Israeli entrepreneur Amit Rosner lives in Tel Aviv and is launching a business in Boston. He spends a lot of time on airplanes. "And whenever I look out of the window before we land, it drives me nuts to see roofs baking in the sun," Rosner says. "I feel this is absurd--that so much energy falls on the roofs, and it just bakes the roofs without doing anything helpful."

He's right; it's crazy. Consider: The price of photovoltaic cells is plummeting; an overwhelming majority of Americans (79 percent, according to a recent Gallup poll) want the U.S. to develop more solar power; and solar power is in fact growing, accounting for 36 percent of all new electric capacity through the first nine months of 2014, according to the Solar Energy Industries Association. And yet, solar power remains all but invisible on the big stage of U.S. electricity generation.

According to the U.S. Energy Information Administration, the United States generated about 4.093 billion kWh of electricity in 2014. Two-thirds of that came from fossil fuels, mainly coal and natural gas, and one-fifth from nuclear. Renewables as a group accounted for only 7 percent, while solar as a subset of renewables--wait for it--was 0.4 percent. In Rosner's view, that's not just a conspicuous entrepreneurial opportunity; it's a demand he thinks he can fulfill to help fight climate change.

The Big Idea

Rosner used to be a product manager at software analytics firm Verint Systems. It was interesting work, absolutely, but after he married and started thinking about a family, he wanted to do something more meaningful. That led to a job at a startup called SolarEdge, which just went public, and ultimately a startup of his own (with co-founders Idan Ofrat and Paolo Tedone) called Generaytor. Generaytor was all about improving knowledge and understanding of solar power; Yeloha, the trio's new company, is all about taking the next step to actual adoption.

Homeowners consume more than one-third of the electricity generated in the United States, making the residential sector a powerful lever for boosting solar power overall. But here's the problem: Surveys suggest that as much as 80 percent of us who would like to install solar panels on our roofs can't do it, for any number of reasons. Maybe we don't have a roof with good southern exposure. Maybe we do but there are trees in the way, or our roof needs replacing. Maybe we don't own the house, we're renters, so it's not our decision to make. Maybe we live in an apartment building. Or maybe none of the above, we're good to go, except that we don't happen to have 10 or 15 grand lying around to pay for installation, or else our credit's not good enough to qualify for financing or a long-term power purchase agreement. Heck, maybe we just don't like the way solar panels look. No wonder you see so many naked rooftops.

How to crack the residential market and spur growth? A lot of cool companies have been working on that problem for a long time. One of the first, San Francisco's One Block Off the Grid (it's Pure Energies now, a subsidiary of NRG Energy), leveraged social networks to whip up interest and bargain with installers on behalf of whole neighborhoods. CloudSolar, a Boston startup that just completed a successful Indiegogo campaign, wants to "offer panel ownership to everyone in the United States," says co-founder Michael Sun (really)--by selling panels to individual investors, building solar farms (in fields and on commercial rooftops), delivering electricity to the grid, and returning 80 percent of the proceeds to the panel owners over the 25-year life of the system.

Like Airbnb, for Solar

Rosner's new business launches today, April 7. It has received two rounds of funding (he won't say how much or who from) from an Israeli angel and a top-tier Israel venture fund. The name is Yeloha, from yellow, "to represent the sun," he says, and "aloha, the globally recognized Hawaiian greeting for both hello and goodbye that literally expresses affection, peace, and compassion." (Right. Naming a company is really hard these days.)

Yeloha combines the power of social networks and the appeal of the sharing economy. Its goal: to remove some of the constraints that make solar power inaccessible to so many. "We'd like to let anyone go solar," says Rosner. "No matter where they live, no matter what their income level is."

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Yeloha will have two sets of customers. The first, which Rosner calls "sun hosts," are people who live under a suitably sunny roof and want to go solar but can't afford to buy or lease the panels. Yeloha will install its own panels on those people's roofs, at no cost, and give them a portion (generally one-third) of the electricity they produce, absolutely free. Bottom line: The homeowner pays nothing for the hardware and pays less overall every month for electricity. Less is not nothing--you'd have to have a very big roof to get all the electricity you need from one-third of your system's production--but it's still less.

And the excess production? That's where the "sun partners" come in. Those are people who want solar power but don't have the right roof for it. They'll be able to buy solar credits from Yeloha in any amount they choose and pay less than they would for electricity generated by other means. Not a huge discount--about 10 percent for those who buy a year's worth of supply, Rosner promises; more for those willing to commit to three years or 10--but a discount nonetheless, which is key. "While they save money, they also save the world," says Rosner, "but this is the order of priorities we see. We don't want to speak only with tree-huggers. We love tree-huggers, we are tree-huggers, but there aren't enough people who care. So we want to drive positive change through what matters most to people."

Partners can choose their hosts, if they want, and hosts can assign their excess capacity to specific partners. Everybody will have access to online tools that measure production and consumption, and help build a sense of community. Yeloha is "the conductor of the orchestra," Rosner says--overseeing the system, selling power to the grid, and brokering solar credits. "The ones who do everything are the people."

Will it work? Ben Mayer, a co-founder of SunBug Solar, an installer, is intrigued, but he wonders about Yeloha's decision to launch in Massachusetts. The state has a dense population, Mayer says, and old houses with complicated rooflines, and a lot of mature trees. "If I were starting peer-to-peer roof rental, I wouldn't start it here," he says. "I might go where the houses are bigger and more boring."

Rosner chose Massachusetts for its generous solar subsidies and its solar-friendly demographic. He's hoping to prove the model here and then expand nationally. "There are two things that compel action," he says. "A crisis, or an easy and actual solution." He's betting on providing the latter.