The Darker Side Of Led Street Lights Power Quality And Energy Efficiency Concerns!

Published On: Sep 17, 2019


India Street Lighting National Program (SLNP) is on its way to become one of the largest replacements of high mast Street Lights with LEDs. The trend to shift to LED Lights is unfolding around the world. With funding and schemes from Central Govt. agencies, and the thrust on smart infrastructure for smart cities, Local administrations are aggressively adopting LEDs for energy savings and remote control. The basic guidelines for procuring the right LED technology are laid out by the support agencies such as Energy Efficiency Services Ltd. (EESL). However, the PQ issues and maintenance challenges from high- concentration of LED light loads are still not understood entirely by the various agencies, including DISCOM who can play vital role of handholding local bodies, involved in these projects – that’s the darker side.

INTRODUCTION

The street lights are important for life and safety of people. In India, public lighting represents 3-5% of the total load, depending on the state and specific areas. The large-scale introduction of LEDs in street lights is disrupting this otherwise dim space. The Govt., along with distribution companies, technology supply agencies and municipalities are set to revamp the lighting infrastructure at an unprecedented rate. The policy initiatives for rapid adoption of LED Lights, in fact, is Government’s priority agenda to propagate social change towards cleaner and efficient energy. The program is also connected to other key initiatives such as smart cities – where large-scale deployment of LED Lights in traffic signalling is underway. All this is expected to feed to the larger goal of ensuring availability of safe and enjoyable public spaces and smart systems for the citizens.

At the same time, one of the key challenges emerging for the power distribution companies is monitoring and management of Power Quality. Issues such as harmonic distortion from non-linear loads are now leading to various problems such as overheating, lower Power Factor, failures, break down of key distribution equipment, failure of protective devices such as relays and instances of greater EMIs interfering with grid circuits. The role of LEDs in street lighting is important to generate energy savings that reduces energy intensity in economy and ensure better illumination experience. However, the harmonic distortions and other Power Quality issues in street lights need to be investigated and understood simultaneously. These energy saving initiatives can threaten the very reliability of the infrastructure, if not adopted with due care and precautions.

KNOWING THE UNKNOWN

The time to assess any new technology by understanding its full impact is shrinking rapidly. The case of adoption of LED Lights is not different. The extent and impact of LED Lights on the electrical network is not known accurately in all aspects. The doubts about LED Lighting technology being superior to its precedents are still not entirely clear. While the benefits of switching to LED Lights in the short run are undoubtedly overwhelming, the adverse impact may unfold rather slowly. It is therefore important to ensure greater caution, and extensive precaution when adopting this technology on large-scale.

To continue to understand the direct and indirect impact of LED Street Lights, investments in regular investigations are a must.

LED STREET LIGHTS - INDIAN MODEL

The business case for use of LEDs in street Lights is well proven. However, the business implementation model is not free of concerns. Currently, the prevalent model is based on Energy Saving Company (ESCO) bringing in the finance and implementing agreed upon energy saving measures.

  • Model 1: Municipality procuring finance from a financial institution to contract with an ESCO or Energy Audit firm to implement the Energy Efficiency Project on a turnkey basis.
  • Model 2: Public-Private Partnership–based Models- ESPC approach (ESCO financing the Energy Efficiency Project implementation under an Energy Performance Contract)
    • Shared Saving Model
    • Guaranteed Savings Model
    • Annuity-Based Deemed Saving Model

While several municipalities are aggressively engaging EESL – India’s leading ESCO under the second model, the concerns too are slowly emerging. These concerns, as of now, may not be entirely due to the Power Quality issues. However, the instances highlight the importance of care and caution required about Power Quality that’s required in the case of such a rapid and large-scale replacement program.

Early warnings: Reports from around the country

GHMC (Hyderabad Municipal Corporation) staring at an inheritance of loss
20,450 LED Street Lights replaced in less than a year; Lights were fixed by 30 different contractors in 30 circles, and monitored by four agencies. Heavy maintenance and repairs for the lights for GHMC maintenance staff.

Source: https://www.thehindu.com/news/cities/Hyderabad/ghmc-staring-at-an-inheritance-of-loss/article26226526.ece

Civic body blames EESL for poor streetlighting – South Delhi Municipal Council goes to HC (July 2016)

  • Energy Wastage – Slow Centralized Control and Monitoring System (CCM) remains slow, streetlights continue to be operated manually even beyond dark hours
  • Poor Workmanship – Bimetallic connector, SPD was not fixed properly, angle of bracket was not proper, rusted and damaged brackets had not been replaced
  • Failures due to Poor quality – Earthing to the fixture was pending. EESL has lifted a number of samples of various wattage from all the four zones of SDMC and has sent them to national accredited labs for testing.

Source: https://www.thehindu.com/news/cities/Delhi/Civic-body-blames-EESL-for-poor-streetlighting/article15002751.ece

EESL fails to maintain city streetlights in Tirupati – In 2016, the Municipal Corporation of Tirupati (MCT) had entered into an agreement with the EESL to replace over 11,000 conventional streetlights with LED lights.

  • Maintenance and Repair – A majority of the 1,000 Centralised Control Monitoring System (CCMS) set-up by EESL are not functioning. The temporary staff of 3 personnel is unable to manage the upkeep and maintenance. Payments to EESL have been stopped by MCT.

Source: https://www.thehansindia.com/andhra-pradesh/eesl-fails-to-maintain-city-streetlights-in-tirupati-550592

LED streetlight project fails to yield results – Greater Visakhapatnam Municipal Corporation (GVMC) that was taken up in association with the State Energy Conservation Mission and EESL fails to achieve results

  • Defunct LED Lights – 20-25% streetlights within the GVMC limits are lying defunct. While EESL claims of 2-3% Lights not working

Source: http://timesofindia.indiatimes.com/articleshow/54320570.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst


Due to non-functional LED lights, Ludhiana Smart City Limited terminates contract of the vendor

  • Slow installation pace and non-functional lights for the contract of 1.07 Lakh Lights– Concerns among local representatives, create unsafe zones, dark road in all the A,B,C and D level zones of the city.

Source: http://timesofindia.indiatimes.com/articleshow/71207614.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst

LED STREET LIGHTS BEST PRACTICES FOR POWER QUALITY

Potential Savings and True Costs – Power Quality

A recent study specifies that under the Street Lighting National Programme (SLNP), over 10,80,000 conventional street lights have been replaced with LED street lights across India leading to an annual estimated energy savings of 143 million units. But, as it’s seen from the news stories above, the concerns in LED lights could be equally overwhelming, with poor implementation and maintenance. This in turn, can raise the capital, repair and maintenance costs significantly. Even the fear of creating NPA for EESL is very real.

Here, we highlight some of the best practices, observed by studies from around the world on ensuring good Power Quality in large-scale implementations of LED Lights.

Procurement only as per the Standards

The BIS Standards require minimum technical specifications for the LED Luminaire set :

  • Powered by the latest bright LEDs with high efficiency and meeting LM-80 standard
  • Average rated life span of 50000 hrs.
  • Power factor > 0.9
  • THD < 15%
  • Ingress protection as per IP 68
  • Operating temperature -5°C to 50°C
  • Storage temperature -5° to 70°C
  • Humidity 10–100%
  • Conform to Photo Biological Safety for the LEDs as per IEC 62471
  • Free replacement warranties of 5 years for technical defects

More importantly, Lab Testing the performance as per the standards
With several instances of poor performance or high rate of failure of Street LED Lights, the lights provided are now being tested in Labs for their adherence to standards. Lack of proper sampling and Lab testing procedures for PQ and electrical protection parameters before installation poses a high risk to the success of the project. Also, involvement of multiple parties, highly price competitive contracts further aggravates this risk.

EESL in a press release issued in 2016, claims to follow and meet the BIS Standards in procurement. However, the press release also observes a failure rate of 2% for the 14 Lakh Street Lights installed until then. It must be noted here, that the cost of replacing an LED Street Light almost always far exceeds the cost of procuring it.

The LED Lights are often provided by third-party vendors. In many instances today, the lights are imported from China. It’s therefore even more important to ensure validation and fulfilment of Indian and International standards by these products – LED Driver, Street Light and protective devices.

Grounding and Protection Procedures – the nuances of ensuring right circuitry in LED Street Lights

  • All Metal Poles, Junction Box Covers and Luminaires must be grounded
  • Fibre junction boxes must be drilled to accommodate a grounding connector
  • Conduit runs shall be as straight as possible between junction boxes
  • The voltage drop from the power source to the last light at the end of the wiring run must not exceed 5%
  • Amp-probe each leg, after energising the lights to ensure lighting loads are properly balanced.
  • The locations of and spacing between lights will depend on the required average illumination levels and illumination uniformity. These must be accurately calculated in fittings as per the roads in respective Zones of the area.

Surge Protection Devices in LED Street Lights
Surge protection is required from direct lightning strike to the luminaire, supply line. The surges resulting from switching operations, earth faults, short circuits or tripping of fuses along with capacitive or inductive couplings could lead to failure of the lights.

Dedicated metering to understand energy savings
LED Street lights are deployed for savings. However, the methodology to calculate and project accurately is not always perfect. Tri-party agreements are common in the implementation of LED Street Lights. The monitoring agencies could again be different from those executing installations or carrying maintenance and repairs. The multi-party framework makes it difficult to assess and monitor real savings. An independent metering for the lighting load, as opposed to a broad savings commitment-based tariff, can help to realise the true savings from LED Street Lights. Beyond this, a more accurate RoI can be calculated based on the costs of maintenance, repairs and replacements of the LED Lights.

Off-grid, Solar LED Lighting – benefits with its own challenges
Solar LED lights use a self-contained battery for charging during daylight. In the night, the power from this battery powers the street lights. More popular for parking lots, residential streets, railways, and other locations where providing and upkeep of electricity is relatively expensive. Other benefits in installation include efforts saved from digging trenches to lay cables no effect of power outages.
The downside is failure of batteries due to heating, with solar panel maintenance and repair being difficult to service. While the Power Quality concerns are not very critical in case of off-grid street lights, the large-scale implementation is limited by its very own advantage – lack of serviceability of remote locations.

LEARNING FROM FAILURE OF OTHERS

Various studies around the world have highlighted the benefits and challenges in LED Street Light implementation. The Indian initiative is unique, given its size, scale and speed. Here, we summarize the observations of general as well as PQ specific failures and cautions that agencies around the world are adopting to perfect their business models.

  • Life-cycle costs of LED Street Lights can be much higher than what is originally predicted. The tendency of governments and related agencies to procure the lowest up-front cost products is harmful. Poor PQ can lead to early failures in LED Drivers and affecting the performance of luminaries.
  • The lack of know-how, adherence to standards, requisite testing facilities, and availability of measurement equipment to assess the performance and impact of LED technology is underestimated. The systems and infrastructure for assessment of LED Street Lights with respect to their impact on PQ is a must for long-term success.
  • Lack of following the best-practices in installation and maintenance are a critical concern and the costs are highly inhibitive. Often, poor workmanship is the root cause of poor PQ.
  • A Unipolar and highly attractive financing option in LED Street Light implementation can prove to be an impediment, in case of its failure. The financing model does not sufficiently consider the adverse impact of LED Lights due to Power Quality in planning of procurement to maintenance.
  • The key challenge facing the Indian LED market is the mushrooming of un-authorised production/distribution units manufacturing substandard products. Enforcements of general and PQ related standards throughout the supply chain is a challenge due to the costs.
  • Chances of failure of LED Street Lights are comparatively always higher as these operate in very hot ambient temperatures and humidity. Therefore, its important that these lights use superior quality components designed as per the highest standards to ensure good PQ.

CONCLUSION

Energy Efficiency Services Limited (EESL) completed installation of 10 millionth LED street lights in 28 States or Union Territories on October 1st, 2019. But, the target under SLNP to replace 1.34 crore conventional street lights with energy efficient LED street lights by March 2019 has been missed with a little over just two-third of the number attained till now.

The SLNP program makes a very attractive proposition for Urban Local Bodies (ULBs). With a great amount of responsibility resting on EESL, the scheme promises a reduction of 50% in energy consumption. More importantly, the savings pay for the scheme and cash strapped civic bodies don’t have to fund anything upfront. There is nothing to lose. However, this sometimes has led to the loss of ownership towards the project by the stakeholders. In some cases, where the LED lights failed or required higher maintenance and repair, the blame-game between ULBs, Utilities and EESL has created a situations which threaten the overarching goals and success of the initiative.

Providing street and public lighting is one of the most expensive responsibilities of a municipality and can account for a significant energy consumption. The LED Street Light replacement programs in India are planned at a vast scale and breakneck implementation speeds. The road for most of these projects comes with point of no return. Given the investments and other stakes, the options are also binary – either succeed or enter a long dark tunnel of failure.

To accurately understand and map the Power Quality concerns in LED Street Lights, a detail study with high-quality data is required. Such a study, also a need of the hour, will not just unearth some long-term impacts of the technology on the health of electrical network, but also help to see the true costs of the shift to LED Lights by illuminating the details on the darker side.

REFERENCES

  1. Energy-Efficient Street Lighting—Implementation and Financing Solutions The World Bank – https://openknowledge.worldbank.org/bitstream/handle/10986/22275/India000Energy0Financing0Solutions.pdf?sequence=1&isAllowed=y
  2. EESL assures of high quality LED Street Lights conforming to BIS standards – https://pib.gov.in/newsite/PrintRelease.aspx?relid=151254
  3. Lessons Learned from the Pilot LED Municipal Streetlight and PLN Substation Retrofit Project (Pilot LED Project) in Indonesia – https://econoler.com/wp-content/uploads/2017/10/led-lighting-best-practices.pdf
  4. Energy Efficient Street Lighting Guidelines – US Aid Handbook – https://www.beeindia.gov.in/sites/default/files/ctools/Energy Efficient Street Lighting Guidelines.pdf
  5. Center to LED Street Light implementation target –https://www.thehindubusinessline.com/news/centre-to-miss-street-lighting-programme-target/article25901125.ece
  6. Tough Road to Getting LED Lights on the Streets – https://www.nationalgeographic.com/news/energy/2011/01/110120-led-streetlights-ann-arbor/
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