricity with sunlight. At current prices an installed, grid-connected system in Interior Alaska could produce electricity for approximately $1.50 per kilowatt hour. Connection to an electrical grid enables a photovoltaic system to avoid expensive electrical storage.
The cost of solar-generated electricity in remote areas with no electrical grid available would be significantly higher due to the cost of additional batteries and inverters. There have been only two Alaskan villages with average electrical kilowatt hour costs over $1 per kilowatt hour for the past five years. Lime Village, which has an installed photovoltaic system, has electrical costs of $1.26 per kilowatt hour. Stony River pays $1.01 per kilowatt hour.
Solar hot water systems offer more promise in Alaska than photovoltaic electrical generation does, although the present installed cost of systems is still expensive. Solar hot water systems suitable for Alaska can provide hot water for space heat or for domestic use. The low density of the Alaskan solar resource precludes the economical use of high temperature solar technologies, such as systems that generate steam to produce electricity. As an example of the difference between the cost of solar hot water and hot water from fuel oil, consider a household-sized solar hot water system with an energy cost spread over twenty years. The cost of the solar energy would be approximately $100 per million Btu. The cost of that same energy from fuel oil, if the fuel price were $6 per gallon, would be about $40. There might be some rural villages where solar could be an economical component of an energy system. On the road system, where fuel oil is less expensive, some might wish to use solar hot water for reasons other than fuel oil price alone.
Net metering is a process by which utility customers operating small generators can purchase electricity from a utility when needed and sell any excess generation back to the utility company.
In January 2010, the Regulatory Commission of Alaska formally adopted net metering for Alaska in January 2010. The new rules only apply to utilities with total retail sales of 5 million kWh or more and require that utilities interconnect with eligible customer generation systems up to a system-wide total capacity of 1.5% of their average retail demand. After reaching the 1.5% level, the utility can choose to add more power through net metering or turn down additional requests.
Homer Electric Association (HEA) and Fairbanks’ Golden Valley Electric Association (GVEA) developed the Sustainable Natural Alternative Power SNAP programs before adoption of state-mandated net metering. SNAPs allow customers who wish to support renewable energy development to do so by contributing to a fund that is held in escrow by the utility company. Individuals in the GVEA and HEA service areas who want to produce up to 25 kW of renewable electricity for the grid are paid from the escrow fund in proportion to the amount of power they produce plus the utilities avoided fuel cost. Other electric cooperatives in Alaska are also considering starting their own SNAP programs.