Willows Swim Club is a private, member-owned swimming and recreational facility located in central New Jersey. The swim club provides kitchen space to a local restaurant to operate a food concession. Being offered as a service to its membership, there is presently no charge for rent or utilities. However, given the current economic climate the swim club is considering charging the concession operator next season to be reimbursed for the utility costs incurred operating the concession area. The primary objective of this energy audit was to measure the electrical demand and energy consumption of the concession area to determine demand and usage during an average summer peak operating period, representing worst case Demand and Energy usage. This information will be used to determine reasonable utility charges when negotiating the contract for next season.

Dranetz Case Study - 2 week energy survey

The swim club is seasonal business operating during the summer months from Memorial Day to Labor Day each year. The concession operates 7 days a week from about 11am to 7pm each day. Certain days have extended hours due to demand and other factors but days can also be shortened due to inclement weather. Swimming pools are outdoors so the facility may close or limit operating hours due to rain or cool temperatures. The concession area electrical loads are primarily comprised of cyclical loads such as refrigerators, freezers and room air conditioners but constant loads such as overhead lighting exist.

A two week energy survey using the Dranetz Energy Platform EP1 was conducted from July 14, 2009 to July 28, 2009. The EP1 was connected to the dedicated 120V split phase sub panel feeding the concession area. Two model TR2550, 100A CT’s were used for current measurements.

Below is the demand profile recording during the survey with the Peak Demand overlaid. Data is show in DranView 6 software:Dranetz Case Study - 2 week energy survey

Survey results indicated the following:

  • Peak demand measured during the period was 7.353 KW.
  • Total electricity consumed was 1375.6 KWh
  • The survey ran for 13.95 days with an average consumption of about 98.5 KWh per day

General observations

  • The demand was cyclical and peaked during mid day hours as expected.
  • More consistent demand profile was observed during the first week of the survey vs. the second week.
  • Local weather data during the monitoring period was obtained from the Internet and compared to the demand profile. The comparison indicated rain and poor weather conditions corresponded with the reduction and inconstancy of the demand measured during the second week of the survey. Since such weather is consistent with a normal summer in the area this demand data should be included in the overall 2 weeks results being considered normal.

Electricity Cost Estimation
The local utility is Public Service Electric & Gas (PSE&G) Company. New Jersey, being a deregulated state provides consumers the option to purchase electricity supply from an independent provider other than the delivery company. The facility owner chose PSE&G as the electricity supplier so both Delivery and Supply charges come from the one utility. Even though the swim club is a comparatively small consumer of electricity the utility bill is more complex than a residential bill. The utility rate structure applied is PSE&G’s GLP, General Lighting & Power rate. Also being the electricity supplier, PSE&G charges their BGS, Basic Generation Service rate structure for supply charges. The resultant utility bill demonstrates the complexity of billing in a deregulated energy environment and also the importance of understanding your electrical usage in order to manage and reduce your utility costs:


  • Service charge: $4.27
  • Distribution charges
  • Annual Demand @ $3.9202/KW
  • Summer Demand @ $7.2755/KW
  • KWh charges @ $0.0145/KWh
  • Societal Benefits (recovery of costs incurred achieving government policy) @ $0.0075/KWh
  • Securitization Transition (bond finance charges)@ $0.0104/KWh


  • BGS Capacity (generation & transmission)
  • This is a complex calculation that represents the customers share of the overall peak load assigned to the utilities transmission zone.
  • BGS Energy (tiered usage per KWh)@ $0.1089/KWh (first tier <9755 KWh)

Being such a complex rate structure with many billing factors, it can be difficult to relate some of these costs to actual usage by the concession. Since the objective is to estimate worst utility costs, a fair method was found with the following assumptions taken into account:

  • The operation of the swim club during the 2 week survey was deemed typical and representative an average two week period during peak summer months.
  • Actual usage results will be used in the estimated charges opposed to determining a percentage of the concession usage vs. the overall bill.
  • Service charge will be 100% paid by the owner.
  • BGS capacity charge will be ignored since there is no fair way to determine the concessions portion of these charges. The owner will bear this charge.
  • The various KW Demand and KWh Energy utility charges can be consolidated into one charge for KW and KWh portions of the estimate:
  • Consolidated KW Demand charge is: $11.1957
  • Consolidated KWh Energy charge is: $0.1413

Demand and Energy Summary Report

Site: Willows Concession final
Measured from 07/14/2009 11:12:09.0 to 07/29/2009 02:37:01.0

Jul (*) 0.0 0.0 7.4 0.580
Max values 0.0 0.0 7.4 0.580

Energy Consumption

Jul (*) 0.0 0.0 1375.6 720.8
Total Values 0.0 0.0 1375.6 720.8

Time of Use Billing

Site: Willows Concession final

Measured from 07/14/2009 11:12:09.0 to 07/29/2009 02:37:01.0

Time of Use Costs

Jul (*) 0.0 0.0 82.3


Jul (*) 0.0 0.0 194.4
Total Values 0.0 0.0 194.4

(*) Indicates partial month.