Four pro-clean energy organizations announced Thursday that they plan to oppose the Energy Choice Initiative on the 2018 ballot, citing potential uncertainty that passage of the measure could create for large-scale renewable energy development in Nevada.

The four organizations — the Natural Resources Defense Council, the Sierra Club, Southwest Energy Efficiency Project and Western Resource Advocates — said they planned to oppose the ballot question, which would amend Nevada’s Constitution by changing its current electric market structure to an open, competitive market by 2023. The measure, which passed 72 to 28 percent in 2016, must be approved again by voters this year to become part of the state’s Constitution.

The groups largely cited a fear of uncertainty if the ballot measure passes, including Western Resource Advocates attorney Robert Johnston, who said his opposition was rooted in NV Energy’s plan to substantially increase renewable energy production contingent on the ballot measure not passing. The utility’s proposed Integrated Resource Plan, a state-mandated planning document for future electric supply and demand management, included plans to add more than 1,001 megawatts of solar capacity by 2021.

“By taking NV Energy out of the electricity generation business at this critical juncture, passage of Question 3 not only will kill these important projects, but it is likely to create a cloud of legal and regulatory uncertainty that could chill the development of new renewable projects by anyone else over the next 4-5 years while the Legislature figures out the complicated details of restructuring Nevada’s electricity markets,” Johnston said in a statement.

Scot Rutledge, a spokesperson for the group backing the ballot question, said that NV Energy had historically been a foe of renewable energy progress, including slow moves to shut down coal-fired plants and its role in lowering reimbursement rates for rooftop solar customers in 2016.

“Energy Choice will lower Nevadans' power bills through competition and vastly expand Nevada’s renewable energy resources,” he said in an email. “The only way to ensure that every Nevadan has the opportunity to choose 100% clean energy, like they do in other markets, is by voting yes on Question 3."

The announcement was applauded by the Coalition to Defeat Question 3, the NV Energy funded PAC opposing the measure.

“Nevada’s clean energy advocates recognize that Question 3 would be damaging to Nevada’s rooftop solar programs, cancel plans to double clean energy production in the state, and be a setback for existing state laws and policies designed to spur growth in our renewable energy sectors,” campaign spokeswoman Tracy Skenandore said in a statement.

The announcement marks a blow for the campaign behind the ballot question, which has been almost entirely funded by the Las Vegas Sands and Switch. Nevadans for Affordable Clean Energy Choices, the PAC backing the ballot question, has claimed in advertisements that the ballot measure will lead to spurred renewable energy development.

The group still lists several pro-renewable energy organizations as supporters, including Go Solar, Solar City and the Clean Energy Project. The Nevada Conservation League is listed as a supporter of the initiative on the organization’s website, but isn’t mentioned on a page listing supporters of the initiative. Andrew Maggi, the group’s executive director, said the organization had decided to move to neutral on the ballot question after supporting it in 2016, and was more focused on supporting a separate initiative that would raise the state’s Renewable Portfolio Standard to 50 percent by 2030.

A recent report by the nonpartisan Guinn Center for Policy Priorities analyzing the ballot question found “no correlation” between states with open, competitive electric markets and higher renewable energy use.