LED street light power consumption?

Dear Guest,

I'm not surprised that you are having a tough time collecting reliable data to answer this question. One of the factors that makes this difficult to answer is the fact that you are comparing one lamp to a cluster of lamps. And with most cluster arrangements, a single lamp failure means several drop out at the same time.

But in a perfect world, the most reliable way to compare performance is to look at the lamp efficacy (conversion of energy to light) or lumens per watt (LPW). As a rule of thumb, the theoretical maximum conversion of energy to light has a physical limit of 110 LPW. In practice, it is very expensive to achieve such outputs for any length of time because there are other trade-offs that compromise performance. So from a practical sense, you will do well to find lamps that perform at or around 95 LPW and at the same time have a reasonable life expectancy.

That being said, it is also important to consider the power supply for most electronic lamp systems, including LEDs. They factor into the total watts consumed to operate such a cluster. So claims of 106 Watts or 30 Watts are highly unrealistic when you consider the lamp system as a whole. Certainly a hpsv lamp will require a ballast which will have some inherent losses. And the cost to replace short life lamps is much higher than the cost of some lamps, so life expectancy is a very important part of the overall calculation.

Lastly, if you look at the spectral content in a hpsv lamp you will find that it has fairly poor color rendering. While this may not be very important for outdoor lighting of the streets (street lights), the LED lamps may offer a wider range of spectral content making it a preferred lamp due to superior color rendering. So, even if it turns out that it takes nearly the same amount of power to operate a LED cluster for 14,000 lumens as it does for one 150 Watt hpsv lamp, the real question is which lamp is going to give the best performance over time.

By the way 14000 Lumen/150 Watts = 93.33 LPW but the spectral content makes it tough to distinguish blue from green or black. What color was the getaway car?