Solar energy tends to be more popular in the Southwest, but as the cost of alternative sources of energy continues to fall, Iowa is testing its limits.

A variety of people and businesses across the state have jumped on the trend in an effort to help the environment and save money.

CyRide is among the few to use photovoltaic panels as a way to provide electricity.

Bill Haman, industrial program manager for the Iowa Energy Center, said PV panels are used to charge batteries for highway signs, near creeks and rivers to power river stages and in residential settings to power homes.

According to the Iowa Energy Web site, PVs are cells made of silicon that produce electricity from sunlight.

In the photovoltaic effect, “bullets” of sunlight strike the surface of a semi-conductor and liberate electrons from the material’s atoms.

Chemicals added to the material’s composition help establish a path for the freed electrons and creates an electrical current.

Through the photovoltaic effect, a typical four-inch silicon solar cell produces about one watt of direct current electricity.

Haman said like most renewable resources, PV benefits the environment.

“PV is an environmentally benign source of energy,” he said. “PV panels consume no natural resources except for the materials of manufacture and the land on which they reside. And [PV panels] create no emissions during the generation of energy.”

Haman said although many think otherwise, the winter weather has little effect on the performance of PV panels. He said the sun has a flatter angle in the winter, so frames track the sun to get the most intense irradiation.

A photo cell measures light intensity and operates a motor that turns the frame towards the highest degree of sunlight intensity, Haman said.

“It’s sophisticated but quite simple,” he said.

Terry Milam, maintenance supervisor for CyRide, said two bus shelters on Mortensen Road use PV panels to produce light in the evening.

The panels cost just under $1,400 per shelter, he said.

“They are working fairly well,” Milam said.

Dan and Kimberly Isbell, of Vinton, use wind along with solar energy to power their home.

Kimberly said the PV panels take care of most of the power, and they haven’t had any problems with the panels not doing their job.

Kimberly said solar energy has a certain benefit they enjoy on a monthly basis.

“We haven’t had an electric bill in a year and a half,” she said.

CyRide also uses a solar wall, known as the Trombe Wall, in the bus storage building to provide heat.

Milam said they haven’t had much luck with the wall.

He said it will be torn down because an energy audit discovered that it costs more to operate the wall than to use it.

Haman said PV panels are not cost competitive with other forms of energy and that’s why a small number are in service.

“Technological advances have brought costs down but they are still considerably more expensive,” he said.

The Web site shows the first PV panels originally cost up to $1,000 per peak watt. Now, panels can be purchased for $4 to $10 per peak watt.

When costs reduce to $1 per peak watt, PV panels will become more competitive.

At $1, residential power would cost about $10,000 for a system with a 20-year life span. The possible payback would be about 10 years.