Autonomous Solar Street Lighting: Pros and Cons
For all its necessary, street lighting is a very expensive item. Even on the site of a private house, the payment for electricity used for outdoor lighting is a noticeable amount, and if we evaluate the costs on a city scale, then the amount of costs increases hundreds of times.
A lot of cost reduction options have been found. One attractive option is solar-powered street lighting that eliminates utility power consumption. Consider how this idea can solve the problem and whether “solar” lights will replace traditional outdoor lighting technologies.
The idea of creating an outdoor lighting system independent of network sources, which will provide itself with electricity, is attractive and very tempting. A complex of lighting devices is emerging, created on completely different principles and creating new opportunities.
Since the luminaires do not have a connection to the power line, there is no need to be tied to one place. Lanterns can be moved as needed, temporarily installed in one place or another. The laying of lighting lines is greatly simplified, the need for earthworks disappears, there is no need for a large amount of expensive cable.
However, considering a stand-alone lighting system, one cannot see only the positive aspects of using it. It should be taken into account that each lamp must have its own set of solar batteries and a storage capacity that allows the lamp to work throughout the entire dark time of the day. The longer it is, the more powerful the batteries must be and the larger the area of the photocells, which complicates the design and makes it much more expensive. As a result, a situation may arise when the creation of an autonomous system will be much more expensive than installing a stationary line.
Autonomous solar-powered lighting is designed to provide normal visibility on city streets or in private house areas at night. Unlike stationary lights, solar street lights for street lighting require a certain amount of time to recharge, which is done during daylight hours. As a rule, lighting is not required during these hours, so the equipment has the ability to restore the energy reserve expended overnight.
Such complexes can perform different functions:
- Lighting of roads or pedestrian roads;
- Solar-powered street lights for a summer residence or a country house;
- Illumination of the territory of industrial enterprises, warehouses;
- Lighting devices for lighting stairs, walkways, railings or parapets, other structures and fences;
Other places of installation of lamps are possible for solving various tasks. The main feature of such systems is their versatility, the ability to move or change the configuration of devices. Since they have the same functions, the tasks performed can be very diverse; this will practically not affect the operating mode of the devices.
Stationary lights are installed taking into account the stability and immutability of the environment. If any buildings are transferred, the configuration of buildings is changed, annexes and other additional structures appear, the operating mode of the lamp may completely change, which will require the transfer of the lamp. This means the need for earthworks, new connections, installation, etc.
The flux of light from stand-alone luminaires, as a rule, is much less than from stationary lamps. This is because the solar lamp uses up the resources stored in its own battery. Its capacity is limited, which makes it necessary to use stocks sparingly. Therefore, the use of stand-alone lanterns, as a rule, is limited to the maintenance of local sites or decorative and auxiliary design of the territory.
The advantages of stand-alone lamps are considered to be:
- Independence from network resources, interruptions or sudden outages, the general state of the power system;
- No need for stationary installation, the ability to quickly and easily rebuild the entire system;
- Compactness, small size of lamps;
- Ease of movement, the ability to quickly deliver flashlights to any point without the use of special equipment;
- Most luminaires perform in parallel a decorative function, decorating a site or an installation point;
it is possible to set the time to turn on and off each lamp separately;
- Installation is very simple and does not require the involvement of highly paid specialists.
In addition to these important and useful advantages, it is necessary to mention one of the most important advantages – complete security. The fall of the pole, broken wires or other incidents with stationary lights can create a lot of problems and injure people. A live wire that falls to the ground is a very insidious trap for a pedestrian. You can forget about these dangers when using solar-powered luminaires.
The disadvantages of stand-alone lamps should be considered:
- Dependence of the operation of photocells on the time of day, weather conditions and the position of the panels;
- Operating time depends on the capacity of the batteries and the amount of charge;
- There is no possibility to illuminate large areas or give out a high brightness of the glow for a long time;
- The installation of such lamps must be carried out in well-lit areas;
- In cold weather, batteries dramatically reduce performance;
the compactness and portability of stand-alone flashlights makes them easy targets for intruders.
To eliminate some of the disadvantages, you can use a solar panel module. A more powerful external battery will help to increase the operating time and brightness of the glow, but all these additions drastically reduce mobility and require a wired connection of all lamps into a single system. This is not always convenient, especially if they are located on the sides of paths, stairs or walkways.
Knowing the shortcomings of stand-alone luminaires helps to anticipate possible problems in advance and better place the lanterns on the site.
Solar powered lamp device
All solar-powered street lamps, for summer cottages or for lighting city streets, have a single set. Regardless of the shape, size, type of installation, they consist of the following elements:
- Bracket or support structure;
- Solar battery (photovoltaic cell).
A large number of lamps of this design are on sale. They all have different parameters, power, brightness level and other features. At the same time, lanterns for outdoor illumination have a common feature – they do not work directly, like clocks or calculators do, since street lighting is used at night when there is no energy source in the sky. Therefore, the main indicator of the quality of the flashlight will be the battery capacity and the approximate time spent on the charge.
Photovoltaic cells during daylight hours receive the flow of sunlight and generate a certain amount of energy corresponding to the type of panel construction. This energy is transferred to the battery, which stores it until its capacity is fully charged. If the weather is cloudy, charging will still take place, since some of the panel’s energy will be given back anyway, but it will not be possible to fully charge the battery. This will shorten the working time of the flashlight at night.
At dusk, a sensor is triggered, switching the system to operating mode. The energy from the battery is transferred to an inverter, which converts it into a voltage with standard parameters, after which it is supplied to the lamps. Their work will continue either until a signal is received from the light sensor at dawn, or until the battery is completely discharged and the power supply is cut off.
There are designs that work according to a simplified scheme. Batteries store energy, which they give to the luminaire in the same form. This is possible for DC lamps. The cost of such lamps is less, since most of the equipment is missing, however, the efficiency and duration of the glow are very short.
Solar-powered road lighting systems use a complete scheme for receiving, storing and converting energy. They are installed on high supports allowing to solve several problems simultaneously:
- Ensuring the optimal position of solar panels to receive the maximum amount of energy;
- The high arrangement of the lamps contributes to a wider coverage of the area;
- The equipment is out of reach of vandals and intruders.
The composition of the set of solar-powered lighting equipment is no different from the usual set of devices:
- Photovoltaic panel;
- Battery, controller and converter located in the equipment cabinet;
- Lamp (usually LED construction);
- Brackets, connecting wires.
The street lighting system does not allow for failures or lack of light for any reason. Therefore, the quality of the equipment, the capacity of the batteries and other parameters of the equipment are selected in such a way as to ensure that the critical part of the road is provided with a standard flow of light. This requires a solid power reserve in case of cloudy weather for many days. The surplus energy accumulated on sunny days is dumped into the grid or sent to power the kiosks located nearby.
Illumination of pedestrian crossings
In the dark, especially in the off-season, when visibility on the roads drops sharply, high-quality illumination of pedestrian crossings is necessary. An effective way of lighting is to use automatic solar-powered lights. They light up on a signal from the motion sensor and stay on until the person moves to the other side. The set is standard, supplemented with a motion control device and a relay that ensures the operation of the luminaire for the period of time required for the transition.
Choice of lanterns for street lighting
The number of autonomous lighting fixtures on store shelves is often perplexing. Solar lamps offered to users have various parameters, sizes, power levels and other features. It is rather difficult to choose the best option, especially since there are many products from the countries of Southeast Asia on sale, relying on the quality and compliance with the declared characteristics of which is risky. Let’s consider the most important indicators that you should pay attention to first of all:
The power value of a luminaire largely depends on its design. Most users are well versed in the parameters of incandescent lamps, but the most efficient LED designs have completely different indicators.
Protection class and housing material
Solar-powered luminaires for summer cottages, a plot of a private house or cottage, other installation sites, have one common feature – they work in street conditions. In order to ensure proper performance and durability, the luminaire must be protected from external influences. It is necessary to choose lamps in strong and sealed housings made of reliable and resistant material. The best option is aluminum or impact-resistant plastic.
Type and method of installation
The way the luminaire is mounted determines its capabilities – the area of illumination, the degree of reception of sunlight, etc. There are different options:
- Ground installation. As a rule, these are solar-powered street lamps for a country house, which are installed along paths, near stairs, entrances or other places that require lighting. For installation, a pin is most often used, attached to the lamp post, which is simply stuck into the soil.
- Wall mounting. Installation on vertical surfaces, walls, trees, fences, etc.
- Suspended models. There are a lot of installation options, any beams, branches, horizontal beams.
- Built-in structures. They are installed so that the flat shade forms a single plane with the supporting structure. They are used to illuminate steps, parapets, pillar supports, etc.
- Decorative lamps. Decorate and decorate the landscape of the site.
Everyone chooses the best option based on their own preferences, capabilities and needs.