You have definitely seen them or even might own them. They are everywhere from scattered across the rooftops of neighborhoods, to the tops of street lights on highways, to large-scale power stations. Solar panels can be found everywhere and are the rave in renewable energy.
But what are solar panels? Solar panels are a giant array of photovoltaic cells. These photovoltaic solar cells resemble a sandwich. Two silicon panels are placed close to each other. One of the panels is positively charged and the other is negatively charged. The top panel is injected with phosphorus which adds electrons to that side of the sandwich, making it negative. The other panel is injected with boron, which removes electrons from that side of the sandwich, making it positive.
When these two charged panels are placed together, an electric field is created. An electric field allows for the movement of electrons and hence, electricity. But how do these two charged plates create electricity from the sun?
For a long time in human history, light was thought of as a wave. Properties of light such as refraction certainly supported this claim. It took a man named Albert Einstein to propose the idea that light was a particle for people to change their mind. He stated that the quantum of light behaved like a particle. This particle would soon become known as a photon. A photon is the fundamental particle of light that is both a particle and a wave.
Now that it is known that light is made of physical particles, the process of electricity creation in solar cells in much easier to understand. When the sun shines, photons strike the top silicon panel of solar cells. The top panel is negatively charged which means it carries excess electrons. When the photon particle hits the panel, it knocks out an electron from the panel into the electric field between both panels.
These jarred loose electrons then flow through the electric field which produces direct current electricity. If created at a solar power station, this direct current electricity is then transported to the desired location. If created at a home, this direct current electricity is useless because homes use alternating current electricity. That is why at some point, the direct current electricity must go through an inverter. The inverter converts DC electricity to AC electricity and then the electrons from the solar cell are able to power homes.
For home use, if the solar array doesn’t produce enough electricity, the house is still connected to the traditional power grid and is able to draw more energy from the utility. On the other hand, if the solar array is producing more energy than is being consumed, the excess power is then sent to the utility company to use. There is a net meter device in each home that measures the amount of electricity going in and out. Net metering is when the local utility company agrees to provide energy credits or a check for any surplus power sent to them.
Most solar panels in use are either monocrystalline or polycrystalline. To make solar cells for monocrystalline solar panels, silicon is formed into bars and cut into wafers. The silicon used a single crystal of silicon. To make polycrystalline solar panels, fragments of silicon are melted together to form bars and then cut into wafers. The major difference in the two lies in the single crystal of silicon versus many melted together. The single crystal in monocrystalline solar panels allows for more room for electrons to flow and thus results in more efficient energy creation. The many melted together crystals in polycrystalline result in less space for electrons to flow and these cells are less efficient. The single silicon crystal in monocrystalline panels however raises the price significantly and these are more expensive than polycrystalline panels.
Monocrystalline versus Polycrystalline
Solar energy, since its inception, has become the second most widely used and abundant renewable energy source. From 2008 to 2018, the amount of solar energy produced in the United States increased from 1.2 to 30 gigawatts. That’s seventeen times the initial amount in a mere ten-year span. This increase was aided by the decreasing price of solar panels. Since 2010, the average price of solar panels has decreased by 60 percent. Due to this fact, solar energy is the fastest growing electricity source in the United States. By 2050, solar energy is expected to account for 36 percent of US renewable energy production.
Pros:
1. Solar energy is the cleanest energy source currently known. Solar power produces absolutely zero emissions and is pollution free. Solar panels do not damage the environment and installing them on just 0.6% of the nation’s total land area could supply enough electricity to power the entire United States.
2. Solar energy can be harnessed anywhere in the world. It is available every single day when the sun is blazing and during overcast conditions. It can never run out as long as the sun still shines. Given that the sun will shine for another 5 billion-year, solar energy really is a long-term solution. When the sun does stop shining, humans have bigger problems than energy consumption to worry about.
3. Solar energy has provided thousands of jobs. Currently there are approximately 209,000 solar workers in the United States which is a 123 percent increase since 2010. Another economic benefit of solar is home solar energy usage allows for energy independence which secures the US’s energy future.
Cons:
1. Solar energy comes with a high upfront cost. Although prices have dropped significantly and with technological advancement will only drop more, the price of photovoltaic cells is significant. In addition, storage of solar energy is expensive as it must be stored in batteries or used right away. These large batteries are pricey but allow for solar power usage at night.
2. Solar energy is weather dependent. Although solar energy can be collected in any weather condition, the efficiency of the cells varies. During cloudy and rainy days, the production rates of solar systems drop noticeably. Solar energy also can not be harnessed at night which takes away approximately eight hours of production every day.
Although there are some very limiting aspects of solar energy, I believe the positives outweigh these negative aspects. Solar energy offers the vision of a very green energy future and a move away from fossil fuels. No carbon emission and self-sufficient households secures the planet’s energy future. Due to its infinite supply for the rest of human history on Earth, solar energy will continue to grow and one day will make up a significant portion of our energy supply.
I didn’t know very much about solar panels going into this blog, but you did a fantastic job explaining the process and the necessary steps that need to be taken to harvest energy! The way you wrote your blog was super easy to follow and kept me interested through its entirety. I think it’s a bit tricky to plan for the weather, but agree with you that it’s worth the higher cost initially and a few slow days without sunlight if it means we can reduce our emissions and maximize the natural energy we’re using as it’s substitute.
What an enlightening post. I knew absolutely nothing about solar panels before reading this post, but the helpful way that you explained it makes me feel like an expert on them now! Your clear and concise explanations on how the panels themselves work provided easy insight into the process, and I like that you included a pros and cons list at the bottom to describe the benefits of their usage. I definitely agree that the higher cost is worth it for such an easy source of natural energy.