Do Solar Panels Work at Night?

Without the power of direct sunlight, solar panels do not work at night. While technically solar panels can work at night when exposed to moonlight or a secondary light source, any amount of electricity produced after dark will be insignificant compared to ordinary daytime generation.

The fact that photovoltaic (PV) panels are not designed to work at night doesn’t mean going solar does not make sense logistically or financially for homeowners in the US. Today, homeowners can still power their properties with cheap and green solar electricity all day and night long using battery-backed solar energy systems. 

In this article, we discuss precisely how a solar energy system can work at night to help you maintain low electricity costs and reduced carbon emissions all year long.

How Solar Panels Work at Night

Solar panels harness sunlight and convert its energy into electricity. Therefore, no sun means no electricity, right?

Well… yes. As the sun rises, hangs in the sky, and sets each day, solar power production is determined by the intensity of the sunlight shining on the panels. The majority of solar electricity is generated during peak sun hours, which fall between the late morning and mid-afternoon when sunlight hits the installation at the most direct angle. 

Then, even after the sun disappears beyond the horizon, solar electricity can still technically be produced at night if the panels are exposed to another source of light. While artificial light sources can be used to charge solar panels, doing so would result in a net energy loss and doesn’t make sense as a nighttime solution. 

Solar panels will generate minuscule amounts of electricity when exposed to ambient light from the moon, street lamps, or city glow. Amazingly, sunlight reflected off of a full moon can charge solar panels at a rate roughly 350,000 times slower than ordinary daytime exposure. 

How Solar Energy Systems Work at Night

A solar energy system consists of much more than just a set of panels, and there are several ways in which solar electricity can be utilized overnight. The nighttime benefits of your solar panels differ depending if your system is battery-backed or grid-tied systems. 

Grid-connected solar panels at night 

At night, homes connected to the grid can still draw power from the energy utility. This electricity is purchased at retail rates, though you may have credits from excess solar energy you sent back to the grid during the day. 

Here’s how those credits—from utility programs like net metering and net billing—work:

1. Throughout the day, your solar panels produce more electricity than your house can use. Let’s say that, on a bright spring day, your solar panels generate 45 kWh of electricity, while your home only consumes 30 kWh before the sun goes down. 
2. The remaining 15 kWh is sent to the grid and credited towards your energy bills. The value of these solar credits vary by state, utility, and policy. Advanced utility-billing mechanisms work to credit homes for excess solar production for their value at the exact moment of transmission, and compensation can be seen on utility bills and within solar monitoring apps.  
3. Overnight, these credits can then be applied to your account to “cancel out” the cost of any electricity drawn from the grid. Those 15 kWh of excess solar can power refrigerators, lights, routers, entertainment systems, and more.

In this case, your credits cover the cost of your overnight electricity. The electricity you get likely won’t be solar power.

Battery-connected solar energy systems at night

Whether your home is connected to the grid or over the river and through the woods miles away from utility power lines, battery storage can give you access to your solar energy at night. If your property is completely off the grid, a battery is 100% necessary to create a sustainable solar energy system. 

A battery-backed solar energy system works like this:

1. Excess solar produced throughout the day is sent to the battery storage bank. Any electricity beyond battery capacity is sent to the grid, if possible. 
2. At night, homeowners can draw solar electricity from the battery bank. The solar power will pass from the battery through an inverter so that it can run home devices directly using wall outlets. 
3. In the morning, the batteries can be recharged when new sunlight is available.

Batteries can also help homeowners tap into their solar resources during rainy days, blackouts, or extended periods of overcast, fog, or smoke. Today’s top solar batteries include app-based controls and advanced features to manage home energy use efficiently.  

How to Optimize Solar Energy Systems for Night-Time Use

When designing your system, solar installers won’t take into account the miniscule amount of nighttime solar energy. Still, there are things you can do to maximize your renewable energy use at night. 

• Seek annual consumption coverage. Find the right size solar system to cover your annual electricity consumption. This way, if you have net metering available, solar credits generated through the day and summer can be applied to your electricity bills at night and throughout the parts of the year with fewer daylight hours. 
• Consider a battery. As net metering policies change, such as in California’s NEM 3.0, battery storage can help PV system owners have more control over their solar energy use and costs overnight. 
• Pair with smart home devices. Whether grid-tied or battery-backed, homes with solar panels can utilize integrated smart devices for optimal home energy use, including timers, sensors, smart thermostats, energy-efficient lighting, heat pumps, and more. 
• Employ smart energy habits. Homes that use most of their energy when the sun is up can benefit the most from solar installations, and homeowners who monitor their solar energy production can make more informed decisions to ensure long-term savings. 

Conclusion

Although solar panels rely on direct sunlight to generate significant amounts of electricity, today’s grid-tied and battery-backed solar energy systems enable renewable power use 24/7/365. Homeowners employing smart energy habits can maximize the value of solar panels, both at night and throughout the year to achieve environmental and financial goals.

For the sake of the environment and your ongoing electricity costs, Palmetto is here to help create the best possible solar energy solution for your home. If you are interested in a free consultation, please contact a Palmetto solar advisor today.

About the AuthorBrian ChurchWriter

Brian is a writer, NABCEP PV associate and outdoor enthusiast living in Denver, Colorado. As a freelancer, Brian has written hundreds of articles to help individuals, businesses and our planet benefit from solar power and sustainable energy systems.