Solar street lights are a type of streetlight system that uses solar energy as a power source, utilizing components such as solar panels, batteries, controllers, and LED lamps for automatic switching and illumination. They offer advantages such as energy saving, environmental protection, safety, aesthetics, and convenience, making them a green lighting product that aligns with the concept of sustainable development.
Market Prospects of Solar Street Lights
With the intensification of the global energy crisis, solar energy, as a clean and renewable energy source, has garnered increasing attention and recognition. As a key area of solar energy application, solar street lights are also experiencing rapid growth. According to statistics, the global solar street light market size was approximately US$5 billion in 2019 and is expected to reach US$12 billion by 2025, with a compound annual growth rate of 16%. The growth of the solar street light market is primarily driven by the following factors:
Policy support. To promote the promotion and application of solar street lights, many countries and regions have introduced a series of policy measures, such as subsidies, tax reductions, and preferential loans, to reduce the initial investment and operating costs of solar street lights, thereby increasing their market competitiveness.
Technological progress. With the continuous advancement of technology in core components such as solar panels, batteries, controllers, and LED lamps, the performance and efficiency of solar street lights are also increasing, while their costs are also decreasing. This makes solar street lights more adaptable to diverse geographical and climatic conditions and better meet diverse lighting needs.
Environmental awareness. With the increasing severity of global climate change and environmental pollution, people are increasingly aware of energy conservation, emission reduction, and green development. As a pollution-free and carbon-free lighting method, solar street lights align with people’s environmental protection concepts and are gaining increasing favor and popularity.
Research Significance and Purpose of Solar Street Lights
As a new lighting method, solar lights have great development potential and social benefits, but they also face certain technical and market challenges and issues. Continuous research and innovation are needed to improve their performance and competitiveness, expand their application scope and market share, and bring greater value and contribution to society and the environment. This article aims to provide a comprehensive and in-depth analysis and review of the current state of solar street light technology, innovation trends, socioeconomic benefits, and environmental impacts. This review aims to provide reference and lessons for the research and development of solar street lights and offer guidance and suggestions for stakeholders involved in solar street light research and development.
Current Technical Development of Solar Street Lights
The technical development of solar street lights primarily involves four aspects: solar panels, batteries, controllers, and LED fixtures. The following describes the technical parameters and performance indicators of each of these four aspects, as well as the technical difficulties and challenges they present.
Solar Panels
Solar panels are the power source of solar street lights, converting sunlight into electricity and storing it in batteries. The key technical parameter of solar panels is their photoelectric conversion efficiency, which is the percentage of sunlight converted into electricity by the panel, generally expressed as a percentage. The higher the photoelectric conversion efficiency of a solar panel, the better the performance of the solar street light, lower energy consumption, and lower costs. Currently, the following types of solar panels are commonly found on the market:
Crystalline silicon solar panels. Crystalline silicon solar panels are the most commonly used type of solar panel. Depending on their crystal structure, they are divided into monocrystalline silicon solar panels and polycrystalline silicon solar panels. The photoelectric conversion efficiency of monocrystalline silicon solar panels is generally between 15% and 20%, while that of polycrystalline silicon solar panels is generally between 13% and 16%. The advantages of crystalline silicon solar panels are mature technology, good stability, and long lifespan. However, their disadvantages are high cost, heavy weight, and temperature sensitivity.
Thin-film solar panels. Thin-film solar panels are solar panels that utilize a thin film layer made of amorphous silicon or other materials, coated on a substrate such as glass or metal. The photoelectric conversion efficiency of thin-film solar panels generally ranges from 6% to 12%. Depending on the material, they are categorized as amorphous silicon thin-film solar panels, copper indium gallium selenide thin-film solar panels, and cadmium telluride thin-film solar panels. The advantages of thin-film solar panels are low cost, light weight, and temperature insensitivity. However, their disadvantages are immature technology, poor stability, and short lifespan.
Flexible solar panels. Flexible solar panels utilize a flexible thin film layer made of organic or inorganic materials, coated on a flexible substrate such as plastic or paper. The photoelectric conversion efficiency of flexible solar panels generally ranges from 3% to 10%. Depending on the material, they are categorized as organic flexible solar panels and inorganic flexible solar panels. The advantages of flexible solar panels are their bendability, foldability, and transparency, making them suitable for complex surfaces and shapes. However, their disadvantages are technical difficulty, high cost, and poor stability.
Batteries
Batteries are the energy storage component of solar street lights. Their function is to store the electricity generated by the solar panels during the day for use at night or on rainy days. The main technical parameters of batteries are capacity, cycle life, and self-discharge rate. Capacity indicates the amount of energy a battery can store, typically expressed in ampere-hours (Ah). Cycle life indicates the number of charge and discharge cycles a battery can withstand, typically expressed in cycles. Self-discharge rate indicates the percentage of energy lost when the battery is not in use, typically expressed as a percentage. The higher the battery capacity, cycle life, and self-discharge rate, the better the performance of the solar street light and the lower the maintenance cost. Currently, the following types of batteries are commonly available on the market:
Lead-acid batteries. Lead-acid batteries are the most commonly used type of battery. Depending on their structure, they are divided into open-type and sealed-type batteries. Open-type lead-acid batteries generally have a capacity between 50 and 200 Ah, a cycle life between 300 and 500 cycles, and a self-discharge rate between 3% and 5%. Sealed lead-acid batteries typically have a capacity between 7 and 200 Ah, a cycle life between 500 and 800 cycles, and a self-discharge rate between 1% and 3%. The advantages of lead-acid batteries are mature technology, low cost, and excellent charge and discharge performance. However, their disadvantages are heavy weight, bulk, high pollution, and a short lifespan.
Nickel-cadmium batteries. Nickel-cadmium batteries use nickel hydroxide and cadmium as the positive and negative electrode materials. The capacity of nickel-cadmium batteries typically ranges from 0.5 to 100 Ah, with a cycle life between 800 and 1200 cycles and a self-discharge rate between 10% and 15%. The advantages of nickel-cadmium batteries are fast charge and discharge speeds, strong resistance to overcharge and overdischarge, and good low-temperature performance. However, their disadvantages are high cost, low capacity, memory effect, and high pollution.
Nickel-metal hydride batteries. Nickel-metal hydride batteries use nickel hydroxide and metal hydride as the positive and negative electrode materials. The capacity of nickel-metal hydride batteries generally ranges from 0.5 to 200 Ah, with a cycle life of 500 to 1000 cycles and a self-discharge rate of 15% to 25%. The advantages of nickel-metal hydride batteries are high capacity, no memory effect, and pollution-free operation. However, their disadvantages are high price, high self-discharge rate, and poor charge and discharge performance.
Lithium-ion batteries. Lithium-ion batteries use lithium compounds as positive and negative electrode materials. The capacity of lithium-ion batteries generally ranges from 1 to 200 Ah, with a cycle life of 1000 to 2000 cycles and a self-discharge rate of 1% to 2%. The advantages of lithium-ion batteries are high capacity, light weight, small size, no memory effect, low self-discharge rate, and long life. However, their disadvantages are high price, poor safety, and the need for a dedicated charge and discharge controller.
The technical difficulties and challenges of batteries mainly lie in the following areas:
Increasing capacity and cycle life, reducing self-discharge rate and cost, and meeting the requirements for long-term stable operation of solar street lights.
Address battery safety and environmental issues, prevent battery explosions, leakages, short circuits, and other accidents, and reduce battery pollutant emissions and waste disposal.
Develop new battery materials and structures to improve battery charge and discharge efficiency and performance, adapting to diverse climates and geographical conditions.
Controller
The controller is the control component of a solar street light. Its function is to control the charging of the battery by the solar panel and the discharging of the battery to the LED light, ensuring the proper operation of the solar street light. The controller’s key technical parameters are charge and discharge current, charge and discharge voltage, charge and discharge mode, and control functions. Charge and discharge current represents the maximum charge and discharge current the controller can withstand, typically expressed in amperes (A). Charge and discharge voltage represents the maximum charge and discharge voltage the controller can withstand, typically expressed in volts (V). Charge and discharge mode refers to the charge and discharge strategy employed by the controller, typically including constant voltage charging, constant current charging, constant voltage and constant current charging, and pulse charging. Control functions describe the controller’s control features, typically including light control, time control, temperature control, reverse polarity protection, overcharge and over-discharge protection, and lightning protection. The more comprehensive the controller’s charge and discharge current, charge and discharge voltage, charge and discharge mode, and control functions, the better the performance, higher the efficiency, and longer the lifespan of the solar street light. Currently, the following types of controllers are commonly found on the market:
PWM controllers. A PWM controller uses pulse-width modulation (PWM) technology to control the charge and discharge of batteries. PWM controllers typically operate with charge and discharge currents between 10 and 60A, charge and discharge voltages between 12 and 48V, and constant-voltage and constant-current charging. Control functions typically include light control, timer control, reverse polarity protection, and overcharge and over-discharge protection. PWM controllers offer advantages such as mature technology, low cost, and good compatibility. However, their disadvantages include low charge and discharge efficiency, voltage loss, and the inability to implement Maximum Power Point Tracking (MPPT).
MPPT controllers. An MPPT controller uses Maximum Power Point Tracking (MPPT) technology to control the charge and discharge of batteries. The charge and discharge current of an MPPT controller typically ranges from 10 to 80A, and the charge and discharge voltage ranges from 12 to 96V. Pulse charging is typically used, and control functions typically include light control, time control, temperature control, reverse polarity protection, overcharge and over-discharge protection, and lightning protection. The advantages of MPPT controllers include high charge and discharge efficiency, maximum power point tracking, and strong adaptability. However, their disadvantages include high cost, technical complexity, and the need for specialized software and hardware.
The technical difficulties and challenges of controllers primarily focus on the following areas:
Improving charge and discharge efficiency and accuracy, reducing charge and discharge losses and costs, and ensuring optimal battery operation.
Implementing intelligent and remote control and management, automatically adjusting charge and discharge parameters and strategies based on specific environments and needs, and improving the performance and reliability of solar street lights.
Developing new controller chips and algorithms to enhance the controller’s anti-interference and lightning protection capabilities, and adapting to different photovoltaic cell and battery types.
LED Lamps
LED lamps are the lighting component of solar street lights. Their function is to convert battery-generated electricity into light energy, providing illumination for roads and public spaces. The key technical parameters of LED lamps are lighting power, lighting efficiency, lighting angle, and color temperature. Lighting power indicates the amount of electrical energy consumed by an LED lamp and is generally expressed in watts (W). Lighting efficiency represents the ratio of light energy emitted by an LED lamp to the electrical energy consumed, generally expressed in lumens/watt (lm/W). Lighting angle indicates the distribution of light emitted by an LED lamp and is generally expressed in degrees (°). Color temperature indicates the color of light emitted by an LED lamp and is generally expressed in Kelvin (K). The more optimal and reasonable the lighting power, lighting efficiency, lighting angle, and color temperature of an LED lamp, the better the lighting effect, lower energy consumption, and higher comfort levels of the solar street light. Currently, the following types of LED lamps are commonly found on the market:
High-pressure sodium lamps. High-pressure sodium lamps generate light using a discharge of high-pressure sodium gas. High-pressure sodium lamps typically have a lighting power of 70-400W, a lighting efficiency of 80-140lm/W, a 360° illumination angle, and a color temperature between 1800-2700K. The advantages of high-pressure sodium lamps are high lighting efficiency, long lifespan, and adaptability. However, their disadvantages include a yellowish light color, long startup time, severe flickering, and high pollution levels.
Metal halide lamps. Metal halide lamps are lamps that generate light using a discharge of metal halides. Their lighting power typically ranges from 35-2000W, with a lighting efficiency of 80-120lm/W, a 360° illumination angle, and a color temperature between 3000-6000K. Their advantages include good light color, high color reproduction, and excellent lighting effects. However, their disadvantages include low lighting efficiency, short lifespan, high heat generation, and high pollution levels.
LED lamps. LED lamps are lamps that generate light using semiconductor light-emitting diodes (LEDs). LED lamps typically have a lighting power of 1-100W, a lighting efficiency of 100-200lm/W, a lighting angle of 15-180°, and a color temperature of 2700-6500K. The advantages of LED lamps are high lighting efficiency, long life, low heat generation, and zero pollution. However, their disadvantages include high price, rapid light decay, and poor anti-interference capabilities.
The technical difficulties and challenges of LED lamps primarily lie in the following areas:
Improving lighting efficiency and lifespan, reducing lighting power and light decay, and meeting the long-term, stable lighting requirements of solar street lamps.
Adjusting and optimizing the lighting angle and color temperature to provide optimal lighting effects and comfort for different roads and locations.
Developing new LED chips and packaging to improve the anti-interference and lightning protection capabilities of LED lamps and adapt them to different photovoltaic cell and battery types.
Technical Development Directions
The main technical development directions for solar street lights are as follows:
Improving photoelectric conversion efficiency and LED lighting power. These are two key factors affecting the performance of solar street lights. Improving these efficiency can make them more energy-efficient, efficient, and brighter. Currently, the photoelectric conversion efficiency of solar street lights generally ranges from 15% to 20%, and the LED lighting power generally ranges from 1 to 100W. The future goal is to increase the photoelectric conversion efficiency to over 30% and the LED lighting power to over 200W.
Implementing intelligent management and remote monitoring. Intelligent management and remote monitoring are two key aspects of improving the reliability and convenience of solar street lights. Implementing intelligent management and remote monitoring can make solar street lights more automated, intelligent, and user-friendly. Currently, intelligent management and remote monitoring of solar street lights primarily rely on components such as microcontrollers, sensors, and communication modules. The future goal is to integrate solar street lights with cloud computing, the Internet of Things, and artificial intelligence technologies to enable data collection, analysis, optimization, control, fault diagnosis, early warning, and maintenance.
Expanding the scope of applications and market share. Application scope and market share are two key indicators of the development of solar street lights. Expanding their application and market share will make them more popular, widespread, and beneficial. Currently, solar street lights are primarily used in urban main and secondary roads, residential areas, factories, tourist attractions, parking lots, and other locations, with market share concentrated in developing countries and regions. The future goal is to expand the application of solar street lights to rural, remote, and specialized locations, and to expand market share to developed countries and regions.
Technological Innovations
The technological innovations achieved in solar street lights mainly include the following:
Ultra-thin flexible solar cells. Ultra-thin flexible solar cells are ultra-thin, flexible, and transparent solar cells made using nanomaterials and printing technology. They are only a few microns thick and can be bent, folded, and conform to any surface or shape. Their photoelectric conversion efficiency can reach over 15%, making them a revolutionary solar cell technology. Ultra-thin flexible solar cells offer greater design and installation flexibility for solar street lights, making them more aesthetically pleasing, lightweight, and adaptable.
Five-color, full-spectrum LED light source. A five-color full-spectrum LED light source utilizes a combination of LED chips (red, green, blue, yellow, and violet) to produce a full spectrum of light close to sunlight. Its color temperature can be adjusted between 2700 and 6500K, and its color reproduction exceeds 95%. This breakthrough LED light source technology offers a wider range of lighting effects and comfort options for solar street lights, making them more natural, realistic, and healthy.
Edge computing and AI technologies. Edge computing and AI utilize edge devices (such as solar street lights) for data processing and analysis, reducing reliance on the cloud, improving data security and real-time availability, and enabling intelligent decision-making and control. Edge computing and AI technologies can provide solar street lights with more intelligent and remote functions and services, making them more automated, intelligent, and user-friendly.
Technical Innovation Mechanism
The technological innovation mechanism for commercial solar street lights primarily involves the following aspects:
Policy support. Policy support is a key guarantee for promoting technological innovation in solar street lights. The government should introduce a series of policy measures, such as subsidies, tax reductions, preferential loans, and intellectual property protection, to encourage and support the research and development and application of solar street lights, thereby creating a favorable policy and market environment.
Industry-university-research collaboration. This is a key path to promoting technological innovation in solar street lights. Enterprises, universities, and research institutions should strengthen cooperation and exchange, share resources and information, integrate strengths and needs, and form an effective technological innovation network and platform to improve the efficiency and quality of technological innovation.
Market competition. Market competition is a key driving force for technological innovation in solar street lights. Stakeholders in the solar street light industry should actively participate in market competition and collaboration, continuously improve their own technological level and market share, continuously create and meet market demand, and continuously innovate and overcome technical difficulties to form a healthy market competition mechanism.
Post time: Aug-21-2025