Solar Energy System site considerations

One of the first things most home owners ask when considering a solar system is "Yeah, but will that work at my house?"  This is soon followed by a litany of concerns such as to which way their house faces towards the sun, overhanging trees, too cold a climate and other factors.  The good news is that both passive and active solar systems can work under a wide variety of conditions.  Photovoltaic systems in particular tend to be much more site tolerant than most people suspect.  Nonetheless, there are a number of site factors you should consider before deciding if solar is right for you, and if so what kind of solar system you should go with.  Here are a few things to consider:

1. Proximity to the Power Grid - If your home or home site is more than half a mile from the nearest power line you may want to consider going with an off-the-grid solar system using some combination of passive and active PV systems with batteries.  Electric utilities can charge $50,000 or more to run a line to your home and battery systems with generators typically run far less than that.
2. Cost of Electricity - PV systems make particular sense in locations which have high electric rates.  In the US states such as California have very high electric rates (20 to 30 cents per kilowatt hour). 
3. Financial Incentives - Many states have become very aggressive in providing financial incentives to homeowners who wish to install PV systems. California, New York, Colorado, Florida and Illinois are among the leaders in providing incentives.  To find out if your state provides incentives go to www.ies.ncsu.edu/dsire a national database on incentive programs.
4. Shade - Shade is always a factor in the use of photovoltaic systems. If you live in a heavily wooded area you may need to determine if the trees blocking the potential site for your PV panels can be removed or cut back.  In denser neighborhoods trees may not reside within your property line and this might not be an option. In such cases, consider alternative locations for your panels.  Sometimes a set of panels mounted on a tracking system in the back yard can accomplish as much as a roof mounted system. If your site has partial shade try using one of the new portable solar meters which can tell you not only the current level of sun a position is receiving but can project what the level of sun will be for that location over the entire year.
5. Roof Direction and Pitch - While it is true that south facing roofs are better for locating solar panels, most systems still can produce strong output even if they do not face south. For example, if a roof is 45 degrees off of due south it will output only 4% less electricity than if it were placing perfectly south.  Roof angles are also fairly robust when it comes to placing panels.  Generally a 30% angle (7:12 roof pitch) is recommended.  However a south facing roof with a strong 45% pitch (12:12) will produce only 3% less electricity than one facing a perfect 30 degrees (source Sandia National Labs).
6. Snow and Leaves - The impact of snow and leaves, in contrast, is often an underrated factor in the performance of PV systems. PV panels work best when they are kept clear of debris or snow.  Even a small amount of obstruction can significantly impair their performance. This is why regular maintenance is always recommended to keep the panels clean.