Solar-powered signage is coming of age

“Little darling, it’s been a long cold lonely winter.
Little darling, it seems like years since it’s been here.
Here comes the sun, here comes the sun, and I say, It’s alright"
-- George Harrison

In 1973 there was a sudden drop in global oil supplies, which was not met by an equally sudden drop in demand, which led to block-long lines of cars waiting to fill gas tanks for twice the price. The period was called the “energy crisis” and awakened a sense of urgency to find alternative fuels and methods of generating electricity. In the years to follow, the United States Department of Energy was created, which soon established the Solar Energy Research Institute (SERI). Also in those years, personal electronics that were powered by tiny photovoltaic (PV) cells, such as hand-held calculators, began hitting the market.

The 1973 energy crisis was a political crisis really, more than a lack of supply. In the 1980s gas for twice the price was the norm, oil pipelines were turned back on and supplies were replenished and for 20 years there was no immediate urgency about developing solar and other energy alternatives.

Events of the past decade have changed that. Now the urgency may be even stronger than it was in the 1970s and the demand for alternative energy comes from all sectors of the economy. And of course, one of the most visible of these sectors is the lighted sign industry.

SERI today has evolved into the more comprehensive National Renewable Energy Laboratory (NREL). Byron Stafford is a scientist with NREL’s National Center for Photovoltaics. He explains that the active ingredient in the majority of PV cells sold today is crystalline silicon and that this technology has been understood and on the market for some time. These are the familiar black or dark blue panels seen attached to electric devices or as part of large solar arrays.

A newer PV technology is emerging called “thin film”. Thin film can encompass three different types of PV materials, Stafford says: amorphous silicon; a blend of copper, indium, gallium and selenium (CIGS); or cadmium-tellurium (CdTe, often pronounced CADTEL).

4“A typical crystalline silicon wafer (the really good stuff that makes the electricity) can be on the order of 300 times thicker than a thin film semiconductor,” says Stafford. “But it’s a moving target because crystalline silicon wafers are also getting thinner.”

The significance of this is that the less material needed to produce a component, the lower the final product cost can be--potentially. Stafford believes thin films can potentially produce an equal amount of power with a much-reduced manufacturing cost, but that both types of PV cells will be around in the future.

Stafford says that some of the new thin film modules are made with more flexible materials such as DuPont Tefzel, a modified ETFE fluoropolymer similar to Teflon, which can provide crucial protection, eliminate problems with glass breakage and possibly also allow more design flexibility.

“Now if you want to consider wrapping it around a pole, you can.” Such developments can shift the selection criteria from efficiency and price to flexibility and durability, Stafford says.

Stafford goes on to explain that there are two main kinds of PV systems. The first and most common is connected to the grid. In a grid-connected system, direct current from a PV module is routed through an inverter that changes it to alternating current, and is then merged with the electric utility. In a sense, the utility in a grid-connected system is the storage mechanism. The second type is one that utilizes energy storage (batteries) and can be installed completely independent of the grid. Some hybrid systems make use of a special type of inverter that can utilize batteries and also be connected to the grid.

There are a few companies that seek to meet the demand for solar- and wind-powered signage and have come to market with a few different products that address some of the unique needs of signage. I asked three of them about their products and what they thought the state of the art is today.

Arizona Solar Wind Group (ASWG) is based in the Phoenix area and sells turnkey systems that include PV panels, batteries, and a controller that also functions as a timer to turn a sign on and off. These components are used to power channel letters and sign cabinets that are lit with LEDs supplied by JTLED.

Dallas-based Solar Wind Technologies provides grid-tied, grid-tied with battery backup and off-grid systems for lighting small signs to large billboards, as well as street and parking lot lighting systems. The customized systems include combinations of PV and wind generators, batteries and spotlights using LEDs supplied by Cree.

Kingston, N.Y.-based PVI Solar offers a programmable power management technology, trademarked PowerLine, which is integrated with components from various other sources into a number of turnkey solar powered illuminated signage applications. The company also provides kits to sign companies for building solar powered signage.

ASWG started in the solar signage business when a dentist approached them after reading a newspaper article about photovoltaics. The dentist wanted to avoid the expense of running a power line to a remote location, so asked about an off-grid solar option. “It’s definitely a newer product for the sign industry, even though it’s been around a long time,” says company CEO Rob Compher.

Mike Correale of Solar Wind Technologies says the company’s products have been on many billboards for years. “Advances in LED technology have dramatically expanded our market for both off-grid and grid lighting solutions,” Correale says. While the company offers a number of products such as LED exit lights, its biggest impact is in being able to provide stand-alone systems for off-grid lighting of billboards, using both PV and wind turbines in combination with batteries. He says the latest LED technology coupled with advanced lens optics enables feasible and cost-effective off-grid solar or wind-powered spotlighting for billboards.

The efficient management of power optimizes those other technologies, according to Paul Mladineo, PVI’s Executive Vice President for Corporate Development. The result is that PV panels can be kept smaller and be integrated into the sign itself. He says the unique value proposition of that kind of power management is that it can stretch the usable life of a battery with an ultimate goal of building a sign with a relatively small PV footprint that can operate for as much as a week in the dead of winter with very little sunlight.

Mladineo believes the biggest advantage is to not be constrained by limitations of the grid. “Remote locations where it’s unfeasible to run power are a perfect situation for this technology,” he says.

Online Resources for Renewable Energy -- Federal, State, and local tax incentives -- National Renewable Energy Laboratory -- Solar Energy Map -- Wind Map -- Solar Energy Industries Association -- US Green Building Council (Leeds) -- The Solar Energy Consortium -- Lighting Research Center -- The North American Board of Certified Energy Practitioners

Depending on what is counted, the cost-benefit analysis and return on investment figures of a solar-powered sign will vary. For a small business end user, it’s about saving electricity and having the sign pay itself off in two to three years. For large companies, it might be more about image and goodwill.

“For sign companies, anything they can do to reduce the electrical needs of the signage makes a tremendous impact on the size of the PV system,” says Stafford. “It’s far cheaper to do the energy efficient lighting than to buy this PV system to provide the extra power.”

In any case, there is some grant money available as well as a number of federal and local tax credits and other rebates and incentives that will help reduce upfront installation costs. The Database of State Incentives for Renewables & Efficiency (DSIRE) website ( is a fairly up-to-date database that lists state and federal incentives.

Terms of Service

When comparing different brands and types of electric lighting, it’s important to understand how the terms, “volt”, “ampere”, “watt” and “lumen” relate to each other. The terms, if used incorrectly, can misrepresent actual product performance.
“Volt” is a measurement of electromechanical force (pressure), or the difference in potential between two points in an electric field. “Ampere” is a measurement of the strength (volume) of an electric current. “Watt” is a measurement of electric power. One watt is the amount of power developed when one ampere of current flows through a potential difference of one volt. “Lumen” is a measurement of the flow of light, or light intensity.
Only three things really matter when evaluating the effectiveness of luminaires: lumens per watt, cost per lumen and perception. Of the three, perception may be the most important (how does it look?), but is probably also the most difficult to measure in any meaningful way because it is so subjective.
University-level studies, such as those done at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y. (, can help sign designers understand the impact of perception.
Design intent, appropriateness and context--including contrast, color choices and ambient light--contribute to power requirements as well as overall effectiveness and aesthetic appeal

At the same time, many potential buyers are wary of predatory marketing that takes advantage of these incentives, as well as other “green” sensibilities. The North American Board of Certified Energy Practitioners (NABCEP, offers a comprehensive program of certification, best practices and resources for the alternative energy industry to address this concern. The certification, which has already been adopted in many locations, provides a reasonable level of assurance that a system is well designed and installed.

As with any other lighted sign, regulations apply to solar-powered signage. The sign component (channel letters, sign cabinet, etc.) must be UL-labeled. The power supply to the sign, including PV panels, wind turbines and storage batteries, as well as wiring, connections, raceways and conduits must conform to local electrical codes, which usually follow the National Electric Code (NEC).

Tim McCloskey of Chandler, Ariz.-based Display Solutions Group describes himself as a “sign broker”. He sold two off-grid signs that ASWG installed in 2007 and says they have performed well. “I’m a believer in this concept,” he says. “New technologies always cost more. Solar could wither on the vine without subsidies to start. But we have to work to drive the costs down so that it’s competitive with the conventional alternative.”

McCloskey’s projects are both pan channel letters, flush-mounted on the building fascia and the PV panel is out of sight on the roof. The roof location allows the south-facing PV panels to gain the full benefit of the sun.

But there may be value in installing PV panels in a more prominent location that have to do with “looking green”. “You can place these modules in a very visible location so people will immediately know a sign is PV-powered,” says Stafford.

Stafford also mentions another concept called “building integrated photovoltaics”. He believes sign people can be creative and not just have a separate system to provide power, but design the PV modules into the signs. “For example, assume you have a black sign with letters backlit and illuminated. Why can’t that black part be the PV? You’d want to orient it southward, or maybe bi-directionally, but why not make PV part of the sign?”

“There’s renewable energy and there’s energy savings, says PVI’s Mladineo. “In places where there is grid availability, but limited sunshine, it makes sense to have hybrids where there may be some energy savings realized in the dead of winter, but during the rest of the year the system would work independently of the grid.”

Like everyone, Mladineo says he’d like to see the more efficient crystalline silicon PV panels come down in price as they increase in efficiency. “We’d also like to see a more efficient commercial grade thin film.”

The idea of alternative energy to power signage can be placed into the larger context of producing electricity. Stafford believes this is where a sign company can leverage the deal. “Maybe they know who needs a sign and they can team up with a solar dealer and present options (e.g., you can have this solar-powered sign, but for just a little more, you can put a bigger PV system on your property and these will be the advantages). So you’re selling both concepts; both products.”

In the larger context of thinking of PV panels as supplying power for lighting signs, light sources are not necessarily limited to LEDs. “We could turn the entire Las Vegas Strip into solar if we wanted to,” says ASWG’s product engineer, Dale Xavier. Although at some point Xavier says it would probably be cost prohibitive, who knows? Some of the products that Solar Wind Technologies has offered, for example, use compact fluorescent light sources. “We have also used neon for years with DC transformers for lighting,” Correale says.

Neon, aside from being a pleasing art form, is actually a highly efficacious light source that could have interesting solar adaptations. David Wilson, for example, might be considered an “early adopter” of solar. He is part owner of Burnsville, N.C.-based Atomic Solar and only recently replaced the 10-year-old lead-acid batteries in his entirely off-grid home, all wired for 24-volt direct current. Wilson is also a hot glass artist and has numerous neon pieces on display at home. They are not switched on all the time, but when they are, they obviously have to be powered by the off-grid solar system. Wilson says DC neon transformers are actually pretty efficient compared to AC and if connected to a flasher will use only half the electricity.

It’s an exciting time for new solar applications in the sign industry. The solar industry is looking at ways to improve some of the systems involved: nano technologies that can improve capacity; battery efficiency and durability; and improved PV panels. ASWG’S Xavier believes a big motivation is that electricity won’t get cheaper. But another motivation is that some individuals and organizations sincerely want to do something for the environment.

Stafford describes the current state of the PV art as “very workable”. “We have ideas. The industry and the federal government have dreams for even more. Some companies are booming. We’re all trying to expand the market.”

Special thanks to Morgan Crook, Transco