The utility industry received good news from the Federal Communications Commission (FCC) on May 13 with approval of an order capping a long-running five-year process to repurpose a critical portion of narrowband spectrum in the 900 megahertz (MHz) band for wireless broadband applications.
The order paves the way for the existing interleaved land mobile radio (LMR) channels to be reconfigured in 3x3 MHz blocks, such that utilities can begin building out their own private long-term evolution (LTE) communications networks. It is envisioned that these networks will help to further enable new applications for distributed generation, energy storage and smart vehicle charging by increasing visibility and control of a more dense, diverse and sophisticated power delivery infrastructure.
Utilities are facing technology revolutions that are transforming longstanding business models. This stems from rapid changes in how electricity is generated, transmitted and consumed. As a result, utilities are doubling down on modernizing their distribution system and improving resilience to recover from critical events like storms. To enable this, they are aiming to establish cost certainty and better control over their assets as they look to build out private networks in the LTE spectrum.
The recent FCC order is a long-awaited step forward that fuels the fire of private LTE build-outs, yet each network has its own unique challenges. Utilities on the forefront of these efforts are paving the way for a new converged core of communications services they can provide with minimal reliance on public wireless carriers.
Spectrum continues to be a scarce resource, and its efficient use is a key objective for the FCC. Now, with the FCC making a strategically important piece of narrowband spectrum available for the likes of utilities, this so-called “beachfront” property will be available to enable the dense array of connected devices that comes with an evolving and more connected grid.
As with any attractive property, early movers like Ameren and Southern Company have already begun snapping it up by obtaining experimental licenses to run LTE trial projects to demonstrate how their use cases will operate. Moreover, this ruling allows technology neutrality, the use of any approved 3GPP (Third Generation Partnership Project) device within the licensed spectrum band. This is a key aspect of delivering efficient use of spectrum.
While LTE standard frequencies range from as low as 600 MHz to as high as 39 GHz (mmWave), the 900 MHz band meets most field communication bandwidth requirements and is sufficient to propagate across a vast utility service territory. The spectral efficiency of 900 MHz LTE coupled with multiple-input and multiple-output (MIMO) also delivers a bits/Hz improvement that has benefited the carrier ecosystem for years. The FCC order will allow for 3 watts of field device transmit power (given interference mitigations), which more closely aligns with the typical needs of a static field device. These characteristics, in conjunction with this key piece of the spectrum, enable utilities to develop a broadband strategy for mobile operations and fixed assets that is flexible and adaptable to their own unique needs.
As with any spectrum acquisition, one band does not fit all. What works for a utility’s rural areas will exhibit a different performance in dense urban deployments. “Beachfront” frequencies can come with sticker shock prices, so scrutiny and engineering analysis are prudent for making a spectrum selection that will impact the utility for decades to come. With the right modeling for total cost of ownership, the payback has proven to be on par with utility return expectations. Depending on the commercial arrangement, spectrum has the benefit of a market value that appreciates over time while its asset book value depreciates.
The utility industry demand for what private LTE networks can provide is growing, but low-band spectrum options to serve these critical needs have previously been scarce. Before the approval of this order, utilities were often optimizing spectrum against suboptimal decisions. For early LTE adopters, we have advised utilities to start building their communications networks within the readily available spectrum, such as Citizens Broadband Radio Service (CBRS), and then layer private spectrum to meet challenges they may face with coverage or control. With 900 MHz spectrum access becoming available for utilities, the way is clear for them to start building within the low-band spectrum and then add capacity in the high-band spectrum, as needed.
There are many diverse views among utilities, but we contend that the 900 MHz option just became the front-runner for those looking to communicate with field devices. This spectrum provides utilities the flexibility to build out private systems that will serve their capacity and coverage needs today and well into the future. The FCC has the ears of the utility industry, which has had no choice historically but to depend on public carriers for many remote broadband needs.
Forward-thinking utilities are transforming their communication abilities to privately owned LTE networks, which provide them increased reliability and control, can scale to the present and future needs of the changing grid, and enable future distribution applications. The FCC order makes it clear that private LTE is a reality in grid modernization, and utilities eager to plan for the inevitable communications transformation can benefit from the newly available spectrum.
Consolidating communications into a unified architecture such as a wireless LTE network offers a host of advantages for utilities.
