What if the UK’s 17,000 car parks installed LEDs and lighting controls? With an estimated 10 million parking spaces the average number of spaces per car park can be estimated at approximately 600.
Car park structure is a major factor when considering the number of luminaires, but for the purpose of these estimates I have used 300 58W T8 switch-start luminaires.
The first stage in developing an energy-efficient lighting solution is the conversion to LED. T5 is a possible lighting solution, however relatively low operating temperatures and higher wattages makes LED a better option in efficiency terms.
There are a number of LED options including LED tubes, integrated LED luminaire or a custom solution. However I have simply assumed that a 24W 2,000lm LED unit will deliver the require lux level, uniformity and efficiency.
I have assumed that the car park lighting currently operates 24/7.
Not a bad initial saving. If lighting controls were introduced together with a small level of car park management the savings are even more impressive.
I have assumed individual occupancy sensors for the luminaires. While daylight sensors have advantages, in car parks with high levels of natural light, a system for turning the luminaires off when it is dark and the car park is closed needs to be installed or a significant proportion of the savings are lost. There is a case for leaving a proportion of the luminaires on as during the winter and at night a low level of illumination can be provided for safety and security.
Car park management can assist in delivering efficiency, for example when car park occupancy is low restrict the number of floors or areas for car parking.
If we assume that occupancy sensors will reduce the operating hours by six hours a day (25 per cent) and the management of the car park an additional 10 per cent, then the annual saving increases from 119,900kWh (and 66.5 tonnes of CO2) to 142,000kWh (and 78.7 tonnes of CO2).
These savings are just for one car park. So what if all 17,000 car parks introduced efficiency? Then 2.4 billion kWh can be saved, with the associated 1.3 million tonnes of CO2 can be saved. Simple steps with the combination of efficient lighting technology and good management, result in spectacular energy savings.