Electrical Submetering to Enable Time Sensitive Pricing

Greenpark Essex, a master-metered, mid rise, four building rental residential complex located on the north side of Barclay Avenue in Flushing, New York implemented electrical submetering during 2005 – 2006. Most of the 168 apartments are occupied by rent stabilized tenants under the jurisdiction of DHCR. Greenpark Essex has participated in a NYSERDA sponsored Time Sensitive Pricing program with residents receiving shadow time sensitive bills for the initial 20 billing months during which they paid for electricity based on usage only (Fig #2). Actual time sensitive billing is scheduled to commence during the spring of 2008.

Equipment – A wireless submetering system with integral temperature sensor

Despite the fact that there are dedicated meter pans for each apartment in the basement electric rooms, each apartment submeter was installed inside each apartment adjacent to the breaker panel in order to take advantage of an integral temperature sensor. The temperature sensor provides management the ability to monitor apartment temperatures and to optimize the building heating distribution system and boiler operation. This feature has assisted in addressing resident heat complaints and should result in significant fuel savings which will more than offset the additional installation cost associated with placing the submeter inside the apartment as opposed to in the basement area.

Billing History
Greenpark Essex Before Submetering
Baseline year before submetering

Greenpark Essex After Submetering
Most recent year after submetering

An analysis of the building electrical data was conducted by Herbert E. Hirschfeld, P.E. in order to determine the impact of electrical submetering on the building’s electrical usage (kWh), demand (KW) and associated utility costs. In order to determine the building’s cost benefit (or cost avoidance) due to submetering, the base line period (7/1/03 – 6/30/04) which was established during the submetering feasibility evaluation prior to submetering implementation was adjusted based on prevailing electric costs and weather data (cooling degree days or CDD) which occurred during the time period of comparison (4/2/07 – 4/1/08) after submetering. In this example the difference between the adjusted baseline period and the current period yielded an adjusted reduction in usage of 255,474 kWh or 26.64% and a cost avoidance (or cost benefit) of $51,609 which represents 26.83% of the adjusted total building complex’s electric costs. Additionally, there was a reduction in peak demand of approximately 22% which would have resulted in Greenpark Essex obtaining additional financial incentives by participating in the New York State Independent System Operator (ISO) Curtailment program. The impact of TOU pricing will be determined after the 12-month TOU billing period has been completed.

Resultant Adjusted Reduction in Usage of 255,474 or 26.64% and a Cost Avoidance from Electrical Submetering of $51,609 or 26.83% as well as a Reduction in Billing Demand of 22%
Submeter Online

Contributed by Herbert E. Hirschfeld, P. E.