All About Solar Panels
Most people are familiar with solar panels in one form or another. Whether you’ve seen solar panels on a neighbor’s house, set up near a construction site or powering one of those little solar toys they are all doing the same thing. The panels are creating electricity from the sun itself without relying on any additional fuel. Solar panels can help meet energy needs and lower utility bills. They’re a cleaner form of energy than power produced by burning coal, oil or natural gas. Solar panels are simple to use and they continue become more accessible as the technology becomes more affordable.
How They Work
Solar cells work by collecting energy from sunlight and directing it through a set of wires for use elsewhere. They rely on complex reactions to continuously generate power, but are highly reliable and designed to function for 20 years or more.
A solar cell works by taking photons, or particles of light from the sun, and using them to knock electrons free from the atoms built into the cells to generate a flow of electrons or electrical current. In order for a cell to work, there needs to be two layers of semi-conducting material, one with a positive charge and one with a negative charge.
After the photon breaks electrons free from the atoms within the cells, the electrons are pulled aside by conductive plates mounted at either side of the cell. The electrons are transferred to wires where they can be fed into inverters and used as an AC power source for your home.
Why Invest in Solar Panels?
It makes sense to invest in solar panels because they produce energy consistently for up to 25 or 30 years without needing fuel. The initial expense to buy a 5 or 10 Kwh system might seem high at first, but that price is more reasonable when you consider that it offers value for between 20 and 30 years after the purchase.
Think about buying solar panels like you would when buying a car. Sure $20,000 sounds like a lot to spend on a vehicle, but as long as you own the vehicle for 10 years you are really only spend $2,000 a year for transportation. $30,000 might seem like a lot initially, but if the panels are saving you a few thousand on your utility bills each year the price makes sense.
Solar Panel Types
There are four main types of solar panels available to commercial and residential customers today. Monocrystalline, polycrystalline, thin-film and string ribbon. Each is made of silicon, but each is constructed differently.
Monocrystalline Solar Panels
Monocrystalline solar panels are constructed from highly pure silicon wafers. Large silicon ingots that are cylindrical in shape are cut flat on four sides and then sliced into thin wafers. The wafers are modified to function as working solar panels when sunlight hits them.
Monocrystalline panels are the most efficient of the most popular solar panels available. These panels offer between 15 and 21 percent efficiency. Since the panels are more efficient, a home can be powered by a smaller array of them, saving roof space. Monocrystalline cells also have the longest lifespan and are commonly warrantied for 25 years by suppliers. In low light situations the panels are known for producing more power than polycrystalline panels.
Although monocrystalline panels have a lot to offer, they’re the most expensive option commonly sold.
Polycrystalline Solar Panels
Polycrystalline solar panels are made up of little square wafers that result from melted silicon poured into molds. They are a more affordable option compared to monocrystalline and are becoming a more popular option for that reason.
Polycrystalline solar panels are more affordable than monocrystalline. They are also more efficient to create since less silicon waste is produced. Polycrystalline panels aren’t as efficient as monocrystalline with efficiency levels of between 13 and 16% so more roof space is needed to meet the same power needs. Polycrystalline panels are less tolerant of high temperatures which can shorten the panels lifespan. Polycrystalline panels also have a less appealing speckled look compared to the highly uniform monocrystalline panels.
Thin-Film Solar Panels
To create thin-film solar panels a photovoltaic material is melted onto a substrate in one or multiple thin layers. Silicon, copper and cadmium are all used for this application. Unlike the crystalline-based solar panels mentioned above, thin-film panels have a flat black appearance. They aren’t affected as much by heat and are somewhat flexible making shapes other than flat possible. The panels are simple to mass produce and highly affordable.
Thin-film solar panels aren’t as efficient, operating at between 7 and 13% efficiency in standard conditions and requiring a large amount of space to produce energy to power a household. This keeps the panels from being used for most residential needs.
String Ribbon Solar Panels
String ribbon solar panels are another type of polycrystalline panel, they are just manufactured differently. During their creation a vat of molten silicon is fed special wire that’s designed not to melt. As the wire moves through the silicon it’s coated, creating incredibly thin layers. The wire-silicon mix is used to fashion economical solar panels. String ribbon panels are some of the most affordable available today because they use about half of the silicon that monocrystalline panels use.
While affordable, string ribbon panels are only as efficient as the lowest grade polycrystalline panels at about 13 to 14% and they take up the highest amount of roof space when used.
Solar Rooftop Mounts
For residential installations rooftop mounts are a very common option. They’re a desirable option because the panels are kept up out of the way, preserving yard space and keeping the panels mostly out of view. Some of the mounts hold the panels flat to the rooftop, while others are adjustable to put them at different angles. The adjustable mounts are more expensive, but improve efficiency levels as the sun changes its height throughout the year.
Rooftop mounts tend to cost more money for installation because it’s more difficult to install panels up on a roof than it is on the ground.
Solar Pole Mounts
For a simpler and easier to maintain solar array, a pole mounted system is worth looking at. It consists of a durable rack positioned on top of a pole. Most pole mounts can hold between four and sixteen panels. They’re advantageous to use because they don’t take up roof space and they don’t take up as much ground space as a ground mount. They lift panels up high enough to get around some smaller trees. Pole mount systems are more expensive than roof mounts, but often more affordable to install. Solar tracking systems are also simplest to implement on pole mounted units.
Solar Ground Mounts
Solar ground mounts are static frames built on top of flat land. The frames are low to the ground making them simple to reach, adjust and maintain. Ground mounts come in a range of sizes from small to large to fit every solar power need. They’re very popular with energy companies and large-scale commercial operations, but not very common for residential customers. That’s because the mounts take up a significant amount of land space and can be considered an eyesore. If you have enough property available, ground mounts are a good affordable way to mount solar panels, just be sure that no trees are near the installation location, or they can impede performance.
Solar inverters are special components that take the DC power produced by solar panels and convert that into AC power that can be used by household appliances. For most solar applications an inverter is a vital piece of the puzzle. There are two different types of solar inverters that most people rely on, string inverters and microinverters.
String inverters are the more affordable power-exchange solution because ten or more panels can be connected to a single inverter. The only problem with string inverters is they force all the connected solar panels to perform at the level of the weakest panel. If a single panel is sitting in the shade, every panel on that string will perform like it’s shaded. Also, if a single string inverter fails, every panel connected to the system stops providing power to your home.
Microinverters are tiny inverters that are mounted under or around each of the solar panels in your system. There is a single inverter for each panel, which is why they are more expensive than string inverters. The benefit of using these inverters is that they convert DC to AC more efficiently, and if a few panels are shaded the rest of the array will continue to perform at its optimal level.