It’s expected that there will be 359million total streetlights in the world by 2026. Just imagine how much power will be consumed by such a huge amount of street lights every year.  In the trend of increasing depletion of fossil energy， much more is required to meet the mounting demand for power consumption.   Fortunately, people have long been aware of this problem and have started to utilize renewable energy sources such as solar and wind power years ago and have made significant progress. 

As a type of renewable energy, solar power is inexhaustible, eco-friendly, and easier to access and utilize compared to wind energy.  The solar-powered street lighting solution is a typical application of solar power, each light is a stand-alone off-grid solar system. 

How does Solar Street Light work? 

Solar panels capture sunlight during the day and convert it to electricity under the control of a solar charge controller. The storage battery will be charged by solar modules. The LED light source is powered by the storage battery at night. A DC controller can prevent the storage battery from damage caused by overcharging or discharging. 

The solar panel is a photovoltaic (PV) module made using the principle of PV effects and acts as a photocell during the day to receive solar energy and convert it into electrical output, which is stored in the battery through the MPPT or PWM smart controller. When the illumination decreases at night, the battery charges to the led lighting fixture after the smart controller detects a certain voltage value. The lamp is lit. This process is reversed during the day.  

Let’s take a look at the consistency of each solar street light system. There are 4 major parts: solar panel, rechargeable battery, led light, and controller.   The solar panel absorbs sunlight during the day and converts it to electricity under the PV effect.  And then store the electricity in a rechargeable battery through a solar charge controller. At night, the led light is powered by the battery and operates to illuminate the road area. With the advanced smart controller, the solar street light works intelligently, when the sunlight decreases in the dark， the voltage from the solar panel is lowered down, and the controller detects the voltage change and orders the battery to discharge and light up the led fixture.  When the sunlight increases during the day, the process reverses.   With the latest technology, the solar street lights can give off light on successive nights even when the sun’s energy is not available for a couple of days.    Nowadays, a number of reasons are driving users to switch to solar street lights.

Advantages and Disadvantages of Solar Power Street Lights

Like any other thing, Solar street light has their advantages and disadvantages in their utilization, it’s essential to understand both.  

Advantages 

Typically, there are a number of benefits to solar lights, including no-needing for grid power and easy installation. However, what you need to think about is that if these advantages are persuasive to replace traditional street lights with solar-powered street lights. 

 1. Energy-saving and Eco-friendly  

 It is an indisputable fact that carbon footprint is causing global warming. There is a growing awareness that using green energy can help reduce carbon footprint. People around the world are pushing hard to promote environmentally friendly green energy for purpose of protecting our planet. All we know is that Coal, natural gas, oil, and other non-renewable energy sources may one day run out. Solar street lights do not require any fuel and run entirely on solar energy. Solar energy is unlimited and inexhaustible, making it an ideal green lighting option.

2. Cost-effective

Solar street lighting is a better investment, both in terms of capital as well as operation and maintenance costs. Solar lights don’t require you to pay for electricity every month since they’re powered by renewable energy.   Installation of the lights does not require any ongoing expenditures as the lights are wireless and not connected to a power grid, there is no cost for trench and cable connection.

3. Low maintenance costs 

 Each solar street light is powered by solar energy, which means you won’t be charged for electricity. There is no need to replace the single solar street light – the solar charge controller manages the light intensity, This results in cheap maintenance. Moreover, after the installation, there is no need for manual intervention, so you may save money on maintenance costs too. Furthermore, solar-led street lights will illuminate throughout the night, regardless of weather conditions or power outages.

4. Simple Installation, without power facilities 

Typical commercial power lighting projects require cable work, excavation, laying cable pipes, threading the cable inside pipes, and ditch waste disposal. Each of these processes requires considerable labor and equipment. Furthermore, the transformer, distribution cabinet, as well as switchboard are all expensive. 

However, there is no electrical connection required during the installation of solar street lights, each solar lighting system is unique. As a result, there are no costs associated with cable laying, trenching, or other similar activities. The preparation work only needs a strong base and a pit for a battery.  In general, the installation process is very simple and easy. 

5.No cable theft or costly cable costs 

Cable theft in remote places is a common issue, and transporting materials and constructing cables can be expensive. 

A solar lighting system eliminates the problems associated with traditional lights. Consequently, there will be no cable to steal since each unit will be independent and without any cable connections. Solar-related thefts won’t affect the operation of any other unit in the system.  

6. Safe and Durable 

Due to aging materials, shoddy construction, and power supply problems, traditional streetlights may be a hidden safety hazard; solar-led streetlights do not use AC power and therefore have no such flaws.   The solar LED street lights to have the ability to generate electricity for their operation for 25 years or even longer. 

Disadvantages

  In recent years, the solar PV industry has been an emerging industry, and solar LED street lights have been widely used for public lighting as well as commercial lighting purposes.  However, there are several defects that hinder the application of solar power street lights.
1. Large initial input cost

 Needs a  large initial input cost for solar street light installation is a  significant defect.  In comparison to traditional street lights, solar power street lights require a larger investment at the installation stage,  the overall cost is 3times of installing traditional street lights with the same efficiency.   This is the key factor that stops us from investing in solar street lights.  

In fact, if we consider the electricity bill and maintenance, and functional costs that will be paid in the long run,  the actual investment in solar LED street lights is cheaper.    

2. The service life of the rechargeable battery  

In general, the common lead-acid battery can not reach full charge in one year or even half a year. Once the charging efficiency declined by 50％, it will definitely influence the lighting status at night, especially during continuous raining days. Thus, it is necessary to choose the high-quality LiFePO4 battery with a long life cycle for your solar street light project

3. Risk of theft

Having said that the solar street light has a large monetary worth component: solar panel and storage battery, which are attractive to thieves. Furthermore, the solar power street lights are not wired to grid power, there is not life-threatening to thieves. So the risk of theft is more than in traditional street lighting systems. 

4. Solar panel efficiency is lowering in Sand-dust or snowy weather.

Solar panels might not work efficiently in extreme weather conditions, especially when dust and snow completely cover the horizontal solar panels and their efficacy will be very low.  It’s typically to install the solar panel with a tilt to assure the dust can be clean by rainwater. Even though, it’s recommended to clean the solar panels periodically to maximize the efficiency and prolong the life cycle of the solar street light system.

5. Replacement of batteries

There are three types of batteries that are commonly used on solar street lights, lead-acid, gel, and lithium battery.  Compared to the other two types, the upgraded Lithium-Iron battery with high durability. Though that, any rechargeable batteries would run out over time and need to be replaced a few times before the end of the life of solar street lights.  

6. Performance is affected by Geographical and weather conditions

 Because solar power comes from the sun, solar radiation differs in various places, and the lighting state of solar street lights may be impacted by the weather situation. 

The place with high solar radiation is perfect for solar street lights, but some places are always cloudy or snowing in winter, the solar street light would not work normally, and the brightness of the lights may not meet the road lighting standard, even not light up.

Conclusion

From this article, you would have had a comprehensive understanding of the advantages and disadvantages of solar street lights.  It’s obvious that the benefits can cover the defects. The improvement of battery technology, it’s expected to reduce the initial input amount and battery replacement costs will be reduced along with battery life-prolonging. The photovoltaic industry will continue to develop rapidly in the coming years. Under the background of reducing carbon footprint, more and more solar street lights will be installed.