Solar Electric Equipment
Thermal Solar Systems
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:
- 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
- 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
- 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
national database on incentive programs.
- 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.
- 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).
- 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.
|We have been getting a lot of questions
lately as to the costs for a solar
PV system and how soon PV systems pay for themselves. It is not always
easy to tell given the host of federal and state regulations. To
provide some clarity on these cost issues we have updated our section on
Typical Costs to reflect the
latest prices and have added a new article on
Calculating the Payback for
a solar PV System. Take a look!
|PV Demand Growing -
Global photovoltaic demand continues to soar in 2010 and is currently projected to double over the rate of installations
year last year, according to Solarbuzz®, a solar energy market research company.
Solarbuzz has raised its 2010 market size to 15.2 GW, which compares with a revised 7.5 GW in 2009.