In these hard economic times with cities and states trimming their budgets to the bone, firing workers, and taking furlough days, the high cost of public outdoor lighting has come in for renewed scrutiny. There are approximately 13 million streetlights in the United States that annually consume 2 billion kWh of electricity. In most cases, outdoor lighting accounts for 40 percent of a city's energy bills.

Curbing these costs is not only budget friendly, but the effort dovetails state and federal plans to encourage the use of renewable energy sources. Solar lighting as a viable alternative for public illumination is a potential avenue for costs savings and one that is more convenient for remote constructions and work crews that currently depend on diesel-powered generators.

Potentially, any outdoor light can be replaced with a solar unit, from a residential porch lamp to a billboard spotlight. Major institutions like the National Institute of Standards and Technology and the University of California use solar panels on top of their parking lot shelters to collect power by day to illuminate the areas at night. Both the state of Florida and the City of San Diego employ similar systems in their public parking lots and bus shelters.

Road signs topped by small black boxes have become a common sight on American highways. The boxes contain solar panels that charge during the day, providing electricity for the signs at night, eliminating the need for more costly energy solutions like long-distance power lines or fuel-hungry generators in sparsely-populated rural areas.

Emergency response teams and crews working on remote construction sites employ portable solar panel generators like those made by GreenTow. These systems are generally backed up by a diesel engine to ensure consistent power in critical use situations.

Some cities, like Adelaide, Australia, have found ways to incorporate solar energy into municipal art. The city's Solar Mallee Trees, an arching, sculpture-like installation, have been in operation since 2005. The trees generate 864 kWh of energy, but need only 125 kWh to light their surrounding area. The remaining electricity is put back into the grid.

Similar constructs are in place in Vienna, Italy and Pittsburgh, PA. Like the originals in Australia, they mimic natural shapes (trees and flowers), designs that obscure their real purpose as solar collecting panels with connected lighting fixtures. By contributing artistically to their cities, these types of solar power plants raise the potential for enhancing their environment in two ways -- aesthetically and through reduced dependence on nonrenewable energy sources.

As energy efficiency gains emphasis for both economic and environmental reasons, solar lighting is quickly being embraced as a cost-saving solution with multiple benefits. Many of the efforts are citizen-driven, with individuals and small businesses leading the way in introducing outdoor solar lighting. The practice, however, is dispersing rapidly, with more state and local governments recognizing the potential of the technology.