In part 2 of our discussion with Michael Siminovitch, California Lighting Technology Center (CLTC) and the Rosenfeld Chair in Energy Efficiency and a professor in the Department of Design at UC Davis, we talk about how standards, biology, energy goals and other factors play a role in setting thoughtful lighting strategies. Don’t miss part 1, where we covered adaptive outdoor lighting and the urban fabrics of light.
Echelon: Can you talk a bit about California’s Title 24 building standard?
Michael Siminovitch: Title 24, Part 6 2013 now requires adaptive lighting in many outdoor lighting applications, essentially for new-building construction. It started with the idea that we could save an awful lot of energy using adaptive lighting for exterior lighting. The CLTC was able to pull together the lighting industry, the utilities, and the codes and standards authors, all with their own specific interests, but tied together into Title 24.
ELON: How did you determine the bi-level guidelines for adaptive exterior lighting, of 100% dimming to around 50% during periods of low activity?
SIMINOVITCH: It took some experimentation. When we first started looking at this, the energy and conservation folks said, we can’t have these lights on at night in parking lots and pathways. It’s a terrible, egregious waste of energy. Let’s just turn everything off.
We had to tread carefully, because on the other side, you had a lot of people concerned about safety and crime and security and the sense of well-being at night. Think about the aesthetics of leaving a building at night, and going into a parking lot that’s dark. That’s just unacceptable.
So we built a full cross-section of a parking garage inside our CLTC building, which is a large, three-story open space. We set up a parking fixture with lighting controls able to adjust the lights. We tried 100% to zero, 100% to 10%, 100% to 20%, and so on. We looked at multiple different fractions of bi-level lighting.
What we found right away was that the 100% to zero, turning the lights all the way off, was very startling. Interestingly enough, though, when going from 100% to 50% power the dimming was almost unnoticeable.
The energy efficiency and dark sky experts, the ones interested in energy waste, were delighted with 50% energy savings. Safety, security, and law enforcement personnel said that at 50% they could barely tell the difference. The range from 40% to 60% was a kind of golden section for us, and that’s how the 50% maximum set point found its way into the standards.
ELON: We hear a lot about the energy-saving advantages of moving from older lighting technologies such as high-pressure sodium (HPS) to LEDs. Why not just mandate that upgrade for energy savings? Why bother with adaptive lighting controls?
SIMINOVITCH: Let’s take the typical scenario of a medium-sized city. If their current portfolio is HPS, there’s tremendous pressure brought by the energy agencies and utilities to move to solid-state lighting, particularly LEDs, to gain energy savings.
And certainly, there are energy savings in moving from HPS to LED. But we’re leaving a lot of things on the table if we just stop there. The idea is that we can get significantly more savings by adding in networking communication control features that enable adaptive lighting—i.e., dialing back lighting in parking lots, streets, and other outdoor areas by around 50% power during periods of inactivity.
Then there’s enhanced safety, better and less-expensive maintenance of lighting, and all these other features that become possible. Knowledge is power, and if a city understands how people are moving about at nighttime, they can use their resources appropriately. Maybe they provide more policing functions in certain areas. Maybe they adjust their signal lights.
This kind of understanding opens new doors that we haven’t even seen yet. That was Lumewave’s initial idea, that there’s a leveraged opportunity, where you get the energy savings as well as the opportunity for doing many other things.
ELON: What’s the risk in not pushing for adaptive lighting controls?
SIMINOVITCH: I’m very concerned that in this country’s rush toward going from HPS to LED without controls, we’re squandering our public trust. The CLTC has been pushing very hard with the Department of Energy and others to say that it’s not just about going to a solid-state technology. It’s that you need to integrate the control systems and the control architectures if you want to truly leverage this kind of transformation.
It’s a pretty serious issue. A lot of decision makers are looking at this in a very myopic and simplistic manner. We should be considering many other things. The control features, the glare, the spectrum of light—a lot of issues are not being addressed.
There’s a tremendous temptation with public entities to do something quickly and get results right away. But if a typical city relights with a static, uncontrolled, un-networked LED street lighting system, for example, they’re essentially trapping any kind of opportunity for the next 20 or 25 years. Because a lot of these technologies are going to last a long time.
We have this public trust now to relight. It’s very difficult to go back and say, look, we made a mistake and now we want to upgrade. But they don’t have the money any more; they’ve already spent it upgrading to LEDs. Unfortunately, we’re going to be paying forever for the myopia of a badly relit street lighting system.
ELON: What do you say to people concerned about the cost of doing more than simply upgrading their lights to LEDs?
SIMINOVITCH: More sophisticated solutions are not necessarily more expensive, especially if you have single sensors controlling multiple fixtures.
If you look at the cost/benefit ratio, a lot of the cost is the transaction cost and the labor of upgrading the lighting fixtures, going out to the site and redoing the fixture head. It’s a relatively small additional cost to put in the network functionality and the control features, for very, very large savings. So actually there’s a very attractive cost/benefit calculation with network controls.
ELON: Can you paint a picture of what you see as the future of exterior lighting?
SIMINOVITCH: I think we’re going to see more attention on glare and the effect of night lighting on biological systems. The biological connection to lighting is tied into what kind of spectrum of lights we should have at night. Our rush in the U.S. to put in very inexpensive street lights has biased things toward high color temperature, high-efficiency LEDs, which produce a lot of light, relatively inexpensively.
But we should be very careful about the kind of lighting spectrum we put into nighttime environments, because our biology is very sensitive to blue light. Our evolution has been such that we have not had a lot of experience with blue lights during dark hours. We probably want to install a much warmer tone, a lower correlated color temperature of light source, in our parking lots, pathways, and street lighting.
Looking ahead, I see multiple forces coming together in exterior lighting. Looking at a typical municipality, I think all the light points are going to be fully networked. And that will give us the whole portfolio of solutions to support energy, sustainability, dark sky, safety, security, reporting, utility, and all the rest. It’s the Internet of Things.
If a city wants a street light to come up to full brightness because they’re having some kind of function, or if they want to dial it down to prevent light going into houses at night, they can do that. A street light that’s not working could report back. We can have lights at a lower level, providing dark sky benefits and preventing neighbors from being disrupted by glare. And these things will all talk to each other. We’re going to see this kind of network functionality, just like we see with our phones.
ELON: Final question. How will standards play a role in reaching this future?
SIMINOVITCH: Think of codes and standards processes as setting a boundary. Once we embrace the idea that street lights should enhance safety, security, and well-being—and then incidentally, also save energy—we can create standards that support these goals.
In the past, codes and standards were typically driven by some minimum level of safety or energy, etc. We want to make sure the building doesn’t fall down or burn, or that it doesn’t use more than X amount of energy. So they’re minimum kinds of things. Now we’re starting to reorient and ask, why aren’t we aspiring to the best things we can be doing instead of minimums? It’s a moving target, a moving opportunity, but I think that Title 24 is starting to touch on this by introducing the adaptive lighting strategy, both indoors and outdoors.
I look forward to a refocusing of the dialog in this country away from a singular pursuit of energy savings, toward having energy savings plus all the other things. I’m hoping the whole relighting discussion will be characterized by a much more thoughtful and mindful kind of pursuit, which really looks at the big picture.
Cities, or municipalities, or universities, or public entities, and even large companies—these folks are in it for the long therm. The last thing you want to do is put in a lighting system that’s driven by single issues. You want to include all these in making a thoughtful decision.
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