Knowing how solar panels work is just as important as making them work for you.
That’s why we’ll divide this post into two parts: 1) An Explanation of how solar panels work and 2) A Checklist for getting the most out of your solar panels.
How Solar Panels Work
The sun produces kilowatt-hours that will hit the solar panels on your roof. The sun’s height, clouds, seasonality, and even the obliquity of the earth will affect the sun’s emission of light.
Roughly 17 percent of the light that hits a solar panel will be converted into actual energy for the home. However, there is slight variation in residential rooftop solar panel efficiency, and a solar panel efficiency rating can help you determine what works best for your needs as a homeowner.
The sun’s position in the sky affects how well your solar panels will work. Given that the sun isn’t elevated as high in the winter, solar panels will produce less energy for your home in the wintertime, albeit still enough to power the average-sized home.
If power goes out on the grid, it goes out on solar too. However, that’s what battery back up is for, and some solar vendors provide that service for free.
1. The Module and the Power Grid
There are 4 parts to every home’s solar product: a module (which is a fancy term for your solar panels), the solar cells, an inverter, and a power grid.
The module connects to the inverter, which then connects to the power grid.
The power grid measures the solar panels’ production, and each panel will provide roughly 250-310 watts.
The panels themselves permit photons emitted from the sun’s light to release electrons from their atomic bonds, therein producing electricity. As the
2. The PV Cells of the Solar Panels
The photovoltaic cells of the solar panels (interchangeable with module) are where powering your home through solar energy begins. Oftentimes referred to as “PV cells,” these semiconductors change sunlight into direct current (DC) energy. Once this process is complete, the inverter comes into play.
In each panel, there are roughly 60 PV cells.
3. The Inverter: Transduce DC into AC
As its name implies, the inverter changes direct current picked up from the photovoltaic cells into an alternating current.
Without the inverter’s process, the energy taken from the sun could not be funneled into a commercial electrical grid.
When talking to solar consultants, be sure to ask about the efficiency of their inverters. Although some power will always be lost in the conversion process, inverters with 95% energy retention in the conversion process are what you should aim for.
There must be at least 5 panels per roof section to get the needed voltage necessary to make the inverter of a home to work.
A micro-inverter, like Solar Edge, is used much less frequently than the typical inverter (5% of the time) and it manages each solar panel individually. Micro-inverters convert direct current to alternating current immediately, and on a panel-by-panel basis.
The benefit to using these inverters is that when there’s a lot of shade on a property around a home, the panels can transduce a greater amount of sunlight. This option also works better for rooftops affording limited space for solar panels.
Additionally, if a roof is very small, a micro-inverter will sometimes work better than an SMA. Do note, however, that a micro-inverter is not a string inverter.
While a typical inverter like an SMA will be more efficient at the peak sunlight hours of any given day, a Solar Edge micro-inverter option will make energy harnessing from the panels more consistent throughout the day despite having a lower peak energy production.
The opti-track functionality of these inverters makes the panel work most efficiently of them all the master panel that controls the other panels. It shifts to see which panel in the string is the most efficient.
A power optimizer on the other hand stands in lieu of a junction box. A typical junction box is behind the panel with 2 cords—one cord for positive and one cord for negative.
On average, string Inverters typically cost a bit less per peak watt. They are also less costly to install because they take a total input from many different panels, and do not need to be installed right next to the solar array itself.
The idea of a string inverter is that the solar panels themselves are only as strong as the weakest link.
SMA and Solar Edge are both battery back up capable inverters.
And, speaking of battery back up…
4. Solar Panels Battery and Battery Back Up
With battery back up, you can still have the electricity in your home work when the power goes out.
Batteries are the next frontier in solar panel innovation, as they are the reason solar costs aren’t driven down far more than they already are.
A battery goes between the module and the inverter.
There are numerous battery back up options available that serve as essential staples to any household emergency preparedness kit.
The Goal Zero Yeti, for instance, is battery back up you can hook up to your panels in the event you need a secure power supply. The Yeti won’t run your entire house, but it will provide a power supply for a few appliances and a refrigerator. You will need a plug in to make the Yeti work.
That’s what makes it a favorite for camping trips and other small power needs. You can also plug the Goal Zero Yeti into an SMA inverter.
Although many solar prospects want to have something that will power their entire house in the event of a power outage, one has to also consider that the average power outage doesn’t last more than a few hours, so the ability to power a few appliances is all one really needs.
The Tesla Power Walls are a more expensive (and non-portable) battery back up option, but these can store and provide a much greater amount of power. Tesla is the best solar battery option in terms of both technology and the affordability of the technology.
The battery back up discussion creates a fork in the path of solar for many prospects—going with a grid-tied or off-grid solar solution. A hybrid solar solution lets the battery store solar energy for later use.
Do remember, however, that if power goes out on the grid, it goes out on solar as well. Off-the grid terrain does have a backup generator via propane and gasoline. If you’re already connected to the grid, don’t go off it—it’s just a lot more costly.
A Checklist for Getting the Most Out of Your Solar Panels
As is the case with most technology, solar panels’ usability hinges on its owners’ ability to make the most of their investment.
When compounded with other cost-effective forms of smart energy consumption, solar panels can deliver an even stronger ROI than anticipated by most homeowners.
1. Know Your Energy Production and Consumption
If you feel your energy consumption is a little high, do know that going solar can virtually eliminate you from Rocky Mountain Power’s highest paying energy block, which drives up the rates Utah citizens pay on their energy bills.
This means that tiered energy consumption will help you gauge how you stack up against the rest of homeowners in terms of energy usage, but it will also incentivize you to use less power as the rates become higher the more energy you consume.
Additionally, you can put solar panels on your roof and scale back on energy consumption alike when you capitalize on these reduced energy consumption incentives.
Understanding your energy production will help you contend with the costs of net metering, too. Net metering is a way of measuring what you consume and what you push back on to the grid, and at what rate.
Currently, Utah’s net metering still allows a 1:1 credit for the energy leftover from solar homeowners that they push back on to the grid.
2. A Decent Credit Score and Homeownership
Among many misconceptions in the solar industry is the belief that going solar is free. However, going solar is better than free: It provides a return on investment.
Now, with that investment comes a requisite credit score. You can go solar for zero down, but you will need financing.
A Credit score in the high 600s is usually the minimum requirement, but this will vary from solar provider to solar provider, and from financing party to financing party.
Adding solar panels to your home literally changes the energy infrastructure of your residence. This makes homeownership a requirement of residential solar.
Although HOAs and apartment complexes have gone solar to reduce their tenants’ energy bills, the decision an individual makes to go solar hinges on him or her owning the home on which they want to install solar panels.
3. A Solar Panel Provider with Great Warranty Options
The hard truth most residential solar providers won’t tell you is that all electrical equipment, no matter how well engineered or produced, will become less efficient over time. The decrease in efficiency is not drastic, but it does occur.
Be sure to find a solar panel provider that offers at least a 10-year service warranty on the panels for your home. Generally speaking, any component that goes toward solar install should be part of the 10-year service warranty.
Additionally, a 25-year production warranty will ensure you get the most out of a solar solution once it’s installed.
Do note that even though the system is warrantied for 25 years, it should run much longer than that. If the panels are at lower than 85% production capabilities under 25 years, pick a reputable solar vendor who will replace them.
4. A Tax Credit, Where Applicable
The solar investment tax credit (ITC) is a federal tax credit that incentivizes homeowners to rely on renewable energy consumption methods.
5. Solar Panel Racking Options
A solar-racking system is a crucial component of how your panels will sit atop your roof, or the ground.
Rooftop racking for homeowners’ residences typically requires a rail-mounting system or a shared rail system for the solar panels to sit in.
Of these two options, a rail-mounting structure works better in areas with lots of wind or inclement weather.
A shared rail system has quicker installation and works on both tile and composite rooftops. Ground mount options are also possibilities for homeowners, but they do cost more.
Ballasted mount systems work well with low wind areas, too, but can cost much more to implement.
6. Understand the Solar Kilowatt Hours Lingo
Sometimes electricians themselves fumble this term when trying to explain solar energy production, but the concept of kilowatt-hours is not a difficult concept once you wrap your mind around it.
A kilowatt-hour is the number of kilowatts produced per hour. So, if a 30-watt light bulb runs for an hour, it’s 30 kilowatt-hours.
This matters when selecting your solar panels, because the average homeowner uses roughly 850-900 kilowatt hours per month to power their homes.
If you take that average number of kilowatt-hours a home produces each month (850) and divide by the number of kilowatt-hours a single solar panel produces over the duration of a month, (32kwh), then you get a 26-panel installation (with a remainder of half a panel).
With 26 panels multiplied by 250 watts = a 6,500 watt system (6.5 kw).
7. Understand Your Solar Provider Options
There are 3 things that determine how efficiently your solar panels will run: 1) The size of the solar panels (or area each array covers atop your home), the efficiency of the solar cells that convert the sunlight to direct current, and the amount of sunlight the solar panels get.
The typical size of a solar panel is roughly 40 inches by 65 inches. And the PV cells
8. Know Your Types of Solar Panels
When it comes to the types of solar panels available to homeowners, there are numerous options available.
However, for the time being don’t opt-in to solar shingles. They may seem like a great idea until you look at the price tag. Tesla does currently sell solar shingles, but they just aren’t viable for those looking for ROI on their solar solutions as of right now.
Also, avoid thin film solar shingles. Not only do these tinseled options have bad efficiency, they also break easily.
But panels are just as important as the system by which you use them. That’s why it’s worth understanding grid-tied vs. non-grid-tied solar options.
With net metering and a grid-tied system, power goes to two places: either your home or to the grid.