What Is Photovoltaic Solar Energy?
PV Panels: Image courtesy of Wikipedia
When it comes to solar energy, we all know there’s a lot of it just waiting to be harnessed. After all, the sun never stops shining. Even when it’s cloudy out, UV rays are still beaming down to Earth.
But, how do we actually turn the sun’s rays into electricity?
One word: photovoltaics.
Photovoltaic panels are the most widely used method for converting the sun’s energy into electricity.
Photovoltaic panel technology was discovered back in 1952. According to the National Renewable Energy Laboratory (NREL) scientists at Bell Telephone discovered by accident that silicon (which is found in sand) created an electric charge when it was exposed to sunlight.
Definitely a EUREKA! moment.
The first pv panels were used to power satellites, but the field quickly began to grow when people realized that we could be using them here on Earth to power everything from our calculators to our homes.
How Do Photovoltaic Panels Work?
Solar panels are made up of tiny cells that contain silicon. Here’s a good illustration from NASA:
Image courtesy of NASA
Now, sunshine contains several different particles. And the particles we’re interested in are the photons. Photons act like bowling balls inside the PV cells. They’re absorbed into the panels and begin knocking around the electrons that are contained in the atoms of the silicon.
Well, the more direct sunlight that hits the panels, the more electrons get knocked off and start moving towards the surface of the panel. The energy of the photon is transferred to the moving electron, which creates an electric current. The more movement, the more electricity is generated.
The conductive wires within the panels draw off the excess electricity, and transfer it for use in our homes.
It’s All In The Angles…
The problem with solar power photovoltaic panels is they’re not super efficient, at least right now.
According to the U.S. Department of Energy, most solar pv panels are only about 20% efficient. This is because much of the light that falls on the panels is lost before it can ever be converted into electricity. Some of the photons coming from the sun don’t even get into the panel at all if the angle is wrong. Others will enter the cell, but not have enough energy to knock around the electrons; all they can do is generate heat.
The angle and orientation of the photovoltaic panels is also vital. If a panel is off by even a few degrees, its electrical output can drop by as much as 50%. It’s a delicate science that you’ve got to get right during the installation.
As you can see, a lot of potential energy is lost with pv panels.
The good news here is that the efficiency of solar panels is slowly improving as new technologies come out. Some companies are claiming they’ve produced panels with up to 40% efficiency, which is a dramatic increase over their competitors.
And if you’re in a good spot, with good installation, solar power can make a dramatic difference in your home’s energy bills.
Won’t Solar Panels Break?
Image courtesy of Wikipedia
The good news here is that solar pv panels are pretty durable. They can withstand rain and searing heat and hail and thunderstorms.
Most pv panels are warrantied for a 25-year lifespan. But, it’s important to realize that they need to be kept clean. When dirt and grim settles onto the glass it blocks sunlight from coming in. So, panels have to be cleaned now and then with soap and water to keep efficiency at its highest.
They’re also going to degrade slightly over time. According to Home Power Magazine, most companies say that over their lifetime, the photovoltaic panels will lose about 20% of their efficiency.
How Many Solar Panels Do I Need To Power My Home?
This is actually a pretty tough question, and there are a lot of factors you have to consider.
You first have to decide if you want your solar panels to fully replace your regular power, or if you just want to supplement your regular power.
You also need to figure out how much power your home is consuming per day.
Lastly, you have to look at your location. You may want solar power to completely replace your reliance on regular power but if you live in Seattle, where the sun hardly ever shines, this isn’t going to be an option.
On the other hand, if you live in sunny Arizona you could easily use solar pv panels to power your home
You can look at this handy map from the Advanced Energy Group to see if your neck of the woods would be a good fit for solar power:
Image courtesy Advanced Energy Group
How Much Do Solar PV Panels Cost?
The good news is that because they’re being used more and more, solar photovoltaic panels are slowly going down in price. But, they’re still far from cheap.
And, how long it takes to recoup your investment depends entirely on the factors we mentioned above: how much energy you use, how much you want to depend on the panels for your energy needs, and where you live.
If you’d like a rough ball park estimate of how much you would need to spend on solar pv panes to power your home (or even to supplement your power), you can use the solar cost calculator at FindSolar.org.
Want a quick example?
Well, if you live in a small home in Michigan and want to use solar panels to power 100% of your home’s energy needs, you’re going to spend about $20,000 on solar panels, and it’s going to take about 20 years to recoup your investment.
But as you can see on the sun map, Michigan doesn’t get a whole lot of juice. So if you live in Texas, Arizona, or New Mexico, it’s going to take you a lot less time, and money, to convert to solar.
So, what’s the final word?
Well, more and more homeowners are jumping into the world of solar. The panels are getting more affordable each year and with most states, and the federal government, offering healthy tax breaks for investing in renewable energy, it’s becoming even cheaper to use solar power in your home.