ASSESSMENT OF ENERGY SAVINGS AND COST EFFECTIVENESS FOR ENERGY
EFFICIENT BARN LIGHTS
Executive Summary
Energy efficient alternatives are investigated for outdoor barn (or yard) light fixtures. Subject matter
experts are consulted to assess the current technologies and practices used for this application. Expert
responses suggest that all utility-owned barn lights operate on a dusk-til-dawn basis using a photocell
for control. Current barn light technologies include high pressure sodium (HPS), mercury vapor (MV),
and a small percentage of metal halide (MH). HPS lights appear to be the most prevalent, with the most
common wattages being 100, 150, and 200W.
Induction and LED lights were identified as two possible energy efficient alternatives to the current HPS
and MV market. Although induction and LED lamps have greater up-front costs than the MVs and the
HPSs, they provide the advantages of lower wattages and longer lifetimes.
ProCost results suggest that the energy cost savings and maintenance cost reductions more than offset
the initial costs of both induction and LED lamps. All twenty replacement scenarios had TRC B/C ratios
greater than one, with some scenarios having ratios as high as 20.
Introduction
This report summarizes the research done to investigate the costs and potential energy savings of
energy efficient barn or yard lights. These outdoor fixtures are common in the BPA area, and their long,
consistent hours of use make them an ideal candidate for a more efficient alternative.
First, a summary of responses from various subject matter experts is provided to assess the current barn
light market. Next, the potential costs and energy benefits of efficient barn lights are estimated using
expert feedback. Finally, a ProCost analysis is included to assess the cost effectiveness of this measure,
given the best data currently available.
Assessment of Current Market Technologies and Practices
Survey of Subject Matter Experts
A total of ten subject matter experts were consulted to assess the current technologies and practices
used for barn lights in the BPA region. A summary of the experts and their responses is included here. A
full list of the questions asked to each expert is included in Appendix A. Table 1 includes the names and
affiliations of the experts consulted for this study:
Table 1: Subject matter experts consulted.
Name
Affiliation
Region
Peter Meyer
Tacoma Power
Puget Sound, WA
Bryan Hulsizer
BPA
Spokane, WA
Erin Hope
BPA
Spokane, WA
Dick Stroh
BPA
Idaho
Randy Whitaker
Harney Electric
Central Oregon
Chris Aiken
Kootenai Electric
Idaho
Dan Villalobos
Inland Power
Spokane, WA
Ross Holter
Flathead Electric
Montana
Curtis Roe
Centralia
Western WA
Jeremy Burt
Clearwater Power
Idaho
2
Summary of Expert Responses
The subject matter experts were asked a number of questions on their experiences with barn lights in
their area. The questions were focused on various topics, including: current lighting technologies used
for barn light fixtures, power requirements of bulbs and fixtures, control and ownership issues,
maintenance procedures and associated costs, barn light customers, and energy efficient barn light
alternatives. The following discussion provides a summary of the experts’ responses:


Technologies Used – The most common lighting technologies used for this application include
mercury vapor (MV), high pressure sodium (HPS), and metal halide (MH). Of these three, HPS
was by far the most frequent response, especially for fixtures less than 200W. Several
respondents mentioned that MVs used to be the most prevalent technology for this application;
however a BPA program in the late 1980s switched many of the MVs to HPSs. Metal halides
were mentioned by only one respondent, and he said they were used mostly in high wattage
(1000W) commercial applications.
Wattages – Reported wattages varied based on the particular technologies and ranged from
100-1000W. The responses indicate that most utility-owned barn lights are closer to the bottom
of this range (100-200W); however, some higher wattage fixtures (400-1000W) were reported.
Table 2 lists the three lighting technologies and their corresponding wattages.
Table 2: Wattages reported for common barn light technologies
Wattage Range
Reported
Most Common Wattage(s)
Reported
Mercury vapor (MV)
175 – 400W
175W
High pressure sodium (HPS)
100 – 200W
100W / 150W
1000W
1000W
Fixture Type
Metal halide (MH)



Control – Respondents were asked how the barn lights in their area were turned on and off;
whether it is via a timer, photocell, or some other control method. The unanimous response
was that barn lights are controlled via a photocell – and operate on a dusk-til-dawn basis, or
about 12 hours per day.
Replacement Procedure – According to respondents, lights are replaced only at the end of their
life. A few mentioned early retirement programs as a possibility, but only if rebates were
substantial. The high costs associated with traveling to many sites were mentioned as the major
reason why early retirements are avoided.
Labor, Travel, and Other Costs – Several respondents provided labor costs for a lineman to
replace a failed barn light bulb. Labor estimates were generally about $50/hour per crewman.
The most specific estimate was from a BPA engineer: $37/hour plus 30% overhead, which
equates to $48/hour. The most common response for the number of crewman involved in a
bulb or fixture replacement was two.
3
Travel time estimates varied for different utilities, based on whether they served a more rural or
urban environment. The most common travel time estimates varied from 10-30 minutes per
bulb, so an average 20 minutes was used.
Other non-bulb material costs were provided by a few of the expert respondents. Experts noted
possible costs due to ballast or starter/igniter failures.


Customer Base – Barn lights are used by all types of utility customers: residential, commercial,
and agricultural. Respondents commonly noted that they are “everywhere” and they number at
least in the “tens of thousands” in the BPA region. One utility alone, Inland Power, estimated
that it owned and operated about 3,000 of these lights. The respondents believe that most of
the barn lights in the BPA region are owned and operated by the utilities; and typically,
customers are charged a flat-monthly rate (non-metered) for the service.
Efficient Alternatives – Experts were asked whether their utilities were using any energy
efficient alternative technologies for this application, or if they had heard of any such
technologies. All utilities except one responded that they had not considered replacing barn
lights with efficient alternatives on a large scale. A few utilities responded that they are testing
efficient alternatives in a small number of test sites. The most common alternative technologies
mentioned for this application were LEDs and induction lamps, with a couple of respondents
also mentioning “high-wattage CFLs”. Only one utility, Clear Water Power, responded that they
are considering a large scale replacement – swapping 175W MV lamps for 40W inductions. No
efficient alternatives were mentioned for the larger wattage (400W+) lamps.
Cost Effectiveness of Efficient Alternatives
Energy Use
An estimate of annual energy use for the most common existing and energy efficient barn light fixtures
was calculated based on manufacturer-listed bulb and ballast wattages. The total fixture wattage was
then defined as the sum of the bulb and ballast wattage. Table 3 shows the bulb, ballast, and total
fixture wattages for the most commonly reported barn light fixtures. The higher wattage fixtures
(400W+) are not included since no efficient lighting alternatives were mentioned by experts for this
wattage range, and none were found. For the original manufacturer dataset, see Appendix B.
4
Table 3: Bulb, ballast, and fixture wattages for different barn light bulb types.
Fixture Type
100W HPS
150W HPS
200W HPS
175W MV
40W Induction
50W Induction
60W Induction
80W Induction
40W LED
50W LED
Bulb
Wattage
100
150
200
175
40
50
60
80
40
50
Ballast Wattage
(% of Bulb)
14.5%
14.5%
14.5%
14.5%
5.0%
5.0%
5.0%
5.0%
0.0%
0.0%
Total Fixture
Wattage
114
172
229
200
42
53
63
84
40
50
Estimated Annual
Energy Use (kWh/yr)
501
752
1003
877
184
230
276
368
175
219
Ballast wattages were calculated based on manufacturer specifications, and then averaged for both
magnetic and electronic ballast types. It was assumed that all HPS and MV fixtures used magnetic-type
ballasts1, while all induction lamps used electronic-types. The induction lamps considered in this study
are all self-ballasted, meaning the ballasts are integrated with the bulb. According to an induction lamp
retailer, although the lamps are self-ballasted, the listed wattage typically does not include the ballast
power consumption; therefore the total fixture wattages were adjusted accordingly2. LED lamps do not
require ballasts, so additional ballast wattage was not included. LEDs have other electronic components
such as drivers, but an LED manufacturer said that the driver wattage is typically accounted for in the
listed bulb wattage.3
Also included in Table 3 are estimated annual energy use figures for all lamps. Annual energy use is
based on dusk-til-dawn operation, or approximately 12 hours daily use, for 365 days per year. This
equates to 4,380 hours of annual operation.
Cost
Costs were gathered for the bulb types shown in Table 3. Specific manufacturer costs were averaged
across the different bulb types, and the results are shown in Table 4. Also included in the table are
incremental installation costs and total replacement costs per bulb. Further details on these
calculations can be found in the barn light workbook. All costs were adjusted for 2006 dollars before
being entered into ProCost.
1
Based on a conversation with Dick Stroh, BPA engineer.
Based on a conversation with a representative from Best in Green Solutions (BIGS), an induction lamp retailer.
3
Based on a conversation with evLuma, an LED barn light manufacturer.
2
5
Table 4: Material and installation costs for different bulb types.
Fixture Type
Bulb Cost
(2011 $)
Adj. Bulb
Cost (2006 $)
Incremental
Install Cost ($)
Total Replacement
Cost per Bulb ($)
100W HPS
$ 16.00
$
14.38
$
-
$
64.43
150W HPS
$ 16.07
$
14.44
$
-
$
64.49
200W HPS
$ 15.92
$
14.31
$
-
$
64.36
175W MV
$ 16.07
$
14.44
$
-
$
64.49
40W Induction
$ 49.76
$
44.72
$
21.57
$
94.77
50W Induction
$ 60.78
$
54.63
$
21.57
$
104.68
60W Induction
$ 74.48
$
66.95
$
21.57
$
117.00
80W Induction
$127.68
$ 114.77
$
21.57
$
164.82
40W LED
$275.00
$ 247.20
$
21.57
$
297.25
50W LED
$245.00
$ 220.23
$
21.57
$
270.28
Barn lights can fail for reasons other than a failed bulb. Ballasts can fail and so can the starters (or
igniters) of HPS lamps. It is unclear how frequent these non-bulb modes of failure occur, but based on
expert opinion, their frequency is not comparable to bulb failures. Furthermore, some experts
responded that they have seen ballasts last for 30 or 40 years. Therefore it was decided not to include
the cost of a failed ballast or starter within the ~15 year lifetime of the LED and induction bulbs.
Additional Parameters
Several other parameters were required to determine cost-effectiveness:


Measure lifetime – Measure lifetimes depended on the particular lighting technology.
Induction lamps were assumed to have a 65,000 hour lifetime, or 14.8 years, and LED lamps
were assumed to have a 60,000 hour, or 13.7 year lifetime.
Load profile – The StreetLight load shape was used for the electric savings. A gas shape pointer
was not used since HVAC interactions were not included in the analysis.
Cost Effectiveness
Twenty scenarios were entered into ProCost to assess the cost effectiveness of energy efficient barn
lights. Figure 1 shows the results of the ProCost runs. Each cell in the figure provides the annual kWh
saved and the ProCost TRC B/C ratio. The figure shows that all scenarios, for both induction lamps and
LEDs, are cost effective under the assumptions of this analysis. TRC B/C ratios range from 2.2 for a 50W
LED replacing a 100W HPS – and 23.2 for a 40W induction lamp replacing a 175W MV. A blended
baseline scenario is also provided, which represents a weighted average of the most common existing
barn light technologies (see workbook for details).
6
Replacement
Baseline
40 W Induction
kWh saved:
HPS
100W TRC B/C Ratio:
kWh saved:
HPS
150W TRC B/C Ratio:
HPS
200W
MV
kWh saved:
175W TRC B/C Ratio:
Blended
kWh saved:
Avg. TRC B/C Ratio:
317.4
50 W Induction
kWh saved: 271.4
11.4 TRC B/C Ratio:
568.1
kWh saved: 225.4
8.3 TRC B/C Ratio:
kWh saved: 522.1
19.3 TRC B/C Ratio:
60 W Induction
637.0
40W LED
2.4 TRC B/C Ratio:
kWh saved: 384.1
18.2 TRC B/C Ratio:
kWh saved: 591.0
16.7 TRC B/C Ratio:
kWh saved: 601.5
kWh saved: 545.1
2.4 TRC B/C Ratio:
kWh saved: 576.9
2.2
kWh saved: 533.1
4.1 TRC B/C Ratio:
kWh saved: 702.2
7.3 TRC B/C Ratio:
kWh saved: 453.1
21.4 TRC B/C Ratio: 16.7 TRC B/C Ratio: 12.8 TRC B/C Ratio:
kWh saved: 282.4
3.9
8.9
kWh saved: 509.5
14.1 TRC B/C Ratio:
50W LED
kWh saved: 326.2
14.9 TRC B/C Ratio: 11.4 TRC B/C Ratio:
5.6 TRC B/C Ratio:
kWh saved: 726.8
kWh saved: 634.8
kWh saved: 647.4
23.2 TRC B/C Ratio:
kWh saved: 133.5
5.9 TRC B/C Ratio:
kWh saved: 476.1
TRC B/C Ratio:
693.4
80 W Induction
kWh saved: 645.8
6.5 TRC B/C Ratio:
kWh saved: 658.4
4.9 TRC B/C Ratio:
4.7
kWh saved: 602.0
4.5 TRC B/C Ratio:
4.3
Figure 1: Cost effectiveness matrix showing TRC B/C ratios for ProCost scenarios.
Conclusions and Recommendations
The cost savings, energy savings, and ProCost results from this analysis suggest that both LEDs and
induction lamps are cost effective alternatives to HPS and MV barn lights. Although the induction and
LED lights have greater up-front bulb costs, these costs are more than offset by the energy savings and
reduced maintenance cost savings of these lights.
7
Appendix A – Survey Questions
Baseline Lamps





Bulb Type
o What types of lamps are currently used in barn lights in your area? (e.g. mercury
vapor, high pressure sodium, etc.)
o What type of bulb (size, shape) is it?
o If different lamp types (MV, HPS, etc.) are used, could you estimate the distribution?
(% of each)
Power
o What is the listed wattage of the bulb(s)?
o Do you know the power usage of the entire fixture? (including ballast)
o Does the power consumption change over time? For example, do older lamps
consume more or less power than new ones? If so, can you quantify this change?
Control
o How are the lights controlled? (e.g. photocell, timer, some other way)
 If a timer, what are the hours of operation?
 If a photocell, could you estimate the hours of operation?
 If some other way, could you estimate the daily hours of operation?
o Are they controlled by the utility or the private residences?
Replacement
o How often are bulbs replaced? (e.g. end of life, early retirement)
o How much does it cost to replace a lamp?
 Labor cost?
 What size crew?
 Travel time?
 Time spent on site?
 Material cost?
 Lamp?
 Other components?
Customers
o How many barn lights are you responsible for?
o How many customers are served by your utility?
o What is the main purpose of these lights? (e.g. general outdoor lighting, security)
o Are these used mainly by residences, commercial customers, etc.?
8
o Is the individual customer responsible for paying for the energy consumed by this
light?
Higher Efficiency Lamps

Are you replacing any barn lights with higher efficiency lights?
o If so,
 What type?
 What wattage?
 How much do they cost?
 What is there expected lifetime?
 What is the retrofit process?
 What is the labor requirement of the process?
 Material cost of the process, in addition to lamp cost?
o If not,
 Do you know of an LED replacement or other high efficiency bulb that would
be well suited for this application?
9
Appendix B – Manufacturer Data
Table 5: Manufacturer bulb data
Manufacturer
Model
Wattage
Type
Avg. Lifetime Cost ($)
Data Source
(hrs)
70,000 $ 245.00 Service Concepts
50,000 $ 275.00 Nasun Lighting
evluma
Clearlight Beacon LED
50 LED
Nasun
E39 base LED
36 LED
PLT
Self-ballasted
40 INDUCTION
BIGS
Self-ballasted
40 INDUCTION
Gladiator
Self-ballasted
50 INDUCTION
BIGS
Self-ballasted
50 INDUCTION
BIGS
Self-ballasted
60 INDUCTION
BIGS
Self-Ballasted
Philips
C100S54/ALTO HPS
100 HPS
GE
LU100/MED HPS
100 HPS
Sylvania
67515 Defused Coated HPS
100 HPS
GE
85369 Clear HPS
100 HPS
Philips
36876-1 Clear HPS
150 HPS
GE
LU150/MED HPS
150 HPS
GE
44206 HPS
200 HPS
Philips
ED28 Clear MV
175 MV
Sylvania
69445 MV
175 MV
60,000 $ 46.14 1000bulbs.com
70,000 $ 53.37 Best In Green Solutions (BIGS)
50,000 $ 64.95 Gladiator Lighting
70,000 $ 56.60 Best In Green Solutions (BIGS)
70,000 $ 74.48 Best In Green Solutions (BIGS)
70,000 $ 127.68 Best In Green Solutions (BIGS)
24,000 $ 13.06 1000bulbs.com
80 INDUCTION
24,000 $ 13.90 ProLighting.com
24,000 $ 19.37 1000bulbs.com
24,000 $ 17.65 1000bulbs.com
24,000 $ 18.23 1000bulbs.com
24,000 $ 13.90 ProLighting.com
24,000 $ 15.92 1000bulbs.com
24,000 $ 19.99 eLightBulbs.com
24,000 $ 12.14 1000bulbs.com
Table 6: Manufacturer ballast data
Manufacturer
Model
Ballast
Bulb
Type
Type
Magnetic HPS
Ouput
Input Difference Difference
Data Source
Wattage Wattage
(W)
(%)
100
115
15
15% 1000bulbs.com
100
115
15
15% 1000bulbs.com
Sola
E-SRN00F100
Howard
S0100-02C-111 Magnetic HPS
Sola
E-SRN00F150
Magnetic HPS
150
170
20
13%
Howard
S0150-02C-111 Magnetic HPS
150
167
17
11%
Sola
E-SCA00W200 Magnetic HPS
200
230
30
15%
Ballast Kit
175W
Magnetic MV
175
205
30
17%
Sunray
Self-ballasted
Electronic Induction
40
42
2
5%
1000bulbs.com
1000bulbs.com
1000bulbs.com
BallastKit.com
Alibaba.com
10