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The USDOE Forrestal Lighting Retrofit: Analysis of Electricity and Thermal Savings
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This report provides an overview of the lighting retrofit and the resultant electricity and thermal savings. It presents results from the whole-building monitoring effort that show that the measured gross electricity savings accounted for $324,705 or 76% of the total monetary savings. The measured energy savings performed within 90% of the estimated savings. Quite surprisingly, the thermal savings which were not included in initial estimates by the USDOE accounted for $102,824 or 24% of the overall savings and increased the total cost savings to $427,529 (107% of expected electricity cost savings of $399,058). The measured reductions in monthly peak hourly electric demand performed within 68% to 91% of estimated demand reductions depending upon the month of the year.
DescriptionIn September of 1993 a 36,832 fixture lighting retrofit was completed at the United States Department of Energy Forrestal complex in Washington, D.C. This retrofit represents DOE's largest project to date that utilizes a Shared Energy Savings (SES) agreement as authorized under Public Law 99-2721. As DOE's first major SES contract, it was important that every aspect of this project serve as the cornerstone of DOE's Federal Relighting Initiative, including the careful measurement of the electricity and thermal energy savings. The Department of Energy estimated that the lighting retrofit would reduce annual electricity use by 6.146 million kWh (62% of the lighting electricity use), and lower peak electric demand by 1,300 kW. Estimates of the electricity savings were $399,058 per year, or $1,350,386 over a seven year period2. Environmental impacts of this project have been estimated in the range of 3,791 to 4,160 tons/yr (3.4 to 3.8 million kg) of carbon dioxide (CO2) avoidance, 31.7 to 33.2 tons/yr (28.7 to 30.1 thousand kg) of sulfur dioxide (SO2) avoidance, and 13.6 to 16.0 tons/yr (12.3 to 7.3 thousand kg) of nitrous oxide (NO2) avoidance. Since this project represents one of DOE's first major SES projects, special effort was given to carefully measuring every aspect of the project in order to create a well documented case study to serve as a model for other federal agencies. One of these efforts, initiated in 1991, included measuring hourly electricity and thermal savings using pre-post, whole-building measurement techniques developed as part of the Texas LoanSTAR program4. In September of 1991, whole-building hourly monitoring equipment was installed and used to develop an hourly baseline record of pre-retrofit, whole-building energy use. Monitoring has continued through August of 1995, twentyfour months after the September 1993 retrofit completion date.
Haberl, J. S.; Bou-Saada, T. E. (1995). The USDOE Forrestal Lighting Retrofit: Analysis of Electricity and Thermal Savings. Energy Systems Laboratory (http://esl.tamu.edu), Texas A&M University; Department of Mechanical Engineering, Texas A&M University. Available electronically from