Legacy AMI Wasn't Designed for Emerging Applications

It has been more than a decade since US utilities began deploying advanced metering infrastructure (AMI). Today, roughly two-thirds of electric meters are smart. The majority of these systems rely on unlicensed radio frequency (RF) mesh networks, which have excelled at the function for which they were built: meter reading.

Fast forward to 2020, however, and these legacy AMI networks have been leveraged by many utilities in support of smart street lighting, grid management and smart city applications. As the demands placed upon the systems grow, it becomes increasingly clear that a more robust, flexible, and higher throughput platform would serve better.

LTE Networks Fit the Bill

Wireless networking technology has advanced markedly since 2010. LTE-based standards are available in a variety of protocols that can support a range of applications. Thanks to recent Federal Communications Commission rulings, there are new spectrum options available to utilities for the buildout of private wireless networks. Also, public wireless carriers have improved their policies and pricing around meter-to-meter offerings for utilities. There are four flavors of LTE networks that may serve utilities well either individually or in concert:

• Narrowband Internet of Things (NB-IoT) operates at sub-gigahertz frequencies to provision low data devices and sensors with low power requirements. It will have the lowest cost and throughput of the LTE-based networks.
• LTE-Cat-M1 consumes more power but offers better downlink performance and interference immunity than NB-IoT. LTE-Cat-M1 is appropriate for more battery-sensitive sensor or device needs, but still has enough bandwidth for low latency communication and mobile devices. Most modems combine LTE-Cat-M1 and NB-IoT into one module.
• LTE-Cat-1 offers broadband capabilities more affordably than 4G LTE and with throughput speed capped at 10 Mbps, it requires less power than traditional 3G or 4G cellular. This option also enjoys near ubiquitous buildout across North America.
• 4G LTE is a broadband wireless network offering latencies as low as 10 milliseconds and bandwidth adequate for the most demanding video applications. 4G LTE is used by public wireless carriers around the globe, and a large ecosystem of vendors and economies of scale already exist.

It’s a Platform Play Now

Rather than taxing an AMI network that wasn’t designed to accommodate a multitude of layered on applications, utilities should consider building a distribution grid network that can serve as a multifunction platform in support of grid management, smart lighting and smart city applications. An LTE-based network, whether public or private, can be leveraged from day one to accommodate all these functions.

Because utilities own over half of the street lights in North America, early smart lighting systems were often integrated with legacy AMI networks. The network was already there and paid for, and these early lighting control systems did not generate a large amount of data. Latency requirements were not stringent. Also, in the case of RF mesh based AMI networks, adding lighting nodes to the mesh densified the network, improving the reliability of AMI data transmission. This collaboration between the metering and lighting organizations within a utility was logical, cost-effective, and mutually beneficial.

As of 2020, however, more sophisticated lighting control systems are widely available. They offer greater functionality but require higher bandwidth and lower latency. In addition to core lighting control needs, these intelligent controls support a wide range of advanced functions, including energy monitoring and billing, performance monitoring, color controls, adaptive lighting, emergency response and other smart city sensor connectivity. Additionally, utilities are looking to support certain smart grid solutions with these networks, further challenging the AMI network to support other devices and applications beyond smart lighting. Efforts to build more capable systems on top of existing AMI networks can create capacity constraints, forcing new investment in the AMI network or result in not prioritizing the lighting system traffic. These effects in turn limit the value and benefits of the advanced lighting control system, which can be significant.

AMI networks were built to automate the critical cash register function of the meter, reducing meter reading costs, and providing basic visibility at the grid edge. In order to fully maximize the value of connectivity across the distribution network, however, utilities should consider decoupling their AMI network from other smart grid, lighting, and city application networks.

For more on how LTE-based networks can serve utilities for these use cases, and several case studies, see the Guidehouse Insights white paper LTE-Based Networks Provide a More Flexible and Future-Ready Platform for Grid Management, Smart Lighting, and Smart City Applications available from Ubicquia.

Also, register here for a roundtable discussion between representatives from Ubicquia, Florida Power & Light, RealTerm Energy, and Guidehouse Insights’ Elberg.