Application vendors have historically been defined by the physical medium of their solution. A vendor might be "wireless" or "powerline," but rarely both. Over the past few years, there has been a dizzying increase in the number of available carrier solutions, including WiFi, Wi-Max, Zigbee, Z-wave, DS2, Homeplug, a variety of cellular standards and more. Each of these "standards" (reflecting Layer 1 and Layer 2 of the ISO seven-layer stack) offers different advantages and disadvantages.
A similar set of choices exist in enterprise IT infrastructure. For example, office computers may connect to the enterprise network either via WiFi or wired Ethernet. In the same way an enterprise can choose computers that connect using a variety of transports, it should be possible for a utility to choose the physical transport that best achieves the business case for any particular part of its service territory (for example, wireless for urban or suburban, powerline for rural). Such flexibility can be achieved by utilities in the same way that it is achieved by enterprises: by deploying standard, interoperable, IP-based products rather than proprietary, transport-specific ones.
Performance: Bandwidth and Latency
Two critical issues when developing the technical requirements of the smart grid network are those of available bandwidth and latency.
Bandwidth is the volume of data per unit time that can move through the network. The first step in determining your requirements is to scope how much data is required from each device and application. Add them up on a time-sensitive basis. Where are the peaks? Where does it break? Does this solution allow you to add bandwidth if needed in the future?
Although smart grid applications generate significantly more data than monthly meter reading and historic low-density, one-way demand response applications, it is not a large volume of data relative to modern IT systems. Take the very familiar example of a modern meter read: Manual meter reading generates approximately 30 bytes per month of data, per customer. A new smart meter, collecting multi-channel, 15-minute interval data with event logs, security logs, power quality and other measures might generate over 10,000 times as much -- perhaps 50 KB to 60 KB of data per meter, per day.
In an environment of application-specific, low-bandwidth solutions, it may seem that this much data could never be supported, nor would ever be necessary. The history of networking, however, suggests that if additional data is made available, customers will always find a use for it. For example, over time, public websites have migrated from serving small text pages of a few KBs, to rich graphical pages of hundreds of KBs, to streaming audio and video at tremendous data rates. These innovations are made possible by the availability of economical but rapidly growing Internet bandwidth.
Solutions from the IP-based networking world, deployed in utility networks today, render it possible for utilities to move and manage much larger amounts of data than heretofore possible. It is no longer necessary for utilities to constrain their business operations -- or, for that matter, their imaginations -- based on the limitations of their vendors' technology.
Latency is equally important. Many smart grid applications, including distribution automation, outage alarming and load control signaling, require very low latency, while others, such as metering, are more latency-tolerant. Smart grid networking needs to support end-to-end and device-to-device latencies not of minutes or hours, but of seconds and milliseconds. To manage traffic appropriately, networking technology must support message prioritization, allowing critical, latency-intolerant messages primacy to other network traffic. For example, meter-reading acquisition is generally expected only within a time window measured in minutes or hours, while some DA applications require that remote devices talk "across" the network (without routing through the back office) in less than a second.
Cost/Performance Balance Drives Value
Hardware economics historically limited the deployment of multi-application networks, forcing utilities to implement vertically integrated, application-specific solutions. While these solutions often solved immediate needs, they also created significant back-office integration issues, increased operational complexity and increased long-term costs. Many utilities hoped that solutions offering greater bandwidth, such as broadband over powerline (BPL), would address this need. Although BPL delivered strong functional performance, the infrastructure costs were measured in hundreds of dollars per home passed, far exceeding the value to be gained from utility applications alone.
Current hardware economics now make it possible to deliver high-bandwidth, low-latency networking at reduced cost. It is now possible to deploy a system-wide networking infrastructure delivering hundreds of Kbps and sub-second latencies at a fraction of the cost of broadband. Specific pricing varies based on utility specifics, but can typically rival traditional AMR/AMI network pricing. This results in the utility realizing significantly greater benefits from a variety of applications while simultaneously saving 30 percent to 40 percent in operational costs versus operating separate communications solutions for each application.
Build It Right, Not Over
Less than 20 years ago, laptops, ubiquitous cell phones, iPods and Xboxes were not in existence. Considering the emergence of new utility applications and devices, it is hard to imagine what is to come in the next five to 10 years. Even today, there is an explosion of new utility and consumer devices, including remote controllable thermostats, consumer-based energy storage appliances, customer displays, fault indicators, distribution automation applications and more. Regardless of the applications or devices that do emerge, a standards-based network ensures that they can easily be incorporated into the smart grid. As exhibited in other industries, including cable, IT and telecom, a robust and flexible network is the basis for competitive advantage.
An IP-based network allows a utility to network devices not yet invented, if they are built on IP. Product development cycles for devices are much faster than the life cycle of the network, so one must expect new devices will become available and utilities will need to connect them.
The Right Network
Utilities around the world are now leading the drive to capture energy efficiency as the "fifth fuel." Smart grid applications including advanced metering, demand response, distributed generation and distribution automation offer utilities all the tools to capture this value.
By specifying and implementing the right networking infrastructure, utilities are building a strategic technology platform that enables a wide range of policy and business initiatives for years to come, avoiding concerns of near-term obsolescence or functionally bridling technologies. IP-based networking is really the only choice when building the network infrastructure for the future.
Editor's Note: This article originally appeared in The Energy & Utilities Project.