How do solar panels work and are they worth the investment? KSAT Explains

San Antonio ranks #1 in Texas and #5 in the U.S. for solar energy usage.

There is no shortage of sun during a south Texas summer, so why don’t we harness that energy to power our homes and businesses? The good news is, we are.

SAN ANTONIO – There is no shortage of sun during a south Texas summer, so why don’t we harness that energy to power our homes and businesses? The good news is, we are. San Antonio is the leading city in Texas when it comes to advancements in solar energy usage, according to a study done by the Environment Texas Research and Policy Center.

San Antonio has over 450 residential CPS Energy customers that use solar in their homes and 65 commercial businesses. Those numbers are made possible by a partnership between Big Sun Solar and CPS Energy. Their “community solar” program makes solar available for anyone who wants it. One branch of the program is made up of a combination of solar farms around the city. The other branch uses solar panels that are atop more than 100 parking structures around the city. The program allows CPS Energy customers to purchase panels then the customer gets a credit on their bill each month. As of July 13th, 2022, that program was at capacity and not accepting new applications.

The Beginning of Solar and How it Works

The technology that turns natural light into energy has not always been available. In fact, it’s fairly new and still being developed. Humans have been harnessing solar energy since the 7th century, B.C. by using sunlight and magnifying devices to start fires. Centuries later, in the early 19-50′s, scientists created the first silicon photovoltaic cell -- that’s basically the technical name of the modern-day solar panel. This new creation was an accident. “They were researching the properties of silicon semiconductors, and they found that when certain impurities were added to the silicon, it generated a strong electric current when exposed to the sun,” says Dr. Krystel Castillo, Director of the Texas Sustainable Research Institute.

So how does energy from a giant star (the sun) millions of miles away absorb into a silicon panel and create electricity? Think back to your high school physics class. Heat=Energy. The sun produces heat and light. The electrons from the sun’s UV rays are absorbed into the photovoltaic cell (solar panel) and create a direct current. Think of direct current as a battery -- it never shuts off and is constant. That direct current goes into an inverter to create an alternating current. That’s the electricity that comes out of the plugs in your wall. That electrical current goes down a long string of wires into an electrical box mounted on the side of the building. The power generated from the solar panels is mixed with the power being supplied by the grid. The smart meter installed on the building decides which kind of power needs to be used. It is programmed to use 100% of the solar energy before it starts pulling energy from the grid. If the solar energy system creates too much power, it is sent back to CPS Energy and shows up as a credit on the customer’s bill.

Is Solar Energy Right for You?

Now that you know how it works, how do you know if it’s right for you? This is where the financial decisions come into play because solar energy is an investment. Big Sun Solar says most of its customers make their decision based on three things:

  • They want to save money on their electricity bill
  • They want to lower their carbon footprint
  • They are interested in the new technology

CPS Energy customers have a few options when choosing solar. Customers can contract a company to install rooftop solar, buy into the “community solar” program, or both. Dr. Raj Narayan is a customer with both forms of solar on his home. " It gives me the advantage of not worrying what CPS is going to do with electricity rights rates. It gives me the advantage of not worrying about what the price of gas is because I drive on sunshine,” says Dr. Narayan. He has two electric vehicles in addition to his solar-powered home.

In 2018, when Dr. Narayan began his solar journey, the price of solar energy was around three dollars per watt. Over the years, that price went down significantly, but due to the recent supply chain issues, the price has returned to around three dollars, according to Big Sun Solar. After rebates and tax incentives, customers can expect to pay around $2.00 per watt. That may not sound like a lot to some, but that number can inflate to around $25,000 total before rebates for an average 8kW solar energy system -- and that money is expected upfront. Dr. Narayan says he paid roughly $40,000 for his system.

The Pros and Cons

That brings us to the pros and cons of solar energy systems.

First, the pros:

  • Save money on your electric bill
  • Produce “free electricity” once the system is paid off
  • Reduce your carbon footprint
  • Invest in the future of cleaner energy
  • Have a high-tech, sustainable home

Now, the cons:

Everyone we spoke to for this story said basically the same thing when asked what the biggest drawback of solar is --“The upfront cost.”

  • Upfront cost
  • Maintenance
  • Weather dependency (the sun doesn’t shine at night)
  • If you move homes, you lose your investment

(these lists could be added to, but you get the idea.)

After paying the upfront costs and installation, customers should start seeing the benefits (credits on their bill) almost immediately. Getting to that point can take some time. The average wait time from the day you sign your contract to the day you turn on the solar panels is around two months.

“My net cost for electricity and power in general to both power my house during that six-month period of time (September of 2021 to February of 2022) and drive my electric vehicles are 140 miles a day between myself and my family was only about $53,” says Dr. Narayan. The payoff time for Dr. Narayan is roughly six to seven years. That time can vary depending on your situation. Once the system is paid off, the customer essentially produces free electricity, and the credits given by CPS Energy increase depending on how much solar energy your system produces.

The Future of Solar Energy

What is the future of solar energy? San Antonio is already on a trajectory to meet the goal of being carbon neutral by 2050, but there is still a lot to do.

“It’s a very promising future. I’m very optimistic on that.” - Dr. Krystel Castillo, Director of the Texas Sustainable Research Institute.

The idea that we can one day disconnect from the power grid is very impractical right now. " If it is completely cloudy for two weeks straight and the solar is not able to charge your battery enough, even if you spent a lot of money on a system, you could still have periods of time without the ability to have power,” says Robert Miggins, the co-founder, and CEO of Big Sun Solar.

One obstacle in the way of renewable energy sources becoming primary energy sources is affordable energy storage systems. “The price for lithium-ion batteries, which is arguably the leading energy storage technology, has remained too cost prohibitive. So the research community is exploring other alternatives, including flow batteries,” says Dr. Castillo.

Can’t Afford Solar? There Are Options.

While solar energy is not for everyone right now, CPS Energy says there are ways you can cut down on your electric bill and reduce your carbon footprint.

  • Close your blinds during the day
  • Purchase blackout curtains
  • Make sure your home is well insulated, including the attic
  • Only use energy when you’re home

For a detailed list of home cooling and money-saving options, check out this link.

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About the Authors:

Dylan Collins is the producer for KSAT Explains. Before joining KSAT, Dylan was a news producer at WAFB in Baton Rouge, Louisiana. He has also worked on multiple productions led by the Discovery Channel.

Myra Arthur is passionate about San Antonio and sharing its stories. She graduated high school in the Alamo City and always wanted to anchor and report in her hometown. Myra anchors KSAT News at 6:00 p.m. and hosts and reports for the streaming show, KSAT Explains. She joined KSAT in 2012 after anchoring and reporting in Waco and Corpus Christi.