How Does Solar Energy Work? A Step-by-Step Explanation for the Everyday Change Maker
Have you ever found yourself in a conversation, out loud or even just internally, about solar energy? Wandering down the path of environmental stewardship, celebrating the power of the sun to…create light? Or charge a battery or something…anyway, it’s just amazing how it can power a house, maybe even a city? Basically for free? Wait…but why is traditional electricity bad again? Where does it even come from? A giant light bulb underground in the city center?
Yeah, me neither…. But these are almost all good questions! Because understanding how solar energy works and why it’s worth celebrating requires somewhat of a grasp on the whole system of energy generation and distribution.
If you’re like the majority of our team, you’re long overdue for an explanation of what solar energy actually is and how it fits into the bigger picture of renewable energy.
And I promise, no matter where you’re starting, we will get you caught up in this post!
If you’re pro and already have a solid understanding of electricity and “the grid,” go ahead and make your merry way to How Does Solar Energy Work 👇. If you’re like the majority of our team, and need a little refresher (or for some an introduction), let’s work our way there with a few necessary pit stops before we get into the nitty gritty of solar.
When you ask “What is electricity,” it may seem like a simple question, but you’d be surprised how few of us actually know what’s happening in the gadgets we use every day—some of our team didn’t…okay most of our team didn’t, but that’s why we are here now providing this explanation.
And if you’re starting here with your explanation, be prepared: we will be using some science terms that may give you flashbacks to your elementary school days. It’s not too complicated, but we just wanted to give you a heads up so you aren’t caught off guard!
So, What is Electricity?
Understanding what electricity is will help us understand how electricity is generated, and why solar energy is different from other methods of generating electricity.
Let’s travel down to the building blocks of matter: atoms. We all learned in school that an atom consists of two pieces: nucleus with a positive charge, and electrons with a negative charge.
The difference in charge creates an electromagnetic force that makes electrons move.
The higher the force in the electromagnetic field, the faster the speed that charged particles move within this field. That force is measured as “voltage.” The higher the voltage, the faster charged particles will move within the electrical field.
The higher the voltage, the larger the current of electrons jumping from atom to atom, and the more power!
So, electricity is the power created as electrons jump from atom to atom through electrical circuits.
We love Bill Nye. Who doesn’t? Check out Bill Nye the Science Guy’s episode on electricity if you want a more comprehensive explanation. We aren’t kidding.
A good, and common analogy for understanding electricity is to think of water in a hose. If you watched the Bill Nye epi, this is something you’re already familiar with.
We can think of the electrons as the water flowing through the hose. As water flows, it moves things in its path. There are 2 components at work here: the amount of water traveling through the hose (the flow) and the pressure level pushing the water through.
The stronger the pressure, the stronger the water flows. The pressure is the voltage.
When there is a weak electrical field in a wire, the electrons don’t jump from atom to atom. As voltage increases, the electrons become energized, and eventually the resulting force overcomes the force holding the electrons to their nucleus and they start hopping around. At this point, we’ve turned up the water pressure and now electrons flow freely as an electrical current.
Types of Electricity
Now that we have an understanding of what electricity is, there’s one last thing. There are two main types of current: AC and DC. DC, or direct current, is a one-directional flow of charge along a conductor. It is used in low-voltage applications where energy losses are small, such as battery-powered devices, or most things you plug into a power outlet.
AC, or alternating current, is the standard type of current for electricity distribution over longer distances. AC power alternates in magnitude and direction continuously with time, like a wave— this is the current that brings electricity to the outlets in your home.
The Electrical Grid, Explained
With me so far? Great! Let’s talk about the electrical grid that all rely on and yet, rarely think about.
An electrical grid is a self-contained system of electricity distribution consisting of high-voltage AC transmission lines, lower voltage distribution lines to homes or businesses, substations to step up and down the voltage within the system (transformers), and power generation stations. If that makes sense to you at all, you’ve made some big leaps through this post!
The goal of the grid is to efficiently generate electricity, transmit it over long distances, and deliver it at the required voltage. It’s divided into two parts:
- The Transmission Grid: This consists of electricity generation stations (power plants) and a network of high voltage transmission lines.
- The Distribution Grid: The electrical line network “downstream” of the transmission grid that sends electricity to homes and businesses. It begins with substations that step down the voltage from the transmission grid.
Think of the grid as the”road” system for electricity. The transmission system is the main electricity highway, and the substations are the exit ramps. Its goal is to facilitate long-distance electrical travel at maximum energy efficiency.
Anything connected to the access roads and streets is the vehicle “distribution” system. The high voltage DC lines are basically the stack interchanges between large highways.
In the United States, we have three main transmission grids: one for the eastern half of the country, one for the western half, and one just for Texas (represent!). Branched off these transmission grids are thousands of smaller distribution grids. It is the job of your utility company to use a utility meter to measure your electricity usage and determine the amount of energy it needs to purchase from the electric grid.
How is Electricity Generated?
So class, we know how electricity works (check!), how it’s distributed as AC electricity and used as DC electricity (check!), and how the power grid works to orchestrate getting this electricity to our homes and buildings (check!). Way to go!
Now…how do we get the dang stuff into the wires in the first place!? Great question! And a central question to understanding why renewable energy sources are better for the environment.
The standard method uses electromagnetic induction. How it works is you spin a magnet within a coil of wire, and the magnetic field creates an electric field in the coil and electrons flow—once again, the Bill Nye episode may have introduced this to you already.
There is very advanced physics behind this, so just take my word for it that it works! Every method of electrical generation except for batteries and solar panels use this principle.
The difference between energy sources is how you spin the magnet. *Idea light bulb turns on!*
Fossil fuel sources use the heat generated from burning them to create steam, which spins a turbine with a magnet.
Its the same process with renewable energy sources: Hydroelectric plants use flowing water to spin a turbine attached to a magnet. The center of a windmill fan is itself a turbine with a magnet. Concentrated solar power systems (CSP) use mirrors to focus sunlight into a high energy beam that creates steam to turn a magnet.
Turbines inside the Hoover Dam
How Does Solar Power Work?
We love to see solar panels lining the rooftops of nearby homes or businesses, and we want to understand a little about solar technology to really know what we are celebrating when we see them.
Solar energy systems convert sunlight to create electricity from the sun. But how do solar panels work? How does solar power systems turn solar energy into electricity we can use at home?
The kind of solar energy we are interested in uses solar panels to create electricity through the “photovoltaic effect.” More simply, photovoltaics is the conversion of sunlight into electricity.
Solar panels capture the electricity created through solar photovoltaics. Solar panels consist of small units called solar pv cells that convert that solar energy into electrical current. The photovoltaic cells consist of two plates of silicon, which is a semiconductor. This material doesn’t normally conduct electricity well, but this changes when you add energy to it (i.e. the photon particles from the sun’s light moving literally at the speed of light).
When sunlight hits the silicon cells, the electrons electrons in the metals become energized, creating a flow of electricity…solar electricity!
So getting back to our water analogy, instead of a hose, think of the water as sitting in a tub. In this case, when the light particles (photons) from the sun hit the solar cell, the electrons are freed but are just floating around aimlessly in the material. We have a tub full of electrons, now we only need to figure out how to pull the drain plug to make them flow.
That’s where the properties of the silicon come in. The charge difference between the two plates of silicon creates an internal electric field that causes the energized electrons to flow. (To learn more about how the properties of silicon do this, check out this video.)
This process creates a DC current; it travels through a solar inverter where it’s changed into an AC current that flows to an electrical panel that then directs electricity to power your home or business.
Thanks SunPower for the graphic!
A solar panel is a group of cells, and groups of panels create a solar array. A solar array gives you electricity from the sun’s energy with very little maintenance. Since the source of the energy is the sun, the source is free, unlike electricity sources that require fossil fuels, which is not free.
And since there are no emissions produced in the process, it makes it a much more eco-friendly option than other sources of energy.
Does Solar Energy Work at Night or in Cloudy Weather?
The sun does not shine all day, and the amount of electricity generated by the panels varies with weather conditions. This creates a problem for the distribution system. As with most power systems, the installed capacity of your solar array will exceed the need of the system, even at peak demand.
When the sun shines brightly, the array generates excess electricity that overloads the distribution system. At night or on cloudy days, on the other hand, little electricity is generated.
So the solution is an array of batteries that store excess electricity your solar panels produce. Then, when conditions are not as ideal, and you need more energy than is being generated, you can pull from the battery to access the excess energy stored. So in short, the energy you use at night or during darker weather conditions comes from the stored energy in the solar batteries.
Why Isn’t Everything Solar?
Free energy?! Little maintenance?! You would think that everyone would adopt solar energy!
Not just yet! Our grid infrastructure is set up for consistent electricity transmission, whereas renewable sources fluctuate, requiring powerful batteries to account for the variability inherent in these energy sources. The battery system causes the majority of the complications in terms of widespread adoption. In addition, batteries have to be maintained and replaced, and they are often expensive.
Of course, there is the reality that the fossil fuel industry is extremely powerful economically, politically, and culturally, despite being environmentally disastrous. The industry earns trillions of dollars every year with the power and influence that comes with each dollar. Disrupting this industry is no small task.
But, we are seeing more and more solar around us every day. Residential solar power is often heavily subsidized to improve access. The cost of solar is slowly changing though as battery technology improves and solar panel research makes them more efficient and easier to maintain. Plus there is a big political push to make the energy more widespread.
The movement toward renewable energy isn’t just up to the solar industry. Our daily actions often support the fossil fuel industry as well. Gross. Banks like Wells Fargo invest billions of its customers’ money in fossil fuels.
And solar programs are taking root across the country. In Nashville, for example, community members can purchase blocks of renewable energy—essentially having a neighborhood go in on renewable energy together. This model of regional solar panel systems eliminates the need for individual home solar panel installation and the costs that come along with it.
Cities also incentivize the switch to solar through net meters. Net metering systems allow excess energy to be sent back to the grid when you create more energy than you need. In exchange, you get credits, saving you money in the long-run.
The Big Picture for Solar
Solar has a long way to go to reach widespread use. Right now, solar power only accounts for roughly 2% of the power needs in the United States. But don’t worry, this percentage is climbing; 10 years ago it was almost nothing!
Green energy sources overall have grown from 1% of U.S. energy generation in 2000 to nearly 12% in 2019. While other renewables like wind are becoming economically viable, due to their costs, solar panels are nearly all subsidized.
As technology drives down the cost per kilowatt, as battery technology improves, and as we begin to live more sustainably and reduce demand on the grid by saving energy, solar energy should grow to become a major source of energy generation. Part of this push will be generated by conscious consumers just like yourself!
In the long-term, these trends can result in a dramatic reduction in our carbon footprint and will transform the way we think about energy. Our switch towards solar energy (and all renewables) is a HUGE part of the changes we as a society need to make to reduce the effects of and reverse human-induced climate change.
Now that you understand how it works, now it’s time to take action! The more we invest in and call for change in our energy systems, the more accessible solar and other renewables become!
Ken Briggs is a San Antonio-based entrepreneur, marketer, writer, and community organizer. Ken grew up in the Dallas area and holds a master’s degree in Mechanical Engineering from Texas A&M University. Currently, he is CMO of the tech startup Decentralized Web Technologies, serves on the SA2020 Ambassador Committee, and is a member of the World Affairs Council of San Antonio
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