Has solar energy evolved?

Installed solar energy capacity in the U.S. is growing dramatically, with numerous record-shattering years in a row. There is now enough installed solar energy to power over 4.6 million U.S. homes and a new solar project is installed every two minutes. Meanwhile, the cost of solar has fallen significantly, helping to fuel this unprecedented growth.

Solar energy (r)evolution

Since 1998, the cost of residential and commercial solar photovoltaic (PV) systems has fallen every year by an average of 6 to 8 percent, according to the National Renewable Energy Laboratory. Since 2006, the installed cost of solar energy has dropped more than 73%. Once a market dominated by environmental motives, many people are now installing solar PV to save money.

“Solar has migrated from being a niche, environmentally-driven product to one where financial savings are driving the interest in solar,” explains Vikram Aggarwal, founder and CEO of EnergySage, the so-called “Expedia of solar”. “Many consumers have misconceptions that solar is very expensive and may not pay off. We are working to help consumers realize that solar can actually be very financially rewarding.”

The solar industry has changed significantly, but how much has the technology changed? Given that solar PV is a relatively new technology, a lot of new and promising products have come to the market. These are some of the top trends.

Solar panel efficiency climbs

Solar panels atop homes
Solar system efficiency also helps homeowners save more money on their electricity bills, making solar energy a more appealing option. Image Credit: Neil Mitchell / Shutterstock

There are now mass-produced solar cells on the market by SolarCity with greater than 22% efficiency, with other promising technologies being developed in laboratories. Efficiency matters because it allows more energy to be generated in a smaller area. Urban dwellings in particular have limited roof space, and quite possibly little or no room on the ground for solar panels.

In 2015 for homes with solar PV systems, solar was able to generate nearly 85% of a household’s electricity, according to EnergySage. This is made possible largely by more efficient panels, although home energy efficiency measures do help the cause.

Solar system efficiency also helps homeowners save more money on their electricity bills, making solar energy a more appealing option. The average 7.9 kW system produces $2,000 in electricity every year. The more clean energy the system can produce, the larger the potential cost savings.

Technologies make solar panels more shade-tolerant


I used to watch the output of my solar system plummet in the late afternoon as the shade from a chimney appeared across the solar array. Although only several inches of the 6-panel array was actually shaded, the output would drop to a mere trickle. This is because this solar system uses one centralized inverter. Like the old saying goes, a chain is only as strong as its weakest link.

Solar systems need inverters to convert solar electricity into AC current for use in our homes. Many solar systems have one central inverter and are wired in such a way that the “Christmas tree light effect”  allows one underperforming panel to disproportionately impact the overall system output.

  • The benefits of microinverters – Microinverters however allow each solar panel to work independently, eliminating the impact of the weakest link. This techlology replaces the central inverter and boosts overall production, especially when the solar system is partially shaded or impacted by soiled panels. Microinverters also make the solar system more reliable overall, but typically increase equipment costs slightly.

Power optimizers

Add-on power optimizers for solar panels are now available that work with a given inverter (the gadgets that convert the electricity to a usable form for your home). Optimizers work by monitoring and communicating the output of each panel to maximize power production. They also report helpful maintenance information if a panel is underperforming, maximizing the speed of addressing potential issues.

  • The benefits of power optimizers – Power optimizers enables greater production from each panel by allowing them to operate independently of other panels in a module. Like microinverters, this mitigates the impacts of shaded and soiled panels on overall output. It also removes design constraints that would have previously hurt efficiency, such as orienting panels in different directions or at different angles. In other words, it allows more properties to be a good fit for solar, even if dormers and various roof lines would have otherwise caused design issues.

Solar monitoring redefines relationships

Smart house technology system illustration
Access to both real-time and historic data presented as raw data and on graphs empowers solar energy system owners to have a greater understanding of how their system is functioning.Image Credit: Oxy_gen / Shutterstock

Solar system owners previously had to view the display on their inverter to determine how much electricity the solar array was generating, while the system installer didn’t have direct access to any information. This had many limitations.

Now, solar system monitoring display solar system output data online, providing lots of information at their fingertips. This access to both real-time and historic data presented as raw data and on graphs empowers solar system owners to have a greater understanding of how their system is functioning. Solar systems with microinverters even allow homeowners to view data for what each solar panel is producing, as well as the array as a whole. 

  • The benefits of solar monitoring – Did your solar PV system produce more power yesterday or the day before? Did snow block the panels after the last snowfall, or did it melt quickly? These answers are all available when logging to a solar system monitoring platform and can shift the relationship between the solar system and the homeowner.  Of course some homeowners may not want to view such detailed information. Solar installers can also review system monitoring data for their customers and use it for troubleshooting and maintenance purposes, enabling them to more easily identify if a solar system is under performing and for how long.

Solar financing becomes easier

The upfront cost of solar was one of the major hurdles to more widespread solar system ownership. Now that many financial institutions are more familiar with solar energy, it is increasingly recognized as a low-risk, reliable investment with dependable equipment. More solar financing options are making it easier and more affordable than ever for homeowners to go solar. 

Numerous local and regional lenders, and even some national banks and solar installers are providing loans for residential solar energy systems. Depending on the term of the loan and the interest rate, the loan payments may be lower than the cost savings on the power bills, resulting in saving money from day one.

Feature image credit: Fabio Berti / Shutterstock 

By Sarah Lozanova

Sarah Lozanova is an environmental journalist and copywriter and has worked as a consultant to help large corporations become more sustainable. She is the author of Humane Home: Easy Steps for Sustainable & Green Living, and her renewable energy experience includes residential and commercial solar energy installations. She teaches green business classes to graduate students at Unity College and holds an MBA in sustainable management from the Presidio Graduate School.