LED Billboards Not So Green

Somewhere in the last couple months I saw an advertisement on one the those newfangled LED billboards that was pitching energy conservation. It caused me to wonder just how much power a giant array of LEDs consumed compared to the old world paper type. Paper billboards are not energy-free by any account. They require energy for facilities where the artwork is printed, energy for a truck to transport a crew to the billboard for hanging the new advertisement, and then energy for illumination at night. The average energy consumption for halide lighting the standard paper billboard is around 7,000 kWh (580 kWh per month, my house used 375 kWh last month). By comparison, a typical 14' x 48' LED billboard that uses around 10,000 "green" LEDs (each using 2-10 watts), lit 24 hours a day, uses about 160 kWh. Less efficient LED billboards can use 300,000 kWh or more. That makes them 20 - 40 times more energy hogging than a paper billboard. One feature in favor of the LED billboards is that they require only a desktop computer for designing the advertisement, and changing the display is done wirelessly via a modem. However, the pollution generated during manufacturing the LEDs, driver electronics, and cooling fans are much greater than for paper billboards.

The cost for installing a full-color LED billboard, not including the real estate, is 1/4 to 1/2 million dollars, but owners get a lot more in fees for the LED billboard ($14k LED vs. $2k paper per month on average, depending on location). On top of that, they can sell space for more than one ad at a time to multiply the revenue. So, with 4 ads rotating in time, that can mean $50k per month, or $600k per year. ROI break-even can occur in the first year, including a $25k per year energy bill. The numbers used here were pulled from Illuminating the Issues Digital Signage and Philadelphia's Green Future, by Gregory Young, but it appears to be typical of other sources readily available. Some municipalities and even states have banned the use of LED billboards because they are considered too much of a distraction. Vermont, where I lived and attended UVM from 1986-1989, has had a total ban on ALL billboards since 1968. It is the only state where you can drive from end to end, top to bottom, sided to side, and never see a billboard. It's kind of funny that as you cross the state line into Canada, Maine, New Hampshire, Massachusetts, or New York, you are immediately inundated with a barrage of billboards.

Posted November 17, 2011