What are the Most Efficient Solar Panels?


One of the most commonly asked questions when people consider installing residential solar is what are the most efficient solar panels?

It’s a question that makes sense to ask — you’re putting down a lot of money up front to install these panels, so you want to get your money’s worth. However, it’s the wrong question to ask. That’s because you shouldn’t base your solar panel purchase on efficiency, but on value.

What does ‘Most Efficient Solar Panels’ Mean?

Solar cells are linked together in a panel, converting sunlight into electricity through photovoltaic materials like silicon. When sunlight hits the panels, that light’s energy is absorbed, and the electrons in the material are captured to produce electric currents that you use to power your home.

Solar cell efficiency is key, and the most efficient solar cells are developed for places like NASA. For example, Soitec & Fraunhofer Institute produces solar cells that are 46 percent efficient. Compare that to SunPower, which hold the commercial solar module efficiency record at 21.5 percent.

It’s a big difference in efficiency, but for a reason! You can’t even buy Soitec & Fraunhofer’s cells, because they’re not available for residential use. They’re insanely expensive and have applications beyond just your rooftop. Yes, they hold the overall solar photovoltaic module efficiency record, but you can’t use them. It’s not about the efficiency rate, but about the value of the panels.

Get the Best Value

The thing is, it’s not about which solar panels are the most efficient, but which are the best value for your money. The rates of efficiency between solar panels you can actually install on your roof don’t range by huge percentage points, so it really comes down to your budget and what you feel comfortable spending.

If your roof has room for 10 solar panels, and your options are panels that are slightly more efficient but twice the price of cheaper solar panels, you will save a lot more by going with the cheaper panels. Of course, you may be concerned the cheaper panels will be less effective. That’s why it’s best to contact a solar installer and have them help you with the research.

The bottom line is that solar panel efficiency is not what you should base your panel purchasing decision on. Rather, you should focus on the overall cost of the panels, and compare energy efficiency rates between the panels you can buy.

Looking for Efficient Solar Panels

Start by looking up solar installers in your area and getting a quote by entering your zip code below.

Ask them which solar panels they would install on the roof of their home, then price search all the possible panels. SunPower, First Solar, Q-Cells, Sanyo Grape Solar, and Canadian Solar are all respectable solar power companies that make efficient solar panels ranging between 16 and 21 percent efficiency. These are also solar panels that won’t break the bank. You won’t be able to buy solar panels designed for NASA satellites, so don’t bother trying (and you won’t want those, either!).

Keep in mind that solar continue to grow exponentially, and the technology is improving rapidly. If you’re planning out solar power installation over the course of a year or more, check in on companies to see if they’ve outdone themselves in terms of a solar panel that’s more efficient than the last.

Ultimately, the solar panels you buy are going to provide dividends for years to come, because they’ll produce renewable energy that allows you to save huge on your utility bills.

Common assumptions about solar panel efficiency

The first mistake homeowners and business-owners make is to assume that solar technology has changed dramatically over the last 10 years. In reality, while some efficiency gains have been realized, the major reason that panel prices have decreased has to do more with production efficiency, not real gains in power output for the panels themselves.

The technology for converting solar energy into power hasn’t changed that much over the last decade, but there are some things you should know about efficiency for certain situations.

Question 2 after ‘how efficient are solar panels’: should I wait for better solar technology to come out before going solar?

The short answer: No!

The idea that current technology isn’t efficient enough may stem from the news bombarding us with stories about some new solar cell that exceed 40% efficiency. Unfortunately this kind of news can lull people into thinking we’re due for a new breakthrough, and that it’s better to wait rather than go solar today.

Most people don’t understand that the current efficiency of solar panels is remarkable, and that we’ve exceeded biological systems by a factor of 3 already.

The best treatise on the topic is a UCSD blog post titled “Don’t be a PV efficiency Snob” that opens with the following:

So 15% is far too low for you? Perhaps you reason that laboratory prototypes and expensive spacecraft applications can get 40%-plus results, so let’s not take the plunge prematurely, given the abysmal 15%.

Perhaps you drive a car. Maybe you’ll stop when you realize that it converts thermal energy from burning gasoline into locomotive power at an efficiency around 15–25% (and this on a finite resource). We should wait for better.

Electric cars deliver battery-stored energy to the wheels at something like 85% efficiency. Now we’re talking. But the charging process imposes another 85% efficiency, and the real kicker is that the fossil fuel (or nuclear) plant supplying the electrical power is only 35% efficient for a net fossil-to-wheels efficiency around 25% (same ballpark as the gasoline car).

If you’re low on energy, you might consider eating. But on second thought, our metabolic efficiency of converting chemical energy into mechanical output is similar to that of a car, so why bother? Turn up your nose.

Read More: Don’t be a PV efficiency Snob

Where high efficiency solar panels matter

If you’re planning to hire a solar contractor to install solar panels for your home or business, the only thing you need to understand about solar panel efficiency is that there are two general types of panels: high-efficiency and standard efficiency. It surprises most people to learn that more efficient panels are actually smaller in size than standard panels (because they produce more power for a give unit of area).

This can be a major advantage when roof space is a consideration for the size of the install. Putting together an array of solar panels where each is 30% smaller can significantly impact the area taken up by the array. The most commonly-known high-efficiency solar panel is made by Sharp, and it has a stylish looking smooth black exterior that some people find more appealing than standard panels.

The costs of solar panel efficiency

It’s really important to understand that yes, you will be paying more for major efficiency gains. In certain situations, buying the most efficient panels available may make sense, but it won’t necessarily save you money.

For example, most systems built with Sharp high-efficiency panels will simply be smaller. This has to do with the fact that the overall system is designed to meet the needs of the home or business in question. In other words, the system is designed to produce enough energy to cover a certain amount of power demand. Once that demand is met there really isn’t much need to add additional panels (unless you get some major tax credit for sending power back to the grid, and you can afford to do so!).

The bottom line here is that you will pay more for higher-efficiency solar panels that take up less space. You will pay less for lower (but not low!) efficiency panels. But both systems will at the end of the day produce the same amount of energy for your home or business!

So what are the most efficient solar panels available?

As stated above, the most efficient solar panels are made by Sharp solar and Sunpower, and these panels are available for solar installations on both homes and business. The availability of these panels depends on the panel brands your local solar installer carries and what’s generally available in your area.

Depending on your installer, you may have the option to purchase, lease, or buy, other middle of the road solar panels with various levels of efficiency. This is something that must be evaluated on a case by case basis and really depends on the requirements of the system.

We’d always suggest talking to a local solar installer to get a true professional’s opinion. They can tell you whether the additional power output produced by more expensive panels are really going to pay off and make sense in your particular case.

Why are some solar panels more efficient than others?

Great question. Solar panels are made up of a number of materials, and like anything else their ability to function properly is largely due to the quality of materials used in production as well as the quality of manufacturing.

Higher efficiency panels may use more expensive materials that are better suited to converting solar energy into the DC current that can power our homes. Some manufacturers (like Sharp) have a reputation for producing quality products.

Where can I find more information about solar panel efficiency?

If you’re looking to purchase a solar array for your home or business the best course of action may be to discuss options with a local solar installer

If you’re just doing research, there are numerous places on the internet with detailed information specific panels, manufacturers, and their efficiency levels. Often the best place to look is at the solar company’s price book that lists the standard solar panels they offer with all the specifications. Visiting Sharp’s website, for example, can tell you a lot more about high-efficiency panels than most internet resources.

The bottom line: today’s most efficient solar panels are efficient enough to save you money!

Image Credit: Albert Bridge via geograph under a Creative Commons license

  • by Nadia Osman
  • |
  • April 1, 2015
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