How Solar Powered Street Lights Work

Lighting up public places like streets, roads, and parks is a necessity. The lights provide a sense of security in the dark of night. However, these street lights consume lots of energy. Only in the United States, street lights consume the same amount of energy as 1.9 million households. The street lights are also responsible for generating carbon emissions equivalent to 2.6 million cars.

Solar Powered Street Lights

An alternative to this that has really caught on in a few states recently is the use of solar-powered street lights. Solar street lights are not only energy and cost-effective but are also environmentally-friendly. 

Let’s take an in-depth look at how solar street lights generate the energy required and how they help the environment.


If we are to put it into layman’s terms, solar street lights work by converting solar energy into electricity. Solar lights are dependent on the photovoltaic cells(solar cells) which absorb solar energy in the daytime. The cells then convert solar energy into electric charge and store that electricity charge into the battery. The charged battery is what allows solar street lights to work at night. 

An interesting thing is that there are different types of solar street lights you can use. The most common are the LED solar lights, other kinds include:

  • Sodium vapor street lights. These lights use sodium as a light source. Sodium is kept in an excited state and discharges the light it stored during daytime exposure to the sun. 
  • Induction-technology based street lights use lamps that don’t have filaments. This prevents the lamps from getting damaged and prolongs their lifetime. Induction based lights also have a lower maintenance cost and generate less heat. 

LED Solar Lights

Now we take a closer look at the most used solar street lights; LED solar street lights.

LED solar lights have LED lamps i.e. light-emitting diode lamps. The LED lamps have a special material that produces light when direct current passes through the diode. 

LED lights are preferred over other types because of several reasons. LED solar lights are available in various sizes and designs. LED lights are more durable as compared to Sodium and Induction-technology street lights. LED solar-street lights can last for as long as 50,000 hours and they use less energy as well. This allows them to use smaller panels as well which makes their overall cost very low as compared to other solar street lights. 

  • LED solar lights depend on the photovoltaic effect which converts solar energy into electricity. This happens when negatively-charged electrons carry solar energy into positively-charged spaces in the photovoltaic cells.  
  • This process transfers solar energy into electrons which generates a direct current. The direct current is then stored into a battery connected to the panels using wires. When night time arrives and the sun goes down, the lights use this charge to continue lighting up the streets. 


Sensors are the reason that solar street lights work so efficiently. There are sensors installed in the solar street light fixtures which control the working of the solar lights. These sensors control when the solar lights will be turned on and off depending on the intensity of daylight. They also control the radiance levels of the lights depending on time and sunlight intensity. 

The time control feature makes sure the LEDs don’t start shining at 100% when the sun barely goes down. For example, they work at 50% radiance at sunset time and work their way up as time passes. So, the radiance level may increase to 80% at 7:00 pm and 100% at 9:00 pm. Simply, the light will get brighter as the night gets darker. 

Rechargeable Battery

An important component that makes solar street lights work is their rechargeable battery. Solar street lights have a battery attached to their fixtures. During the daytime when the sun is shining, the solar cells can generate electricity from solar energy and power up the lights. 

However, at night these solar cells cannot generate any energy and that is where the battery comes in. During the daytime, the cells generate electricity and also charge the battery simultaneously. If not for the fully charged battery, the solar street lights won’t work at night at all. 


With the above guide, you now hopefully have a basic idea of how solar street lights work. The guide also describes a couple of components that help the solar street lights run efficiently and without any problems. 

Street lights are a necessity, they are very important for the safety and security of the people but they consume too much energy. However, solar street lights have provided a cost-effective and green alternative to street lighting. 

It feels good to see the strides we are taking towards switching to a renewable energy source that doesn’t have any adverse effects on our environment. There is still a long way to go and hopefully, we will get there soon. 

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