By Scott Foster
A full, two-way advanced metering solution delivers benefits for utilities and consumers, including more efficient outage management, improved load optimization and demand response, automated remote disconnect and access to information critical for managing energy usage. Although advanced metering infrastructure (AMI) is a key enabler for meeting present and future demands on the electrical grid, justifying the investment in a full AMI solution and ensuring continued returns over the years has not been easy for many utilities. Territory-wide AMI deployments are still limited, but many early AMI deployments have been hindered by escalating costs to cover a majority of meter locations-especially those hard-to-reach meters-or limitations on expanding use of an AMI network for other utility monitoring needs. Whether a utility is implementing its first grid modernization communications solution, or looking to technologies to upgrade or augment an existing one-way meter reading solution, breaking down the problem helps develop an objective selection approach.
Of the three major elements of an AMI solution-the meters, the communications network and the meter data management applications-many utilities have established preferred vendor solutions for the meters and back office application suite. It makes sense to focus on the selection of an interoperable communications technology that will rapidly enable automation of advanced metering with minimal additional investment or operational overhead- while also being a platform to deliver future operational benefits.
Selecting the Right Advanced Metering Infrastructure Communications Network
Utilities hunting for the most efficient and effective communications network to meet their current needs and those in the future often are presented with numerous networking options that are difficult to compare because they provide AMI functionality in different ways. If we focus on the key AMI communications requirements to satisfy utility business objectives, we can use a single set of selection criteria that allows a utility to evaluate functionality and affordability across technology options.
Simplicity-Deployment That Fits Business Objectives: Although the hope is that a single communications technology will satisfy a utility's grid automation objectives for decades to come, it is imperative that the utility can deploy those network assets only as needed and as justified by concrete business returns. Choosing a simple network architecture that is not dependent on a critical mass of endpoints gives a utility flexibility when selecting which endpoints to automate over time. Coupling a cost-effective network technology with the ability to deploy high-value targets first-e.g., start with high revenue C/I meters, high risk residential meters or selected distribution automation assets-provides a utility immediate business benefits and a rapid return on investment (ROI). It is also critical that the network technology is simple and quick to deploy and easy to integrate using industry-standard interfaces. Phasing in additional monitoring requirements to the existing network should also be seamless extensions as business objectives and budgets dictate.
Reliability-Timely and Secure Communications: The basic requirement is that all the data coming from all of a utility's endpoints arrive reliably on a timely basis. It sounds simple, but there are several aspects of a communications solution that should be reviewed to ensure this basic capability will be delivered, including:
• True wide-area coverage: Translated to communications with above ground and below ground endpoints in urban, suburban and rural areas, such as a single network that needs to support communications with an electric meter on the outside wall of a residence as well as communications with the water meter in the basement. In addition, the communications solution should provide coverage for any service territory, even when factors such as low-density endpoints or rugged terrain are taken into consideration. Communications technologies should be compared in terms of providing the required functionality over a wide area at the lowest cost per square mile for coverage.
• Unlimited capacity: Investing in a network technology for the coming decades also requires no inherent capacity limit on the network that will constrain future deployments. It is not enough for the network to deliver connectivity over a wide area. That connectivity must also support high levels of information to realize the benefits of grid modernization. Such a network must be able to scale thousands, if not millions, of meters. Planning for capacity is especially important when considering robust support for two-way AMI communications as well as the additional communications related to demand response (DR) or home area networks. This capacity "future-proofing" must be cost-effective. In addition to comparing the cost for coverage previously noted, a utility should compare the cost per endpoint for the required capacity.
• Robust and secure communications: Assurances that the data sent by an endpoint is received requires that the network provides guaranteed delivery and the entire communications link is secure. The communications network needs to provide high data throughput and low system latency to efficiently manage the rich data updates from the meters simultaneously with the broadcast, multicast or unicast messaging to the endpoints for commands such as on-demand reads and firmware updates. Several factors can affect the reliability of network delivery, but, with smart sensor design, effective network planning and reliable backhaul services, a communications network should provide data delivery guarantees. A utility also should insist on a communications solution that supports National Institute of Standards and Technology (NIST) recommendations, and that the network is designed so the security implementation does not consume too much of the capacity built into the network.
Versatility-One Network That Does it All: Many utilities have implemented hybrid communications networks to adequately address different needs of metering, DR or distribution automation (DA). While possibly sufficient to serve connectivity requirements, a hybrid solution may result in higher complexity and cost than a utility should have to manage. A single network technology that interoperates with all types of endpoints-e.g., electric meters, water meters, gas meters, load control devices, FCIs, smart transformers and cap bank controllers-and that has support for main line-powered and battery-powered devices greatly simplifies the implementation and operational burden on the utility. It isn't difficult to see how this is also a tremendous cost advantage.
Value-Best Return on Investment: Following these guidelines should improve a utility's chances of managing its investment in a new communications network. Even so, a utility should insist the prospective technology vendors provide information required for determining the initial investment to begin seeing benefits, additional investment phases to fully automate the utility's assets, and ongoing operations expenditures required to continue realizing the smart grid promise. A reliable, high-capacity wide area network is the basic requirement; doing the diligence to also evaluate the ROI on various technology options will pay dividends for decades to come.
A Smart Wireless Solution for a Smarter Grid
There is still work to do, but, if a utility is determined to find the most effective AMI network for the lowest cost, comparison of the critical selection criteria will clarify the decision.
Simplicity-Deployment That Fits Business Objectives:
• Supports a flexible business case-full AMI rollout or steps to get there;
• Supports a gradual migration path-prioritize the highest-return meters first;
• Rapid integration with existing meters and meter data management, outage management, data historian and other back office systems; and
• Rapid deployment-high square miles deployed per day.
Reliability-Timely and Secure Communications:
• Coverage for above and below ground,
• Capability to support millions of endpoints on a single network,
• 99.5 percent or greater daily delivery reliability,
• Data integrity and resolution that supports rate analysis and dynamic pricing, and
• NIST security standards.
Versatility-One Network That Does it All:
• Single network for all monitoring needs;
• Support for any type of endpoint-meters, DR and DA; and
• Support for mains-powered or battery-powered endpoints.
Value-Best Return on Investment:
• Low network investment per square mile,
• Low network cost per endpoint,
• Minimal infrastructure to deploy and maintain,
• Meter-to-cash benefits immediately, and
• ROI in a few years from launch.
About the author: Scott Foster, vice-president smart grid sales at On-Ramp Wireless, is working with large and small utilities interested in making the right AMI communications decisions. If you would like to know more about the available On-Ramp Wireless solutions, please contact Scott at email@example.com.