Solar photovoltaics are the backbone of the transition to a clean electric grid. Learn how solar PV works, how much we need, and the role it will play in securing our clean energy future.
Many may be surprised to learn the earliest solar photovoltaic (PV) technologies, which convert sunlight into electricity, were first patented in the mid-1800s!
Like the origin story of Jell-O, and the plot of the Netflix blockbuster series Stranger Things, scientists developed solar photovoltaics for commercial use in a lab in the 1950s. Today, solar is a linchpin technology for energy sector decarbonization.
Before we jump in you may be wondering, how exactly does solar PV work?
Here Comes the Sun
Consider that the amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year. So how do we harness that sunlight into useable energy? One form of conversion is solar PV.
As solar radiation, or sunlight, strikes solar panels, it creates a voltage. The voltage generation causes electricity to flow in a circuit. Single solar panels, or modules, generate small voltages that installers string together in chains. We call these chains of solar panels “solar arrays”. The arrays aggregate the cumulative voltage of the panels into a single source of electricity to power homes and businesses.
Solar arrays generate electricity in the form of direct current (DC). But our grid operates on a different form of electricity, called alternating current (AC). Since our appliances don’t work on DC voltage, we rely on inverters (see image above) to convert solar energy (DC) into usable (AC) electricity. When pairing solar panels with that crucial inverter, we refer to the assemblage as a solar PV system.
Check out this video from the Department of Energy to learn more.
Independence Day
Spurred by the energy crisis of the 1970s, governments and concerned citizens turned to the commercial potential of solar photovoltaics as a home-grown, abundant energy source. Many found the idea of creating renewable energy in our own backyards as American as a “Hot-Dog Apple Pie”. (It’s a new recipe I’m tinkering with in the name of American efficiency and innovation.)
And today, the US electric grid is powered by 100% renewable energy. And they lived happily ever after. The end. Right?
[Disappointed Sigh.]
Contrary to the glossy images adorning corporate sustainability reports portraying happy actors living in harmony with fields of solar panels, we are far from a clean energy utopia.
Solar Adoption: Not at the Speed of Light
The US’s historic lethargy to solar PV adoption presents a perplexing dichotomy with the country’s celebrated ethics of independence, self-reliance, and freedom. But there’s a reason for hope.
The road to large-scale solar adoption in the US is historically long and arduous. Low costs of fossil-fuel sources, like natural gas, bolstered by generous subsidies for the fossil fuel industry, made it hard for solar to reach cost-competitiveness. Also, unfriendly state policies and well-documented utility-funded smear campaigns have added to the solar industry’s hurdles.
Despite attempts to dispel clean energy technologies, consumers demand renewable energy. A recent poll by FM3 found that over 70% of Americans already prefer to power appliances with energy sourced from renewables, like wind and solar, over natural gas. That preference is met with promising news: solar is reaching record low costs.
Source: NREL U.S. Solar Photovoltaic System and Energy Storage Cost Benchmark: Q1 2020
The cost of solar has fallen by over 80% since 2010. It’s now the cheapest form of energy for utilities to build according to the US Energy Information Administration (EIA), the federal government’s authority on energy.
The Sunshot: Decarbonizing Our Electric Grid
Despite the best attempts to hamstring solar adoption, the most recent decade marks a benchmark year for solar PV deployment. Solar’s recent growth explosion is fueled by capital cost reductions, supportive state and federal policies, and growing social concern about the carbon intensity associated with the way we generate electricity. These trends converge in support of the burgeoning “Electrify Everything” movement, calling on electrification from everything from electric stoves to electric vehicles.
Federal leadership recently called for a 50% reduction in US greenhouse gas (GHG) emissions, below 2005 emissions levels, by 2030 and net-zero emissions by no later than 2050. With electricity generation accounting for 25% of US GHG emissions (2019), solar PV will undeniably play a key role in reaching these goals. But demand for clean energy doesn’t stop at the federal level.
California set a goal of 100% carbon-free electricity by 2045. More states are expected to join in on the fun.
Houston, We Have an Opportunity
The sun is just starting to rise in the solar industry.
According to the Solar Energy Industries Association (SEIA), the US installed a record-breaking 8.4 gigawatts (GW, or million kW) of new solar capacity in 2019. Experts expect the US will install another 83 GW of solar capacity by 2025, led by California, Texas, and Florida.
83 GW can simultaneously power (roughly) 83 million microwaves!
Microwaves and Macro Trends
So that’s a lot of project solar. But just how much PV capacity do we need to decarbonize our electricity generation sector?
Energy Innovation, an energy and environmental policy firm, estimates the US needs about 550 GW (550 million kilowatts) of installed solar capacity by 2050 to prevent the global temperature from rising more than 2 degrees Celsius. That’s the energy equivalent of simultaneously powering roughly 550 million microwaves.
To support this ambitious goal, expect more states to adopt win-win solar-friendly policies which support electric grid decarbonization and save consumers money.
For example, California passed a 2019 bill requiring solar PV systems on all new homes. With a few minor exceptions, the bill went into effect in January 2020. A study by the California Energy Commission found the regulation will save the average California homeowner about $500 annually in addition to reducing fossil fuel emissions. Other policies, such as net energy metering, require utilities to pay customers for excess solar generation.
Can’t Stop, Won’t Stop
Regardless of past attempts to stifle adoption, solar photovoltaics will be a backbone technology for decarbonizing our electricity sector. While we have a long way to reach our long-term targets, plummeting installation costs, supportive policies, and intelligent pairing with innovative technologies like energy storage will unlock solar’s full potential.
Until we reach those targets, solar PV is like Jell-O. There’s always room for more.
About Solutions in Sustainability
Considering investing in solar PV to your business? Solutions in Sustainability helps businesses inventory their energy-related carbon emissions, recommend science-based reduction targets, and identify clean energy technologies to reach their goals. Contact Solutions in Sustainability to learn how solar can help you meet your long-term goals today.
About the Author
Alex Kaufman is a science communicator, clean energy specialist, sustainability nerd, professional engineer, travel enthusiast, and resident of San Diego, California. When not helping clients, you can usually find him cycling, hiking, reading, spending time with loved ones, or planning the next big adventure. He is open to speaking engagements. You can contact him at alex@alexkaufmanpe.com.