Horizon Wind Energy's Simpson Ridge wind proposal in Carbon County -- once slated at a capacity of 500 megawatts -- has been put on hold indefinitely.Project manager Nate Sandvig said Friday the company has decided not to submit a permit application to the Wyoming Industrial Siting Council based on the state's recent decision not to allow wind energy development in key sage grouse habitats.

"There are too many unknowns," Sandvig said.

Earlier this month, Gov. Dave Freudenthal's chief of staff, Ryan Lance, said the decision not to allow wind energy in sage grouse core areas came after consulting with the U.S. Fish and Wildlife Service, which is expected to decide before year's end whether to list the bird as a threatened and endangered species.

Freudenthal issued the core areas sage grouse management plan by executive order in August 2008. It maps out the state's best sage grouse habitat areas. It also lists a number of requirements that severely restrict new development -- all activities, including coal, wind, oil, gas, recreation and agriculture -- within those areas.

The plan is hailed by some as a leading strategy to avoid listing the sage grouse under the Endangered Species Act. However, Sandvig said the collaborative effort between agriculture, industry, state and federal agencies to design the core areas plan did not include consideration for wind energy development.

In response to the state's position, wind developers teamed up with wildlife agencies across nine western states to launch a $10 million, five-year research effort. The coalition hopes to gather scientific data needed to understand the impact of wind farms on sage grouse so they might configure them in a ways that avoid impacts.

In a phone interview, Freudenthal said that renewable, or green, energy developers have to follow the same rules as the fossil fuels industries. He said the impact of a sage grouse listing would have much further-reaching impacts than the state's core areas restrictions.

"The gas and oil industry are not any more enthused about doing this than we are. But they understand the seriousness of this issue," Freudenthal said.