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Do Solar Panels Work on Cloudy Days?

Do Solar Panels Work on Cloudy Days?

Last updated on October 23, 2024

So you’re thinking of installing solar panels and wondering if they will still generate power when the sun isn’t shining.

After all, if solar panels don’t work on cloudy days, that could put a real damper on your energy independence.

The good news is that solar panels do work even when the sun is obscured by clouds. However, they operate at a lower efficiency since fewer photons from the sun hit the panels.

Here’s how solar panels work;

Solar panels contain photovoltaic cells that convert sunlight into electricity through a process called the photovoltaic effect. When photons of light strike the cells, they knock electrons free from their atoms, creating a flow of electricity.

On sunny days, solar panels perform at peak efficiency because more photons are reaching the surface. On the other hand, on cloudy days, fewer photons penetrate the clouds, so less electricity is produced.

However, solar panels can still generate a fair amount of power from the diffuse light that crosses the clouds.

The actual output will depend on the density and type of clouds, but you can still expect an output between 10-25% of the maximum power on an average cloudy day.

So while solar panels are most efficient in direct sunlight, they can absolutely work and produce power even when the sun is obscured behind a blanket of clouds.

Going solar means having an energy source you can depend on, rain or shine. The sun may be hidden, but its power is still reaching your panels.

How Solar Panels Convert Sunlight Into Electricity

Solar panels work by converting sunlight into electricity using the photovoltaic effect.

As photons of light strike the solar cells in the panels, they knock electrons loose from their atoms which frees the electrons to flow through the cell, creating an electric current.

More light hitting the panels means more electricity produced. So while solar panels do work on cloudy days, they are most efficient in direct sunlight.

During cloudy days, solar panels can still generate electricity, but at a reduced output. The amount of power produced depends on the intensity of light and the time available.

Working diagram of a solar power system

The Impact of Diffused Sunlight and Solar Irradiance on Power Output

Even on cloudy or overcast days, solar panels can still generate power, just not as much as on sunny days. Here’s why.

Solar panels work by absorbing sunlight and converting it into electricity through the photovoltaic effect. They operate based on the solar irradiance, which is the amount of sunlight energy that reaches a given area, which is measured in watts per square meter (W/m2).

On sunny days, depending on the area, solar irradiance can be 1000 W/m2 or higher, which means more available energy for your panels to convert into electricity.

On cloudy days, the sunlight is diffused by the clouds, so less irradiance reaches your panels, close to 200-500 W/m2 are common, resulting in lower power output.

However, as long as some irradiance reaches the panels, your solar panels will produce power. The actual output depends on factors like:

  1. The density and type of clouds. Thin, high clouds have less impact than thick, low-lying clouds.
  2. The panel’s efficiency rating. More efficient panels can generate more power from less irradiance.
  3. The inverter’s performance. A high-quality inverter helps ensure maximum power output in low-light conditions.
  4. Panel orientation. Panels facing the sun directly collect the most irradiance and produce the highest output, even on cloudy days.

Inverter Technology and Energy Storage Enable Solar Panels to Work Even on Cloudy Days

Solar panel systems can still generate electricity even on cloudy or overcast days, thanks to advancements in inverter technology and energy storage.

Inverters Convert DC to AC

The solar panels themselves produce DC (direct current) electricity, but our homes and electrical grids use AC (alternating current) power. Inverters are used to convert the DC power into AC so you can use the energy from your solar panels.

Also read; What is a Solar Power Calculator

Modern inverters are very efficient at converting DC to AC, even when the sun isn’t shining brightly. They can work with the minimal energy production on cloudy days and convert it to usable AC power for your home.

Batteries Store Extra Energy

Many homeowners also install battery storage units to complement their solar panel system.

These large battery banks store extra energy produced by the panels on sunny days so you can use it when the sun isn’t out. The batteries ensure a power supply to your home using the stored solar energy.

Some solar panel systems can recharge the batteries on overcast days when there is still some limited power generation. The batteries ensure you always have access to renewable, sustainable energy, even at night or during storms.

Maximum Power Point Tracking

Inverters also use maximum power point tracking (MPPT) to get the most power possible from the panels under all weather conditions. MPPT is technology built into the inverter that helps solar panels operate at their highest efficiency.

It can detect the maximum power the panels can produce at any given point in time based on factors like temperature, sunlight intensity, and cloud cover.

The inverter then draws the maximum available power from the panels to charge batteries or to power your home. MPPT allows you to take full advantage of your solar panels on cloudy and rainy days.

Do Solar Panels Work on Cloudy Days – The Takeaway

So while solar panels will produce less energy on cloudy or overcast days compared to sunny days, they can still generate power as long as some light gets through.

The solar cells don’t need direct sunlight to operate, they will be able to operate on diffuse light from the sky and clouds.

As solar panel technology improves, their efficiency in low and indirect light conditions is increasing. For most residential setups, solar panels are capable of meeting a good portion of your energy needs even on cloudy days.

If you have energy storage systems like batteries, the excess power generated on sunny days can help supplement your power needs on cloudy ones.

the weather can’t be controlled, solar panels and a solid energy plan can help ensure you maximize the benefits of your system no matter the forecast.

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E-Green Electrical

E-Green Electrical is a top tier energy efficiency company based in Sydney. We focus on utilising government rebates to help reduce our clients energy consumption by installing energy efficient solutions. E-Green boasts a rich heritage within the realm of energy efficiency, consistently staying up to date with cutting-edge technologies to deliver optimal results for our valued customers.

We don't just sell products and services; we also provides tips and information on how to help reduce energy consumption. We believe in using energy wisely and teaching others how to do the same. For E-Green, it’s important to share knowledge with the community. That's why we regularly write articles about saving energy, new government rebates available and increasing sustainability.

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