A Digital India Initiative

New Town Kolkata: Smart Energy Efficient Street Lighting

January 29, 2022

New Town has installed multiple solar power based LED street at various locations throughout the city. The intention of the LED installation was to reduce the energy consumption compared to conventional LED lights and also reduce greenhouse gases emission by ensuring that energy efficient lights are used. In order to provide illumination throughout New Town, New Town Kolkata Development Authority (NKDA) installed approximately 1800 LED streetlights.
These street lights have a smart module built into them that allows control over their functionality remotely. The communication platform used is LoraWan that allows long range low power communication over long distances (~ 5 kilometers).


The key objectives for installation of LoraWan based LED lights:

  1. Improve safety and security in New Town
  2. Reduce dependence on use of energy inefficient conventional lights
  3. Reduce expenditure of the city authority
  4. Reduce carbon offset from the project
  5. Control the lights remotely to switch on automatically based on the outdoor luminosity level
  6. Auto dimming based on traffic movement beneath the lights
  7. Remote diagnostics, performance and health monitoring

Figure 1: LoraWan lights in New Town reflected in the dashboard

Solution Components:

To reduce dependence on conventional streetlights and energy consumption, NKDA installed LoraWan based streetlights in New Town. This helped to reduce the expenditure on street lighting and reduce the carbon footprint of the city. The smart street lighting system uses a cloud connected LoraWan communication platform which is a low power wide area network radio frequency technology, that allows the streetlights to be remotely monitored and controlled through a dashboard.

Figure 2: LoraWan Streetlight process flow

The lights were initially configured in Luminosity (lux) Mode wherein they automatically switched on/off based on the ambient natural brightness level at dawn or dusk. However, a citywide survey discovered that due to high rises and trees obstructing the luminosity sensors, shadows made the lights switch on erratically. The solution implemented was that the lights were configured remotely to operate on astro-calendar mode rather than lux. The astro-calendar mode automatically switches on the lights based on the daily preset sunset timings and switches them off based on the daily preset sunrise timings.

The below dashboard shows the status of lights and the astro-calendar settings on the top right.

Figure 3: LoraWan Streetlight Dashboard displaying status of lights in aggregate and individual basis, alerts and configuration settings

In the below report we observe the monitoring of the switch on/off operations of the lights based on astro-calendar mode that enables energy savings by preventing unnecessary operations. The data has been extracted for 1 month from December 22, 2021 to January 21, 2022. We observe that there are variations in time everyday when the lights are switched ON/OFF based on the sunset and sunrise timings. As the data is extracted for a period of one month the daily differences in time may be small but, on a season-wise basis the time variations will be large and also the corresponding energy savings.

Figure 4: Report displaying the variable time of streetlight ON/OFF based on sunset/sunrise time.

Benefits Achieved:

1. Reduction in expenditure of City Authority

The City Authority using through this LED lighting project solar lights saves approximately INR 5.44 lakhs per month or INR 65.34 crores per year for the project.

2. Reduction in Carbon Offset

The solar street light project thus results in an offset of 84,397.5 kg of CO2 per month or 10,12,770 kg of CO2 per year.

3. Analysis of data to adjust brightness of the lights. After midnight the lights are gradually dimmed till zero level at dawn.

The solar street light project thus results in an offset of 84,397.5 kg of CO2 per month or 10,12,770 kg of CO2 per year.

4. Energy saving analysis using data generated from the LoraWan application to analyse old vs new wattage, burn times, energy consumed and energy saved.