When most people think of renewable energy, solar power is frequently the first source to come to mind. Folks are accustom to having the sun come up every day providing basic lighting, and on clear days, the warmth of the radiant energy striking your skin can be quite noticeable. Most individuals recognize the potential of solar in the summer when Alaska is basking through long hours of sunshine, but they wonder if the short days of winter make solar power unreasonable. Actually, even in Fairbanks, solar power can be very useful and cost effective. The exact potential depends on the details of the specific site. The keys are proper system design and looking at the total annual production.
Power from the sun is generally called solar radiation. The amount striking the earth at a specific moment is termed irradiance, and is usually expressed as watts per square meter (W/m2). What is important in evaluating a site's solar potential is the total amount of irradiance received over a period of time. This total solar irradiation is typically expressed as kilowatt-hours per square meter per day (kWh/m2/day). It may also be called solar insolation. Generally, it is measured as the amount of energy that hits a fixed flat panel which is tilted at the appropriate angle to face the sun.
Solar Potential in the Far North
In Fairbanks, Alaska, annual solar irradiation averages 3.4 kWh/m2/day. To find the value for your area you can go to the US Department of Energy’s website Solar Energy Potential map and hover the cursor over your city. You'll have to first grab and drag the map if you want to see Alaska. (Note the calculations are presented in watts per square foot per day, so to convert to square meters multiply by 10.76, then divide by 1,000 to convert watts to kilowatts.) For Alaskan communities, you can also check the tables in the back of the book, A Solar Design Manual for Alaska by Rich Seifert of the Cooperative Extension Service at the University of Alaska, Fairbanks. This book can also be downloaded at http://www.alaskasun.org/, and for solar irradiation data, click on “Appendix C.” Different agencies may report slightly different numbers, but this variability is generally not significant. Depending on which source agency you reference, Fairbanks' average annual solar irradiation ranges from 3.10 to 3.99 kWh/m2/day. When comparing one city or large area to another, utilizing only one source for your data should provide an accurate comparison. When looking for an absolute value, reviewing several sources and analyzing their range might be more precise.
The typical citizen initially may have difficulty putting Fairbanks’ solar irradiation level of 3.4 kWh/m2/day into perspective. For comparison, in Germany, where there are more installed solar panels per capita than anywhere else in the world, the level averages only 3.0 kWh/m2/day. The United States is blessed with much better irradiation, as the annual amount is linked more closely to weather patterns than geographic latitude. At similar latitudes, sunny Phoenix receives 6.6, but Atlanta only 4.8. Seattle gets 3.3, but Bismarck, North Dakota scores 4.7. In Alaska, clearer weather accounts for Fairbanks at 3.4 beating Anchorage at 3.1. Bethel, at 3.8, outshines most of the state, while Juneau, with the most southernly location but persistent clouds, averages only 2.6. (All of this data is from the US Department of Energy). As you can see, solar potential is location specific, but most of Alaska receives enough irradiation for solar to be a viable energy source; even more so than in world-leading Germany.
Every Case is Unique
While your city may receive plenty of sunshine, you also need to evaluate your specific building site, and even the exact location within your site. There are complications that may limit your ability to collect the solar energy that is generally available in your area. Tall trees, neighboring buildings or mountains, or the slope of your lot are a few of the things that can affect your solar potential. If you are serious about investigating solar power for a site, it is best to have a solar professional evaluate your specific location. Arctic Sun has the diagnostic equipment to determine what percentage of the locally available sun you should be able to collect.
There are many ways to capture and utilize solar energy. Brief overviews of several of the more popular methods are presented under the tabs labeled "Passive Solar," "Solar Electric" and "Solar Thermal."
Online Tool to Get You Started
The following link brings you to a free, online calculator that can get you started thinking about the potential for solar energy at your home or business. Keep in mind, while this is a handy place to start, it cannot replace thorough, professional advice.
Additional information is also available in the following books:
Examines renewable energy options for grid-tied homeowners, including solar- and wind-generated electricity, solar water heating, passive solar, and geothermal heating / cooling. System configurations and equipment, average costs, financial incentives, and installation considerations are also covered--Provided by publisher.
Presents a broad overview of solar potential in general and specifically in Alaska.