The key to success with solar panels is having access to sunlight. While technically, solar panels do not work at night, they capture sunlight during the day so homes can use the electricity when the sun goes down.
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The Basics of How Solar Panels Work
During the day, solar panels collect energy from the sun by absorbing light particles (photons) through photovoltaic cells. The cells generate direct current (DC) that inverts into alternating current (AC). The current then moves through the home to generate electricity after the sunsets and the sky darkens.
Solar Panel Overview
Most solar panels have silicon cells covered by a glass casing held together by a metal frame. Wires connect the silicon cells to send the collected energy to an inverter. Silicon can absorb sunlight and convert it to electricity. As photons work with a silicon cell, electrons start the electric current. This process is called the photovoltaic effect.
When technicians install solar panels on your home, they have to connect the panels to an inverter. Some homes have a single inverter that manages the entire panel array, while others have several microinverters behind every solar panel. The inverter changes the DC energy into AC electricity.
The technician also connects the inverter to your electrical panel. It sends the AC electricity into the solar array then your home’s electrical system uses that energy to power your electric devices, lights, and appliances.
As long as you have energy flowing into your electrical panel, your devices should function just like they would on a municipal electric grid.
How They Store Solar Energy
Homeowners can store solar energy in a variety of ways. Many homeowners have solar batteries that collect the energy gathered during the day. The solar battery gives homeowners access to power when their solar panels cannot collect sunlight at night or on cloudy days.
Solar batteries can also collect a charge from the municipal electric grid. Interestingly, most homes do not use much electricity during the day, as most people are at work or school.
When the solar panels are working, they fill the battery with energy rather than wasting it or sending it back into the power grid. Homeowners can use the battery any time they want.
Another way you can store solar energy is by connecting to the grid and signing up for net metering. The process of incentivizing solar energy is net metering. Homeowners can send power back to the electric grid if their solar panels are overproducing.
Once you have connected your solar panels to your electrical grid, you can help supply electricity in your area. After your solar panels collect energy throughout the day, anything left at the end of the day goes into the electric grid so you can earn credits toward energy bills.
When the solar panels can’t produce, homeowners can draw that energy back into their homes to meet their energy needs. The electric grid essentially stores energy for homeowners with net metering and solar panels.
How to Use the Stored Energy at Night
Fortunately, homeowners can access solar energy at night, but only if they store it during the day. When you purchase your solar panels, you can decide what energy storage system you want to use. These systems let you collect energy during the limited daylight hours and use electricity when sunlight is no longer available.
When you use a solar battery system, you get to use your solar energy without relying on the electrical grid. If you use electricity from the grid, you will still have to pay for it, even if you use net metering. Although, your rate will be lower. With your battery system, your energy bills could drop to zero.
Your electric panel connects to the solar battery and pulls energy from it when the sunsets. Your solar panels will go into sleep mode at night, thus turning on your solar batteries.
Bottom Line: Solar Panels Don’t Produce Energy at Night
Solar panels do not produce energy at night. Interestingly, some solar panels can continue to collect minimal amounts of energy at night. They can only do this if the community has street lights with substantial outputs.
Solar panels can also glean a small amount of energy when the moon is full and bright. Otherwise, solar panels are relatively useless after the sun sets each evening.
Usually, the amount of energy collected on bright, moonlit nights or when the street lights have new bulbs is negligible. Without a solar battery or a net-metering agreement with the electric grid, homeowners will not be able to eke out any electricity from solar panels at night.
As solar panels are growing in popularity, homeowners often have several questions about how they work. These frequently asked questions can help you decide if installing solar panels on your home can help you save money on utility expenses.
Do solar panels work in cloudy weather?
Solar panels can collect energy on cloudy days, but they don’t contain as much energy as they do on sunny days. The amount of energy they collect is connected to the thickness and consistency of cloud cover.
Ironically, solar panels work well in communities that do not have excessive temperatures. Solar panels tend to produce less energy when the temperature climbs above 77°F or 25°C. Solar panels can get so hot that their efficiency drops. So, some cloudy days won’t hurt your energy collection.
Rainy and cloudy days can help your solar panels. The photovoltaic panels can use indirect sunlight and sunlight that is reflected by clouds. Over time, dust and pollen cover solar panels, and on rainy days, the water clears the dirt so the solar panels can function at their peak.
Cloudy places like Seattle and Portland in the Pacific Northwest pull significant energy from solar panels. Even the perpetually cool and foggy San Francisco also gathers a plethora of solar energy each day. The mild temperatures create ideal solar production conditions, which helps balance out the drop-off in the cloudy winter months.
Do solar panels work without direct sunlight?
Solar panels work best when the sun is shining, the sky is clear, and the panels are clean. However, solar panels do not need sunlight – they need light. So, solar panels will collect energy when the weather turns cloudy. Indirect sunlight produces power, but not as much as direct sunlight.
Most solar panels are black so that they can absorb more light, even on cloudy days. When daylight hits the silicon semiconductors in the glass-covered board, chemical reactions generate an electric current. The panel turns the photons into electrons, then sends them off to an inverter so your home can use the AC energy.
When solar panels are shaded, they cannot function at their total capacity. If a percentage of the solar panels are shaded, the rest of the panel will continue to collect light, and the electricity production drops.
Solar panels need direct sunlight to work at their peak. When they get full sun throughout the day, the arrays can collect a maximum amount of energy to store for days when clouds get in the way. Usually, most solar panels function around 60% of their standard capacity on overcast days with indirect sunlight.
Fortunately, homeowners can connect their solar panels to the electric grid or install a battery storage system. These systems give homeowners access to electricity, even if the solar panels get minimal sun for several days.
Peak sun hours only last for three or four hours per day. During this time, when the sun is directly overhead and not covered by clouds, it can provide up to 1,000 watts per square meter on a solar panel. This statistic should give you some perspective on how long solar panels efficiently collect sunlight to convert to electricity.
Do solar panels work in the shade?
Solar panels can work in the shade, but they don’t work at their maximum capacity. Technicians will install them in an area that gets the most sunlight throughout the day, but many homes do not have locations that can be out of the shade all day.
Solar panels can work in low-light conditions, but homeowners who want the most out of their panels should find a spot that gets the most direct sunlight. Some types of shade will affect solar panels more than others.
The most common cause of shade on solar panels is the clouds in the sky. While there is nothing that technicians can do to avoid placing solar panels in areas that get clouds, they can put them in the regions that eliminate the majority of causes of shade.
Another common reason that solar panels are covered by shade is trees. Residential areas often have trees, and in some communities, technicians cannot avoid them when installing solar panels.
Other panels can also cause shade. Technicians that do not consider where shade occurs during the day can accidentally place panels where other panels can block direct sunlight throughout the day. Usually, panels do not completely block the sunlight on other panels. So, they may not work at total capacity, but they can still collect energy.
Panels on the ground can be covered by shade from surrounding buildings and their rooflines. Communities with dense populations tend to create challenges for installers with limited places to get maximum sunlight for solar panels.
When installing solar panels, at least half of the panel mustn’t be covered by another panel, a roofline, or a tree. If more than 50% of the panel is covered, the entire panel could become useless. Fortunately, solar panel manufacturers find solutions that help the panels work effectively in shady and low-light conditions.
If you have a lot of shady spots in your yard, you could decrease the lifespan of your solar panels. When shade covers some photocells, the uncovered cells have to work harder to compensate for the covered ones. These hard-working cells tend to overheat or fail sooner because they have to over perform.
Does the moon generate solar power?
Solar panels can generate power from the moon. Remember that the moon reflects sunlight so that indirect light can create some power through your solar panels. The reflected light is weak, so you will get a minimal amount of energy, usually about 300 times less than you would get during the day, and only if the moon is full.
When the moon is half-full, you will get even less energy. So, if you get 10 W of power from a full moon, you would only get about 5W from a quarter moon. You can maximize the output by creating a device that would reflect or refract the moonlight.
Photovoltaic cells will create energy if the light’s wavelength is violet to near-infrared. But, on a moonlit night, the best solar panels cannot generate enough energy to power one LED bulb.
Unfortunately, the inverter won’t work if the moonlight is low, even if the solar panels produce small amounts of energy. Engineers are working on creating panels with photovoltaic cells that can capture more light from the moon to function throughout the night and reduce the need for net metering and battery storage.
Solar panels need sunlight in some form to generate energy. While they can work on cloudy days and in shady locations, they do not create as much energy as on sunny days. However, solar panels tend to decrease efficiency in hot and sunny places, especially when temperatures are above 80°F.
The placement of each solar panel matters, especially if you live in an area with a high population density and plenty of trees. Excessive shade can dramatically reduce energy collection, making it hard to get the most of your solar panels.
Interestingly, solar panels can work at night, but they do not collect much energy. To truly benefit from solar panels, homeowners need to store the energy they collect during the day with net-metering or battery storage technology to properly utilize it at night.