While planning to harvest the wind, the Hazleton City Authority wants to protect bats.

The threat to bats will be weighed as the authority continues planning for a wind turbine that could provide electricity to its water treatment plant on Route 424.

"There are rare species of bats in the area. There has been some concern with wind projects and bats across the country," Jay Carlis, marketing director for a company developing the wind turbine, said.

How to save bats while saving energy is among the questions that the authority must answer while proceeding with a project that is unique in Pennsylvania.

The authority tested wind at the site for nearly a year, obtained $500,000 in state grants for the turbine - expected to save $393,585 over 20 years - and is selecting the size and style of turbine that could generate up to 1.5 kilowatt hours per year.

"We're putting all the pieces together. A wildlife study is certainly one of those pieces," said Carlis of Community Energy in Radnor, Chester County.

Wind turbines are one of two recent dangers to bats in Pennsylvania.

Last week, two colonies of bats hibernating in mines in Lackawanna County were reported to be dying of white-nose syndrome, a mysterious disease that earlier struck bats by the thousands in New York and New England.

To die around wind turbines, bats don't need to hit the blades. Low pressure that forms around the turbines causes bats to die as they hemorrhage and their lungs fill with fluid.

Tracey Librandi Mumma, wind energy coordinator for the Pennsylvania Game Commission, compared the deaths to the bends suffered when a deep sea diver ascends rapidly to the surface from the depths where water pressure is higher.

"We found the bats aren't visibly injured," Librandi Mumma said.

Researchers led by John Barclay at the University of Calgary in Canada figured how the bats were dying, termed the phenomenon "barotrauma" and published their findings in "Current Biology."

Librandi Mumma said other researchers are studying whether turbines attract bats.

One theory is that male bats gravitate to the highest structures in an area.

"Nobody's tested or proved it yet," she said.

Males seem to outnumber females among the casualties from turbines. Likewise, bats that migrate out of Pennsylvania generally face greater risks from turbines than bats that spend the winter hibernating in caves and mines.

Species that hibernate, however, face greater danger from white-nose syndrome, which causes bats to lose weight they've stored for the winter, emerge from hibernation too early and die in the cold.

Scientists haven't determined what causes white-nose syndrome or where it started.

While white-nose syndrome kills thousands, wiping out 90 percent of colonies in some estimates, wind turbines appear to take a lesser toll. Each turbine claimed 18 bats in Barclay's study.

Susan Gallagher, a naturalist at the Carbon County Environmental Education Center, said death tolls might be undercounted at turbines. Researchers might fail to see bodies, which also could be removed by coyotes and other scavengers beforehand.

"Unfortunately there is a lot that is not known. When it comes to figuring the best way to prevent harm to the bats, there's still a lot of questions to be answered," Gallagher said.

She pointed out that people will notice as bats decline.

"We're all going to suffer. Farmers are going to suffer (as are) people bothered by nuisance insects because that's what bats eat," Gallagher said.

Little brown bats, the most common species in Pennsylvania, eat 1,200 insects per hour.

Though they eat voraciously, bats breed slowly. In many of the nine species common to Pennsylvania, including the endangered Indiana, females give birth to one pup per year.

"We don't even know where all the Indianas are in Pennsylvania yet," Gallagher said.

The first annual report of the Game Commission on wind energy, released Jan. 23, told of the discovery of the second largest maternity colony of Indiana bats in Pennsylvania. A company researching where to put wind turbines used radio collars to track female bats to trees where they had their young.

The report also said three companies voluntarily stopped plans for building wind farms after studies indicated their sites were along migratory routes for birds.

"Migratory paths are usually where the best wind is. That's why the birds are there," Librandi Mumma said.

She serves on the Pennsylvania Wind and Wildlife Collaborative, chaired by former Hazleton Mayor John Quigley, which is compiling a set of best practices for wind farms. The group's recommendations might include keeping turbines at least five miles and possibly 10 miles from places where bats hibernate.

"We're working with wind companies to see what is acceptable," Librandi Mumma said.

Randy Cahalan of the Hazleton City Authority said bats are among the issues that have to be dealt with for his project.

"I don't know that it's holding up the wind turbine," Cahalan said.

Carlis of Community Energy doesn't expect the project that his company is developing for the authority will have a major impact on wildlife. The project involves one turbine planned for a grassy site on industrialized land, he said.

"The project takes up less area ... There is more room for species to co-exist with it. That's my general sense," Carlis said.