The science behind solar panels
by Michael Choe | March 6, 2022
Although photovoltaic (PV) technology has been around for a while, I still find it remarkable that we’re able to convert energy from sunlight into electricity. And it’s amazing that this energy can be stored in a small power bank and charge a smartphone or generate a couple megawatts of power for an entire neighborhood.
And I didn’t know how expansive solar arrays could be until I visited West Loch Solar!
So how does it work? A solar cell is made up of two layers composed mostly of silicon, one negatively charged and one positively charged. Silicon is used because it works well as a semiconductor and it’s abundant. When sunlight hits the solar cell, that energy causes electrons within the silicon layers to move. The electrical field created by the negative and positive charges causes the electrons to move in a single direction otherwise known as direct current (DC). However, most household appliances use alternating current (AC) instead of DC, which is why PV systems use an inverter to change the current type.
Solar cells are small and can only give off about half a volt, which is three times less voltage than a typical AA battery. To generate more power, solar cells are strung together to make a solar module. Multiple solar modules are assembled to create a solar array (also known as solar system) to produce even more power and are most likely what you see on rooftops and at grid-scale solar facilities.
Factors like weather and location play a huge role in the efficiency of solar panels. For example, solar cells probably won’t have much sunlight to absorb during the rainy winters compared to the bright, sunny summers. For that reason, customers powered by solar energy will often notice differences in their electric bill statements throughout the year. When relying on solar energy, you can expect to use more power from the grid when there is less sunshine. Conversely, less power from the grid is used when sunlight is more abundant. Customers can offset this by installing their own battery storage system. Hawaiian Electric also offers bill credits for extra power that’s sent back to the grid for some of our renewable energy programs.
It’s become common to see PV panels in most neighborhoods here in Hawaii. Our recent news release revealed that just last year, 4,956 private rooftop solar systems with 53 MW of capacity were added to Hawaiian Electric’s island grids, helping us achieve a 38% renewable portfolio standard. We’re so close to hitting the state’s next milestone of 40% by 2030! Even those who can’t install private PV systems may be able to participate in the shared solar program, which is expected to launch soon. The program is geared toward customers who aren’t able to install private rooftop solar. It’s great to know that there’s an option for everyone to help move Hawaii closer to a clean energy future.
For more information on our customer renewable programs, visit our website: https://www.hawaiianelectric.com/products-and-services/customer-renewable-programs.
Michael Choe is a digital communications and social media specialist at Hawaiian Electric.
