Officials with the city and executives at the SfunCube — perhaps mindful of criticisms that gentrification has made real estate in parts of New York’s Brooklyn more expensive than Manhattan — say they are trying to ensure that Oakland residents have access to whatever benefits come from the growth.

Toward that end, Ms. Kahn said, they are working to support or promote organizations like Hack the Hood and others that are dedicated to high-tech training and education programs, while the SfunCube has an outpost of the California Center for Sustainable Energy, which runs jobs and youth education programs as well.

Mr. Kennedy, along with his Sungevity co-founders Andrew Birch, the chief executive, and Alec Guettel, a company director, began developing the incubator at something he calls the Solar Dojo, a collection of start-ups in Berkeley that included Mosaic, the crowdfunding platform. After moving operations to Jack London Square, he co-founded the program with Emily Kirsch, who had been pressing him to do so. As chief executive of the SfunCube, she now oversees a handful of companies that share its values, as she put it. They are offered space for nine months and encouraged to get their products out to market quickly.

“If it’s going to fail, we want to know as soon as possible — and they probably do, too, even if it’s their baby,” she said.

Those include BrightCurrent, which helps funnel residential solar customers to installation companies; Standard Microgrid, which is bringing solar systems combined with storage to underserved communities in Africa; BlocPower, which aims to aggregate nonprofit, small business and property owners into groups to buy lower-cost solar and energy efficiency products; and a company called What Up that is working on financial services software that would make solar leases more readily available to customers with less-than-stellar credit.

Through the program, entrepreneurs get access to free legal and financial services, networking events and contacts, and, of course, the capital they say has proved invaluable. Christopher Hornor, chief executive of Powerhive, which develops and finances solar microgrids, said he found important staff members at one of the program’s periodic hackathons — problem-solving jam sessions of a sort. Aside from that, they say, there is value simply in being around others dedicated to missions that at times seem impossible.

“When you’re an entrepreneur, there’s a period that you go through, which is like, ‘Wow, there’s another mountain to climb,’ and it’s really helpful to have this environment that you can just show up in,” Mr. Hornor said. “Knowing that other people around you are in the same boat — that’s morale-boosting.”