A view of downtown at night from the Pearl brewhouse’s copula. Photo by Scott Martin.

Do you get enough sun? If you live in Texas, you probably do just fine – maybe even too much sun. But do you get enough starlight? Do you get enough darkness?

“Texas has taken the lead on lighting control,” said Bill Wren of the McDonald Observatory. Light pollution – which occurs when light is unnecessarily directed up or out, rather than down where it’s needed – is a growing problem across the globe. Studies estimate that it is impossible to see that Milky Way from more than two-thirds of the planet. Approximately 99% of the population in the United States lives in light-polluted areas. It’s an economic burden, too, as tens of billions of dollars are wasted every year by sending light upward, as documented in dramatic aerial light pollution images.

Light pollution's past and future in the U.S. Image courtesy of McDonald Observatory.
Light pollution’s past and future in the U.S. Image courtesy of McDonald Observatory.

But this is changing, and Texas is at the forefront of enacting solutions to light pollution. Excess lighting is not only ineffective and inefficient, but it also has an unquantifiable effect on our health and culture.

Increasing studies have linked an absence of darkness with lower melatonin levels, which in turn are linked with breast and prostate cancer. Further, light pollution has disrupted everything from the migration of certain bird species to the photosynthetic cycles of deciduous trees. The effect on culture, and the inspiration a clear night sky has provided for literature, mythology, art and science, is less tangible, but no less significant.

As light pollution maps demonstrate, there are parts of San Antonio where the stars are almost completely obscured and the night sky is significantly discolored. The city casts a bright glow on the horizon as far away as the Bandera area of the Hill Country.

Light pollution map of San Antonio and surrounding areas. Image courtesy of Google Earth and David Lorens (University of Wisconsin-Madison). Click here for map key. http://cleardarksky.com/lp/SanAnTXlp.html?Mn=astronomy
Light pollution map of San Antonio and surrounding areas. Image courtesy of Google Earth and David Lorens (University of Wisconsin-Madison). Click here for map key.

“The pervasive standard for a long time has been ‘the more light the better.’” Wren said. We are afraid of the dark.

In fact, light pollution is one of the simplest environmental problems to solve. The answer is as easy as replacing compact fluorescent and incandescent bulbs with longer-lasting, energy efficient LED (Light-Emitting Diodes) bulbs and shaded fixtures, which direct light where it’s needed. Easier still: just turn off unnecessary lights.

Homeowners and businesses, however, are still concerned with the upfront cost of lighting and fixtures, particularly where retrofitting is required, as this week’s New Braunfels’ City Council meeting on a proposal to increase outdoor lighting regulation proves. Boerne already has an ordinance in place requiring that an Illumination Plan be submitted for new building and development, and regulates outdoor lighting, including requisite shields, color control, cut-off capability and timing of exterior lights.

Hill Country towns are particularly interested in preserving the true Texas Hill Country experience, of which those “stars at night…big and bright” are an essential part.

In 2012, Austin set aside $15 million to replace the bulbs and fixtures on approximately 70,000 streetlights with LED bulbs and flat-glass lenses that focus the light downwards. Laura Eakins at the University of Texas Department of Astronomy estimates that the change has stabilized, if not decreased, light pollution in the city, even as it expands.

San Antonio is well on its way to matching that. In 2012 the San Antonio City Council approved a plan to upgrade the city’s streetlights from high-pressure sodium bulbs to light emitting diodes (LEDs). CPS Energy, in association with the city of San Antonio, has already replaced 25,000 out of approximately 70,000 street lamp bulbs. This represents lighting on all major thoroughfares.

CPS Energy estimates that this will save the city more than $1 million per annum, with significant further savings anticipated in reduced energy and upkeep costs. San Antonio will soon be implementing pilot programs to replace neighborhood streetlights, which comprise the majority of the remaining fixtures (highway streetlights are regulated by the Texas Department of Transportation).

The technical difference is traditional bulbs work by heating a piece of metal so hot that it emits light, while LEDs excite electrons, which then emit light.

Tracy Hamilton of CPS Energy explained that LED bulbs installed in San Antonio use approximately 80 watts, versus a High Pressure Sodium bulb’s 250 watts. Sodium bulbs last approximately five years, while LEDs last up to 15. LEDs can be made to focus light.

In November 2014 CPS Energy partnered with H-E-B for a limited-time sale of LED bulbs for 97 cents (usually priced at $7), which was a resounding success. One we can only hope they’re inclined to repeat in the future.

But, Hamilton said, the benefits for San Antonio extend beyond reduced light pollution: all LEDs purchased by CPS were made here in San Antonio by GreenStar, a company founded by Paul Duran in Boerne in 2009. The company employs over 40 people and sources local parts and materials whenever possible.

This street switched to LED streetlights (bottom) from high-pressure sodium bulbs (top). Photo courtesy of McDonald Observatory.
This street switched to LED streetlights (bottom) from high-pressure sodium bulbs (top). Photo courtesy of McDonald Observatory.

When Duran founded the company, he noticed that none of his engineers came from San Antonio. He pledged that for every LED bulb the city of San Antonio purchased from GreenStar (that’s 25,000 so far, and 70,000 anticipated), the company would put $10 towards the University of Texas San Antonio’s College of Engineering for the college’s first energy-related endowed professorship.

GreenStar now supplies LEDs internationally, and continues to grow.

As Wren points out, reducing light pollution isn’t just about changing fixtures: it’s about education and awareness. In San Antonio, he points to The Rim shopping center as an excellent example of effective lighting. The Rim falls under San Antonio’s lighting ordinance restricting lighting within five miles of a military base or training site (Camp Bullis, in this case), which require darkness for training purposes. Although the city has no other lighting ordinances in place yet, they are becoming increasingly common nationwide.

There also are three Texas State Codes regulating outdoor lighting, including in the vicinity of observatories (within 28,000 square miles in the case of the McDonald Observatory), as well as regulations regarding outdoor lighting in state-funded areas (for example, a state university parking lot).

“The places you can go to see a naturally dark sky are rapidly disappearing,” Wren says, but there is hope that we could see the stars at night above San Antonio again.

You can find more information at the Texas branch of the International Dark-Sky Association, a non-profit organization founded in 1988, fighting to “preserve the night.”

The light pollution from cities spills over into the Texas Hill Country. Photo courtesy of McDonald Observatory.
The light pollution from cities spills over into the Texas Hill Country. Photo courtesy of McDonald Observatory.

*Featured/top image:  A view of downtown at night from the Pearl brewhouse’s copula. Photo by Scott Martin.

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Gretchen Greer

Gretchen Greer

Gretchen Greer is a freelance writer and photographer, born and raised in San Antonio. She has lived in France and England, and currently divides her time between Texas, London and Burgundy. You can find...