How can LED streetlights achieve ultimate energy savings in urban road lighting?

Urban road lighting is a crucial component of municipal energy consumption, and its energy-saving transformation has become a key measure under the "dual carbon" goal. Data shows that traditional high-pressure sodium lamps account for over 70% of the total energy consumption of urban public lighting, while LED streetlights, with their high luminous efficiency and long lifespan, have become the mainstream choice to replace traditional light sources. However, achieving "ultimate energy saving" requires more than just replacing the light source; it necessitates end-to-end technological innovation, from dimming control and intelligent sensing to heat dissipation optimization and IoT management. This article will combine the latest industry practices and technological breakthroughs to explain the energy-saving secrets of LED streetlights.

I. Core Technology: A Paradigm Revolution from "Constant On" to "On-Demand Lighting"

Traditional streetlights use a "one-size-fits-all" lighting mode, maintaining full power operation regardless of changes in traffic and pedestrian flow, resulting in significant energy waste. Modern LED streetlights, through a combination of "dimming technology + intelligent sensing," achieve precise matching between lighting needs and energy consumption.

1. Dual Dimming Technology Synergy: Balancing Flexibility and Stability

Currently, mainstream dimming solutions employ a synergistic application of PWM (Pulse Width Modulation) and constant current dimming. PWM dimming controls the average current by adjusting the pulse duty cycle, achieving dimming accuracy of 1%-100% with an efficiency loss of less than 3%, making it particularly suitable for scenarios with low traffic volume, such as late at night. For example, when traffic volume drops by 80% after 2 AM, PWM technology can reduce the brightness to 50%, resulting in immediate energy savings. Constant current dimming, on the other hand, uses a dedicated chip (such as TI's LM3464) to stabilize the drive current, avoiding flickering caused by current fluctuations and ensuring lighting stability in critical areas such as traffic intersections.

Danghong Technology's mains-powered IoT energy-saving streetlights utilize this combined solution, supporting more than 10 customizable time-of-day control strategies. Brightness curves can be preset according to traffic patterns on different road sections, achieving a drive efficiency of over 90%.

2. Multi-Sensor Fusion: Enabling Streetlights to "See and Calculate"

Intelligent sensing systems are a prerequisite for achieving "on-demand lighting." By integrating light sensors, infrared pyroelectric sensors, and traffic flow monitoring modules into streetlights, real-time data on ambient light intensity, pedestrian activity, and vehicle movement can be captured. For example, the light sensor can automatically trigger the lighting program at dusk, preventing premature switching on; when the infrared sensor detects an approaching pedestrian, it can increase the brightness from 30% to 100% within 0.5 seconds, returning to low brightness mode after the pedestrian leaves.

A more advanced solution is the "AI + Light Chain" system adopted in Yichang City, which collects mobile phone signals through communication base stations to accurately monitor pedestrian density. Data shows that when pedestrian traffic around schools reaches a peak of 248 people at 9:55 PM, the system automatically adjusts the brightness to 100%; while in residential areas late at night, the brightness can be reduced to 20%, meeting safety requirements while reducing light pollution.

II. Key Guarantees: From "Short-Term Energy Saving" to "Long-Term High Efficiency"

The energy-saving effect of LED streetlights is not static; light decay and heat dissipation issues cause their energy efficiency to decline year by year. Therefore, extending the lifespan of the lamps and controlling the light decay rate are another core aspect of achieving "ultimate energy saving."

1. Heat Dissipation Optimization: Controlling Junction Temperature is Key

LED light decay is mainly caused by rising junction temperature. When the junction temperature exceeds 85℃, the light decay rate increases exponentially. Solving this problem requires addressing both materials and structure: A ceramic substrate (AlN) is chosen, with a thermal conductivity ≥170 W/m·K, more than 50 times that of traditional aluminum substrates; the heat sink uses a fin + heat pipe combination design, combined with graphene thermal grease (thermal resistance <0.2℃·cm²/W), which can control the chip temperature within the 70-80℃ range.

Hailongxing Optoelectronics' COB light source uses superconducting heat transfer technology, achieving a 5-year zero light decay guarantee through a three-in-one heat dissipation solution of "chip-vapor chamber-heat sink," significantly reducing replacement and maintenance costs.

2. Energy Management and Fault Early Warning: Improving Operation and Maintenance Efficiency

The intelligent energy management system can monitor the current, voltage, and power consumption of streetlights in real time, generating daily/monthly/yearly power consumption statistics reports. Danghong Technology's IoT platform also supports remote modification of lighting strategies, such as automatically extending low-brightness lighting time on cloudy or rainy days and shortening it on sunny days. Simultaneously, the fault self-diagnosis function can proactively report issues such as short circuits and overvoltages. A case study in Yichang City shows that this system reduced fault response time from an average of 4 hours to 30 minutes, and lowered maintenance costs by 35%.

III. Practical Case: Yichang's Energy-Saving Achievements with 30,000 Smart Streetlights

As a benchmark application of "AI + Light Chain" technology, Yichang City connected over 30,000 streetlights to the "China Mobile·Kunling Light Chain" smart platform, achieving "unified management through a single network." By customizing regional lighting schemes using AI algorithms, combined with dynamic dimming and fault early warning, the project achieved an average annual energy saving of over 6 million kWh, a saving rate of up to 40%, equivalent to reducing carbon emissions by 4,500 tons.

This case demonstrates that smart LED streetlights are not only lighting tools but also sensing nodes for smart cities. The traffic flow data they collect can be used to optimize bus routes, and the illumination data provides reference for meteorological departments, realizing "one light, multiple values."

IV. Future Trends: Deep Integration of Photovoltaics, Energy Storage, and Digital Twins

The next stage of ultimate energy conservation will focus on "energy self-sufficiency + intelligent decision-making." On the one hand, energy storage systems combining photovoltaic panels and lithium iron phosphate batteries can enable off-grid operation of streetlights, particularly suitable for remote areas. For example, a pilot photovoltaic energy storage LED streetlight in a Shenzhen industrial park charges during the day using 200W photovoltaic panels and is powered by a 100Ah lithium battery at night, maintaining illumination for 72 hours during continuous cloudy or rainy weather, completely independent of the power grid.

On the other hand, digital twin technology will construct virtual models of streetlight systems, simulating energy-saving effects under different weather and traffic scenarios to optimize control strategies in advance. In a smart city project in Jiangsu, the digital twin platform can map the operating status of 5,000 streetlights in real time, automatically generating optimal dimming curves by simulating traffic flow changes during morning and evening peak hours, achieving 15% more energy savings than manually set strategies.

Industry forecasts predict that by 2027, the market share of smart LED streetlights integrating photovoltaic energy storage will exceed 30%, with a comprehensive energy saving rate expected to exceed 70%, becoming an important component of the urban energy internet.

Conclusion: Energy conservation is not just about technology, but a systems engineering project.

The ultimate energy efficiency of LED streetlights is not a breakthrough in a single technology, but a system integration of dimming control, intelligent sensing, heat dissipation optimization, and IoT management. From the practices in Yichang to the product innovations of Danghong Technology, we see that through the three-pronged approach of "technology + management + data," urban road lighting is transforming from "high energy consumption" to "high efficiency." In the future, with the deepening of smart city construction, streetlights will become a crucial hub connecting energy, transportation, and the environment, injecting continuous momentum into sustainable urban development.