Boston Mayor Martin Walsh defended the city’s plans to accommodate General Electric’s new 300,000-square-foot headquarters but said details of the real estate deal remain in flux.

At an introductory press conference yesterday, GE CEO Jeffrey Immelt laid out an expansive vision for the company’s future influence on the region’s economy, schools and nonprofits, predicting it could catapult Greater Boston into a Silicon Valley-like crossroads of data-driven applications optimizing manufacturing and health care.

GE threw a belated Valentine to its soon-to-be-adopted home with a promotional video awash in Boston history, landmarks and folk heroes from Aerosmith to Tom Brady, asking the rhetorical question: “What city would you choose to start a revolution in?”

But on the sidewalk 33 stories below, protesters milled back and forth in a snowstorm decrying up to $145 million in state and
city incentives to GE as a corporate handout that would be better spent on public schools, the region’s unreliable public transit and clean-up of the Housatonic River.

Earlier in the day, GE announced its commitment to spend $50 million over the next five years on education and workforce training, including $25 million on Boston Public Schools.

GE has been working with Walsh’s economic development team on its vision for a permanent headquarters on Necco Way in Fort Point, on a 2.5-acre site currently owned by Procter & Gamble subsidiary Gillette. The site includes two 6-story former warehouses and a parking lot, where GE plans to build a “state-of-the-art” headquarters surrounded by lab space employing 600 employees in GE’s digital, current, robotics and life science divisions.

GE would lease the buildings, which are still under Procter & Gamble ownership, from the Boston Redevelopment Authority, Walsh said. GE would be responsible for operation and maintenance of the buildings, and future revenues from the property will be higher than in their current vacant state, Walsh said.

The buildings are part of a larger 9-acre parcel, most of which is surface parking, valued at $32.6 million, according to Boston assessor records. Gillette’s annual property taxes are $875,091.

“Those buildings would have sat there getting a small bit of revenue probably for the next 15 or 20 years,” Walsh said. “There’s an opportunity to get one of the largest companies in the world, and the spinoff from that will be reinvested in our police and in our schools.”

Immelt spoke of GE’s potential to leverage Boston’s tech cluster and partner with startups and established companies in a wide range of industries.

GE will occupy its leased temporary headquarters at 33-41 Melcher St. in Fort Point beginning in August, Immelt said. The permanent headquarters is scheduled to open in phases beginning in 2018.