UNDERSTANDING SOLAR TECHNOLOGIES

Solar power’s popularity continues to grow every year, and along with that popularity, the number of solar technologies has grown. Three of the most popular solar technologies are:

Photovoltaic Solar Panels: A Proven Technology

What It Is. Photovoltaic (PV) solar panels convert sunlight to electricity. The most common types of PV solar panels are madeof crystalline silicon solar cells. The electricity produced runs through an inverter that converts the current into electricity that can power anything from a toaster to a TV to an electric car.

What to Expect. Photovoltaic solar power is an established technology, and with no moving parts, photovoltaic solar panels

offer reliable, long-term energy production. The best residential solar panels offer efficiencies of up to 18% to 19%, producing the most possible electricity per square foot. Typically, residential solar panels are roof-mounted, although ground-mounted PV systems can be installed where more land is available. Photovoltaic solar panels generally require very little maintenance, and in areas that offer net metering, excess electricity can be sent to the local grid so that you earn money from your solar investment.

When to Buy. With better efficiency than thin film solar panels, conventional crystalline silicon photovoltaic solar panels are usually the go-to solar technology because most rooftops have limited space for optimal photovoltaic solar energy produc- tion. Conventional crystalline silicon photovoltaic solar panels generate the maximum electricity possible in the space avail- able. Subsequently, this tried and true solar technology can offer the best long-term return on investment.

Thin Film Solar Panels: A Flexible Solar Solution

What It Is. Thin film photovoltaic solar panels convert sunlight to electricity like conventional PV panels, but they are typically thinner and more flexible. Generally, the semiconductor layers on thin film solar panels are only a few millionths of a meter thick, although the name “thin film” comes from their production process and not from thickness.

What to Expect. Thin film solar technology is, however, less efficient than conventional solar panels due to how they are cre- ated and the elements in use. Subsequently, thin film solar panels only reach 6% to 11% efficiency and will require more roof space to produce the same amount of electricity as conventional PV solar panels. Typically, thin film solar technology’s best use is for commercial buildings with lots of rooftop space. Installation time and costs can also be higher with thin film because more solar panels and mounting materials need to

be installed to meet the same output as conventional crystalline silicon PV solar panels.

When to Buy. If your home has a very large rooftop and requires very little electricity, this technology can make sense. Thin film solar panels also can make sense if you have special architectural needs that limit installation of conventional PV panels. Thin film solar panels can have cheaper upfront costs, but you need to do your homework to see if the long-term output actually gives you a positive return on investment in comparison to conventional PV solar panels. Paying less upfront only to get less electricity over the long-haul may not make financial sense.

Solar Thermal Systems: A Complementary Solar Option

What It Is. Solar thermal panels transfer the sun’s heat, as opposed to generating electricity. Their most popular application is to heat water. Subsequently, solar thermal is a great technology to offset energy usage for your water heater or for heating an outdoor pool. Solar thermal power can also be used to heat or cool a home, depending on the specific solar thermal technol- ogy. Since most residential heating systems use gas, this solar technology primarily offsets gas usage.

What to Expect. One popular type of solar thermal heating system uses pipes filled with water in conjunction with solar ther- mal panels. The sun’s heat is conducted through the solar thermal panels to heat the water in the pipes. There are generally two types of these solar thermal systems: active and passive systems. Active systems use pumps and controls to regulate the hot water. Passive systems do not, and they are typically only feasible in mild climates where risks from extreme temperatures (like freezing) aren’t present. There are also solar thermal heating systems that heat homes by radiating the heat from the pipes to warm the air.

When to Buy. Solar thermal heating systems can be a great complement to a photovoltaic system. Especially when your home has high gas usage, solar thermal systems can be installed to offset that usage while a PV system can be installed to offset electric usage. Combined, they may allow you to become nearly energy independent. The key component is reviewing where your home’s biggest energy demands are to figure out which type of solar system or what combination will make the most sense for you.