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How ‘smart poles’ can save energy and enhance smart cities of the future

Smart city with lightsAlthough “fixed position lighting” was recorded in Beijing as far back as 500 B.C., and London and Amsterdam introduced public street lighting in the 16th Century, Paris set the example of widespread street lighting. First, King of France, Louis XV, introduced oil lamps into the city in the mid 18th Century; then mass gas lighting was introduced in 1818 followed by electric lighting in 1878[1]. Since then, public street lighting has become an essential infrastructure for every city.

Back when the Parisian utility engineers were doing their work, the job of the streetlight was to make navigating dark city roads safer and more convenient. Today streetlights still perform that vital task, but in addition, city authorities are looking to maximize the potential of this ubiquitous piece of street furniture by using it as a keystone of the smart city. By adding connectivity and computing power to widespread existing infrastructure, streetlights can become intelligent and do much more than just light the way.

The benefits of smart poles

Smart lighting company Signify reports that replacing conventional street lighting with energy-efficient LEDs is an effective way to reduce energy consumption and associated emissions. Just by switching conventional public lights to LEDs yields a 50 percent reduction in energy consumption. But when those same lights incorporate connectivity allied to automatic dimming and presence detection, the energy savings can by upwards of 90 percent.

So-called smart poles can optimize their own power consumption and provide feedback on the operational status of the LED array producing the illumination. But more than that, smart poles also provide a platform for a suite of sensors with edge processing capabilities. Each streetlight has the potential to include sidewalk surveillance and traffic cameras, air quality monitoring, weather monitoring, flood detection, information displays, contact with the emergency services, public announcements, and even Wi-Fi hotspots and electric vehicle (EV) charging.

State of the market

Already valued by Grand View Research at $8.90 billion in 2022, the smart pole market is expected to experience a compound annual growth rate (CAGR) of 20.8 percent from 2023 to 2030. By that year, there are anticipated to be more than 10.8 million smart poles across the globe, says analyst ABI research.

Ambitious smart pole programs are underway in China, Korea, and India among other Asian countries. China’s smart pole market, for example, was already valued at $17 billion by the end of 2020, according to the China Daily newspaper. In Europe, the EU’s Humble Lamppost Project also aims to upgrade 10 million lampposts across EU conurbations to “kickstart” smart cities. The political body estimates that up to 50 percent of a city’s energy bill is made up of street lighting costs, and that up to €1.9 billion ($2.07 billion) could be saved through the move to LED lighting across Europe.

In the U.S., a “digital transformation project” was announced in 2021 by the City of Hampton in Virginia, which will involve replacing street lighting with solar powered poles. These poles will offer charging ports and Wi-Fi access and will be equipped with security cameras.

And several major brands are getting involved with smart poles – some key vendors of relevant technology include Verizon, Huawei, and Nokia (according to ABI research).

Using sensors to make cities smarter

There are several factors contributing to this booming market. The most important is the energy savings the smart poles bring that not only cut carbon emissions but also save a city’s citizens money.

Smart poles can analyze natural lighting trends using light sensors, to provide necessary illumination but without wasting electricity. For instance, throughout the summer the sun will rise earlier and set later, meaning that streetlights only need to be on for shorter periods. With automatic light detection the poles can adjust to these changes. Yet on overcast days, or in areas that experience more shade, the lights can compensate for the lower lights levels and increase safety by coming on earlier and staying for longer, even within regular “daylight” hours.

Elsewhere, smart poles can enable predictive maintenance. The connectivity allows for fast and frequent reporting of the overall health of the LED lighting—such as its illumination output and energy consumption—and the information can be used to predict failure ahead of it happening. Maintenance crews can then be dispatched to replace the LEDs. In addition to bringing cost benefits, predictive maintenance improves safety because it ensures areas of the city aren’t plunged into darkness.

And as traffic congestion in many major cities grows worse, monitoring air pollution becomes more important. Smart poles can use sensors to monitor the carbon monoxide (CO), nitrogen dioxide (NO2), and sulphur dioxide (SO2) that’s emitted from vehicle exhausts. Then, policymakers can be made aware of the times and regions that are regularly plagued with poor air quality and introduce initiatives to reduce the problem.

As street lighting originally had the purpose of increasing the safety of the general population, it’s only appropriate that smart poles continue to enhance public wellbeing. By including more security cameras and monitoring street traffic, smart poles can help protect individuals. For example, using an audio sensor, smart poles can even detect significant events like the sound of a gunshot and then notify law enforcement.

Data processing

Modern connectivity solutions such as Nordic nRF91 Series SiPs, LTE-M/NB-IoT cellular IoT and DECT NR+ products, are equipped with powerful microprocessors, ample memory, and machine learning (ML) algorithms that allow sensor information to be analyzed locally. Then, only notable information is forwarded to the Cloud. By only transmitting when necessary, cellular IoT devices can reduce power consumption and save on data charges.

For instance, smart poles may detect no foot traffic on a sidewalk for long periods during the night and will therefore not send any data. However, if there is suddenly evidence of several people running quickly down the road at an unusual hour, this data can be transmitted to the authorities for investigation. Or perhaps the smart pole detects no unusual noises until a vehicle loses control on a slippery surface and hits a wall. Such an event would be worth reporting among an otherwise unchanging stream of data.

The power of wireless in smart cities

Cellular IoT connectivity is an ideal technology for connecting smart poles. For instance, even though streetlights are connected to mains power, the nRF9160 SiP can run from small batteries for long periods, making it easier and more convenient to retrofit connectivity to legacy installations. Cellular IoT also offers the convenience of “plug-and-play” connectivity, kilometer plus range, and reliable service. And the near-ubiquity, maturity, and security of cellular infrastructure (especially in major cities where smart poles are often deployed) makes cellular IoT a compelling option.

By combining cellular IoT and standard protocols such as LwM2M (Lightweight Machine-to-Machine - which is included in Nordic’s nRF Connect SDK), smart cities can leverage a fully standardized IPv6 end-to-end solution for smart cities.

Widespread cellular infrastructure also opens up the opportunity to introduce the benefits of smart poles beyond the city into towns and smaller settlements so that a greater portion of the population can benefit from this technology. Combining with Bluetooth LE, each pole becomes a gateway, to which low power Bluetooth LE sensors can be connected.

In addition to cellular IoT, DECT NR+ will play an important role in street lighting applications. For high density areas or regions without cellular coverage, or whenever smart cities do not want to rely on a mobile network operator (MNO), it is now possible to use the Nordic nRF9161 to implement private 5G networks to interconnect street poles, and then provide a connection to the Cloud using gateways.

Streetlighting has been a fundamental part of our city for hundreds of years, keeping us safe and making life easier. By adding connectivity, whether NB-IoT/LTE-M/DECT NR+/Bluetooth LE, this established infrastructure can now do so much more for a city’s population while at the same time helping us address the challenges of climate change by cutting carbon emissions.

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