Independent SIMs and their Significance to the Electric Utility Industry
In this blog
The emergence of the independent SIM
Thinking of the future of the electric utility industry, I am excited about the advent of what can be referred to as "independent SIMs." A SIM (Subscriber Identity Module) is a small but powerful card that plugs into a wireless device, allowing 4G/5G network operators to securely identify the device, determine if it is authorized to attach to their network, understand the services the device is asking support for, and know who is responsible for paying for those services. Historically, 4G/5G service providers would provide their SIM card to their customers. But now SIMs can be obtained through a variety of sources, essentially making them "independent."
What is an independent SIM?
These new independent SIMs offer the capability for IoT device owners to control most of the characteristics of their 4G/5G services. Whereas legacy SIMs were static and tightly associated with one service provider, independent SIMs flip this model by being associated with the device owner and offering them the flexibility to choose among various service providers as well as unique characteristics of the services to fit the IoT operator's needs. Device owners will easily be able to change from Service Provider-A to Service Provider-B due to loss of service, quality of service, cost of service, or any number of situations that might occur.
Independent SIMs are an outcome of the efforts the GSMA (Global System for Mobile Communications Association) developed for the mobile ecosystem (think 4G/5G). Their latest specification, SGP.32, was introduced in 2023 and implemented by late 2024. It expanded and empowered new software-based SIMs. Now we are on the verge of a transition from the limitations of fixed SIMs and wireless services, entering a whole new era of flexibility and growth enabled by a tiny little device called an eSIM or iSIM. eSIMs are integrated circuit chips that are embedded or soldered onto a modem, while iSIMs are virtual SIMs operating in a software container supported by the modem.
Why are independent SIMs important for electric utilities?
Electric utilities already make extensive use of 4G/5G network services—mainly for supporting devices across their transmission and distribution grids. Whether in capacitor banks, voltage regulators, reclosers, or Advanced Meter Infrastructure (AMI) devices, most utilities have thousands if not hundreds of thousands of devices supported by modems containing one or more SIMs.
These various devices exist across the utility's entire service territory in substations and on pole-tops which are not conducive to easy access for hands-on changes.
Utilities have already entered a new grid modernization era brought on in part by renewables and EV charging, introducing new devices that will dwarf legacy devices in terms of quantity, service characteristics and data usage.
Many electric utilities are considering building their own private 4G/5G networks, which will necessitate SIMs that contain their information and likely also that of an alternative service provider. Independent SIMs enable field devices to automatically switch to the utility's private network after a radio is put into service.
Who wants to be stuck with an enormous fleet of inflexible devices for the next fifteen years or have to wait years to begin taking advantage of their private wireless investment? Fixed SIMs that are restricted to a single service provider or use static services for the life of a grid asset seem unreasonable. Instead, these new software-based independent SIMs, the latest addition to the continual move to Software Defined Networking (SDN), are not merely strategic, as we'll see in the next segment, they are inevitable.
Where do I get independent SIMs?
If the power of independent SIMs comes from having the autonomy to reprogram the services associated with your devices, it is then imperative to find someone willing to help you get and keep that autonomy for the life of the grid device. Independent SIMs can be obtained from existing classic service providers, newer independent service providers, independent SIM providers, and even modem vendors whose products incorporate eSIMs or iSIMs. What will become important, though, is to also obtain a means for administering independent SIMs. SIM management tools or systems is a topic for future discussions.
Obtaining independent SIMs from your existing service provider might be possible, even though it reduces their grip on each device you deploy. Most service providers acknowledge the decline of physical SIMs (especially for the IoT community) and the growth of embedded or integrated SIMs (eSIM or iSIM), regardless of whether they are 'independent' or not. But if the conditions exist and they benefit the utility, there shouldn't be reasons why your existing service provider cannot supply independent SIMs and SIM management. They do not mean you're moving off of their services.
Classic SIM manufacturers are now addressing the IoT industry, including electric utility needs, by offering independent SIMs and SIM management tools. Many of them also offer independent connectivity by leveraging the dominant 4G/5G US-based wireless providers' networks and those of regional operators. Similarly, we see an emergence of independent connectivity providers catering to the IoT industry who, conversely, offer independent SIMs. But the biggest source of independent SIMs will be from the device manufacturers themselves as they embed and integrate SIMs into their equipment. These SIMs will essentially be blank and will need programming according to their owner's needs, therefore one justification for obtaining SIM administration capabilities. Embedded and integrated SIMs will be a growth engine for independent SIMs.
How can utilities start using independent SIMs?
First, the costs to acquire and the risks of utilizing independent SIMs are very low. The SIMs cost about as much as a cup of coffee, but supplier review, negotiations, setup, and administration can be a small project to complete—but it's not at all a significant project.
As noted above, the impact of changing anything in field devices can be cost-prohibitive. Accordingly, independent SIMs are most likely to be used in greenfield deployments or when there is some other reason for dispatching to a remote device. Also noted above, the manufacturers are adopting embedded and integrated SIMs, but we are in the early stages. For these two reasons, the most immediate opportunities for independent SIMs are the new physical SIMs that conform to GSP.32 and that can be inserted into legacy devices about to be deployed into the field.
Utilities should consider discussing with existing and competitive service providers, with SIM manufacturers, and with their vendors, strategies for adopting independent SIMs. They all play a part in the solution. As noted earlier, the adoption of independent SIMs does not require movement away from your service provider nor the private services they've configured for you. But independent SIMs make that option available should that change be necessary—especially if you're planning a private 4G/5G implementation.
Adopting independent SIMs can actually mitigate risks by empowering you to switch over to alternative service providers, whether temporarily due to service outages or for longer-term reasons. In some situations, alternative service providers might offer lower cost services. And they can offer many of the customized services you've been using, such as virtual private networks.
Final thoughts
This paper has characterized the adoption of independent SIMs as a voluntary decision. This is true today; however, as equipment vendors further transition to shipping embedded and integrated SIMs in their devices, the decision will change from voluntary to mandatory. So 'adoption' is a matter of time.
Why not adopt now? The costs are very low, it reduces several forms of risk, your wireless service can stay the same or even improve, and every time a field device is deployed with an independent SIM is a step toward more autonomy and flexibility.
World Wide Technology's (WWT) extensive experience in the 4G/5G wireless industry enables us to see these emerging opportunities and share them with our clients. We support all four major Mobile Network Operators (MNOs), are partnered with various SIM and alternate connectivity providers, and have deep relationships with modem equipment providers. Independent SIMs are an innovative solution we want to introduce to the electric utility industry.