Humans have been taking advantage of solar energy for thousands of years. Early uses of solar energy started with harnessing the sun for fire and heat. In the last few hundred years, the photovoltaic effect was discovered and solar energy could be converted to electricity. While solar is still used for heating, this discovery was a significant turning point in solar history. How is solar energy used today? Let's take a look at the top uses for solar energy in the 21st century.
Photovoltaic (PV) cells for solar electricity came about in the 1800s and were developed for commercial use in 1954 by Bell Labs. In the last 70 years, we’ve seen massive improvements in the efficiency of photovoltaic solar cells. Not only has the efficiency gone up from 4% to nearly 40% in research and settled around 20% efficiency for commercially available solar panels, but the price per watt has also dropped significantly. In the 1950s, solar panels started around $100 a watt, in 2005 they were $4 per watt, and now it’s only one or two cents per watt of power for a solar panel.
When we take both the increase in efficiency and the drop in price into account, that means that solar panels have improved to be 100,000 times better in the last 70 years. For comparison, humans have improved our energy conversion rate by about 0% in the last 70 years, in fact we just continue to consume more energy, we’ve doubled our energy consumption in that same time. However, the good news is that we humans have also been adopting solar energy at an unprecedented rate. Solar energy has grown faster than anyone has predicted.
California passed a statewide mandate to have one million homes install PV cells on their roofs by 2020, and they reached that number by 2019. As of 2021, California leads America with over 3.3 million homes that have solar energy systems installed, producing over 13000 MW of energy a year. How much solar energy do you think the state with the next highest solar capacity installed on their homes produces? Which state do you think that is?
It’s Arizona, with ~2300 MW of solar power installed on their homes. That means California, the state with the most homes with solar, has over 5 times as much solar power on their homes as the next highest state. Want to know how many homes in Arizona have solar? It’s under 330,000, in other words Arizona has less than 1/10th of the number of homes with solar power systems installed that California has. The US state with the highest number of home solar electricity systems has twice the number of homes with installed solar power as the second highest, how crazy is that?
Home solar energy systems are important, but what we really need to look at is utility scale solar power. Why? As a country, the United States currently consumes over 110,000 MWh of electricity every day. It’s a good thing solar energy is now the cheapest form of energy to build isn’t it? Not only does solar energy provide us with clean power to do everyday tasks like browsing social media, reading blogs like this one, or watching YouTube, each 2 MW of solar power we build takes a ton of carbon dioxide out of the atmosphere.
Solar power for heat has been used for ages, Seneca documented how the Roman bathhouses would have glazed walls to trap the sun’s heat inside. These solar rooms seemed to be pretty successful as Seneca wrote that people would be boiling inside by late afternoon. I would not want to be in one of these bathhouses, but these guys didn't have internet. In the 1700s, a Swiss scientist created what he called “solar collectors” which were essentially boxes that collected and reflected sunlight to heat up the space inside, much like an oven.
Heating space and water with solar power is not just an archaic idea, it’s still used, even in today’s world. The concept of heating up rooms with sunlight lives on in the solar rooms of houses. Solar thermal collectors are still used to heat water for homes. I even saw a project to build a solar oven like one of those solar collectors from the 1700s in a science magazine when I was like 10.
Remember when you would go trick or treating in your neighborhood as a kid? Did you ever walk up to one of those houses with a line of little standing lights along their sidewalk? Those lights are solar powered! Okay cool, what about those little pocket sized calculators you used in high school or junior high with the little black strip on the front? Those are also solar powered! That was my first introduction to interacting with solar power. I covered up the strip for a while once while the calculator was on and watched the number fade from the screen.
The use of solar power does not end with heating our homes and supplying us with electricity. In 1985, Switzerland hosted the Tour de Sol, the first ever solar car race. Long distance racing is not the only form of solar car racing, there are also solar car drag races. The record for the fastest run in a solar car drag race was set in 2007 by a high school team. Today, there are solar cars being produced by a company called Aptera that are meant for everyday use.
We've been improving our ability to leverage solar power for millennia. In the last 70 years, we've gone from barely being able to make solar panels to solar power being the cheapest form of energy to build. Producing electricity from solar power isn't just economically smart, but it also prevents tons of carbon dioxide going into the atmosphere a year.
In an effort to fight climate change, and in alignment with America's goal to run on 40% solar energy by 2035, we aim to fund and build 50,000 MW of solar power across America by 2030. We need your help, please sign up to stay updated.