The Environment Magazine

Karen Huang

Quarry Lane School, Dublin, CA 94568

In the face of a deteriorating environment and excessive CO2 emissions, many urban and suburban areas of our cities have been increasing their search for methods to incorporate more renewable energy in their daily lives. As one of the most representative technologies in the effort to go green, solar panels are a common go-to and can be found on the roofs of buildings and in parking lots.

No longer a niche method of energy generation, there are two types of solar panels: solar thermal or photovoltaic. This article will discuss details of photovoltaic solar panels, which are more straightforward than solar thermal — they convert light to electricity, while solar-thermal produces heat used in large power plants for electricity. Photovoltaics are clean and silent, and don’t need to be processed in plants, making them arguably greener than solar-thermal technology.

Figure 1. The inner workings of a single photovoltaic cell (source: www.eia.gov)

Photovoltaic cells (PV cells for short) are linked to each other electrically in panels or modules, which may then be combined or connected to form arrays. Arrays can be connected to a larger electric power grid (used to distribute electricity to different places).

Most people are probably familiar with images featuring huge fields of solar panel arrays. The increasing use of solar power helps decrease carbon dioxide and other related emissions, and takes advantage of one of our long-term resources: the sunlight that Earth receives. In an hour and a half, the sunlight that hits the surface of our planet can sustain the world’s energy consumption for an entire year.

But it’s difficult to harness solar power well. The electricity generated by PV cells is DC — direct current, only directly usable when powering devices that use DC. Since most large-scale distributions only involve AC (alternating current) electricity, panels and arrays are usually linked to “inverter” devices before the power is sent to the grid, allowing the DC to be converted to AC.

Efficiency has also been a major obstacle in the development of solar panel technology: each cell only generates one to two Watts of electricity, making it necessary to set up huge arrays in open areas to get more electricity. The current industry efficiency of solar panels, in general, is around 15% to 20%, which is already an improvement from 5% in the early 2000s. Labs are constantly working to improve efficiency and have achieved levels of over 50% so far, with high expectations for future advancements.

Figure 2. Photo of a solar panel array (source: news.mit.edu)

Since solar panels rely on the sun, they face the challenge of inconsistency: the sun changes positions throughout the day, and it could even be a cloudy day. It’s expensive to use tracking systems that rotate to match the trajectory of the sun, so panels usually have to be installed at a fixed angle, specialized to their geographical location, to maximize their power throughout the day.

Despite these complications, there have been major improvements in solar power technology, such as continued increases in efficiency and lowered production costs. Given the variability of the power grid, which adds to the constantly-changing electricity market, PV power’s value is often hard to keep consistent. Overall, though, its accessibility has increased in recent years. Along with decreases in the cost of production, it’s very feasible that solar photovoltaics will soon be a widespread source of electricity and replace a substantial amount of fossil fuel power. As a cleaner alternative with low greenhouse gas emissions, PV and solar panel technology is a good investment for those of us with the resources to buy them, and has a promising future in the green energy industry.

References

Stauffer, Nancy W. “Researchers Find Benefits of Solar Photovoltaics Outweigh Costs.” MIT News | Massachusetts Institute of Technology, June 2020, news.mit.edu/2020/researchers-find-solar-photovoltaics-benefits-outweigh-costs-0623.‌

“How Does Solar Work?” Energy.gov, U.S. Department of Energy, 2023, http://www.energy.gov/eere/solar/how-does-solar-work. ‌

“Photovoltaics and Electricity. ”  Eia.gov, U.S. Energy Information Administration, 2023, http://www.eia.gov/energyexplained/solar/photovoltaics-and-electricity.php. 

“Solar Photovoltaic Technology Basics.” Energy.gov, U.S. Department of Energy, 2023, http://www.energy.gov/eere/solar/solar-photovoltaic-technology-basics. 

“Solar Photovoltaic Technology Basics.” Nrel.gov, National Renewable Energy Laboratory, 2023, http://www.nrel.gov/research/re-photovoltaics.html. 

“Solar Photovoltaic Technology.” SEIA, 2023, http://www.seia.org/research-resources/solar-photovoltaic-technology.‌