With energy savings of 50-70 per cent compared to standard streetlights, LED based street lighting systems are getting popular across India. The huge financial savings and the considerably lower carbon emissions make LED streetlights a compelling choice.
By Potshangbam July
Street lighting is one of the main energy consuming segments on which public authorities spend a large amount of money. In many parts of India, the complete replacement of incandescent and CFL bulbs with LEDs is yet to happen. Concerted efforts are needed to do away with the outdated systems that consume excessive energy and produce a lot of heat. However, the situation is changing with growing awareness about the benefits of LEDs. Various ambitious LED programmes and schemes introduced by the Centre are accelerating the adoption of LEDs to achieve the target of replacing 35 million conventional streetlights with LED lights, and many cities are upgrading their public lighting systems to LED technology. But LED streetlights are yet to make major inroads into the remote and far flung areas of the country. In this article, we will analyse how converting to LED streetlights makes sense from an energy saving as well as an environmental perspective.
Benefits of LED based streetlights
Listed below are the key reasons for switching to LED streetlights.
Longer life span: LED streetlights can last for over 100,000 hours on an average, while the traditional bulbs work for a shorter time. LED lights do not contain filaments that can burn out or toxic chemicals like mercury that pose a challenge during disposal. Traditional bulbs are designed with high-pressure sodium and mercury vapour that contribute to environmental pollution. Since the lifetime of LEDs is long, they are ideal to use on streets where the frequent change of bulbs is inconvenient.
Energy efficiency: Various studies have shown that LED streetlights consume 80-85 per cent less power than conventional lighting sources. LED bulbs of a lower wattage can be used to deliver the same brightness as traditional tubelights of a much higher wattage. With more advances in technology, LED lights can control the unnecessary wastage of energy to a great extent.
Brightness levels: There is no warm up period in the case of LED streetlights, which reach their full brightness levels in a matter of seconds. They are perfect for any emergency situations. The glare effect is minimal, resulting in less eye fatigue for both pedestrians and drivers.
Safety for traffic: LED street lighting has a focused and directional beam, whereby light is directed onto specific places. LEDs ensure better visibility for drivers, riders and pedestrians. Unlike CFL bulbs, they do not emit a diffused glow which hampers night time driving.
Low maintenance costs: LED streetlights do not need extra investments for maintenance. They have a solid structure and long life span, and hence do not require replacement too often. Besides, they are not made of ballasts and filaments; as a result, they can resist varied weather fluctuations.
Environmental safety: LEDs do not produce ultraviolet light, making them environment-friendly. These lights do not contain lead or mercury, or emit any poisonous gases. They also result in less CO2 (which attracts insects) emissions.
|Some of the top manufacturers of LED street lighting products
Philips: This is one of the most popular brands of LED lights. The company’s LED street lighting systems are accurate and versatile, and easily manage all connected streetlights securely and remotely. Their products require low maintenance.
Havells: This company delivers streetlights with high lumens, while consuming less power and providing excellent illumination.
Wipro: Wipro’s LED street lighting systems are versatile enough to be maintained and monitored with ease. They are available in compact designs.
Bajaj: These LED streetlights are available in low, mid and high wattage ranges. They last for more than 50,000 hours compared to the life of 8000-10000 hours of most CFLs.
Syska: With a two-year warranty, the lights from this company come with an operating temperature range of of -20° C to 60° C, and brightness up to 3000 lumens.
Charlston: The firm’s outdoor streetlights are designed specifically for street and roadway applications.
Oreva: The company has a vast LED streetlight portfolio. The products come with an aluminium body and EMC compliance. They are water-proof (IP67), have over- and under-voltage protection and polyester powder coating, and come in various colours.
Moser Baer: With expertise in electrical design, mechanical design and optical design, Moser Baer has started manufacturing LED lights and streetlights.
Crompton: There are two models for streetlights – Hawk (90W to 135W) and Hawk II (150W to 220W).
Surya: The company offers aluminium/CRCA MS street lighting luminaires with acrylic covering, prewired with all accessories and ballast.
IoT enabled LED streetlights
The management of streetlights is largely manual in India. The lights are operated on the ‘off/on’ mode, which results in electricity pilferage, energy wastage, inaccurate billing, etc. The loss of power is considerably higher in public street lighting as there is a lack of concern among people. Therefore, the aggressive adoption of IoT in street lighting systems is the ideal solution to deal with the huge losses of power and money.
IoT enabled LED street lighting systems effectively monitor and control the operations of the city’s streetlights even from remote locations, giving information on the patterns of energy consumption, areas that need maintenance, energy wastage, etc. The biggest advantage of IoT in streetlights is the automatic operation of switch points, based on light conditions. The light is switched ‘off’ when the day is bright and switched ‘on’ as evening falls, without any manual assistance. With advanced motion sensors, IoT enabled LEDs also send alerts about malfunctioning systems that need urgent attention and repair, thus streamlining operations. IoT enabled lighting systems ensure energy efficiency and safety, by harvesting data based insights into a city’s lighting from connected sensors and lighting nodes using cloud computing, machine learning, Big Data and semantic technology.
There are various factors to consider before purchasing LED based streetlights. The LED chip should not be of inferior quality as its efficiency drops quickly. Theoretically, chips have a limitless life span if there is a good power supply. As in the case of any outdoor product, the outer body of LED streetlights should be powder coated with a pure polyester paint, so that it remains immune to harsh weather conditions. Besides, it should have toughened glass with a minimum thickness of 4mm, a heavy aluminum body, IP65 waterproofing, as well as stainless steel screws and small parts. Also, it is important to check the lumens of the bulb, i.e., the brightness of a light. People often erroneously measure the brightness of an LED bulb by watts.
Another aspect to check out is the streetlight’s wattage and pole height. The latter should match the wattage rating of the streetlights. Last but not the least, one should never make the mistake of choosing a product based on low price rather than quality. In a short period of time, the body of a low quality streetlight gets rusted or broken due to bad weather, the protective glass breaks and the waterproof gasket malfunctions.
|The test methods and standards for LED streetlights
“Today, the functioning of streetlights is getting complex with the influx of multiple new LED light sources and functionalities. The scope of testing for safety, EMC (electromagnetic compatibility), EMI (electromagnetic interference) and performance further add to the challenges. The German DIN SPEC 91347 standard essentially provides us with an outlook of what street luminaires may potentially contain in the future.For the basic safety aspects of street luminaires, international test methods like IEC 600598-2-3 and Indian standards like IS 10322-5-3 are applied along with the LED module safety standard, IEC 62031. In addition, IEC 62262, together with IEC TR 62696, provides the testing requirements for rough service environments for the IK code (degrees of protection provided by enclosures).The electronic controls of LED street lighting are tested according to IEC 61347-2-13, IS 15885-2-13 and IEC 61347-2-11. When street lighting is powered by solar energy, i.e., via PV panels and batteries, then standards like IS/IEC 61730, IEC 62133, IS 16046-2 and IEC 62619 need to be considered, in addition.EMI/EMC testing is performed as per CISPR15, EN 55015, IEC/EN 61547, IEC/EN 61000-3-2 and IEC/EN 61000-3-3 for India as well as the global market. These tests evaluate the product’s behaviour in terms of unwanted electromagnetic emissions that are discharged by it, as well as the performance when subjected to electromagnetic noise and disturbances from other sources.Performance parameters such as colour temperature, distribution of light, longevity and efficiency for LED streetlights get certified by standards like IS 13383-2 and IEC 62717, by using test methods like EN 13032-4 /CIE-S-015, as well as lifetime prediction by applying the LM80 test method.For compatibility of new light source technologies and components, Zhaga books, which will later be transferred into IEC standards, are providing the first industry standards. Similarly, connectivity protocols are also addressed in the DALI standards of the IEC 61368 series.”
—Ezhilan Neelan, senior vice president, product service, TÜV SÜD, South Asia
On January 5, 2015, the Indian government launched an ambitious programme called the Street Light National Programme (SLNP) with an aim to replace 35 million conventional streetlights with energy efficient LED lights. The Energy Efficiency Services Limited (ESSL), a public energy services company under the administration of the Ministry of Power, government of India (GoI), is the implementing agency for SLNP. Recently, it has been reported that only about 2.1 million conventional streetlights have been replaced with LED lights across the country so far. This has resulted in annual energy savings of 295 million units and a reduction of 23 million tonnes of CO2 emissions annually. Rajasthan leads the states with the replacement of 704,000 conventional lights with LEDs, followed by Andhra Pradesh (586,000) and Delhi (264,000).
To facilitate the faster adoption of energy-efficient LED streetlights in every corner of India, more aggressive public awareness campaigns should be organised in every state, which talk about the advantages these lights deliver and their importance to the environment.