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Street Lighting: LED to Replace Sodium?

LED gradually replaces these legacy sodium luminaires in street lighting and public facility lighting

As an electric contractor specializing in light pole repair, Blanco Electric can handle work on the 2 technologies used in street lighting: High-Pressure Sodium lamps (HPS) and LEDs.

Street lighting is a critical component of urban infrastructure, contributing to both safety and visibility. In fact, the decrease in urban criminality in European cities coincides with the introduction of gas-based street lighting.

Gas lights disappeared in the mid-20th century, and the traditional choice for street lighting since WWII has been high-pressure sodium (HPS) lamps. However, the advent of light-emitting diodes (LEDs) has presented a compelling alternative.

In this article we will explain why LED is bound to replace sodium street lighting in view of 3 key advantages: cost, efficiency, and environmental impact. The data accumulated in scientific studies point

Street Lighting: Cost Comparison LED vs. Sodium

The initial purchase cost of LED lights is generally higher than that of sodium lights. However, when considering the total cost of ownership, which includes energy consumption and maintenance costs, LED lights prove to be more cost-effective.

A study by Friedemann Polzin et al. (2015) titled "Exploring the Role of Servitization to Overcome Barriers for Innovative Energy Efficiency Technologies – The Case of Public LED Street Lighting in German Municipalities" suggests that the servitization of public lighting can accelerate the commercialization and diffusion of energy-efficient technologies like LEDs.

Note ― Servitization: industries using their products to sell “outcome as a service” rather than a one-off sale.

This approach can help overcome the high upfront costs associated with LED lighting, making it a more cost-effective solution over time.

A report titled "Cost Savings Analysis of LED Street Lighting Ownership" from the U.S. Department of Energy's Better Buildings Solution Center also emphasizes the importance of considering the total cost of ownership when evaluating the cost-effectiveness of LED street lighting.

The report suggests that municipalities need to understand which LED street lighting conversion strategy is most cost-effective for their jurisdiction, taking into account responsibilities like maintenance and replacement of street lighting.

An article on the World Bank's blog titled "LED street lighting: Unburdening our cities" states that LED lights are 40 to 60% more energy-efficient than traditional lighting technologies, which contributes to their cost-effectiveness.

LED vs. Sodium: Efficiency Comparison

LED lights outperform sodium lights in terms of energy efficiency. A study by A. Gil-de-Castro et al. (2013) titled "LED street lighting: A power quality comparison among street light technologies" found that LED lamps achieved the lowest total harmonic distortion of current, implying better energy efficiency.

In terms of lifespan, LED lights also have a significant advantage over sodium lights. According to the U.S. Department of Energy, LED lights have a lifespan of 50,000 to 100,000 hours or more, significantly longer than the typical lifespan of a sodium light, which is around 24,000 hours. This longer lifespan reduces the need for frequent replacements, thus lowering maintenance costs.

The light quality of LED lights is also superior to that of sodium lights. LEDs produce a white light that closely resembles daylight, improving visibility and safety. In contrast, sodium lights emit a yellow-orange light, which distorts colors and reduces visibility.

A study titled "The Comparative Analysis of the LED and High-Pressure Sodium Lamp as Road Lighting" indicates that LED light efficiency is higher than that of high-pressure sodium lamps under the same lighting time, and the average illuminance of high-pressure sodium lamps is higher than 160 W LEDs, but the power consumption is also higher.

However, light quality can be subjective and dependent on specific applications and personal preferences. For instance, the yellow-orange light emitted by sodium lights might be less desirable for some applications but could be preferred in certain circumstances due to its ability to cut through fog better than white light.

It is possible that cities will opt for using LED lights with some form of color control application capable of auto-switching to the best possible lighting depending on weather conditions.

LED vs. Sodium: Environmental Impact

The environmental impact of LED and sodium-based street lighting systems is a critical consideration in the context of cities’ efforts to control and reduce their energy consumption.

A study by the U.S. Department of Energy found that LED lights have a smaller environmental impact compared to high-pressure sodium (HPS) lights. The study assessed the environmental impacts of both lighting systems across their life cycles, including manufacturing, transportation, use, and disposal. The results showed that LED lights have lower impacts in almost all impact categories, including global warming potential.

Another study published in the Journal of Cleaner Production also supports the environmental benefits of LED lighting. The study conducted a comparative life cycle assessment of LED and HPS street lighting systems and found that LED lights have lower environmental impacts in all categories, including global warming, human health, ecosystem quality, and resource depletion.

A more recent study published in Energies further confirms the environmental benefits of LED lighting. The study employed Techno-Economic Analysis (TEA) and Data Envelopment Analysis (DEA) to measure the performance of HPSV and LED road lighting technology in the Penang Bridge, Malaysia. It found that the average eco-efficient score for LED (74.77%) exceeds the performance of HPSV (40.06%) road lighting.

It also showed that LED technology generates higher eco-efficiency compared to its technical efficiency scores, suggesting that environmentally-friendly road lighting technology would further improve the efficiency level of road lightings.

Street Lighting: A Clear Winner

Though the initial cost of LED street lighting is higher than that of sodium street lighting, the long-term benefits of LED technology in terms of energy efficiency, maintenance costs, light quality, and lifespan make LED lighting a more cost-effective choice for street lighting.

As cities around the world strive to become 'smarter' and more sustainable, the transition from sodium to LED street lighting is likely to accelerate.

Role of Blanco Electric Ltd

Public safety remains at the forefront of many a city council’s deliberations, and the upkeep and repair of lighting poles directly proceeds from the need for safety in our streets.

Blanco Electric has a strong specialization in light pole repair, and is committed to remain at the edge of electrical engineering technology to offer clients the best possible solutions to complex technical and budgetary challenges.

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