The Bismarck Planning and Zoning Commission will revisit a draft small wind energy ordinance at 5 p.m. Wednesday at the City/County Building.

It will be highlighted at a Nov. 18 public hearing.

Bismarck City Planner Gregg Greenquist said the proposed law would focus on wind turbines producing less than an 25 kilowatts.

He said the city is weighing permitting the wind devices because people have asked about them. City ordinance doesn't cover them at this time.

The draft ordinance requires a minimum setback of 150 percent of the height of the structure.

It would limit noise levels to:

n 55 decibels in the day and 45 decibels at night in residential area.

n 60 decibels in the day and 50 decibels at night in a commercial area.

n 65 decibels in the day and 60 decibels at night in an industrial area. Day is defined as 7 a.m. to 10 p.m.

The wind turbines' rotor blades could not swoop down any lower than 35 feet above the ground. Blades would be banned from extending over parking lots.

Even with approval, local city blocks won't be cluttered with twirling rotors. Few areas of town may qualify. "The smaller lots in high-density areas wouldn't be able to meet setback requirements," Greenquist said.

Aesthetics of the devices also will be considered into the new law. Greenquist said monopole structures are required for any turbines within the city (rather than lattice towers) and the color and surface finish are regulated.

He said most people would remain on a power grid with the turbines and use them to supplement their electrical energy needs.

"If the turbine is producing electrical energy that isn't being used by the owner, it would flow back into the grid," he said. "In which case, the power company would pay the turbine owner for surplus electrical energy."

He said the pay back period of an owner's investment depends upon costs, turbine output and wind.

Greenquist said city zoning applies to the extra-territorial zone but based upon new legislation, some areas in the ETA are under joint jurisdiction.

Greenquist said the timeline for adopting a law depends upon what the city commission does.

Bismarck State College installed a wind turbine on its property in early September. Because it is on state land it is not is not subject to local zoning authority permitting.

(Reach reporter LeAnn Eckroth at 250-8264 or leann.eckroth@bismarcktribune.com)