The word "Photovoltaic" means light-electricity, from a combination of the Greek word for light and "volt," referring to electricity. Photovoltaic cells convert solar energy into electrical energy - or, even simpler, they turn sunlight into electricity. They range in scale from rooftop solar panels to the squares at the top of your calculator.

Photovoltaic cells, also known as solar cells, are composed of semiconductor materials (silicon is most common). Semiconductors have molecular structures that are beneficial to generating electricity. The atoms of the material have electrons that can easily be knocked out of place, which generates electricity. When light hits the cell, a certain amount of it is absorbed into the semiconductor material. This energy knocks those previously mentioned electrons loose, allowing them to move freely, which creates a flow of electrons. This flow of electrons is the electrical current that travels through wires and electrical circuits. PV cells vary widely in terms of size and capacity to supply power - all the way from your calculator to large buildings with equally large energy needs.

PV cells are often connected together to form PV modules, which can supply more energy than a single cell. Modules can also be connected to form even larger units that generate even more power called arrays. The ability to change the power level through the amount of cells allows solar technology to satisfy a large range of power needs.

PV systems are made up of multiple cells, modules, or arrays and include balance of system (BOS) components. BOS components include structures that point the cells toward the sun, components that condition the electricity produced, and may also include batteries.

PV systems can be set up in many different ways or places as long as they are stable, durable, and can withstand severe weather. Different set ups include solar panel roof mounts, ground mounts, pole mounts, and even carport mounts. Structures can either be stationary or tracking. Stationary mounting structures take into account the latitude of the site, sunlight availability, and load requirements, which means the PV array is tilted at a fixed angle based upon those items. One type of stationary mounting structure called rack mounting can be installed on either slanted roofs or on the ground, making it very versatile. Tracking structures, on the other hand, have two basic types: one-axis and two-axis. One-axis trackers usually track the sun from east to west, where two-axis types track the sun’s seasonal course between the northern and southern hemispheres, along with its daily east to west movement. Two-axis tracking systems tend to be more expensive and require more maintenance.

Photovoltaic cells produce direct current (DC) power, but most appliances and electronics require alternating current (AC) power. In order to use the DC, a PV system requires a conditioner. Power conditioners process the electricity produced by the system and make sure it is compatible with the specific demands of the load. These power conditioners can also match the converted AC to a utility’s electrical network, and have safeguards to protect both personnel and the network from any harm during repairs.

On occasion, it may not be possible to generate power through the PV system (i.e. clouds, poor weather, or nighttime). However, electricity is still needed, so it must either be stored or come from another means. Many PV systems are also connected to the power grid. When the PV system is not generating electricity for any reason, power is supplied through the grid. As an added bonus, when the PV system is generating more power than needed, the excess power can be transferred to the grid. There is a monthly fee to be connected to the grid, even if your system's production offsets the costs. In the case of a power outage, a home equipped with solar will also lose its power. Using a battery backup system is a way to store energy when being connected to the grid is not an option or is not desired. The system will be completely independent and will remain powered even if the grid goes out. However, only about 80% of the energy that enters a battery can be reclaimed, which lowers the efficiency of the system. They are also large and require periodic maintenance.

There are multiple photovoltaic cell technologies being used and in development today, including PV solar shingles and PV thin film.

For more information on PV technology, please visit: Energy.gov or NREL: National Renewable Energy Laboratory.

PV Solar Shingles

 

PV Thin Film (Photos courtesy of DOE/NREL)

Solar energy can be used for heating and cooling needs. Solar heating systems use solar energy to heat a fluid (liquid or air) and the heat is transferred to a storage system for later use. It can also be transferred directly to the interior of a building.

Solar water heaters use the sun’s thermal energy to heat water.

Solar energy can be used for cooling too, whether it is a cooling system that primarily uses a PV system to run, or through solar-powered absorption chillers. Some air conditioning units are designed specifically to run primarily on solar energy.

For more information on Solar Heating and Cooling, check out: SEIA - Solar Energy Industries Association.

Yes, just not as much. Under an overcast sky, panels will generate less electricity than they produce on a clear, sunny day.

Without a battery backup, grid-tied Solar PV Systems won’t operate when the power goes out. You can add a battery backup to your solar panels to keep the lights on during a blackout, typically battery backups costs range from $5,000- $15,000.

From the day you sign a contract with your contractor, it will take between a few weeks to a few months before your Solar PV System will be turned on. The physical installation of the solar panels typically takes anywhere from two to three days, but the time it takes to order and receive equipment, secure permits, or schedule your installation can vary. Once installed, systems will need to be inspected by the town, utility and the Connecticut Green Bank (CGB).

Solar PV Systems require very little maintenance. Rain showers will generally take care of the pollen and dust that fall on your solar panels. If your system is shaded by trees, you may have to trim and maintain branches to protect your system from falling limbs, and to minimize shading and maximize production. During extremely snowy winters, you may have to clear snow from your roof to protect your solar panels and maximize winter energy production. It is important to note that snow will melt off of a tilted system, except when there is an extremely heavy snow or prolonged, freezing temperatures. To clean snow, homeowners are cautioned to use a tool specially designed for solar panels that has a soft working surface, because metal or other hard surfaces can damage the panels.

Every home is different. Your system size will be determined by your roof space and electricity needs. The average residential Solar PV System in Connecticut is approximately 7 kW and produces approximately 8,400 kWh per year, but this could be too big or too small for your home. If you use certain technologies that are highly dependent on electricity, such as an electric car or geothermal heating and cooling system, you might require a larger system. Your contractor will work with you to design a system that meets your specific needs.

Typically, Solar PV Systems add to a property’s value, because solar costs will never go up, unlike electricity rates. Once the system has paid for itself, the electricity it generates is free!

Your solar savings depend on the size of the system you choose, your annual electrical usage, electricity rates and any financing option that you choose. To start, ask your eligible solar contractor how much electricity your new system is expected to produce on an annual basis and then compare that to how much electricity your household uses to get an idea of how much you could save. Additionally, a homeowner’s solar power savings are affected by the financing package chosen. Your contractor can also help you determine how much money you could save if electricity prices escalate over time.

Typically, a residential electricity bill is comprised of charges from a variety of supplier services, generation services, delivery services, transmission charge and distribution charge. For further reference, please go to your utilities website and search for “average bill” in the “Rates” section.

Yes. You will receive a monthly bill from your utility company as you always have, but the amount owed will differ depending on your monthly electrical usage. Depending on how your system is sized, you may accrue credits in the more productive summer months, which can be carried over and used in the less productive winter months. Even if your system entirely offsets your electrical usage, there is still a flat monthly fee required, in order to stay connected to the grid.

More and more Connecticut homeowners are going solar. Connecticut homeowners have commissioned over 100 MW of residential solar power in the last decade, that’s over 16,000 systems! Although this represents the cumulative result of over a decade of dedicated work, nearly half of those systems have come in the last two years alone. Across the state, 15 communities have seen at least 20 residential solar installations within their borders, while 52 communities have seen at least 10 installations, and 110 have seen at least five installations. As more people see their neighbors going solar, more residents are installing these systems across the state.

To take advantage of the tiered pricing structure offered through the Go Solar CT program, you’ll need to work with your pre-selected installer. However, other solar installers may be able to offer you competitive pricing and can access many of the same financing tools available through Go Solar CT. Residents in your town or city are free to work with any solar contractor they wish to do business with, but may feel more comfortable working with the installer that was competitively selected by community leaders. If for any reason you would like to work with an installer other than the one working on the outreach efforts in your community, a list of eligible contractors is available on our Find A Professional feature.

If you prefer to own your system directly and either purchase it outright or finance it via a loan, you should check with your insurance agent to find out whether your system will be covered under your existing policy. However, if you go solar using the CT Solar Lease, your system’s third-party owner will provide all insurance.

The Connecticut Green Bank (CGB) provides incentives to help Connecticut homeowners go solar. The amount of incentive provided is based on the size of your system, orientation, shading and other factors, but for an average solar installation, the incentive will be between 20% and 35% of your system’s total installed cost.

The federal government provides an investment tax credit equal to 30% of your system’s total installed cost, net of state incentives. This can be claimed on your 2014 tax return. This tax credit is set to expire in 2016.

The Connecticut Green Bank offers financing to help homeowners go solar:

• The Smart-E Loan allows you to go solar for no money down with flexible terms from 5 to 12 years and rates as low as 4.49% and no repayment penalties. Bundle solar with additional upgrades and save even more with rates as low as 2.99. You can finance over 40 energy upgrades that generate clean energy or reduce your home’s fuel or electricity use.