How significant are the energy-saving benefits of LED streetlights?
The energy-saving impact of LED streetlights is substantial, as evidenced by both real-world case studies and statistical data. Consider a 10-kilometer-long urban arterial road: the existing setup uses 250W high-pressure sodium (HPS) lamps (consuming approximately 280W when accounting for ballast losses). With a pole spacing of 30 meters, there are about 334 lamps in total, resulting in a combined power load of 93.5 kW. Operating for 11 hours each night, this system consumes roughly 375,000 kWh of electricity annually. If these were replaced with 120W LED streetlights—which offer a luminous efficacy of 150 lm/W and can match or even exceed the illuminance of the original 250W HPS lamps—the total power load would drop to 40 kW, with an annual consumption of approximately 160,600 kWh. This represents an annual saving of 214,400 kWh, or an energy-saving rate of 57%. At an electricity price of 0.8 RMB/kWh, this translates to an annual cost saving of 171,500 RMB.
For wider roads requiring higher illuminance levels, where 400W HPS lamps might otherwise be necessary, LED alternatives would only require 200W—achieving energy savings of 60% to 70%. On a city-wide scale, assuming a total of 100,000 streetlights, the transition to LED technology could yield annual electricity cost savings in the tens or even hundreds of millions of RMB. Beyond electricity costs, there are also savings on lamp replacement expenses; HPS lamps typically require annual replacement, costing about 50 RMB for the bulb plus 100 RMB for labor per unit—amounting to 15 million RMB annually for 100,000 lamps.
Furthermore, when integrated with smart dimming systems, LED streetlights can automatically reduce their brightness to 50% during the late-night hours when traffic is sparse, providing an additional 30% to 40% in energy savings. Consequently, the energy-saving benefits of LED streetlights are comprehensive and far-reaching.
