A 1,500-acre farm in Huntsville-annexed Limestone County is in line to become Alabama's only TVA Megasite for large-scale manufacturing.

Shane Davis, the city's director of urban development, said he is confident the Sewell property along Powell Road will be certified as a TVA Megasite by late June or early July.

Last week, The Huntsville City Council agreed to pay the Barge, Waggoner, Sumner & Cannon civil engineering firm $72,773 to map wetland areas on the sprawling tract, obtain the necessary approvals from both the Army Corps of Engineers and U.S. Fish & Wildlife Service, and design a site plan for industrial development.

"They should have that finished in the next 30 days," Davis told AL.com.

Becoming a TVA Megasite should ramp up interest in what Davis said is already one of the best large industrial sites around. It is located about three miles north of the Target distribution center and Polaris' planned $142 million all-terrain vehicle factory.

Volkswagen seriously considered building its first U.S. automotive plant on the Sewell farm in 2008 before choosing an existing Megasite in Chattanooga.

"We've had site selectors tell us that logistically, workforce, and the way the property is easily developable, it's one of the better sites in the country," said Davis.

Huntsville has been paying the Sewell family $300,000 a year to keep the farm under option until a large industrial user comes along.

Davis said he envisions a "Honda or Mercedes or Volvo-type" industry in the center of the property, surrounded by smaller parts suppliers. That model has played out at the four TVA Megasites that have been sold so far:

Chattanooga

Company: Volkswagen:

Site: 1,400 acres

Employees: 3,200

Investment: $1 billion

Produces: VW Passat

Tupelo, Miss.

Company: Toyota

Site: 1,700 acres

Employees: 2,000

Investment: $1.3 billion

Produces: Toyota Prius

Columbus, Miss.

Company: PACCAR

Site: 1,800 acres

Employees: 500

Investment: $400 million

Produces: Diesel engines for Peterbilt, Kenworth trucks

Columbus, Miss.

Company: Severstal

Site: 1,400 acres

Employees: 650

Investment: $1.4 billion

Produces: Rolled steel

Two other Megasites remain for sale in Hopkinsville, Ky., and near Memphis.

The Tennessee Valley Authority created the Megasites program in 2004. Sites are pre-certified for large-scale manufacturing to streamline the selection process. Potential Megasites must contain at least 1,000 acres; have easy access to highways, rail and utilities; no known environmental problems; and a large nearby labor pool.

Only properties within TVA's service area are eligible for Megasite listing. TVA serves the upper third of Alabama, roughly from Cullman north.

Having the Sewell farm pre-certified "takes some of the legwork away so a corporation could get out of the ground even faster," said Davis.

The gently rolling farm borders two-lane Powell Road in the rural Greenbrier community. But the planned four-lane Greenbrier Parkway will skirt the western edge of the property, speeding up access to both Interstate 65 and I-565.

Updated at 3:18 p.m. with information on TVA's Alabama service area.