By Andrew Lund
On a muggy July day in the mid-Atlantic, an independent system operator (ISO) requested additional capacity from a partner utility to meet increased demand. The partner utility was also experiencing a demand increase and used its commercial load shed program to get the extra megawatt (MW) needed. It sent a load control event over the public wireless network to load controllers at several of its larger customers.
Under normal conditions, the message would be received and the customers would switch to generator power or turn down their operations. On this summer day, however, there was a problem: The load control devices were on a 2G network and the 2G network was down.
This particular utility's experience with 2G network disruption began with a notice from its wireless carrier about the upcoming phase-out of its 2G network. Soon, the utility started noticing dropped connections and periodic outages. Then came the surcharges for 2G SIM cards and outright refusals to activate new 2G devices.
Although the disconnection only affected a small number of load shed participants, each participant contributes a significant portion of the utility's capacity. Consider, for example, a commercial load shed program with hundreds of participants, each contributing an average of 0.75 MW. If 10 average-sized participants are offline during an event, that represents 7.5 MW of unavailable capacity--a significant amount of power when it's needed most.
This utility's experience is a warning about the dangers of cellular-network disruptions. Indeed, the message from major North American cellular operators is clear: 2G is not a long-term solution for connecting long-lived utility assets. It's a warning that utilities would be wise to heed as carriers begin plans to phase out 2G cellular networks and shift to next-generation 3G/4G technologies. Are you ready?
To build out 4G LTE networks that require significant spectrum, carriers are aggressively pursuing new spectrum and some are starting to decommission legacy networks. Examples of this include AT&T's recent $1.9 billion purchase of 700 MHz B Block spectrum from Verizon and Verizon's pending sale of 700 MHz A Block spectrum in exchange for $2.365 billion in cash and some of T-Mobile's AWS/PCS spectrum. AT&T is also decommissioning its 2G GSM network to free up spectrum for its LTE build-out. The company's recent announcement of its plans to shut down its 2G GSM network sent shock waves throughout the machine-to-machine (M2M) industry where most devices in the field rely on low-cost 2G technology.
If you have meters, reclosers, capacitors or substation intelligent electronic devices connected over a 2G network, there should be a sense of urgency in planning for the 2G sunset. "The clock is ticking… you need to get started yesterday," as one program manager said. For many, just one budget cycle remains before the expected sunset in January 2017. Following are some practical steps to start planning:
- Start talking with your wireless carrier about its plans for the 2G network. They will be able to share specifics about the timing and impact of the 2G sunset in your service area and are motivated to help you transition to more efficient 3G or 4G networks.
- Take an inventory of all 2G connected devices in your operation. This can be a daunting task, since some devices may have been deployed as long as 20 years ago by different teams within your company. Again, your wireless carrier can help.
- Identify a replacement strategy. The first question most utilities face is whether to move to 3G or go straight to 4G. While both networks will be supported for the next two to four years, 4G LTE will be around longer than 3G. Beyond its longevity, 4G offers additional speed and throughput to support future bandwidth-intensive applications.
About the author: Andrew Lund, product marketing manager at Digi International, searches the market to find Digi-powered solutions to challenges in the energy, retail and transportation industries. Lund manages Digi's 2G network sunsetting initiatives and the go-to-market strategy for Digi's associated product solutions, including the TransPort line of M2M routers with Gobi 4G LTE technology. Lund holds a Bachelor of Arts degree in History from Bethel University and a Master of Business Administration from the University of Minnesota.