Demand Response: An Overview of Enabling Technologies
- Meter Upgrade -An existing induction disc electro-mechanical meter can be upgraded to a full remotely readable interval meter. A pulse initiator is installed in the meter to generate a pulse for every revolution of the disc. Pulse initiators range from $25 to $45. A data recorder counts the pulses and converts to energy consumption for the appropriate interval (5, 15, 30, or 60 minutes). The data recorder also contains the communications interface. Options on the data recorder include the number of channels it can accommodate (for watts, vars, water, gas, etc.), the amount of data it can store, the number of communications ports (one for the energy service provider, one for the customer, and a third for outage notification), and the communications medium. Data recorders range in price from $80 to $200.
- Advanced Meters -ABB, General Electric, Schlumberger, and Siemens dominate the electric meter market. Advanced meters from these manufacturers include the interval data collection and communications interface. Options with advanced meters also include the number of channels, the amount of data that can be stored, the number of communications ports, and the communications medium. Each manufacturer also offers meters that monitor power quality. Prices range from $250 to over $3000. Further integration of data recording and communications into the meter itself will likely continue. As with most electronic systems that gain acceptance and mature, hardware costs will likely decrease while functionality increases.
- Automatic meter reading -Focusing down to more localized communications needs brings us to the important field of automatic meter reading (AMR). Utilities have been interested in AMR for many years, even apart from interest in responsive load. Electric and gas utilities have 164 ongoing and scheduled AMR projects. The projects include 12.4 million units using CellNet fixed radio networks. 3 Much of the technology available today was originally designed with only AMR in mind. Not only does AMR overcome the need for reading meters in bad weather or when access is difficult or dangerous, it also provides improved accuracy, collection of greater amounts of information, reduced need for estimated readings, theft detection, and automatic outage notification.
One option taken by some utilities is to let a metering communications company install and operate the meters and the communications network. It could then sell the information back to the utility and the customers. Planergy, a load aggregator, uses this industry model. Their sometimes-elaborate methods include data loggers, phone lines, and even orbiting satellites which may be of limited interest for small customers. However, it is important to understand that, based on utility curtailment requests, Planergy notifies each of its loads and monitors their response. Loads that do not respond are contacted. Replacement loads are available to respond if necessary.
Another company, CellNet, provides data collection and data management services. 2 It uses fixed networks that it does not sell. Instead an energy service provider enters a long-term contract and CellNet installs and operates a network. A MicroCell Controller communicates via radio with up to 2000 CellNet communications modules placed on meters in a 1/3-mile radius (greater in rural areas). A CellMaster