When the grid goes down and the lights go off, what will you do? Be prepared to go off-grid, that's what. And solar power is the key. But how does solar power work?
We're going to tell you.
But first, have you ever wondered why solar power is such a big deal?
Well, first of all, it's clean. Also, it's cheap. If that's not enough, you can take it with you. And finally, it's easy to set up.
Yes, really. But first, you need to know what it is, how it works, and what you'll need for your own OTG (off the grid) setup.
Solar Power: A Short History
Solar power is one of the oldest human technologies, and chances are, you're already using it.
Well, have you ever hung your clothes out to dry? Or laid out for a suntan? Have you ever opened the curtains to let in the light?
Solar power means using the sun's heat or light like we all do every day. But that's a pretty limited definition.
The technologies currently exist to not only gather the sun's light but also to convert it into electrical energy that you can use to power your devices and appliances.
And this technology has been around for quite a long time.
A lot longer than you might think.
The Industrial Revolution
The first serious steps toward widespread solar technology came during the Industrial Revolution, from the mid-eighteenth to the mid-nineteenth century.
That might seem weird, as the Industrial Revolution was powered by what people then thought was an inexhaustible supply of fossil fuels.
But check this out.
Even as the Industrial Revolution was changing the world, fueling faster development than anyone had ever seen, there were questions.
Some recognized that fossil fuels are nonrenewable -- that is, when they're gone, they're gone. And they questioned what would happen to everything society had built once we'd used up all the fossil fuels.
Also, from the very beginning, fossil fuel technology created terrible pollution.
In fact, Britain's peppered moth, once white with black spots, evolved to be all black to better camouflage with the polluted atmosphere.
It would take more than 150 years and a lot of clean air legislation for it to revert back to its original color.
For these reasons, even in the eighteenth century, people started thinking about alternatives to fossil fuels.
So, what did they do about it?
In 1861, Frenchman Auguste Mouchout earned a patent for a solar-powered motor. By 1865, he had developed a solar-powered steam-creating engine.
He also came up with a tracking technology, so that his collector could track the sun.
And in 1878, he put his solar steam engine together with new refrigeration technology to create ice using just the power of the sun!
Mouchout was one of the first, but he was certainly not the last.
The period of 1860 to 1914 saw huge developments in solar technology from not only the French, but also the British, the Swedish, and the Americans.
OPEC and the energy crisis
For various reasons, fossil fuel power eventually overtook these early efforts. The world wouldn't see another serious, widespread exploration of solar power development until the energy crisis in the 1970s.
What was that?
Well, a series of political events in the Middle East disrupted the supply of oil to the United States, western Europe, and other places.
Then, when the United States entered into the events, the Organization of Oil Producing Countries (OPEC) decided to punish the U.S. by withholding oil.
This, in turn, caused oil and gas prices to shoot through the roof -- not just a little bit, but to the point where it was affecting the everyday lives of most people.
The fact that OPEC could deliberately cause such chaos in the United States made many people think about technologies that could make us energy independent.
Solar was one of those technologies.
Great strides were made toward education and development of solar and other alternative technologies.
But widespread fossil fuel infrastructure already existed. Once again, people opted to do what was easier in the short-term.
However, those original questions of energy independence, pollution, and renewability still remain.
We all know that fossil fuels are a finite resource.
And many people believe we're quickly approaching "Peak Oil," that is, the point at which it will start becoming increasingly more expensive and more difficult to extract oil and other fossil fuels.
And this will mean that, just like in 1973, fossil fuels will become not only scarce but also unaffordable for most people.
What will happen then?
And what about the climate?
There's also the question of national security and independence.
To look at the news, many governments don't seem to be too concerned about these questions. But we all should be.
What will you do when the lights go out?
What can solar power do for you?
Energy independence isn't just for societies. If you can independently generate and store your own electricity, you can:
When You Might Need Personal Solar Power
People are converting their homes to solar power left and right.
And we'll talk about how to do that!
But when it comes to survival situations, your setup is going to be a bit different. You might ask, what are some of those situations?
We all know that even a strong wind can disrupt your electrical power. But climate change is increasing both the frequency and severity of weather events such as storms and floods.
To name one example, Hurricane Maria slammed into Puerto Rico in 2017, and thousands of homes were still without power more than a year later.
And then there are tornadoes, earthquakes, wildfires, and more.
Solar power can keep your home power on, even when the power is out in the rest of your neighborhood.
And if you have to leave your home, a personal, portable solar power system can help keep you connected.
Did You Know?
The number and duration of power outages doubled from 2016 to 2017. The U.S. Energy Information Administration blames that year's extreme number of powerful storms for the increase.
You might have heard about "The Grid," but wondered what it was.
Let us tell you!
"The Grid" is the power grid -- that is, the system by which electricity gets from a power plant to your home.
Anatomy of a Power Grid
(1) First, a power plant generates electricity via coal-burning, hydroelectric, solar, or wind.
(2) Next, substations convert this electricity into very high-voltage electricity.
(3) Then, the power travels along power lines.
(4) Finally, the power arrives at homes, businesses, etc. and is ready for use.
"Grid Crash" is a dramatic way of describing a failure of this system.
So what? You might ask.
Well, consider this:
On one hand, there are many, many power stations across the United States that generate power for their local areas. A failure of one local grid won't affect everyone, will it?
The fact is, America's local power networks are all connected. This means that failure in one may cause failure in a connected one.
And this, in turn, may cause a cascade of power failures that could affect huge numbers of people. In effect, a grid crash.
What might cause a grid crash?
Running out of fossil fuels might eventually cause the system to crash. And the age and condition of your local power infrastructure might also lead to such a situation.
But cyber attacks are also a possibility. In fact, USA Today reports that America's power grids suffer a cyber attack an average of once every four days.
Having your personal solar system set up and ready to go can protect you and your family when the lights go out.
And converting your home to solar power will save you money in the short run -- and be a good hedge against shortages and price increases as fossil fuels inevitably become more scarce.
How Does Solar Power Work?
How does solar power work?
It's simple, and it's not.
The sun bathes the earth in its energy. We see its light. We feel its heat. But how do we convert that energy into electricity?
How Does Solar Power Work?
(1) The sun produces light, which contains energy.
(2) When sunlight hits most objects, that energy becomes heat.
(3) But when the light hits some materials, like silicon, that energy becomes electricity.
(4) Solar cells contain special materials that turn the sun's energy into electricity.
(5) We can store this electricity in batteries for later use.
Home solar power has four steps:
Depending on your setup, you may or may not end up storing the energy you generate. What's more, your distribution system may or may not include sending energy back to the main grid.
Home solar power systems generally rely on rooftop-mounted solar panels. There are also portable systems with panels and ports for charging devices.
How do solar panels work? This TED short lays it out.
How does solar power work with the grid?
If you convert your home to solar power, can you stay on your local power grid?
Why would you want to? Well, there are a few reasons.
First, it's a good backup, in case your setup fails. The grid can also ensure that your power continues uninterrupted at night, or during other times when your system isn't generating power.
How does solar power work with the grid?
(1) Sunlight hits rooftop-mounted solar cells.
(2) The solar cells convert the energy into DC electricity.
(3) A solar inverter converts the DC electricity into AC electricity.
(4) The AC electricity powers your home devices and appli
(5) Your system feeds excess electricity back into the main grid.
Another good reason to hook your system up to the grid is money.
Many areas offer financial incentives to install an on-the-grid solar power system in your home.
The government might also offer rebates on your purchase or lease price, for example. Your state may offer tax breaks for solar power as well.
They may even pay you to generate power for them.
If you generate more power than you need, your system feeds it back into the grid.
Some places may pay you for that energy. Other places may give you credit for that power, to be used when you draw power from the grid.
Win-win. And you can add a third win to that if you're thinking about the environment.
How does solar power work off the grid?
But what if you want to get away from the grid? Or what if, as is the case in Hawaii, power companies don't want people's excess energy?
Well, then, you need an off-grid system. But how does solar power work off the grid?
It's similar, but not exactly the same.
The biggest difference is that you'll be storing your overflow power in a battery for later use.
Wow, that sounds complicated. Can you really do it yourself?
Of course you can!
This clip from the home improvement show This Old House can give you an idea how it's done.
Designing Your Personal Setup
How does solar power work? Now that you know, it's time to start thinking about your personal setup.
But first, there are a few questions you have to consider:
How much power do you need?
This is probably your most important consideration.
The amount of power you want to generate is going to dictate the number and size of your panels. It will also influence your decision to store energy or not.
But how do you determine that?
It's time to go back to school.
Watts, volts, amps and kilowatt hours
If you're checking out solar panels or solar kits, you'll notice that many of the product descriptions read like this:
100-watt solar panel for charging a 12-volt battery.
So far so good. Maybe. But then when you look up how much power you'll need to charge, say, your mobile phone, you find something like this:
Your mobile phone battery holds a charge of 5.45 kilowatt hours and uses 2 kilowatt hours per year.
What on earth does that mean? And what does that mean for your solar setup?
Let's break it down:
Watts, Volts, Amps, and Kilowatt Hours
So what does this mean for the 100-watt portable solar power system you might see on the open market?
Well, the number of watts refers to the number of watts that panel (or system) is capable of generating in the space of an hour.
Of course, you have to understand that the rating of a solar panel ("100-watt," "250-watt," and so on) is based on that panel's performance under standard testing conditions. So your mileage may vary.
But under ideal conditions, a 100-watt solar power system will produce 100 watt-hours (or 0.1 kilowatt-hours) in the space of an hour.
A 250-watt rooftop solar panel will produce 250 watt-hours (or 0.25 kilowatt-hours) in that same amount of time.
Does that mean that your 100-watt system can generate 1000 watt-hours (or 1 kilowatt-hour) if you leave it out in the sun for 10 hours?
The amount of energy a solar panel generates will depend on how much sunlight there is during any given time.
And this, in turn, depends on the time of day, time of year, the weather, the way you position your panel...and a few other things.
But seriously, what does it mean?
Enough math. You want to know how to charge your phone or run the washing machine. Fair enough.
Here are some numbers you can use:
1 Kilowatt-hour can power:
So now you have an idea, not only about how solar power works, but also about how much power you might need.
Now, what about that setup?
How many solar panels do you need?
This will, of course, depend on your power needs. It will also depend if you're building a stationary system for your home or looking for something you can pick up and take with you.
Either way, it's going to take some planning.
To run a home
How does solar power work for your home, and how many solar panels should you buy?
The U.S. Department of Energy has some excellent information about planning your home solar power system.
Their recommendations include the following:
First, figure out how much energy your home is currently using. Is there any way to use less? If so, it could save you money on your build. Lower power needs means fewer panels, after all.
How do you find that information?
Your electric bill will show how many kilowatt hours you use in a month, as well as annually.
U.S. Sun Power recommends using these figures to calculate two additional numbers: your daily usage (kilowatts per day) and your hourly usage (kilowatts per hour).
From there, you can start thinking about panels.
How much energy does your home use?
(1) Look on your electrical bill to see how many kilowatt hours your home uses in a month (or a year).
(2) Divide this number by 30. This is your kilowatts per day. (If you're calculating using the yearly usage number, divide by 365.)
(3) Take the number from (2), and divide it by 24. This is the average number of kilowatts your home uses in an hour.
Just how many panels you might need will depend on a lot of things -- and many of these might not occur to most of us.
Think about this:
Are there any large shade trees in your yard or your neighbors' yards? This could affect how much energy your panels generate.
What's the climate like in your area? An area with a sunny, temperate climate will provide more sunlight than an area with a lot of clouds and rain.
How many hours of sunlight per day can you expect in your area? Does this change significantly with the seasons?
Do you want your solar power system to provide all of your electricity, or to supplement your current setup?
How much power do you need? According to U.S. Sunpower:
Number of panels
How does this translate into panels?
Well, it depends on your panel. Low-wattage panels generate around 150 watts in an hour. Higher-wattage panels can generate as much as four times that.
On top of that, different designs and materials can make a solar panel more or less efficient.
They can also affect the price.
How many panels will you need? If you're building a home system, it could be well worth your time to consult a professional to help with this decision.
Think you're ready to buy?
Not so fast!
You can buy your own solar power system, but your area may have other options that could work better for you.
You could also:
Buying your system outright may be the best option for you. But then again, it may not, so make an effort to find out what else is out there.
A personal, portable solar power system
There are a lot of portable solar power systems on the market.
You can buy a solar phone charger that's a little bigger than a deck of cards. You can also buy slightly larger chargers to keep your car battery topped up.
Finally, there are carry-along systems of panels that can connect directly to devices, or to a battery to store the power they generate.
What size system should you get?
Well, again, you're going to look at your needs. A lot of people use portable solar power systems to power their devices.
But how much power do your devices use?
Fortunately, almost every electrical product comes with a label that tells you exactly that. The label may give you the power usage in watts, or in amps. To convert amps to watts, multiply by 120.
Saving Electricity warns that the label rating might not always be accurate.
If you want to be sure, you can measure the energy usage of any device using a watt-hour reader. These are generally cheap and easy to use.
If you're buying a portable solar panel system to charge your devices directly, you can find them in a wide range of watt-ratings, from comparatively modest 10-watt systems to 100-watt systems or even more.
And many of them come with USB charging ports to connect directly to your devices.
What about storage?
Storage options depend on a number of factors.
One of these factors is, of course, whether your setup is a stationary home system, or a portable.
Home energy storage
An off-the-grid home solar power system will store generated energy in a battery.
But how do you choose one?
Here are a few essential terms:
Capacity: the total amount of power (measured in kilowatt-hours) your battery can store.
Power rating: how much energy your battery can provide at any given moment (measured in kilowatts).
Depth of discharge: the amount of a battery's capacity that has been used. Most batteries will have a label stating the maximum depth of discharge before the battery needs to be recharged.
Round-trip efficiency: the amount of a battery's energy that can be used as a percentage of the amount of energy it took to store it.
For example, if you store 5 kilowatts of energy, and can get 4 usable kilowatts out of it, then the round-trip efficiency of that battery is 4/5 or 80 percent.
The greater the round-trip efficiency, the better value for money the battery is.
Energy storage on-the-go
If you're considering a portable system, you want to get the most out of it. And that means storing any excess.
How do you do that?
One way is with a generator or power station.
The generator, or power station, is a handheld device about the size of a car battery. You can charge it using your portable solar panels, then use it to charge your devices.
You can, of course, charge your devices directly from many portable solar panel systems. But if you want to save the power you generate and take it with you, you'll need a power station.
Anatomy of a portable solar power system
(1) Portable solar panels
(2) Generator/power station (check compatibility carefully!)
(3) Cables to connect panels, generators, and devices
Can you build your own?
Can you build your own off-grid solar power system?
Yes, you can!
Well, first, you need to evaluate your power needs. Then you need to get your hands on the relevant components.
What are they?
You no longer have to ask, how does solar power work. You already know! And you have a good idea what solar panels are, and how they work as well.
But what about those other things?
The charge controller
A charge controller sits between the solar panels and the battery.
What does it do?
Well, it regulates the voltage -- you remember, the force at which a current travels -- of the electricity coming from the panels.
It makes sure that when this current gets to the battery, it is at the appropriate charging voltage for the battery. This will keep your battery from overcharging.
And that's important.
There are three different kinds of charge controllers. Which one you choose will depend on a number of factors, including price and efficiency.
Great. That's sorted. What's next?
Next, of course, you'll have to think about your inverter.
As you already know, your solar panels take sunlight and turn it into an electrical current. But it's not quite that simple.
There are two types of electrical current: DC (direct current) and AC (alternating current). Solar panels turn sunlight into DC electricity.
An inverter turns DC electricity into AC electricity that you can use to power your devices.
There are, of course, several types of inverters. Which one is right for you?
That will depend on:
Your battery is the final component, and it's one of the most important, too.
Because you can't just use any old one.
You want a battery that allows for slow, deep discharge. Do you remember what discharge means?
Car and bicycle batteries are made to release short bursts of high current before being recharged. But a solar power system needs a battery built for deep discharge.
Learn more here:
There are batteries made specifically for solar power systems, and though they may cost a bit more, you'll be happy you chose the right one for your system.
If you want to read more about building your own off-grid solar power system -- and even see some schematics -- check out this detailed article by electrical engineer Open Green Energy.
Keep Your System Running Strong
Once you've built your solar power system, you want to keep it in tip-top shape.
And that means two things:
Maintenance and troubleshooting.
Fortunately, if you (or your solar company) have done your job, this shouldn't be too difficult.
The best defense is a good offense. And the best way to solve problems is to keep them from happening in the first place.
But how do you take care of a solar power system?
We're glad you asked!
Cleaning your solar panels
Dirt and dust can reduce the efficiency of your solar panels by up to 30 percent by some estimates. It's in your best interest, therefore, to keep your panels clean.
How do you do that?
How often should you clean them?
Well, that depends.
Ecomark Solar recommends cleaning your solar panels two to four times a year. But if you live in a dry, dusty area, you may want to do it more than that.
And if you notice your system isn't producing like it should, checking for dust and dirt on your panels should be your first line of defense.
Inspect your panels
You should also inspect your panels from time to time, to make sure they're not cracking or sustaining other damage.
You can do this when you clean them.
Troubleshooting your system
Even the most robustly constructed solar power systems can experience problems from time to time. It always pays to have a professional lined up for major problems.
But some things you can deal with yourself.
If your system isn't producing like it should, Do It Yourself says there are a few possible causes.
First, check your wiring.
Look for loose connections, rust, and corrosion.
Check every connection.
When heat from the sun causes a solar panel to overheat, it affects the output of the panel. This is called heat fade.
The hallmark of heat fade is a large difference in production between peak production time and other times.
If you suspect your system has heat fade, Do It Yourself recommends having a look at the wiring.
There may be a poor connection or a wire that's too small. You may have to replace that wire with a heavy gauge wire.
You know what a burnt terminal looks like in a car battery: oxidation.
In the case of a solar power system, burnt terminals may be caused by trying to wire too many panels to one terminal.
If this is the case with your system, Do It Yourself recommends first, replacing all metal parts in the affected terminal. Then add an extra terminal.
A Solar Future?
Fossil fuels aren't going to last forever. Solar technology is just one of many promising replacements. We already have the technology to run our homes and devices on solar power.
But what might the future hold?
Attempts to cover cars in solar panels and power them that way have proven impractical. But solar roadways have shown some promise.
The first designers hoped that their solar roadways would generate their own light for signage, their own heat to keep ice away, and would charge vehicles as they drove.
Initial attempts have proved less successful than hoped. However, it remains an interesting idea.
The developing world
Fossil fuels brought great wealth to oil-producing countries.
Could a solar energy boom bring similar wealth to arid places like Saharan Africa?
Many thinkers believe it could. And that's exciting for everyone.
Your solar future
Solar power has a lot of proven potential. It's not ideal for all power needs, however. The post-fossil fuel future will probably include an array of different technologies.
But when it comes to powering your home and devices, solar is a great option with proven results.
Are you ready to declare your own energy independence? Share your thoughts with us in the comment section!