Dark Sky Lighting and Energy Savings Gary Schroeder RMUE - PowerPoint PPT Presentation

Dark Sky Lighting and Energy Savings Gary Schroeder RMUE September 26, 2019 1

2003 Northeast Blackout 2

The Energy Cost of Light Pollution • 30% of all outdoor lighting is wasted, ending up in the night sky International Dark-Sky Association (www.darksky.org) • Unshielded outdoor lights waste $2 billion (17 terawatt-hours) of energy in the U.S. each year • Equivalent of 8.2 million tons of coal burned annually to light up the night sky https://www.scientificamerican.com/article/outdoor-light-pollution/ http://adsabs.harvard.edu/full/1991ASPC...17...89H 3

Skyglow Brightening of the night sky over inhabited areas 4

Light Tresspass Light falling where it is not intended, wanted or needed 5

Glare Excessive brightness that causes visual discomfort or disability 6

Light Clutter Bright, confusing and excessive groupings of light sources 7

Safety and Security 8

Lighting Best Practices 9

Saddlebrook Townhomes • 102 Townhomes • 172 Porch/deck lights • 65 Post-top lights • City Neighborhood Innovation Grants • 2017 – Porch Lights • 2018 – Post-top Lights 10

Saddlebrook Townhomes Porch Lights New Old 11

Saddlebrook – Out with the old Original fixtures Sample of original bulbs 12

Porch Lights After Before 13

Unshielded vs Shielded Porch Light Old New Unshielded: 46x brighter (Glare) Shielded: 2.5x more light on porch Max Luminance: 7,732 cd/m 2 Max Luminance: 170 cd/m 2 Ground Luminance: 0.66 cd/m 2 Ground Luminance: 1.66 cd/m 2 14

Post-top Fixtures Before After 15

Post-top fixture retrofit 16

Post-top light metrics Old New Unshielded: 180x brighter (Glare)! Shielded: 6x more light on ground Max Luminance: 10,000 cd/m 2 Max Luminance: 56 cd/m 2 Ground Luminance: 0.1 cd/m 2 Ground Luminance: 0.6 cd/m 2 17

Saddlebrook Night Sky Event 7/9/2019 18

Energy Savings Porch lights • Baseline = 60 Watts average, New fixtures = 9 Watts • 172 Fixtures 11,526 kWh/yr Savings Post-top lights • Baseline = 6.3 Watts (previous 60 Watts), New fixtures = 10 Watts • 65 Fixtures -1,053 kWh/yr Savings Net Savings = 10,672 kWh/yr ≈ $1,000/year (possibly some take-back from more people leaving their porch lights on) 19

Lighting Value / Distribution Efficiency Porch lights • 60 Watts → 9 Watts ( 85% savings) • 800 lumens → 750 lumens • 13.3 lumens/W → 83.3 lumens/W (↑525% ) • Luminance Efficacy: 0.011 Cd/W → 0.184 Cd/W ( ↑1,577% ) 20

Lighting Value / Distribution Efficiency Post-top Lights • 6.3 Watts → 10 Watts (↓59% savings) • 450 lumens → 450 lumens • 71.4 lumens/watt → 45.0 lumens/watt (↓37% ) • Luminance Efficacy: 0.016 Cd/W → 0.060 Cd/W ( ↑278% ) 21

Other Benefits • Measure persistence – integral LEDs • Uniform look in neighborhood • Better light distribution • Safety/security • Quality of life – “I now enjoy sitting out on my patio at night without being bombarded by glaring lights” (resident referring to old post- tops) 22

Typical Box Store Offering 23

Fort Collins Utilities / Efficiency Works Rebates • Integral LED • Fully shielded • 3000K or less $25 RaaS https://efficiencyworksrebates.com/ 24

Suggested Path Forward for Outdoor Lighting • Provide rebates only for lighting fixtures that are night-sky friendly • Disqualify “glare bombs” • Implement color temperature requirements (e.g., 3000K or less) • Create channel for homeowners and businesses to purchase quality fixtures. 25

Thank you! Gary Schroeder Sr. Energy Services Engineer Fort Collins Utilities 970-221-6395 gschroeder@fcgov.com www.fcgov.com/nightsky 26