solar maps

Maps of solar energy can you give you a sense of what the solar energy potential is for your location.  By far the best source of these maps is the site run by the National Renewable Energy Laboratories (NREL) operated by the U.S. Department of Energy at www.nrel.gov. This Web site provides maps in many areas of energy use.  In the solar section you will find both interactive and static maps showing solar radiation, solar energy generation potential and solar radiation by time of year.

Here are some of the solar maps you can find on the NREL site:

• United States Solar Atlas—Dynamic Map -This powerful interactive map shows the monthly average potential energy generation using photovoltaic panels for any given location in the United States. It also provides access to spreadsheets giving average monthly radiation for 14 different types of solar collectors. A great thing about this map is that it provides a zoom tool which allows you to look at the solar potential for your local area.  You can zoom manually or by putting in your zip code or latitude and longitude. Note: Pop ups must be enabled to view these maps.
• PVWATTS Version 2—Dynamic Map - This map calculates electrical energy produced by a grid-connected photovoltaic (PV) system. Researchers at the National Renewable Energy Laboratory developed PVWATTS to permit non-experts to quickly obtain performance estimates for grid-connected PV systems within the United States. Note: Pop ups must be enabled to view maps.
• Annual Direct Solar Radiation - This is a static map that shows the monthly average daily total solar resource information on grid cells of approximately 40 km by 40 km in size which are mounted on a two-axis tracking system that can track the sun throughout the day.
• Direct Solar Radiation in January  - This is the same type of map but taking the average just for the month of January.  Compare this with the next map and you can see the significant difference in radiation by time of year.
• Direct Solar Radiation in July - A solar radiation map for a two axis tracker for the month of July.

Another great site for solar maps is www.nationalatlas.gov.  This is one of their maps which shows solar energy generation potential for the United States.  As you will see form the map the vast amount of land area in the U.S. has the potential to generate between 4 and 6 kilowatt hours per day of energy using a flat-plate collector facing south at a fixed tilt equal to the latitude of the site. Capturing the maximum amount of solar radiation throughout the year can be achieved using a tilt angle approximately equal to the site's latitude.  The one part of the United States that has lower potential is the Northwest coast because it frequently has cloudy weather.