57 Street-lights use about 0.1kWh per day per person... There's roughly one sodium street-light per 10 people; each light has a power of 100 W, switched on for 10 hours per day. That's 0.1 kWh per day per person.
- ... and traffic lights only 0.005kWh/d per person. Britain has 420 000 traffic and pedestrian signal light bulbs, consuming 100 million kWh of electricity per year. Shared between 60 million people, 100 million kWh per year is 0.005 kWh/d per person.
- There are fewer signs and illuminated bollards than street-lights. [www.highwayelectrical. org.uk]. There are 7.7million lighting units (street lighting, illuminated signs and bollards) in the UK. Of these, roughly 7 million are street-lights and 1 million are illuminated road signs. There are 210 000 traffic signals.
According to DUKES 2005, the total power for public lighting is 2095 GWh/y, which is 0.1 kWh/d per person.
- 55%-efficient generator - source: en.wikipedia.org/wiki/Alternator. Generators in power stations are much more efficient at converting mechanical work to electricity.
Bulb type efficiency (lumens/W)
white LED 35
compact fluorescent 55
large fluorescent 94
sodium street-light 150
Table 9.5. Lighting efficiencies of commercially-available bulbs. In the future, white LEDs are expected to deliver 150 lumens per watt.
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