As the cost of solar has plummeted in recent years alongside major improvements in technical efficiencies and manufacturing quality, many homeowners across the U.S. are starting to look at solar as a viable alternative energy solution. And as solar enters mainstream energy markets, the big question is, “how do solar panels work?” In this article we’ll break down exactly how solar panels produce energy for your home and how pragmatic going solar really is in 2017.
How do solar panels work, step by step?
- Solar panels absorb sunlight with photovoltaic cells, generating direct current (DC) energy
- Solar inverters convert the DC electricity to usable alternating current (AC) energy
- AC energy flows through the home’s electrical panel and is distributed accordingly
- Your home’s electric meter sends the excess unused solar energy to the grid in exchange for net metering bill credits
The overview on how solar panels work
A standard solar panel consists of a layer of silicon cells, a metal frame, a glass casing and various wiring to allow current to flow from the silicon cells. Silicon (atomic #14 on the periodic table) is a nonmetal with conductive properties that allow it to absorb and convert sunlight into electricity. When light interacts with a silicon cell, it causes electrons to be set into motion, which initiates a flow of electric current. This is known as the “photovoltaic effect,” and it describes the general functionality of solar panel technology.
In the general photovoltaic process, as described in the step by step breakdown above, the silicon cell absorbs and converts sunlight into direct current (DC) electricity that is then turned into alternating current (AC) electricity with the help of a solar inverter. That AC energy is then distributed through your home’s electrical panel and becomes readily available for devices and appliances to use.
In addition to silicon solar cells, a typical solar panel includes a glass casing that offers durability and protection for the silicon PV cells. Under the glass exterior, the panel has a layer for insulation and a protective back sheet, which protects against heat dissipation and humidity inside the panel. The insulation is important because increases in temperature will lead to a decreases in efficiency, resulting in a lower solar panel performance.
Solar panels have an anti-reflective coating that increases sunlight absorption and allows the silicon cells to receive maximum sunlight exposure. Silicon solar cells are generally manufactured in two cell formations: monocrystalline or polycrystalline. Monocrystalline cells are made up of a single silicon crystal, whereas polycrystalline cells are made up of fragments or shards of silicon. Mono formats provide more room for electrons to move around and thus offer a higher efficiency solar technology than polycrystalline, though they are typically more expensive.
How does grid connection work with solar panels?
Though electricity generation with solar panels may make sense to most people, there’s still a lot of general confusion about how the grid factors into the home solar process. Any home that is connected to the electrical grid will have something called a utility meter that your energy provider uses to measure and supply power to your home. When you install solar panels on your roof or on a ground mount on your property, they are eventually connected to your home’s utility meter. The production of your solar system can actually be accessed and measured by this meter.
Most homeowners in the U.S. have access to net metering, a major solar incentive that significantly improves the economics of solar. If you have net metering, you can send power to the grid when your solar system is overproducing (like during the day in sunny summer months) in exchange for credits on your electric bill. Then, during hours of low electricity production (such as nighttime or overcast days), you can use your credits to draw extra energy from the grid and meet your household electricity demand. In a sense, net metering offers a free storage solution to property owners who go solar, making solar an all-in-one energy solution.
Considering that the most common aversion that people have to going solar is the issue of what to do at night or on days with bad weather, a free storage solution as efficient as net metering is a game changer in terms of solar adoption. These types of incentives, plus the fact that the cost of solar has dropped by almost 70 percent in the past decade, can explain why the solar industry is growing at an exponential rate in the United States.
How homeowners can guarantee major solar savings
For those starting to consider a solar panel array for their home, there are a number of factors to consider including financing, equipment, installer selection and warranties. In addition to all of these topics is the question of how to make sure you can get a good deal and generate strong energy savings in the long run. For people new to the solar shopping process, we have some key points of advice that will guarantee you get the best deal on your solar array.
Three tips for solar shoppers
Homeowners who get multiple quotes save 10% or more
As with any big ticket purchase, shopping for a solar panel installation takes a lot of research and consideration, including a thorough review of the companies in your area. A recent report by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) recommended that consumers compare as many solar options as possible to avoid paying inflated prices offered by the large installers in the solar industry.
To find the smaller contractors that typically offer lower prices, you’ll need to use an installer network like EnergySage. You can receive free quotes from vetted installers local to you when you register your property on our Solar Marketplace – homeowners who get 3 or more quotes can save thousands on their solar panel installation.
The biggest installers typically don’t offer the best price
The bigger isn’t always better mantra is one of the main reasons we strongly encourage homeowners to consider all of their solar options, not just the brands large enough to pay for the most advertising. A recent report by the U.S. government found that large installers are $2,000 to $5,000 more expensive than small solar companies. If you have offers from some of the big installers in solar, make sure you compare those bids with quotes from local installers to ensure you don’t overpay for solar.
Comparing all your equipment options is just as important
National-scale installers don’t just offer higher prices – they also tend to have fewer solar equipment options, which can have a significant impact on your system’s electricity production. By collecting a diverse array of solar bids, you can compare costs and savings based on the different equipment packages available to you.
There are multiple variables to consider when seeking out the best solar panels on the market. While certain panels will have higher efficiency ratings than others, investing in top-of-the-line solar equipment doesn’t always result in higher savings. The only way to find the “sweet spot” for your property is to evaluate quotes with varying equipment and financing offers.
For any homeowner in the early stage of shopping for solar that would just like a ballpark estimate for an installation, try our Solar Calculator that offers up front cost and long term savings estimates based on your location and roof type. For those looking to get quotes from local contractors today, check out our quote comparison platform.