Many strides have been made since we last reviewed advanced electric metering in this column in 2001. The concept of "demand response" using such meters (wherein a power user reduces his load when called upon to do so by a utility or grid operator) is being accepted as an adjunct to the permanent demand reductions common under demand-side management.

Amidst the fallout from the California power debacle is an expanded understanding of the need to make power loads responsive to power pricing and grid reliability. In its 2001 report to the California state legislature, the California Energy Commission indicated that: "Electricity and other markets function efficiently only when customers have access to timely price information and the capability to adjust their purchases accordingly....Providing customers with the necessary price information and demand response tools will moderate excessive price increases and improve system reliability...."

"In light of the clear benefits of demand response, two key principles stand out:

  • Customers should pay the actual costs of producing and delivering power at the time that it is used, to the greatest extent feasible.

  • Customers should have access to the greatest feasible range of price information, metering and communications technologies, and energy management equipment to assist them in demand response efforts."

Thus, there is little disagreement that, failing to see the cost of the power they are using at different times of day, retail power customers are unlikely to adjust their power demand. The keys to creating that awareness involve meters that show demand across time (and not just the monthly peak), and electric rates that either charge more when power generation and delivery costs are higher or offer incentives to cut load at such times.

To encourage demand reductions when grids are under pressure, several regions (in the Northeast, Great Lakes, and West Coast) have been pursuing demand response programs that pay endusers for load reductions at incremental wholesale prices. Tracking such usage requires a meter that can capture demand as it occurs and report it back to a central location for later evaluation. Called at various times "automated," "advanced," "smart," or "interval" metering, these devices (when supported by appropriate dataloggers, modems, etc.) typically communicate through telephone, radio, Internet, or other automated communication methods. It is that mix of technologies that has seen rapid development in the last two years.

A Few Of The Developments

The peak demand at which interval metering is now routinely being required has dropped. While once limited to loads exceeding 1,000 kW, it is now not unusual to find tariffs requiring time-of-use metering for loads of 500 kW. California now has 80% plus of loads exceeding 200 kW on interval meters.

Some utilities have been experimenting with time-of-use rates even at the residential and small commercial levels, with mixed results. In 2000 (when wholesale prices were high in the Northwest), Puget Sound Energy embarked on a voluntary time-of-use program, promising lower costs for participants.

While initially successful (over 300,000 customers switched), yielding both load shifting and dollar savings, rapidly falling market pricing caused most customers to see little or no savings in 2002. Customers fled back to flat pricing, and the experimental program has been shut down for "retooling."

More "energy enterprise" software (which monitors and controls the energy use of large/complex facilities) is now designed to accept interval meter data signals and issue operational commands based on them. Several Web-based energy service firms (e.g., Honeywell's Atrium, ( now commonly use interval meter data in their analysis to guide subscribing customers on problems revealed by such data.

The number of meter data service providers that supply interval meter output directly to customers through Internet sites has also expanded greatly, eliminating the need for separate on-site data acquisition systems. A good example of such a service is Genergy Inc. (

Greater differentiation is occurring among high-end and low-end automated meters, with low-end units allowing low-cost installation and the ability to be later upgraded at reasonable cost. One vendor's specs call for five levels of metering, based on degree of need and complexity.

To help potential customers navigate through this maze of equipment and services, the New York State Energy Research and Development Authority assembled "A Primer On Smart Metering" which offers an overview of issues related to interval metering and communications. Find it at