Why an ordinance?
Exemptions: Where color rendition is needed:
Intersection Type | LPS Lamps | HPS Lamps
Major
|
75 W
|
110 W
|
Internal
|
50 W
|
70 W
| |
---|
Intersection Type | LPS Lamps | HPS Lamps
Major
|
125 W
|
175 W
|
Internal
|
75 W
|
110 W
| |
---|
Comparison: | Energy use ratio:
Unshielded ==> Shielded | 70%
|
HPS ==> LPS | 70%
| Unshielded HPS ==> Shielded LPS | 49%
| |
---|
Exceptions:
Street Light Operating Costs: | 340 hours/month * 12 months/year * $0.172947/KWH | = $705.62/year per KW
Street Light Retrofit Costs: | Luminaire ~$150 | Labor ~$100.
| |
---|
Retrofit: | 250W Unshielded HPS ==> 125W Shielded LPS | 150W Unshielded HPS ==> 75W Shielded LPS | 100W Unshielded HPS ==> 50W Shielded LPS
Savings per year: | $88.20 | $52.92 | $35.28
| Retrofit marginal cost: | Payback time:
| Retrofit when bulb burns out: $150 | 1.7 years | 2.8 years | 4.25 years
| Retrofit immediately: $250 | 2.8 years | 4.7 years | 7 years
| |
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http://dynamics.org/MAUI_NIGHT_LIGHTS/