Solar Electricity
Solar panels produce electricity.

The pv module or panel is the heart of the solar electric system, capturing sunlight and turning it into usable electricity. Today most residential or commercial scale modules are 125-300 watts each.  We work with many different manufacturers to provide the best possible module for each project. We  prefer to use Sanyo  as they are the most efficient module made right now (but also the most expensive). All Sanyo modules sold in the US are manufactured in OR. Sanyo also offers a HIT Double module that is well suited for awnings and integrated roofs. The HIT double allows some light to pass through the panel, more info can be seen at www.sanyosolar.com. We have also recently used Evergreen and Scott modules.. 

Modules that are integrated into the building façade are called BIPV (building integrated photovoltaics) such as pv shingles or metal roof laminates manufactured by Uni-Solar (www.uni-solar.com). This can be a viable option in communities with covenants against roof mounted panels or historic districts. Building integrated solutions are becoming more available and Schott (www.us.schott.com) has developed thin film building integrated glass modules that can be incorporated into the walls or roof of a residential or commercial project.

There are 2 types of photovoltaic systems – utility intertied or stand alone (battery based).

Grid or Utility Intertied

With a grid tied pv system all of the output of the pv array is put onto the grid. In a net metered system the energy produced is usd in the house 1st and any excess is put on the grid for a credit from your utility. In a dual metered system all energy produced from the pv system is put on the grid for a premium and the customer buys all electricity needed for a lower rate. In our area most grid tied systems separately meter incoming and outgoing power. Through a partnership with NC Green Power and avoided costs from your utility you can sell electricity that you provide to the grid at 1 ½ -2 times as much as you purchase it for. Please see (www.ncgreenpower.org) and your local utility for program specifics.We typically use SMA inverters for grid tied applications (www.sma-america.com). They are produced in many sizes for different applications and have a proven track record in the field. SMA also offers options for web based data logging capabilities with remote monitoring.

Grid tied systems will not provide power to the house or business if the utility power is out. Batteries are necessary to provide power during a utility power failure.

Battery Based Systems

There are 2 types of battery based systems – grid tied with back up and stand alone. In a grid tied system with back up the critical loads wished to be backed up are run to a smaller sub panel. The batteries are sized to only back up the critical loads for a predetermined amount of time, (while the grid is down) the rest of the time they are at full charge from the grid awaiting use.In a stand alone system all loads to be used must be identified to properly size the battery bank. In this type system the batteries are the only source of energy to the loads so it must be able to back up the system for several days  when the sun is not shining.

We typically use Outback inverters (www.outbackpower.com) for battery based inverters, chargers and balance of system components. For small to medium battery systems we recommend Surrette Solar Batteries (www.surrette.com) , for larger systems Solar One Batteries (www.hupsolarone.com) or Deka (www.deka.com) are recommended. All of our solar electric systems are custom designed for each project and its particular needs, please contact us for more specifics.