Technological progress and sharply rising energy prices are dictating a shift in the paradigm that utilities have historically used to make AMR investments. As utilities quantify the value of advanced two-way communication features, this data becomes an integral factor in their ROI (return on investment) calculation on AMR decisions. The result has been a dramatic increase in demand for two-way fixed network AMR systems, specifically those based on RF (radio frequency) and PLC (power line carrier) technologies.
Drive-by and walk-by systems are designed for oneway communication. A study sponsored by the California Energy Commission concluded that driveby systems save utilities the cost of the manual meter read, which ranges from $0.61 to $0.85 per month for a US utility. With advanced metering systems the savings for utilities include the cost of meter reads, business process improvement, and theft reduction. A US utility can expect to see savings anywhere from $1.36 to $7.58 per month from an advanced metering system, according to the Meter scoping Study.
Utilities are now increasingly recognising the value of twoway fixed networks. A recent UtiliPoint International study of Texas IOUs shows that the top three benefits included in a utility AMR business case are rate choice options – 50%; system reliability – 56%; and outage management – 69%. 43% of IOUs also found two-way communication and a daily meter read to be of value, while 73% found it valuable to have the capability for an on-demand read.
PLC VERSUS RF
In PLC implementations, the utility has the advantage of using its own infrastructure to communicate with the meters; however, if the utility is in a developing country, the condition of the distribution network can become an impediment to error-free communication, making deployment difficult. The fact that PLC systems cannot easily be used for multi-utility applications is a limitation for many municipal utilities and co-ops that may want to implement such solutions. PLC technology is also limited in its ability to detect outages – one cannot use the distribution network for transmitting information that monitors the distribution network.
RF communication is sometimes viewed as unreliable. Also, while RF systems do not depend on grid conditions for communication between the meters, they must often overcome physical obstacles and range limitations. The radios have a transmit power ceiling if licence-free bands are used for communi-cation, and thus a limited range. To overcome this, several RF-based AMR systems employ a point-to-multipoint architecture and the use of licenced bands to communicate with the meters. The drawback of this approach is the expense involved in obtaining the licenced frequencies. Having a single point of failure adds to the drawbacks.
Independent of the communications technology used and of the network architecture implemented, two-way fixed network AMR systems share the challenge of efficient commissioning and network management. A utility that has hundreds of thousands of meters will face the challenge of efficiently allocating and managing the network topology, security and the communication address assignment of the installed AMR base. To overcome this, AMR systems must be self-configuring – requiring no address assignment or network configuration or management from the system operator.
WIRELESS MESH AMR SYSTEMS
Several AMR solutions based on wireless mesh architecture are available today. Because of the complexities involved with forming large mesh networks, solutions that support a ‘true mesh’ architecture require innovation in both hardware and software in order to be secure, reliable, scalable and serviceable, while remaining economically feasible. For the most part, the solutions that are available in the market are ‘controlled mesh’ solutions – simplified and managed versions of the ‘true mesh’ architecture. While clearly viable, these solutions do not offer many of the advantages of ‘true mesh’ solutions, such as the reliability and self-configuration.
The AMR solution of Eka Systems, Inc., headquartered in Germantown, Maryland is a noteworthy exception. Because the company was founded as a wireless mesh networking innovator, it has from its inception focused on solving all the hard engineering problems associated with enterprise level mesh networks, including security, self-configuration, true mesh architecture for reliability and ease of installation and serviceability, battery operation, multi-utility capability, and many others. The system is meter-independent and radio agnostic. Eka has adapted its advanced mesh networking technology to AMR, and has been growing significantly in the AMR market over the last three years. The result is a system with no compromises – field-proven, reliable, flexible, and cost-effective to deploy, maintain and use.