When describing solar energy street light, which criteria do you use? Perhaps you distinguish them based on their design or appearance, which is commonly used by many. There is another way to differentiate these types of street lights, and this is by considering the kind of connection they have with the mains grid.
Using this criterion, you will find that there are three types of solar powered streetlights: grid-tied (on-grid), off-grid, or hybrid. Let’s go through each one of them and get to understand when to use them.
Grid-tied (on-grid) Solar Energy Street Light
These types of street lights use solar energy and are usually connected to an electrical power grid. This means by the end of the month, there would be an electricity bill, which is less than what you would expect from a fully grid powered street light.
These street lights are powered by a microgrid system, which is basically a mini-version of the electrical power grid. Where the streetlight grid is connected to the mains g, then the whole system will be affected by an outage.
The micro-grid can be a stand-alone system that uses batteries as back up storage. This system generates its own local energy for use during emergencies caused by severe weather and outages or when the power is used up.
Using a grid intertie system can help you offset your electricity bills by installing solar panels on existing poles to contribute to the grid. During the day, your PV arrays convert solar energy to electricity and feed it to the mains. During the night, you will be able to utilize grid power from your local power company for your street lighting needs at a lesser cost.
These types of street lights can be applied when it is costly to run distribution lines through homes or buildings and where there are restrictions in running these lines. The grid system makes works best when you wish to eliminate the use of solar panels on the post.
For this case, solar energy is harvested in one place and then supplies the electricity to a set of street lights. This unit has only two primary components: the lighting fixture and the pole.
Stand-alone (off-grid) Solar Energy Street Light
These types of solar-powered streetlights do not connect to any electricity grid. Stand-alone solar street lights are found in remote areas where it is expensive to run distribution lines to the unit due to its distance from the grid. They are popular in rural areas where there is no electricity connection.
The Solar photovoltaic equipment in the street lights generates and supply electricity to the lighting source. This unit has four essential components: the power source, storage, light source, and pole. A direct-coupled street light system is rare since it does not necessarily need a battery; The solar energy produced is directly consumed by the lighting system, so it is only useful during the day.
Most modern solar energy street lights fall in this category. They come with compact designs that integrate the photovoltaic cells and the battery onto the surface of the lighting system. Therefore, some of them could come with two essential components, the lighting fixture, and the pole.
This retrofit is more expensive to purchase but offers life-long years of service to compensate for the initial cost. We are talking up to 30 years for the solar panel and replacement of the solar bulbs after two years and battery after 15 years.
Hybrid Solar Energy Street Light
The hybrid type of solar-powered street light uses both of the above-listed systems. This kind of system is useful in an area where the weather conditions do often fluctuate. Here, the grid system is only activated in terms of emergencies, especially when the standalone battery runs out of electricity.
The source of energy stored in the grid may not necessarily be from solar arrays, other sources include wind and diesel power. This system needs a power management center to regulate the power generated from each source, protect the battery, and control the flow of energy to the lights.
Hybrid solar street lights use grid power as a backup system. Similar to the on-grid type, the smaller batteries backup systems feed excess energy to the grid. During the night, the streetlights are run on its batteries for a set amount of time and then followed by grip power for the remainder of the night.
This setup is ideal in areas where it is prone to power outages. One may choose to run the streetlight on-grid and later switch to battery use when there is a power outage. In situations where brighter illumination is required, the battery may offer about three to four hours of power supply, the rest of the power can be obtained from the mains.
In the case where the solar energy is used as a backup, this setup will require a more extensive battery backup to provide sufficient power in times of grid outages.
Solar Energy Street Light: Conclusion
These are the three types of strategies you may use to maximize your costs when it comes to solar energy street lighting. Various external factors may lead you to choose one of the three categories. In some countries, the hybrid and on-grid power systems may not be supported.
The popular type of solar streetlight based on grid connection is the off-grid or stand-alone power system since the installation is just a snap. However, in a situation where more power is required at night to meet the illumination levels needed then it would not be a suitable choice.
The off-grid beats the two in terms of electricity bills, total disconnection from the network incurs only repair and maintenance costs. In terms of an unlimited supply of energy, the grid-tied and hybrid power systems are the most preferred.
Whether you choose grid-tied, off-grid, or hybrid solar energy street light, you will still make a significant amount of savings. More savings can be achieved when you optimize the main components of your streetlight.
Read our article on Advantages of Solar Street Light in Developing Countries.