Renewable energy advocates, dissatisfied with how the state's 2008 clean power law was implemented, want voters to help strengthen the measure.

P.J. Wilson, director of Columbia-based Renew Missouri, plans to file papers with the secretary of state's office today as the first official step toward getting a revised a new renewable energy standard on the ballot next fall, he said.

The proposed rewrite of the state's existing clean energy standard would require investor-owned utilities to get 25 percent of their electric generation from the wind, sun and other renewable resources by 2025. The current law requires 15 percent by 2021.

Just as importantly, it would clarify certain parts of the existing law that have been a source of sharp disagreements between Missouri's small-but-growing renewable energy industry and the state's biggest utilities.

In an emailed statement, Warren Wood, Ameren Missouri's vice president of regulatory and legislative affairs, said the utility was still reviewing a copy of the ballot initiative it received late Wednesday. "It is premature for us to offer an opinion on the impact of this ballot initiative on our customers' rates," he said.

Renew Missouri and other supporters must collect almost 100,000 valid signatures from across the state by early May to get the measure on the ballot next fall. First, language for the petition must be approved by Secretary of State Robin Carnahan.

Two-thirds of Missouri voters approved the renewable energy measure three years ago. Polling conducted by Renew Missouri this summer suggested similarly strong voter interest in a law to aid renewable energy development. But not for the same reason, Wilson said.

"I wouldn't be filing this if I didn't think it had strong public support," he said. "But I think the reason for voter support has shifted."

The selling point then was energy security, he said. Today, it's jobs.

The 2008 ballot measure drew no organized opposition. But months of contentious debate followed during the administrative rulemaking process at the Public Service Commission. In the end, a little-known legislative committee stripped a controversial provision from rules advanced by the commission.

The change allowed utilities to meet the green power mandate by purchasing so-called renewable energy certificates instead of building wind or solar farms in Missouri or contracting to buy renewable energy from neighboring states. Utilities can purchase the certificates from out-of-state renewable energy producers and count each of them as 100 kilowatt hours toward their mandated goals.

Renewable energy backers, including solar and wind companies that would have benefited from the rules as originally written by the PSC, balked at the change. Their dissatisfaction jump-started effort to rewrite the law and implement a stronger renewable energy standard.

The renewable standard being proposed by Renew Missouri would require utilities to develop renewable energy in or purchase it from Missouri or at least within the regional power grid.

It would also clarify ambiguity concerning the impact on electric rates. The existing law caps the impact on electric rates at 1 percent. The proposed ballot initiative would prohibit utilities from spending more for green power than they would spend to purchase or generate fossil fuel-based energy.

The rewrite of the law would also eliminate the legislative review of PSC administrative rules and prohibit Ameren Missouri from counting its century-old Keokuk, Iowa, hydroelectric plant toward the green power mandate.

Nationwide, 32 states and the District of Columbia have renewable energy mandates, according to the Department of Energy. Missouri is one of few states with a voter-approved law.

The current law requires utilities to gradually increase renewable energy sales until they reach the 15 percent target in 2021. The proposed goal of 25 percent by 2025 equals the renewable energy target in Illinois.

"It's pretty middle of the pack," Wilson, said.

Renew Missouri is recruiting and training volunteers to help collect petition signatures and soliciting donations to support the effort. The has conducted held training sessions around the state in recent weeks, including one at the St. Louis County Public Library in Frontenac on Thursday night.