With deep pockets and an environmentalist's zeal, retired American football player Syd Kitson dreamed up a plan to build the United States' first solar-powered town on a vast swath of rural land in southwest Florida.

Now, nearly a decade after he first purchased the 91,000 acres (37,000 hectares) known as Babcock Ranch, construction is bustling at what developers say will be the nation's first eco-friendly city, built from the ground up, with enough room for some 50,000 people.

No homes have been built yet, but the first residents will move in by early next year says Kitson, 57, who played professional football for five years -- first with the Green Bay Packers and later, the Dallas Cowboys -- before he became a real estate developer.

"We are building a new town together. It is just remarkable," Kitson told a crowd of several hundred visitors at an Earth Day event last week to show off plans for Babcock Ranch to the public.

"It is our mission to prove that preservation and responsible growth can work together."

- The big idea -

Rather than build another gated community or a cluster of homes far away from a city center, Kitson's idea was to build an eco-friendly town that contains most of the necessities for modern life.

Plans allow for a public school, a downtown area with shops and restaurants, hiking trails and lakes for kayaking.

Eventually, residents may use their smart phones to hail driverless cars to shuttle them from one area to another.

Housing options will include condominiums and larger homes with front porches, priced between $200,000 to $800,000, designed to accommodate residents both young and old, Kitson says.

The first phase of 1,100 homes is to be complete by 2017.

The entire town aims to use the latest in green technologies, and will be certified as sustainable by the Florida Green Building Coalition.

- Many hurdles -

Along the way, Kitson faced a steady stream of obstacles, beginning with the global financial crisis which struck in 2007, just after he purchased the land. The real estate market took a dive, and construction stalled.

Some local residents have opposed the plans, fearing harm to the environment and the eventual loss of their rural lifestyle. The Sierra Club -- a leading grassroots environmental group -- threatened to file a lawsuit to block Kitson's purchase of the land from the Babcock family, owners since 1914.

But Kitson overcame opposition by buying the 91,000 acre ranch and selling most of it -- 73,000 acres -- back to the state of Florida for a wildlife preserve.

Kitson bought the family-owned corporation that held the land, Babcock Florida Company, for about $700 million and sold the Babcock Ranch Preserve to the state of Florida for $350 million, his spokeswoman told AFP.

Since then, wetland areas have been restored and some farmland has been converted to panther habitat.

"Here we have conservation," said Eric Draper, executive director of the Audubon Society environmental group.

Kitson "stepped in at a critical moment" to protect the water and wildlife in the area, he said.

- 'Never been done' -

There were also doubts about the feasibility of making solar energy affordable.

"A city that is powered by the sun? It had never been done before, anywhere in the world," said Eric Silagy, president and CEO of the state utility company Florida Power and Light (FPL).

Upon meeting the real estate developer for the first time nine years ago, Silagy told him about the high price of solar, explaining why Kitson's vision was just too costly.

"Syd was dutifully paying attention and he said 'Ok. We'll just give you the land,'" Silagy recalled.

"It frankly caught me by surprise. I was like, 'Pardon me?'"

Kitson donated 443 acres to FPL for the solar farm.

Press materials for Babcock Ranch tout the development as the "world's first solar-powered town," but in truth, the energy from the solar farm will not directly power the new eco-village.

Instead, the energy it creates will go straight to FPL's electrical grid.

The 75-megawatt solar farm will, however, produce enough energy to power 21,000 homes, about the same number as planned for Babcock Ranch, an FPL spokesman said.

FPL says the Babcock Ranch solar panels will triple the utility's current solar capacity.

"He pushed us to be better, to think creatively, to do things differently," said Silagy.

"This is a man who just doesn't take 'no' for an answer."