To: Terry Logee, USDOE

From: Jim McMahon, Jiang Lin, Barbara Atkinson, Isaac Turiel, LBNL

Date: August 7, 1996

Re: EUIs in Table 5.6 of 1996 Draft Report on Ballasts

In a May 17th telephone communication with Isaac Turiel of LBNL, Bob Wisbey of NE MA

questioned the reported trend in commercial sector EUIs, specifically, the upturn at the end of the

forecast period. (This issue was referred to as Question 7 in LBNL's May 20th letter to NEMA.)

This memo presents a replacement table and an explanation.

In the attached table, Energy Intensity (EI) replaces Energy Utilization Index (EUI) in Table 5.6

in the February 1996 Draft Report. Both EUI and El were calculated in the COMMEND 4.0

model, but EUI was reported. As defined in COMMEND Detailed Lighting Module, EUI reflects

only changes in equipment efficacy over time. El is a more complete measure of kilowatt-hours

per square foot per year, since El includes changes in efficacy as well as in annual lighting hours

and in footcandle levels.

El in year y = EUI in year y

* (Annual operating hours in year y / Annual operating hours in base year)

* (Footcandles in year y / Footcandles in base year)

In the old table, EUI increased slightly in later years of the forecast because of the change in the

share of total lumens contributed by fluorescent lighting. The lumens are used as weights to

calculate the overall average efficacy (which is reflected in the EUI) each year. Over time, T8 and

T12/ES lamps replace T12 lamps in existing buildings, decreasing lumens per fixture (and

footcandle levels as lumens per square foot). As a result of two factors, 1) lower lumens from

fluorescent lighting (in contrast to constant lumens assumed from non-fluorescent lighting), and 2)

decreased share of fluorescent lighting in new compared to existing buildings, fluorescent lighting

delivers a smaller share of all lighting over time. As efficacy of fluorescent lighting increases, EUI

decreases. But then decreasing shares of fluorescent lighting (as a share of total lumens) cause

EUI to increase slightly after 2010.

The new table (attached) presents Energy Intensity (EI), which includes the changes in efficacy, in

footcandle levels, and in annual lighting hours. As described above, efficacy increases over of

forecast period, footcandles decrease, and annual lighting hours also decrease slightly (as

consumer behavior responds to projected increased electricity prices). El consistently shows a

decline in kilowatt-hours per square foot per year.

FLUORESCENT LAMP BALLASTS WORKSHOP JUNE 20, 1996 COMMENT 12
Interior Lighting Energy Intensity kWh/sq. ft/year

1992 1995 2000 2005 2010 2015 2020 2025 2030

Commercial Sector

Basecase 3.61 3.24 2.87 2.76 2.67 2.61 2.55 2.50 2.45

Level 1 2.86 2.70 2.61 2.55 2.49 2.45 2.41

Level 2 2.86 2.67 2.57 2.51 2.46 2.42 2.38

Level 3 2.85 2.66 2.55 2.50 2.45 2.41 2.37

Level 4 2.85 2.66 2.55 2.49 2.44 2.40 2.36

Industrial Sector

Basecase 3.80 3.61 3.34 3.19 3.13 3.09 3.06 3.03 3.01

Level 1 3.33 3.14 3.06 3.03 3.00 2.98 2.97

Level 2 3.31 3.07 2.93 2.92 2.91 2.90 2.89

Level 3 3.30 3.05 2.91 2.89 2.88 2.88 2.87

Level 4 3.30 3.05 2.91 2.89 2.88 2.88 2.87

FLUORESCENT LAMP BALLASTS WORKSHOP JUNE 20, 1996 COMMENT 12