Navigating the Smart Grid Middle Mile
- Posted on April 17, 2012
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As utilities and municipalities continue to build out their grids, the technology choice connecting the "middle mile" to networked devices will become increasingly critical. Unfortunately, they are faced with options that leave them caught between two conflicting imperatives. On one hand, they want to deploy a private smart grid network that can be tightly controlled. On the other, utilities desire the simplicity and availability of public operator networks.
4G and the Middle Mile
Utilities and municipalities are looking to enhance the way power is delivered and consumed, in order to improve efficiencies, drive down costs and enable integration of renewable energy sources.. However, the majority of the current smart grid network infrastructure was built with just one application in mind - reading meters - and cannot meet the long term bandwidth, low latency and QoS (Quality Of Service) that new services will add to the network.
The middle mile segment of the network, plays a dominant role of connecting multiple Smart Grid sub networks, such as Smart Metering Neighborhood Area Network (NAN), Field Area Network (FAN) covering distribution automation devices and mobile work force, and Substation Automation backhauling. However, the mesh networks or PLC (Power Line Communication) covering the last mile (from homes to pole tops) and the connected devices on the neighborhood area network (NAN), is currently traversing narrowband networks with rather high latencies. Unfortunately, this limited connectivity is not suited to flexibly address the requirements of the new era of services slated to hit the smart grid in the next five to 10 years.
The next generation of smart grid networks demands low latency high bandwidth and QoS to support activity such as monitoring grid assets through applications such as video, allowing contact center agents to quickly access customer data remotely or delivering mobile broadband to technicians reading data across the service territory. Having a 4G network will not just be "nice to have" but is a necessity in future-looking environments where bandwidth demands will soar and multiple applications will each have diverse requirements of their own.
Public versus Private
Generally speaking, private networks provide greater control, reliability, performance, return on equity (ROE) and coverage. As for public networks, utilities and municipalities can take advantage of availability, managed services and smaller initial investment benefits. However, the debate between selecting public or private 4G infrastructure is complicated by the fact that there are various approaches within those parameters:
- Public network - Public cellular networks are often ideal for running pilot programs because utilities can obtain communications as a service. No internal expertise or costly network build-out is required when leveraging public capabilities. Drawbacks of this approach include lack of control, coverage limitations (especially to outer edges of the territory) and no ROE, which could impact rates and the utility business objectives. Security is also a major concern and can only be as stringent as the service providers ensure.
- Non-cellular Public network - The major advantage of non-cellular networks, such as wireless ISPs, is that they don't accommodate the needs of mobile subscribers. While cellular networks cater to revenue generating subscriber demands, which could lead to disconnections and delays in utility network coverage for the smart grid, wireless ISPs are able to deliver 4G service without disruption.
- Private utility built network - Building a wireless network from the ground up can be more costly but it provides added control and ROE. Utilities can rest assured knowing the network is properly maintained according to utility protocols and industry standards. As a result, utilities can deliver enhanced performance with guaranteed QoS and service level agreements (SLAs), as well as comply with utility communication standards. While most projects start with small pilots, utilities should be careful in selecting the wireless vendor and ensure that it brings the years of experience and size of deployments that the Smart Grid project will eventually end up with.
- Private City/cooperative owned network - There are currently over 900 electric cooperatives in the United States responsible for the distribution of power and some large cities that own the power distribution company that could potentially provide the network infrastructure for Smart Grid. Deploying a "Smart City" network infrastructure, owned by the city/co-op, can provide "Smart Grid" connectivity as well as connectivity to other municipal services such as public safety, Smart Traffic that reduces gas emissions, Smart Lights that reduce costs, and internet access to underserved population, helping promote education and create new jobs, The challenge is to select a wireless vendor that has the experience in building Smart City wireless networks for multiple applications, on one hand, and brings the long term expertise in large and complex carrier grade deployments with dozens of thousands of connections, which is required for the mission critical Smart Grid applications.
The future of bandwidth-hogging and low latency smart grid applications is quickly nearing and utilities need to determine next steps in their 4G infrastructure roll-out today. There is no one-size-fits-all when it comes to smart grid infrastructure given the wide variance in service territories and organizational priorities, but I believe a hybrid and optimized technology approach with unified network management will be necessary to achieve seamless smart grid service delivery.
To make the connected smart grid and an effective middle mile a reality, however, a "network of networks" with unified policies and management will be essential to preparing for the next generation of applications. We as an industry will need to carefully evaluate which technologies are capable of connecting the dots between homes, devices, the middle mile and last miles and vendors in the ecosystem. By carefully evaluating the options, utilities can determine the architectural approach and vendors that best fit specific needs for control, reliability and performance, security, proactive management capabilities and streamlined deployments.