ALAMEDA — The engineers pedal quietly across deserted roads and parking lots, passing a rusted naval cannon before they reach their secret workshop in an old seaplane hangar.

Their multicolored bicycles — using the same palette as Google’s logo — stand out as vibrant oddities in a weathered, post-apocalyptic landscape. They are the only clues identifying this as an outpost of the global tech giant.

But ever since Google bought Alameda’s homegrown wind energy company, Makani Power, two years ago, the former Alameda Naval Air Station has become a laboratory for weird inventions.

“Once we inked that Google deal, it put Alameda Point on the map,” said Nanette Mocanu, a city official who handles leases at the old base. “A lot of high-tech companies have been looking, especially with real estate so expensive in San Jose.”

Google’s largesse last year helped tiny Makani expand from its 17,000-square-foot headquarters in a faded air control tower to a 100,000-square-foot hangar across the street. It pays $55,000 each month for the city-owned properties, according to the lease.

Its neighbor, Natel Energy, is working on hydro-power turbines. San Jose-based Wrightspeed announced earlier this year that it is relocating to Alameda as it refashions a hangar to develop electric power trains for big-rig trucks. And nearby Kai Concepts, run by Makani co-founder Don Montague, is designing recreational kiteboats.

“I think what they see is these unusually large, cool spaces. It gives them a lot of room to work in privacy, to be creative,” Mocanu said. “Those hangars are just really beautiful on the inside. You don’t get that kind of structure anywhere else.”

Mountain View-based Google takes that privacy so seriously that none of the workers who help manage the old naval grounds would talk about the company or what it might be doing. Google also declined to comment but revealed in a May 27 blog post that a huge prototype it assembled in the hangar is ready for real-world testing.

Makani’s 9-year-old project to harness wind using aerial turbines it calls “energy kites” went unnoticed by many Alamedans until a few weeks ago, when Google erected a tower and mast-like structure bearing a pirate flag on a paved lot near the aircraft carrier USS Hornet.

“They’ve been very hush-hush,” said April Hartness, using hand motions to describe the contraption she saw rising near her roofing company office. “It was this way, then it was that way, then this way, then that way.”

At some point when Hartness wasn’t looking, Google opened the giant doors of its hangar and trucked to the lot its newly built aircraft — eight propellers lining an 84-foot-long wing. The engineers tethered it to the tower. The kite is programmed to lift itself into the sky and fly in huge gyrations, generating up to 600 kilowatts of energy, according to Google’s blog.

By the time Hartness returned to work the next morning, however, the power-generating aircraft was gone. Google had been replaced on the lot by stage lights and giant blow-up safari animals. The rumors were that Google was having a “rave,” she said, but officials said it was direct-selling company Amway hosting a dance party.

Alameda Point’s surreal edge has grown since the Navy closed the base in 1997.

Hangars that once housed the world’s biggest flying boat — the World War II-era Martin JRM Mars — have long attracted admirers finding ways to creatively reuse them. One is home to a popular indoor sports center while other naval buildings house distilleries, breweries and tasting rooms overlooking San Francisco Bay. The TV show “MythBusters” has found the weed-strewn tarmac a perfect spot to blow things up.

Despite Google’s aversion to having any association with war technology — the company dropped out of a robotics contest recently because of its military ties — its leaders also have a fondness for old bases.

NASA handed over management of the runways and historic airship hangars of Silicon Valley’s Moffett Airfield, another former naval base, to Google in April. Google executives have long parked their personal fighter jet near the runways that will now be used for futuristic research. The company also spent the past year testing its self-driving cars at the former Castle Air Force Base in the Central Valley. In Alameda, the company has held holiday parties aboard the USS Hornet, now a museum.

But Alameda Point’s new role as a playground for green inventors came from an unlikely collaboration between the kiteboarding founders of Makani — Montague and scientists Saul Griffith and Corwin Hardham — and Montague’s friends Larry Page and Sergey Brin, the co-founders of Google who pushed the trio to channel their wind-chasing ideas into energy research.

All these green energy projects are a good match for Alameda’s eco-minded culture and inventive spirit, said Mayor Trish Spencer, who was invited to visit Google’s hangar last month.

Even as the island’s political factions battle over the future of housing, traffic and economic development on Alameda Point — the City Council is set to vote on a 68-acre development project there on Tuesday night — the tech companies have met no resistance.

“Anytime Google is in town, it’s a game-changer, very positive,” Spencer said. “They are constructing things that are big, and the hangar is the perfect spot for that.”

Contct Matt O’Brien at 408-920-5011. Follow him at Twitter.com/mattoyeah.