SOLAR PANELS Solar panels are the most recognizable component of a solar power system. Solar panels convert sunlight into electricity through a process called the photovoltaic effect. Individual panels are made of up several solar cells, which are silicon wafers that are wired together and held in place by the backsheet, frame, and a pane of glass. A panel string is a group of (typically 4-10) panels wired together in series, which then plugs into an input on a string inverter. Your solar array refers to all the panels that make up your system. An array may contain one or more panel strings wired into a string inverter, or any number of panels individually paired with microinverters. When you’re browsing solar panels, you’ll come across two types: monocrystalline or polycrystalline, and two different sizes. Monocrystalline vs. polycrystalline Monocrystalline (mono) solar panels contain solar cells which are cut from a single source of silicon. Polycrystalline (poly) solar panels are created by melting smaller silicon fragments and blending them to create solar cells. The blended nature of poly cells makes them slightly less efficient than mono cells, which means mono panels allow you to fit more solar in a smaller space. While mono panels used to carry a higher price tag due to their increased efficiency, that is no longer the case. As companies have geared their production lines to focus on mono panels, more efficient manufacturing processes have brought the cost of mono and poly panels right in line with each other. Mono cells now represent about 75% of the panels on the market. 60 / 120-cell vs 72 / 144-cell Full-sized solar panels come in two standardized sizes: 60-cell and 120-cell panels are about 40” by 66”, give or take an inch depending on the manufacturer. 60-cell panels contain 10 rows of 6 cells each. 120-cell panels are the same size and configuration, but the cells are cut in half, which boosts panel efficiency slightly. 72-cell and 144-cell panels are about 40” by 78”, again with small variations depending on the manufacturer. 72-cell panels contain 12 rows of 6 cells each. 144-cell panels are the same form factor, but with half-cut cells. Larger solar panels are about a foot taller and 8 pounds heavier, which can make them a bit harder to carry during installation, especially if you are installing a system on your roof. Regardless, it should be easily doable with 2+ people assisting the install. Larger panels can be slightly more cost effective, however your choice often comes down to whichever one will fit best on your rooftop. If you have a tall roof, you may be able to fit two rows of 60-cell panels, whereas a smaller roof may need 72-cell panels to fit as much solar as possible into a limited space.

STEP 1:  SUNLIGHT ACTIVATES THE PANELS. Each solar panel is constructed of a layer of silicon cells, a metal frame, a glass casing surrounded by a special film, and wiring.  For maximum effect, the panels are grouped together into “arrays” (an ordered series) and placed on rooftops or in large outdoor spaces.  The solar cells, which are also referred to as photovoltaic cells, absorb sunlight during daylight hours. STEP 2:  THE CELLS PRODUCE ELECTRICAL CURRENT. Within each solar cell is a thin semiconductor wafer made from two layers of silicon. One layer is positively charged, and the other negatively charged, forming an electric field. When light energy from the sun strikes a photovoltaic solar cell, it energizes the cell and causes electrons to ‘come loose’ from atoms within the semiconductor wafer. Those loose electrons are set into motion by the electric field surrounding the wafer, and this motion creates an electrical current. STEP 3: THE ELECTRICAL ENERGY IS CONVERTED. You now have solar panels working efficiently to transform sunlight into electricity, but the electricity generated is called direct current (or DC) electricity, which is not the type of electricity that powers most homes, which is alternating current (or AC) electricity. Fortunately, DC electricity can easily be changed into AC electricity by a gadget called an inverter. In modern solar systems, these inverters can be configured as one inverter for the entire system or as individual microinverters attached behind the panels. STEP 4:  THE CONVERTED ELECTRICITY POWERS YOUR HOME. Once the solar energy has been converted from DC to AC electricity, it runs through your electrical panel and is distributed within the home to power your appliances. It works exactly the same way as the electrical power generated through the grid by your electric utility company, so nothing within the home needs to change. Since you still remain connected to your traditional power company, you can automatically draw additional electricity to supplement any solar shortages from the grid. STEP 5:  A NET METER MEASURES USAGE. On cloudy days and overnight, your solar shingles or panels may not be able to capture enough sunlight to use for energy; conversely, in the middle of the day when nobody is home, they may collect surplus energy—more than you need to operate your home. That’s why a meter is used to measure the electricity flowing in both directions—to and from your home.Your utility company will often provide credits for any surplus power you send back to the grid. This is known as net metering. CONCLUSION Now that you know the basics about solar energy, you can marvel at how today’s photovoltaic technology can capture the vast power of the sun to operate a home. It may not be rocket science—but it definitely is human ingenuity at its best.

Advantages of Solar Energy Energy independence Eliminate electric bill Profitable investment Strong government incentives Sustainable Low maintenance 1. Energy independence Traditionally, most people depend on the utility company to supply them with power. When the grid goes down, If you own a solar system with energy storage, you can keep generating power during emergencies. That peace of mind is invaluable if you live in a place with an unreliable power grid, or are regularly threatened by severe weather conditions like tornadoes and hurricanes. Utility power also restricts people who want to live off the grid, like a remote hunting cabin. Solar can generate energy where it would be too expensive to run power lines. 2. Eliminate your electric bill With a properly sized system, you can drastically reduce or completely eliminate your electric bill. Even if you extend your payback period by taking out a loan to finance your project, you still enjoy reduced electricity costs from the moment you flip the switch on your PV system. 3. (Grid-tied) solar is a profitable investment If you buy a grid-tie system (the type of system you build if you have access to power lines), you can expect your investment into solar to turn a profit in the long run. In fact, over the 25-year life of the solar panel warranty, we estimate you would earn $31,031 on energy bills after clearing the initial payback period. 4. Lucrative government incentives The investment into solar becomes even more appealing when you take government incentives into account. State and federal programs are in place to encourage people to invest in renewable energy. Claiming these can put a ton of cash back in your pocket. 5. Sustainability A sustainable energy source is one that we can use without depleting the source of power. Oil and gas are not sustainable, because we consume those resources as we use them. In contrast, solar is sustainable because the source of energy (sunlight) is constantly replenished. We can use solar energy without worrying about whether we will deplete the Earth’s natural resources for future generations. 6. Low maintenance Solar systems don’t have a lot of moving parts. As a result, they rarely break down or require maintenance to keep them running optimally.Panels are warrantied to last 25 years, but many have a much longer lifespan. It’s common to replace your inverter at least once over the life of your system. But that’s about the only scheduled maintenance you will encounter for grid-tied systems. Off-grid systems are a bit more complex because they must include batteries, which often require routine maintenance. Specifically, flooded lead-acid batteries (the cheapest option available) must be checked and refilled with water regularly to keep them functioning properly.