Clean energy developer Enel Group will appeal a federal judge’s new order to dismantle, in less than one year, its 84-turbine onshore wind energy site operating since 2015 on Osage nation land in Oklahoma—in the latest update of a years-long multi-court legal battle with the tribe over claimed permit lapses in building the 150-MW project.

Judge Jennifer Choe-Groves of the U.S. Court of International Trade, who made the Dec. 18 ruling setting the takedown timeframe and monetary penalties, took the action following her January 2024 decision that excavation during construction of the Osage Wind project in Osage County, Okla., without obtaining subsurface mineral rights constituted unauthorized mining. 

The judge gave the Italy-based developer’s North American units until Dec. 1, 2025 to remove the turbines and related infrastructure—an effort the defendants told the court would cost $259 million. Enel Group had acquired lease rights for the 8.400 acre wind farm area but did not have subsurface permits. The area includes oil, natural gas and minerals, the tribe said.

"The harm resulting from defendants’ continuing trespass is not only continued use of the wrongfully obtained backfill, but also interference with Osage Nation sovereignty,” said Choe-Groves.

The legal battle has involved lawsuits by the Osage Mineral Council dating to 2011, alleging that excavation of rock that was crushed and redistributed on site for foundations of each 1.79MW turbine violated tribal mineral rights. As a trustee for the tribe’s “mineral estate,” the U.S. Justice Dept. also filed suit.

The order follows an exchange of arguments in legal briefs and by attorneys for the tribe and developer last year and several months of unsuccessful efforts o reach a settlement.

Foundation Building

Turbine construction involved use of explosives to create craters over 10 ft deep and 60 ft wide to install reinforced concrete foundations, said the lawsuit. Significant amounts of site minerals were engineered and used as backfill for, and positioned around, the foundations.

The project was built by Infrastructure and Energy Alternatives Inc., a subsidiary since 2022 of energy contractor MasTec Inc., with turbines supplied by GE Renewable Energy. The firms are not named as lawsuit defendants.

An earlier round of dispute litigation had reached the U.S. Supreme Court in 2019, but justices did not agree to hear the case.

An Enel spokesperson confirmed the company will seek an immediate legal halt to the latest mandated action, while it appeals the ruling. “We strongly disagree with the court’s ruling that the wind project must be removed by Dec. 1, 2025, and will seek a stay pending appellate review,” he said in an email response to ENR. “The ejection of the wind farm would adversely impact economic and environmental benefits to the local community.”

The project provides energy to 53,000 households under a 20 year power purchase agreement that was reached in 2015, according to a profile.

Italy-based Enel Group energy services businesses in the U.S. and Canada include 9.6 GW of renewable energy, 160,000 EV charging stations, 4.7 GW of demand response capacity and 14 utility-scale battery energy storage systems that total 1.4 GWh of capacity under construction or in operation.  The developer's trailing 12-month global revenue as of Sept. 30 is $81.3 billion.

The judge also awarded compensatory damages of about $311,000 against the developer, more than four times higher than the total it told the court, but significantly less than the estimated $38 million the plaintiffs sought. Enel also owes $4 million for plaintiffs’ legal and other costs. 

An Osage spokesperson did not reply to ENR’s query, but in an earlier statement said the tribe “will always fight to defend our Mineral Estate that our ancestors reserved for our benefit and the benefit of generations to come.”