A local environmental group plans to push back against a company's efforts to build a water-based energy facility along the Susquehanna River in southern York County, although to what extent and exactly how is uncertain.

York Energy Storage has a permit from the Federal Energy Regulatory Commission to study their proposal's feasibility and impact, which would take more than 1,000 acres of land from property owners and flood 580 acres along the Susquehanna, according to a news release from Lancaster Conservancy.

But developer Bill McMahon argues his Reading-based company's $2.1 billion project upside of more, cleaner and cheaper energy will benefit residents and the local economy.

The dam would be 9,800 feet long and 225 feet high, surrounded by two dikes forming a reservoir, according to the permit. It would be accompanied by a 150-foot-long, 50-foot-wide concrete-lined emergency spillway. Lake Clarke would be used for a lower reservoir.

It would put out 1.5 million megawatt hours of energy annually, according to the permit. It would also seek to secure land rights of nearly 50 properties — possibly through eminent domain.

Smucker described the hydroelectric project as reckless, saying it would destroy farms, trails, natural scenery and forests that help protect the ecological health of the landscape and an impaired waterway.

“More than $100 million has been invested in this scenic area over the last decade to preserve our rich agricultural heritage and make the Susquehanna region a tourist and outdoor recreation hub," Smucker said. "We cannot sacrifice that growth in the name of 'clean energy.'"

He said the project, earmarked to improve the energy grid for other providers, would not be completed until 2033 or later.