How efficient are modern solar panels?

Solar energy has been all over the news lately. It feels like there’s a new “breakthrough” in solar technology (and a new use for graphene) every other week. So we had to ask the question– How good are modern solar panels?

Defining terms is a great place to start. Photovoltaic solar cells convert solar energy into electricity. These cells are placed into a protective casing that forms what’s called a “module”, as shown by the Florida Solar Energy Center.

This distinction is important for our purposes because efficiency is lost when forming cells into modules. “Efficiency” in this context refers to the amount of electricity generated per unit of solar energy that hits the panels. Solar cells with 40% efficiency don’t necessarily form modules that provide the same level of power output.

Residential applications

SunPower is one of the largest companies in the solar panel market, and they produce panels for homes, businesses, and utilities. Their residential “E-Series” panels boast 20.4% efficiency, as taken from this data sheet about the product line.

Finding this information took a bit of digging– probably because leading with “Our product is 20% efficient!” isn’t the best slogan for a marketing campaign. This efficiency is at the top of the market for residential solar panels, but it just doesn’t sound like a great deal.

Surely 20% isn’t the best we can do!

Residential solar applications are limited by cost because most people can’t afford (and don’t need) many high-tech solar panels in their back yard. Large-scale power utilities differ because there’s more money involved and a demand for higher energy output.

solar panels

Solar farms benefit from economies of scale. (Credit: Thinkstock)

Many large solar farms use solar concentration technology to increase efficiency. These plants use special mirrors or lenses to focus the sun on a tube of liquid to produce steam and drive a turbine, according to the Solar Energy Industries Association.

These concentration technologies increase efficiency to a range somewhere around 40% depending on environmental conditions and the specifics of a certain array, according to the International Energy Association. Increased performance comes with an increased cost, and these setups are extremely expensive.

Answer the question!

So the verdict: Modern solar efficiency floats around 20% for residential applications and 40% for large-scale power utility applications.

Solar power technology continues to improve just like anything else. However, cutting-edge breakthroughs can’t be implemented overnight. Breakthroughs in the lab are great, but it takes a while for the technology to reach consumer-grade hardware. Panel prices continue to drop, so do some searching if you’re interested in going green.

The Future of Solar Energy (Featuring Elon Musk)

Recent technological advances show that solar energy is on the cusp of growing in popularity into the future.

Everyone’s favorite billionaire Elon Musk wants to get into the solar power market– his electric car company Tesla recently acquired solar panel provider SolarCity for $2.3 billion. He sees the current state of consumer solar power as a huge business opportunity for the company.


Elon Musk’s solar roof product could really shake up the residential solar panel industry (Credit: Tesla)

Musk recently revealed SolarCity’s newest product, the Solar Roof. Consumers can replace their roofs with specialized shingles containing solar technology. His company claims the tiles are tough enough to withstand inclement weather, and can even be cheaper than a traditional roof.

The Solar Roof would be paired with Tesla’s Powerwall– a battery that can actually hold the electricity generated from the Solar Roof. Tesla and Solar City hope the panel-and-battery combination will help bring renewable energy to many more homes across the United States.

Will Musk’s ambition change the solar panel business forever? Only time will tell. We’re rooting for him.


Image credit: Thinkstock