FREMONT -- Gordon Kingsley stood next to his exhibit in the Fremont Marriott grand ballroom on Thursday, explaining his brainchild that uses blimps and kites to harness wind energy that would produce electricity less expensively than coal-fired power plants or traditional wind turbines.

It may sound like science fiction, but Kingsley -- a Reno-based chemical engineer -- was one of many alternative-energy entrepreneurs at the hotel pitching outside-the-box yet plausible ideas they hope lead to a cleaner planet.

More than 35 entrants competed there in the 2013 Cleantech Open Western Region Awards and Innovation Showcase, an annual contest where experts, visionaries and dreamers pitch their ideas for cleaner energy while competing for award money and recognition.

Call it March Madness for tech geeks, with one key difference from the college basketball tournament: In the burgeoning cleantech industry, nearly every newcomer is an underdog.

"Just 4 percent of any patent ever makes any money," said Kingsley, who was joined by his wife, Dorothy, and daughter, Anne. "So you have to believe in your idea and have great support."

The contestants were vying to win $20,000 in cash and business services and the chance to advance to the cleantech Global Forum, where finalists will compete for a grand prize worth $200,000.

Sandwiched around the competitions were panels of experts and speeches from the energy industry's heaviest hitters, including Chevron President Jim Davis, and Dan Witt, a Tesla Motors executive. Tom Steyer, a San Francisco asset manager and philanthropist, was the afternoon keynote speaker.

Despite the presence of those wildly successful companies, some speakers made special note of the uphill climb that green companies face while competing against traditional energy giants.

"I'm here to say that reports of cleantech's death are greatly exaggerated," said Nancy Pfund, managing director of DBL Investors, a San Francisco venture capital firm that funded Tesla Motors, Oakland-based BrightSource Energy and many other alternative energy corporations.

Pfund, the morning keynote speaker, told the crowd that she believes in the industry's financial prospects and in its mission to leave the planet in a cleaner state than traditional energy sources do.

"Everyone in this room is making history," she said. "We're going from an economy based on fossil fuels to a low-carbon economy."

Fremont hosted the daylong event for the first time, and city leaders are hoping it won't be the last, especially because of the city's already strong reputation in the biotech industry. The Fremont Marriott is just a stone's throw from the Warm Springs district, home to about 35 clean and green tech firms such as Oorja, Solaria, Deeya Energy, Soraa and Leyden Energy.

"This reinforces our cleantech infrastructure," said Kelly Kline, Fremont's economic development director. "It highlights their role in the city and calls attention to them."

Fremont parlayed the Cleantech Open's side events into networking opportunities, hosting a special entrepreneur reception Wednesday night at Tesla Motors' Fremont factory, Kline said.

"Tesla really is Exhibit A of what a successful outcome looks like," she said. "At the reception, there were a lot of aspiring Teslas in the audience -- people that have an innovative idea and are trying to find an audience for it."

Contact Chris De Benedetti at 510-353-7011. Follow him at Twitter.com/cdebenedetti.