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MidAmerican Energy Company

City of Bettendorf, Iowa

Outdoor LED Demonstration and Business Case Report

May 2011

Prepared by: Outsourced Innovation, LLC 721 Arlington Ave., Suite 200 Naperville, IL 60565 630.697.0571 www.outsourced-innovation.com

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Table of Contents

I. Executive Summary

II. Suggested Recommendations

III. Background and Objectives

IV. Iowa Policy on Energy-Efficient Solid State Lighting

V. Solid State Lighting Basics

VI. City of Bettendorf, Iowa, LED Conversion

VII. Philips Lumec’s Capella LED Fixtures

VIII. Illumination Comparisons

IX. Projected Energy Savings

X. Lifecycle Cost Analysis

XI. Conclusions and Final Thoughts

XII. Appendix

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LED Streetlight Demonstration – City of Bettendorf, Iowa

I. Executive Summary

Recent advancements in solid state lighting (SSL) provide new opportunities for achieving energy efficiency, lowered maintenance costs and higher quality illumination for municipal street and area lighting.

The efficient use of energy has been an important goal for many initiatives at MidAmerican Energy. Municipal customers look to their utilities for ways to improve energy efficiency and implement solutions that create real value and contribute to a better environment.

A collaborative light-emitting diode (LED) demonstration has been established between the city of Bettendorf and its utility, MidAmerican Energy, to help understand and communicate the benefits and performance of the technology in real-world applications.

Primary results from the installation of 32 Philips Lumec’s Capella LED luminaires replacing 32 twin-mounted high-pressure sodium acorn fixtures as a one-for-one replacement on 16 poles along State Street in front of the Quad-Cities Waterfront Convention Center show the following:

A forecasted 49 percent annual k/Wh savings from Philips Capella fixtures using MidAmerican’s general municipal light and power rate (rate 45) for the city of Bettendorf.

The entire 16-pole LED lighting system is projected to save 14,115 kWh each year for an estimated annual savings of $1,213. The dollar savings is realized from reduced wattage and reduced usage from the sidewalk-mounted LED luminaires.

Compared to the option of keeping the existing HPS lighting system in place, payback of >20 years implies the technology is expensive for full-scale retrofit market adoption and suggests the importance of utility rebates to incentivize municipal technology demonstrations. A comparison of new LED and HPS lighting systems showed different results with a payback of 7 years primarily because of the lower maintenance cost coupled with a longer expected life for LED lighting.

The question of LEDs meeting RP-8-00 Roadway Lighting Standards for a collector road with respect to light output and uniformity from the Capella LED fixtures on State Street was inconclusive at this time.

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Methods to predict long-term LED fixture reliability are unclear, implying that strong product warranties are critical for a municipal application. More time and experience is required to predict if the Capella LED fixtures will continue to deliver to proposed ENERGY STAR® and Illuminating Society of North America (IESNA) standards of delivering 70 percent light output after 50,000 hours. Findings in this report are projections as an LM-79-08 Electrical and Photometric Report of Solid State Products was not provided for the LED fixtures at this demonstration site.

II. Suggested Recommendations

It is understood that the light output of LED technology is improving but wide variations exist in performance by manufacturer. It is common for LED product claims to be exaggerated or communicated incorrectly by manufacturers (Caliper Round 11, DOE). Although that may not hold true for this demonstration, measurement and validation is recommended for emerging SSL technology.

The following recommendations are suggested to ensure the LED luminaires meet performance criteria:

1. Conduct third-party validation using IESNA measurement protocol and a unified system of photometry (scotopic/photopic readings), glare assessment or small target visibility to ensure the LED lighting system meets IESNA RP-8 standards for safe and uniform roadway lighting on State Street in front of the convention center.

2. Meter a sample of five LED poles to validate if input wattage, power factor and total harmonic distortion are accurate to performance claims. The tracking of power quality performance against time, temperature, humidity, weather and environmental swings is recommended to understand impact from load from an immature technology.

3. Conduct an evaluation of the Philips LED lighting system with Bettendorf residents to gauge community perceptions and acceptance of the Philips LED Capella fixtures, especially as it relates to LEDs in front of their homes.

4. Consider a demonstration that compares multiple LED outdoor products. Product features, energy savings and optics can deliver completely different results depending on the manufacturer and lighting objectives of the city. An evaluation of the application of lighting controls and occupancy sensing will further leverage the energy-saving capabilities and understanding of solid state lighting.

III. Background and Objectives

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Many municipalities are installing LED streetlights. Bettendorf and its utility, MidAmerican Energy, collaborated on a SSL project to evaluate emerging LED technology as a solution to potentially save energy and reduce costs.

Bettendorf has a residential population of 33,098 and prides itself on its leadership and use of new technology that saves energy costs for local citizens. Bettendorf is one of the few cities in the world to have a fiber optic network available for business use. The installation of SSL technology was a natural extension of a downtown beautification project at the Quad-Cities Waterfront Convention Center.

With funding assistance from the American Recovery and Reinvestment Act of 2009 (ARRA) and MidAmerican Energy, the lighting demonstration included the installation and evaluation of 32 LED fixtures manufactured by Philips-Lumec.

The purpose of the demonstration was to investigate and compare the energy savings, light output and cost of emerging LED technology as a direct replacement to conventional high-pressure sodium fixtures that were in place on State Street directly in front of the convention center.

The main objectives of this study are to answer key questions and concerns related to emerging LED technology:

1. Can a retrofit replacement of 2-150 watt HPS lamps produce an energy savings following a replacement with LEDs manufactured by Philips-Lumec?

2. Will photometry following replacement to LEDs meet design guidelines and match or surpass IESNA RP-8 standards for roadway lighting?

3. What is the actual energy savings for the LED replacement? 4. How will the conversion to LED lighting impact the quality of electric load? 5. What are the visual impact changes for the LED replacement? 6. How does the conversion to LED lighting impact the community perception of safety in

front of the convention center? 7. Does the conversion to LED lighting today make sense economically?

Other primary research suggests the community plays a key role in municipal lighting decisions and is common practice for lights to be removed if the community is not satisfied (Outdoor Municipal Lighting Study, Illinois Technology and Sustainability Center – University of Illinois, Oct 2008). A secondary research project objective might be to gauge community acceptance of LED lighting in Bettendorf.

IV. Iowa Policy on Energy-Efficient SSL Lighting

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On Sept. 15, 2010, the Iowa Utility Commission adopted a new policy (35.15-3) as pertains to the replacement of high-pressure sodium lamps with solid state lighting as specified below:

“the new lighting consists of Solid-State Lighting (SSL) luminaries that have an efficacy rating equal to or greater than 66 lumens per watt according to a Department of Energy (DOE) Lighting Facts label, testing under the DOE Commercially Available LED Product Evaluation and Reporting Program (CALiPER), or any other test that follows Illuminating Engineering Society of North America LM-79-08 test procedures.”.

V. Solid State Lighting Basics

Before discussing the results of this project it might be helpful to define key aspects of exterior lighting as it pertains to LEDs, using the IESNA definitions for roadway lighting.

Efficacy (lm/watt): The amount of light measured in lumens divided by the total power consumed (watts)

Light Distribution: The manner in which fixtures distribute light produced by the source; LEDs are directional light sources that deliver light only where it is needed while minimizing wasted light and glare.

Horizontal and Vertical Illuminance: The amount of light delivered to horizontal surfaces such as the ground or the top of a surface, or vertical surfaces such as walls or people, measured in foot-candles.

Glare: The sensation produced by the luminance within the visual field that is greater than the luminance to which the eyes are adapted. Disability glare can be classified as annoying, intolerable, discomfort and could create loss in visual performance.

Color Rendering Index (CRI): A measurement for how accurately a lighting source renders colors. CRI for LEDs can typically range from 60-75. A CRI of 100 is considered to be excellent.

Correlated Color Temperature (CCT): The appearance of a light source, measured in Kelvin. CCT can have a strong impact on the appearance of the street being illuminated. HPS lamps have CCT of ~2100K and are very orange in appearance. Many outdoor LED products are bluish white and tend to have a Kelvin rating of 5000-6000K.

Lumen Depreciation: The decrease in light output that occurs as a lamp is operated. Lumen depreciation in LEDs varies depending on package and system design. LEDs continue to operate even after their light output has decreased to very low levels. This becomes the important factor in determining the effective useful life of the LED.

Lumen Maintenance: The opposite of lumen depreciation, lumen maintenance is how well a light source maintains light output over time. Good quality LEDs should deliver 70 percent of initial light output after 50,000 hours or more of use.

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LM-79-08: A third party test report of Electrical and Photometric Measurements of SSL Products that publishes photometrics, color and electrical power as measured in controlled environments. Reputable LED vendors will show this report.

LM-80: An approved method for measuring lumen maintenance of LED light sources and describes how lumen maintenance testing should be conducted for LEDs. Reputable LED vendors will show this report.

BUG Rating: A new cutoff classification for outdoor LEDs that represents B-backlight,U-uplight and G-glare. BUG ratings limit the lamp lumens to values that are appropriate for lighting zones.

Unified System of Photometry: A proposed new measurement that combines photopic light levels (spectral sensitivity of the eye during the daytime) and scotopic light levels (spectral sensitivity of the eye at nighttime) to achieve optimal light level and maximum energy efficiency for outdoor lighting.

Cost of Ownership: LED lighting sytems have advantages and disadvantages. When selecting fixtures it is important to evaluate beyond first cost and consider long-term energy, maintenance and environmental savings.

VI. City of Bettendorf, Iowa, LED Conversion

The focus of this project was to replace 32 HPS street fixtures with 32 LED luminaires provided by Philip Lumec. The Capella LED fixtures were chosen for the sidewalk features 30 LED packages and a Type III, short distribution (model # CPLS-MS51863A). The Capella LED fixtures chosen for the street features 98 LED packages, type III distribution (model #CPLMLMS51863A).

Illustration I show the existing HPS fixtures mounted in State Street in front of the convention center. These twin-mounted acorn HPS lamps produced 150 watts each (not including ballast), were mounted at 25 feet with 160-180 feet between poles and a Type V light distribution pattern.

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Illustration 1 – Conventional HPS Fixtures Prior to Conversion to LED

The Illumination Engineering Society (IES) writes many of the industry standard specifications for fixtures. The IES has designated several standard types based on their light distribution patterns for the basic types of conventional luminaires. The LEDs were designed as a type III distribution rather than a type V from conventional HPS fixtures to show directionality inherent in LED lighting.

The area of required illumination from each pole measured approximately 11,040 square feet with 69 feet between four lanes of traffic and 2-10 foot sidewalks on both sides of the street.

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Instructions for LED conversion were to design to meet or exceed IESNA RP-8 specifications for roadway lighting. The State Street roadway classification in front of the Quad-Cities Waterfront Convention center was rated as a Collector road with medium pedestrian conflict and pavement classification of R2/R3.

New poles were installed and 32 Lumec-Capella fixtures were mounted in May, 2010. Foot-candle measurements were taken by NRG Sales using a hand-held meter. See Appendix A.

VII. Philips Lumec’s Capella LED Fixtures

Figure 1 – Capella Fixture Temperature Rendering (24.9C to 97.72 C)

Heat is a primary enemy of LEDs. Failure rates can double when the junction temperature increases by 10˚-20C˚ (Reliability and Lifetime of LEDs, Osram Opto 2011). Fixtures engineered with good thermal design are essential to achieving long hours of service life.

Figure 1 shows a temperature rendering of the Capella fixture, the amount of heat they produce, manage and dissipate within the fixture.

New poles were part of the project redesign as shown in Figures 2, 3 and 4 below.

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Figure 2 – Pole Showing Sidewalk Mount 12 feet (left); Street Mount 25 feet (right)

Figure 3 - Sidewalk Mid-Pole LED – 68 watts Figure 4 - Street LED 147 watts

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Illustration 2 – LED Capella Fixtures

The new LED mounting design (shown in Illustration 2) used a single head, 68-watt LED fixture mounted at 12 feet to illuminate the sidewalk and a single head, 148-watt LED fixture mounted at 25 feet to illuminate the street.

The main LED product attributes for the Lumec Capella fixtures compared to the conventional HPS lighting system are outlined in Table 1.

Since the 150 watt HPS fixtures on each pole used ballasts, they actually consume about 380 watts each. The wattage for the LED fixtures on each pole, including power supply, is projected to consume 215 watts, representing a savings of over 44 percent.

The HPS lamps are rated for 24,000 hours. The LEDs are rated for 70,000 hours.

The CCT and CRI for are vastly improved with the LEDs, going from 2100K and 22 CRI with HPS to 4331K and 67 CRI from LED.

Proposed ENERGY STAR standards (ENERGY STAR Program Requirements for SSL Luminaires - July 2009) for outdoor pole-mounted area and roadway luminaries appear to have been met with the Capella fixtures at between 62 and 80 lm/watt, 99.5 percent power factor and total harmonic distortion published at <20 percent.

There was no LM-79 report submitted for the LED fixtures and lamps are not UL tested at the time of this report.

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Table 1 –Philip Lumec Capella LED versus Conventional HPS

VIII. Illumination Comparisons

The central question to the project was to understand whether the LEDs installed on State Street achieved IESNA RP-8 standards for light output and uniformity required for safe roadway lighting as outlined below in Table 2.

Road Classification Pedestrian Conflict Area Pavement Classification Uniformity Ratio (Ave/Min)

Collector Medium R2&R3 (.9 foot-candles) 4.0:1 Table 2 – IESNA Lighting Handbook – Light Level Recommendations for Roadway Lighting

A light rendering (Illustration 3) was created using a vendor-provided IES file and AGI32 software to show anticipated light distribution at ground level from the Capella fixtures on State Street.

LED Street Side- Capella Luminaire

LED Sidewalk – Capella, Mid-Pole Luminaire

Conventional Twin Acorn 150 watt HPS

Wattage 147 watts 68 watts 380 watts Lumens 11,780 4250 32,000 Lm/watt 80.13 62.5 84.21 Kelvin 4331K 4331K 2100K Color Rendering Index 67 67 22 Drive Current 428mA 600mA - # of LEDs 98 30 - Rated Life 70,000 hrs 70,000 hrs 24,000 BUG Rating B2 U1 G2 B1 U1 G1 No cutoff ROHS Compliant yes yes no LM 79 and LM 80 Reports (yes/no)

LM79: no LM80: yes

LM79: no LM80: yes

Active or Passive Cooling Passive Passive - Maximum Operating Temperature

-40˚F - 130˚F (40C- 55C) -40˚F - 130˚F (40C- 55C)

Can you provide an IES file? Yes (scaled) Yes (scaled) IP Rating IP-66 IP-66 UL Tested? Not yet but will be Not yet but will be Power Factor 99.4% 99.5% THD <20% <20% Voltage 120 V 120V 120V Warranty 5 years –full/limited?

5 years – full/limited? 1-2 years

Light Distribution Type III Type III, short Type V Hours of Operation 13 hours 9 hours 13 hours

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Illustration 3 –Forecasted LED Light Rendering on State Street

The combined IES files illustrate projected light renderings from a single pole with 25 foot and 12 foot mounting heights with each fixture oriented in opposite directions and staggered poles along a four-lane street (Illustration 4). Three-dimensional foot-candle projections are meaningful by illustrating the role of optics in minimizing glare or hot spots to create uniform lighting on the street.

Projections like these are important to answering whether light intensity of the Capella LED fixtures creates sufficient horizontal illuminance and vertical luminance without creating disability glare to the drive.

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Good measurement and validation protocol using a unified system of photometry will help answer whether the Capella LED fixtures distributed light sufficiently to meet IESNA RP-8 standards as outlined earlier in Table 2.

Table 3 shows estimated and measured light levels produced from the HPS and LED fixtures. Initial foot-candle results using a hand-held light meter are promising as baseline average illuminance was measured at .911 foot-candles for HPS and 1.43 foot-candles from LEDs. These findings suggest that LED fixtures resulted in slightly higher overall photopic illumination on the street compared to HPS. There was insufficient data to assess if a uniformity ratio of 4:1 was met.

Table 3: Projected and Measured Illumination from Capella LED Fixtures (foot-candles)

Av IL Projected

Av IL Measured*

Max IL Projected

Min IL Projected

Ave/Min Projected

Max/Min Projected

Uniformity Ratio (X:1) Projected

Sidewalk 99 N/A 3.96 0.07 14.14 56.57 N/A

LED Street 1.11 1.43* 3.49 0.15 7.40 23.27 N/A

HPS Street .911* *Represents 10 light readings with hand-held meter

Illustration 4 – Projected Foot-Candle Distribution from 1 Pole with Capella LED

Fixtures (no LLF)

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A word of caution, these measurements were taken using a hand-held light meter. For accurate measurement and validation of LED lighting systems it is common practice to use a vendor-neutral engineering firm using NIST approved, scientific-grade light meters, an 80-90 point grid system with a sufficient number of horizontal illumination and vertical illumination measurements at about 4 feet above grade with consideration for surrounding ambient light. This would include both photopic and scotopic light measurements as both are relevant when evaluating new outdoor LED street lighting systems.

The Rensselaer Lighting Research Center recommends using a new unified system of photometry as a better way to characterize seeing under nighttime lighting (Outdoor Lighting: Visual Efficacy, January 2009). This means applying an S/P ratio to baseline photopic luminance to determine optimal light output for LEDs.

IX. Projected Energy Savings

Based on the spec sheets provided by Philips Lumec it is forecast that this LED demonstration will deliver an estimated 49 percent energy savings. There was no LM-79 report provided by the manufacturer so these estimates are projected without validation.

Assuming the LED street lights operate at 4,745 hours annually and the LED sidewalk lights at 3,285 hours, the annual energy savings that could be realized are shown in Table 4.

Location Number of Fixtures Original Fixtures Watts kWh

LED Fixtures Watts kWh

Estimated Savings Annual kWh %

HPS Street 32 380 28850

Street LED 16 147 11,160

Sidewalk LED 16 68 3574

Total 14,734 49% Table 4 – Annual Energy Savings

Installing power meters on a sample of >five fixtures will validate input wattage and other important power quality attributes of solid state lighting. This includes measuring power factor and total harmonic distortion, input wattage in the on and off state, any potential voltage swings, impact on load from temperature changes and other power quality risks associated with a scalable deployment of outdoor electronic lighting.

Based on a 160 foot distance between each pole, the estimated reduction in lighting power density resulting from the conversion from HPS to LEDs on State Street went from 0.03 w/ft² watts to 0.019 w/ft².

X. Lifecycle Cost Analysis

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While technical performance in street settings is critical to technology adoption, potential purchasers likely will look at financial performance first.

In conversion applications, product lifetime and reliability are critical contributors to a financial analysis. This is especially true when payback is measured in years, where long warranties are a business necessity and where reduced maintenance costs form a significant portion of the return on investment. Also, since the LEDs are expected to last more than 3-5 times longer than conventional HPS lamps, lighting maintenance costs should be considerably lower.

The key financial metrics of payback period are discussed below to help understand if LED technology today makes financial sense for Bettendorf. The economic analysis captures two comparisons: 1) the city decides to invest in LED streetlighting or keep the existing lighting in place, and 2) the city decides between a new LED lighting system or a new HPS system.

The lifecycle analysis will take into account the assumptions indicated in Table 5.

Existing System - HPS

New System – HPS New System - LED All

Energy Savings

Wattage (Watts)

HPS HPS-1 HPS-2 LED-1 LED-2

380 190 120 147 68

Hours of Operation

Daily Annual Annual Electricity Usage (kWhr)

13 13 9 13 9

4,745 4,745 3,285 4,745 3,285

1803 902 394 698 223

Electricity Cost (cts/kWhr)

Summer 9.906

Winter 7.936

Maintenance Savings

Rated Life (Hrs) 24,000 24,000 24,000 70,000 70,000

Years to Replacement 5 5 5 15 21

Warranty (Yrs) 1-2 1-2 1-2 5 5

Maintenance Cost

Full Labor Rate ($/hr) 125 125 125 125 125

Maintenance Time (hrs) 1 1 1 1 1

Cost to Replace $345 $705 $484 $818 $598

Financial

Time Frame (yrs) 20

Electricity Escalation (%/yr) 2.0%

Discount Rate (%) 6.5%

Table 5 – Lifecycle Cost Assumptions

The applicable rate for this streetlighting application in Bettendorf is MidAmerican Energy’s Rate 45, the general municipal streetlighting service rate. The summer rate is 9.906 cents per kWhr and the winter rate is 7.936 cents per kWhr. The average rate over the full year is 8.6

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cents per kWhr. At this time, MidAmerican Energy only offers a metered rate for LED streetlighting. The $5 monthly meter charge applies to all metered consumption (typically many street and traffic lights) and is considered a negligible component for this analysis.

The LED fixtures are projected to save 882 kWh each year from each pole for an annual savings of $76. The entire 16-pole LED lighting system is projected to save 14,115 kWh each year for an annual savings of $1,213. Compared to the current HPS lighting in place, a new LED system will use 49 percent less energy and the new, efficient HPS system will use 28 percent less energy.

The maintenance cost savings are expected to be an important component of the value of LED lighting. With a 70,000 hours lifetime, LED lights are expected to last about 3 times longer than HPS. However, in order for these savings to be fully realized, LED equipment costs will need to come down. The savings are based on the assumption that the LED systems are reliable in the field, but more experience is needed to verify this.

When the investment in new LED lighting is compared to keeping the existing system in place, the energy savings did not payback the installed cost of the LED lighting within the 20-year horizon of the analysis. The installed cost of the LED lights would need to be around $2,000 for the project to pay off the additional capital cost for the LED lighting. Lower lighting costs would also reduce replacement cost and improve the life-cycle cost. An additional price reduction would be needed for scalable deployment of LED lighting with a payback under 10 years. These calculations also illustrate the importance of utility rebates to incentivize deployment of outdoor solid state lighting products.

A head-to-head comparison of new HPS and LED lighting systems produced a different result. In this case, mainly because of the maintenance cost savings, the LED system had a 7-year payback.

LED technology is reported as following Haitz Law which suggests that light output increases by a factor of 20 and costs decrease by a factor of 10 every 10 years (DOE SSL Projections). This has financial implications for projected future capital investments and perhaps will help to make solid state lighting technology a more realistic business decision with higher costs being less of a market barrier in the coming years.

XI. Conclusions and Final Thoughts

The primary conclusion from this demonstration is that LED lighting systems, although expensive, could deliver a 49 percent energy savings to Bettendorf compared to existing HPS streetlights while achieving higher light levels and better quality illumination in front of the Quad-Cities Waterfront Center.

It is uncertain whether the Philips Lumec products met IESNA RP-8 Standards for safe roadway lighting on State Street. Further, sub-metering a sample of LED fixtures will help validate input wattage and power quality factors to understand the corresponding wattage reduction that will be realized from a large scale replacement of HPS with LEDs.

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Anecdotally, impressions of the LED lighting have been extremely favorable suggesting that continued deployment of LED lighting could be acceptable to Bettendorf residents.

Emerging technology demonstrations such as this can provide valuable insights regarding emerging solid state lighting technology. Lessons learned from the project include the following:

Laboratory testing suggests that the useful life of LED fixtures should reach a minimum of 50,000 hours. There is insufficient experience with LEDs to achieve those claims as more real-world demonstrations are required to back reliability claims. The DOE is comfortable with useful life claims of 35,000 hours but not beyond that. Strong product warranties are essential to mitigate the risk of early system failure.

The DOE continues to report a wide variability in product performance and performance claims that are untrue to specs (Caliper 11). This necessitates the importance of your own product demonstrations with solid measurement and validation procedures over time and evaluating multiple products before making a scalable purchase decision.

MidAmerican Energy will offer energy efficiency incentives for qualified LED exterior fixtures beginning March 2011. Please go to www.midamericanenergy.com/ee for more details.

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XII. Appendix

Foot-Candle (photopic) Readings of LED Compared to HPS (provided by NRG Sales)

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