DES MOINES -- The Iowa Utilities Board has approved a crucial permit for Alliant Energy's proposed $1.5 billion power plant at Marshalltown.

The 2-1 vote came shortly before noon on Wednesday at a hearing in Des Moines. Darrell Hanson cast the lone dissenting vote.

 The approval came with three main conditions attached to it:

-- The burning of bio-mass must reach 5 percent of the plant's capacity within 2 years and 10 percent within 5 years.

-- The company's energy supply must be 10 percent renewable energy when the plant goes online in 2013. The use of renewable energy must then increase 1 percent annually for 15 years.

-- The IUB will periodically review the feasibility of retrofitting carbon capture technology, which deals with capturing the emissions from generating power, and reserves the right to require Alliant to install that technology at its new plant.

Board Chairman John Norris proposed the conditions attached to the permit , indicating it was the only way he would vote "yes" for the permit's approval.

A written ruling will further explain the conditions attached to the permit. That ruling is expected to be issued in a few weeks.

The meeting marked the first time all three board members had the opportunity to debate the permit application.

The plant could generate enough power for 472,000 homes and business. The plant must still receive approval from the Department of Natural Resources and clear other hurdles.

Read more in the Thursday edition of the Times-Republican.