Misallocated Energy
Sometimes when I drive from place to place I take the long way. I drive the long, winding roads back home and allow my mind to wander. In some cases my mind is present within the surrounding contexts. I can see how the urban environment is shifting in both potential ways and kinetically. Things are built up, others torn down, others repaired and maintained.
Although I know exactly where I am heading, there is a sort of notion of being lost within ones own city. During a drive on a recent dark night, I took notice of all the streetlight posts. I was travelling on a road and came perpendicular to a main avenue. The streetlights cascaded away into the distance.
I continued on for another block and became perpendicular again at the next intersection. It was the same scene; a well-illuminated street, lined with sidewalks and shops. I noticed that the streetlight posts were layered. There were tall lights to brighten the street and shorter lights for the sidewalks. Driving further for another block exhibited the same organization with the addition of a set of double lights in the center median. If you are walking there you surely won’t stub your toe in the dark!
As I drove further I noticed the variety of colors emanating from the street lights. Some lamps were the new LED type and others were the older high pressure sodium bulbs which have a glowing orange hue. I began to think that it is possible that the streets might be illuminated too well. There is all the talk about the term called “Dark Sky” and how city street lights reduce the visibility of stars in the night sky. This is true and can be clearly seen if you drive out to the dark outskirts of your city and look up to the stars. I am not speaking about the total amount of illumination. I am referring to the total amount of streetlights in general.
I thought about the amount of excessive lighting and how that would be a natural strain on the power grid. What if we were more thoughtful on that? What if we properly coordinated the locations of streetlights and reduced unneeded lighting?
I thought this was a good for an AI LLM. I asked: What is the average nightly energy consumption of street light energy in San Diego?
The average nightly streetlight energy is 160 megawatts (MW), which is equivalent to the energy required for 160,000 homes.
The city’s street light energy consumption equals roughly $30 million per year.
For some time the City of San Diego and its energy provider has been upgrading the street lights with LEDs. This reduces the required energy and cost. Once the upgrades are complete, the city expects to save approximately $10 million per year. Additionally, the LED lights will be equipped with motion sensors so that they may shut down during hours of the lowest activity. The lights in our community were upgraded and it is interesting when they pop on when you’re driving down the road late at night.
I believe there is much more cost and energy savings that can be found by removing street lights in certain locations. Doing this could result in a healthy amount of savings. Again, I asked AI: “what would be the estimated cost savings of removing 10% of the street lights in San Diego?”
Removing 10% of the street lights in San Diego would save the city 15,000 kilowatt-hours per year and save an estimated $3 million dollars.
The AI LLM did note that there are negative aspects to removing street lights like public safety and property values. This is true, however, I am speaking about removing street lights in locations where the lighting is already acceptable.
On a commercially zoned street like the one I drove passed, it is important to not inly consider the amount of illumination from the street lights but also the amount of illumination provided by the shops themselves. If we have layer upon layer of lighting then that is a waste of energy and cost. The removal of certain street lights can be just as beneficial to a city as replacing those lights with LEDs.
My thoughts continued during my drive and there was a good test. My path home took me along a dark road adjacent to the local light rail corridor. On both sides of the narrow valley, the backyards of homes are up on slopes that face the road. This quarter to half mile stretch of road has no street lights. Daring as I can sometimes be, I turned off the car headlights. Wow! Now that is dark. I could barely see the line of the center median and lane dividers. Fortunately, there were no other vehicles close by.
I am sure that there are illumination standards for streets but this street does not really require it. What if there was a street light every 200 feet. It would be better than it is now that is for sure. This test set up the comparison between a street that has too much lighting and one that does not have any at all. That is where the city can find the right balance.