Greensburg ? Work on a new Greensburg City Hall sign has been under way for a couple of weeks, but a lot of the final pieces came together Thursday.

First came the LED light bars, which arrived when Curtis Shaddox, president of Kansas City-based Sunpower Sign, unwrapped the bars while Brian Eliot, manager of The Sign House in south Salina, grabbed a 12-volt power pack from a cordless tool and touched the leads on the light bar to the contacts to make sure it worked.

Then, the permanent power source arrived when Sunpower Executive Vice President Troy Haefner arrived from Minnesota, carrying a roll of flexible solar film wrapped around each arm.

Like much of the rest of rebuilt Greensburg, the new city hall sign packs some serious environmentally friendly tech; the LED lights will use a small fraction of the power a bank of fluorescent tubes would, and the solar film will power it.

The Sign House has been using LED lighting on some signs for about five years now, Eliot said, “But this is our first experience with solar power. It’s very new for the industry and definitely for this area.”

The sign was scheduled to be delivered to Greensburg on Friday, though it won’t be permanently installed until warmer weather, when the concrete base can be poured.

The design calls for a bank of LEDs at the top and bottom of the sign, illuminating the lettering and pushing light through a frosted acrylic layer near the top, causing a “glowing halo” effect, Eliot said.

Shaddox said the LEDs will have a 15-year lifespan, as opposed to maybe five years for a fluorescent tube — and there’s no ballast to go bad.

Eliot said solar-powered signs will likely become an important part of his company’s business, and he and his employees are having fun learning about the new technology.

The flexible solar panels are also a relatively new technology and are starting to replace older designs, which are heavier, bulkier and more fragile.

And, Shaddox said, the thin film will generate power in almost any light.

“You don’t need full sun, and it doesn’t have to be tilted at 30 degrees south to get the right angle,” he said, explaining those benefits allow for more design possibilities. “Instead of this big panel standing there, we can just apply it to the top of the sign.”

Flexible solar film has been in use by NASA and the military for several years, but as more companies start producing it, the price is dropping to where it’s cost-effective in situations where that’s an important consideration.

“The cost per kilowatt is dropping every week,” Shaddox said.

It will also generate power even in very low-light conditions, such as light from the moon or a nearby streetlamp.

The adhesive-backed solar film has about a 25-year lifespan, Shaddox said, and is much more resistant to damage than more-traditional photovoltaic panels.

It’s really a combination of advances in solar-power and LED technology that makes such signs possible, Shaddox said; it wouldn’t be practical to try to power a fluorescent-tube sign with solar.

“You could do it, but it would only last a couple of hours,” he said. “It’s the low power usage of the LEDs that makes it possible.”