California Solar roof system FAQ’s
You have questions, we have answers. Cira Energy, your solar roof system specialist.
Q: Why do other countries use more solar energy than the U.S.A.?
A: Oil is three or four times more expensive in many non American countries. Solar energy alternatives are less expensive than fossil fuels and grid power. Simple as that.
Q: What is a photovoltaic cell?
A: A photovoltaic cell, or “solar cell,” is the smallest semiconductor element that converts sunlight into electricity. Each cell is made of silicon or another semi-conductor material, like a computer chip. The silicon is treated so that it generates a flow of electricity when light shines on it.
A stack of thin layers of semiconductor materials exhibit the photoelectric effect, such a silicon or cadmium telluride. The layers contain small amounts of doping agents. The dopants give the semiconductor the ability to produce a current when exposed to light. Solar cells are solid state devices in which photons collide with atoms. This process transforms the resulting energy into electrons. These electrons flow into wires connected to the cell, thus providing electric current to the house or building.
Q: What is a solar module?
A: Solar modules, or panels, are series of solar cells wired together into strings and enclosed in self contained glass units for harsh weather protection. Solar cells are mounted into groups called modules that produce volts of current to power lights and appliances. Modules are connected together via cables, which link them to the inverter.
Q: What is a PV array?
A: A PV array is an interconnected system of PV modules that function as a single electricity producing unit. The modules are assembled as a discrete structure, with common support or mounting.
Q: How well do solar panels work in cloudy conditions?
A: A cloudy day provides sufficient diffuse light by which the panel will produce electricity. Optimum electrical production occurs with bright and sunny weather conditions. Under a light overcast, the modules might produce about half as much as under full sun. In remote, off grid applications, a PV system is connected to a battery storage system as a backup power source. In grid connected applications, the PV system works in parallel with the utility power grid. So, if electrical needs exceed the solar power output, the local utility makes up for the shortfall. Conversely, when the PV system generates more energy than the building requires, the excess power is exported to the utility grid, reversing the electrical meter.
Q: When did solar cell technology develop?
A: Modern solar cells with practical efficiency were invented in the early 1950’s and have been used to power satellites since 1959. They became popular for terrestrial applications in the mid 1970’s, mostly remote telecommunications, navigational aids and other rugged, remote industrial uses including microwave, TV, radio and cell repeater stations. They have been powering urban applications such as roadside emergency telephones, and traffic signs since the mid 1980’s.
Q: How does a residential solar electric system work?
A: Solar cells in the modules mounted on our roof or elsewhere convert sunlight directly into DC power. A component called an inverter converts this DC power into AC power that can be used in your home. The system is interconnected with your utility. During the day, if your solar system produces more electricity than your home is using, your utility will allow net metering or the crediting of your utility account for the excess power generated being returned to the grid. Your utility would provide power as usual at night and during the day when your electricity demand exceeds that produce by your solar system.
Q: Can I use photovoltaic solar to power my business?
A: PV systems can be blended into virtually every conceivable structure for commercial buildings. You will find PV systems being used outdoors for security lighting as well as in structures that serve as covers for parking lots and bus shelters, generating power at the same time.
Q: How many solar panels do I need to produce enough electricity to run my house?
A: The array size you need depends on your average electrical usage, climate, roof angle, shading problems and many other factors. To approximate the array size you need, multiply your average daily electrical demand in kilowatt hours by .25. The result is the approximate size of solar array, in kilowatts, needed to meet your electrical demand.
Q: Will I need a building permit to install a solar energy system in my home?
A: Yes. You’ll need a building permit to install and the installation must follow building and electrical codes. Some cities offer permits and no cost and others have a separate fee.
Q: Will a home solar system increase my property taxes?
A: No. Even though your property will increase in value, there is legislation that prevents your property taxes from increasing. In California, the specific legislation is Section 73 of the California Revenue and Taxation Code which provides a property tax exclusion on most types of solar systems, including home solar electric systems.
Q: Can my homeowners association stop me from installing solar electric system on my home?
A: Usually not. An HOA may try, but in many states this is not allowed. In California, the California Solar Rights Act says that homeowners associations (HOAs), can’t stop you from installing a home solar system. However, they may ask you to modify the design and /or location for aesthetic reasons as long as the changes fon’t significantly impact solar electricity production (a decrease greater than 10%) or cost more than $2,000.
Q: How long do photovoltaic (PV) systems last?
A: The basic PV module (interconnected, enclosed panel of PV cells) has no moving parts and can last more than 30 years. The best way to ensure and extend the life and effectiveness of your PV system is by having it installed and maintained properly.
Experience has shown that most problems occur because of poor or sloppy system installation. Failed connections, insufficient wire size, components not rated for DC application are the main culprits. The next most common cause of problems is the failure of the electronic parts in the balance of systems (BOS): the controller, inverter, and protection components.