Called the Solar Circle, it is a quiet sort of brain trust made up of members hand-chosen for their talents and commitment to the cause (see sidebar). It has systematically explored and sought to improve every aspect of the supply chain, playing a behind-the-scenes role as solar transformed from a hippie curiosity into the fastest-growing source of new energy on the power grid.

Twice a year, the group meets like clockwork, despite having no budget, no legal structure and no staff. Members travel on their own dime to weekend retreats that have been held everywhere from Maine to Mexico. And now, after years of brainstorming sessions, deep dives into policy and finance, and late-night guitar sessions, the circle has matured from industry association into something else.

“It has become akin to a family,” said Denis Hayes, a founder of Earth Day and an early director of what would become the Department of Energy’s National Renewable Energy Laboratory.

The group, founded by 30 representatives from every slice of the solar value chain, is exceedingly diverse. Members are entrepreneurs, philanthropists, engineers, manufacturers, venture capitalists, architects, project developers, activists, lobbyists, physicists, journalists and policymakers, and specialists in most technological means of deriving energy from the sun, as well as adjacent fields like wind power. While the group’s thrust is American, it has had delegates from India, Japan, Germany, Great Britain and Hong Kong, and includes innovators who designed the pillars of today’s solar landscape.

Many of the founders have been active in solar for decades and are now retired or approaching the end of their careers. They have been supplemented by newcomers who bring the roster of inactive and current members to about 50.

The coterie’s older members include Steven Strong, an architect who installed solar panels on the George W. Bush White House; Stanley Bull, a former associate director of the National Renewable Energy Laboratory; and Mike Eckhart, the founding president of the American Council on Renewable Energy and now the head of environmental finance and sustainability at Citigroup. Other, younger members are in the thick of today’s turbulent solar market, like Danielle Merfeld, a technology director at General Electric Co.; Tom Starrs, a vice president of solar panel manufacturer SunPower Corp.; Rhone Resch, the recently departed head of the Solar Energy Industries Association; Danny Kennedy, a founder of solar rooftop installer Sungevity (EnergyWire, Feb. 4); and David Hochschild, a member of the California Energy Commission.

The circle was founded in 2002, when the notion of solar playing a serious role on the electric grid was enough to make a congressman laugh. Solar panels were those things that got attached to satellites and blasted into space.

The circle’s recruits were early believers in the science of climate change and had a fervent hope that solar could replace the carbon-spewing coal plants that formed the country’s energy backbone. But their industry — if it could even be called that — was so small and fragmented that many of its members had never met.

Now most are astonished at how fast and how large solar has grown. Since the circle’s founding, the price of an installed residential rooftop solar system has dropped from $11 a watt to less than $4, and the solar industry employs over 200,000 Americans, more than the number who work in oil and gas extraction (EnergyWire, Jan. 12). Solar farms produce only a slim fraction of U.S. electricity — six-tenths of 1 percent as of last year, according to the U.S. Energy Information Administration — but adoption is skyrocketing. If trends hold, this year will see solar bring more new capacity to the U.S. grid than any other source.

That acceleration has some members of the circle wondering whether they still have a role to play. On one hand, solar has scaled to a size they could scarcely imagine; on the other, it has a long way to go if it is to meet the group’s professed goal of ruling the world’s energy system.

In any case, the circle has tapped its members into an energy source they could find nowhere else.

“It allowed us to take a breath for a moment, marshal our resources and be stimulated intellectually,” said Scott Sklar, a solar lobbyist and a former director of the Solar Energy Industries Association. “It was a way to cloister away with people who were as crazy as you were.”

The roundtable

The group hopscotches across the country, alternating between the East and West coasts, seeking out nature retreats and organic food when it can. It has converged near a space observatory in the Colorado Rockies, at a convent, at an eco-conference center outside Washington, D.C., and several times at Asilomar, the famed meeting spot on the central California coast. Members have brought their families to Hawaii and met on the shores of Mexico’s largest freshwater lake.

Other times, they come together at members’ offices, such as in Seattle (at the Bullitt Center, run by Hayes); Oakland, Calif. (headquarters for Sungevity, co-founded by Kennedy); and Chicago, at the offices of Howard Learner, the executive director of the Environmental Law & Policy Center.

Everyone’s contribution is different. Hochschild tees up tantalizing political conversations. Joel Makower, the founder of GreenBiz.com, who attended in the early days, counseled on how to expand the group’s message to the larger energy industry. Julie Blunden, a former vice president of SunEdison and SunPower, delivers a detailed talk on the financial state of the industry, while Donald Aitken, an educator and sustainable building expert, gives the latest on climate change. Barbara Harwood, an advocate for affordable energy-efficient homes, was a deep thinker who spoke rarely; Dan Shugar, one of the most successful serial entrepreneurs in solar, is known for yelling and pounding the table when he gets worked up.

Most conversations revolve around photovoltaic solar power on the U.S. power grid. But some members doggedly remind their colleagues that there are plenty of other ways to produce solar power and many other places that need it.

Robert Shaw, an early investor in solar manufacturing, talks about the possibility of using sun power to create hydrogen fuel. (“It’s a lonely subject to bring up, but I do it at every meeting,” Shaw said.) Bill Guiney, who started the solar arm of industrial conglomerate Johnson Controls, is a vocal advocate of solar-thermal power. Others advise their compatriots that it isn’t all about the grid. An early member was Harish Hande, an Indian entrepreneur and a founder of the movement to provide solar lighting for the billion or more people in the developing world who have no electricity. Others in small-scale solar are Titus Brenninkmeijer, an heir to a German clothing fortune who backs clean energy projects, and Richard Hansen, an engineer who focuses on rural Latin America. (“I keep the message going like a parrot,” he said. “The sunshine’s for all.”)

A constant topic of discussion has been finance and how solar power can become affordable. That discussion, led by such members as Blunden, Shaw and Eckhart, is where many of the circle’s members say they got their most valuable money lessons.

How could the young industry stimulate manufacturing? How about green banks, which make low-cost loans to low-carbon projects? That latter topic was explored by Alisa Gravitz, the CEO of nonprofit Green America, who served as moderator for the group’s early meetings. Other sessions dissected the anatomy of the yieldco, a renewable energy finance instrument that has now fallen on hard times.

“There was a rigorous attention to the costs of solar, very careful tracking, where the chokepoints are, where the points of leverage are,” said Bracken Hendricks, former executive director of the Apollo Alliance, a group that in the early 2000s sought to rally labor and environmental groups around renewable energy.

Straight talk

To understand the circle’s value, consider what happened when Strong showed off about his solar buildings.

Strong is a little-known but influential architect. His company, Solar Design Associates, created the United States’ first entirely solar-powered house and the first solar-powered sports stadium (for the San Francisco Giants), and installed photovoltaic solar panels and a solar hot water system at Bush’s White House, on an outbuilding. At one meeting, he proudly gave a slideshow of arrays he had placed on U.S. embassies. His colleagues weren’t entirely impressed.

“A number of us said, ‘Steve, what’s really great is you got the government to realize that solar matters,'” said Jito Coleman, former president of Northern Power Systems, a wind turbine manufacturer. “But the problem is that none of this shit looks good.”

That was the starting point for one of the first high-level conversations about the aesthetics of solar panels — a topic that remains vital today. (Tesla Motors Inc.’s Elon Musk in late July revealed that part of his master plan is to make rooftop solar panels “beautiful.”)

Every member interviewed for this story said the same thing: The chance to share rough-hewn ideas and get unvarnished feedback made the circle invaluable.

“It’s a group that is internally pretty critical of missteps,” said Dan Kammen, an energy professor at the University of California, Berkeley. Circlers felt safe sharing sensitive information — the prices of solar modules, the valuations of companies — because conversations were off the record and members came to learn they could trust each other.

Participants also cherish the “calibration exercise” held on Saturday morning, when each member gives an update on how things look from his or her part of the industry. No other venue exists where members get a 360-degree view of what’s going on. Afterward, the group follows an agenda through the rest of the weekend that includes small group sessions, presentations and discussions.

“I’ve never left a meeting wanting more,” Guiney said, “other than more time.”

Secrecy has been essential to the circle’s success, members said, though secrecy might be the wrong word; “hiding in plain sight” is more like it. Some members mention the circle on their websites or LinkedIn profiles, without elaboration. “It has not had any visibility, and it has not sought any visibility,” Hayes said. By meeting out of the public eye, members said, they are able to speak freely.

EnergyWire learned of the circle’s existence from a chance comment of one of its members at a public meeting last fall. Since then, 19 members have gone on the record to tell the Solar Circle’s story. Many said the circle has been able to stay so low-profile for so long because of a fierce commitment to keep its container tight, as well as a trait that is common in the circle but rarely found among those at the top of an industry: humility. The group has self-selected for members disinclined to boast or brag.

The group has grown, but slowly, as it seeks out a rare combination of traits: unswerving commitment to solar, a high level of expertise, a humble and generous outlook, and the ability to mesh with a well-established clique. Candidates are auditioned and often turned away. “We look at not just what they are but who they are,” said Guiney. “We’re sharing some personal information, and we want to make sure that is a person who’s trustworthy and honorable. They’ve got to be in it for more than a buck. It’s got to be a passion.”

Among the additions have been Kennedy and Blunden, as well as Jigar Shah, the founder of solar developer SunEdison, and Merfeld of GE, who caught the attention of Shaw when she gave a talk at Cornell University.

The group has no members from newer companies in the clean energy space that come closest to being household names, such as Tesla, Sunrun Inc. and SolarCity Corp.

“We know people in all of those companies,” Shaw said. “I just don’t think they matched the personality, the work-together ethic of the group.”

A guest speaker or two can be found at almost every retreat. Once, the guest was a Stanford professor who proposed a road map to the U.S. getting 100 percent renewable energy (ClimateWire, June 2); another was a social media expert from President Obama’s first presidential campaign. Often it is a local politician who can give the group a ground-level view, such as Jay Inslee, who spoke before the group when he was a congressman and is now the governor of Washington.

Sometimes the guest stirs things up.

A solar city

In 2004, the circle invited Marvin Keshner, a director at Hewlett-Packard Laboratories, who proposed an idea that astonished the circle.

He suggested that photovoltaic solar panels could follow the curve of another silicon-based industry — semiconductors — that had in the 1980s and 1990s scaled to titanic size, using economies of scale to usher in our era of ubiquitous, cheap computing. Keshner proposed that the United States lead an effort to build hundreds of huge solar factories that would produce several gigawatts of panels a year and spread solar to every roof by slashing its price to a dollar a watt. He called this factory a “solar city.”

Keshner’s proposal was prescient. Massive factories that produce gigawatts of solar modules a year did get built — in China. The cost of an installed solar system may reach $1 a watt — by 2020. And one U.S. company is attempting to steal back China’s lead with a solar “gigafactory.” Its name? SolarCity.

But back in 2004, when the idea first fell on the circle’s ears, it was a revelation. Shaw said, “It was so far away from where the industry was at that point that it was almost unthinkable.”

The group briefly considered mounting a manufacturing effort like Keshner suggested but changed its mind after it realized how much that would cost.

The circle was a venue where exciting prospects first entered the minds of some of the industry’s leading lights. Ideas are bandied about, in the leisure of a conversation among equals, with little attempt to make them concrete. Thus the Solar Circle has served as a sort of salon for the solar industry, directing intellectual heat onto promising ideas that subtly percolated outward, often at the state level.

The circle counts among its members some of the architects of today’s solar landscape. Starrs, the SunPower vice president, originated key parts of net metering, which compensates small-scale solar generators, like homes, for the power they supply the grid — a proposition that now underlies the financial value of much of the country’s fleet of rooftop solar panels. Aitken helped draft the first renewable portfolio standards, which are now in place in a majority of U.S. states. Shah of SunEdison pioneered the power purchase agreement, the model that is used by utilities and businesses to contract the power from renewable energy power plants.

The circle often lends a hand to a member in need.

Some of the younger members, now in their 40s, look to the older cohort, many in their 70s, as mentors. Several members said Hochschild got crucial support from the circle as he co-founded Vote Solar, a San Francisco ballot initiative that was one of the first successful attempts to make solar power a voting issue. (Hochschild declined to be interviewed for this story.)

“What’s interesting to me is that it remains a tightly correlated group that will help each other out at the drop of a hat,” Blunden said. “I go to them for a kick in the pants.”

Others, like Kammen, discovered the power of the circle’s network. An introduction from another circle member brought two startup founders into the professor’s office. Kammen was impressed and became chairman of the startup’s research board. Today that company, Enphase, dominates the market for microinverters, which convert direct current to alternating current at the point of the solar panel and have become a key link in smart and efficient solar arrays.

“This was really a group that just had a lot of interesting conversations,” Kammen said, “many of which became companies, ideas or white papers.”

But conversations are ephemeral, and even the circle’s own members don’t agree on whether they have had an impact.

“I think that key leaders within the industry were able to be significantly more effective and nimble and creative and timely because of the circle’s existence, and I can’t help but believe that the incredible success of the solar industry has been greatly supported by the existence of the circle,” said Hendricks.

Others are more circumspect. “If we were all shot and killed,” Sklar said, “solar would still be here.”

The next dawning

What does a group dedicated to dominance do when it finally starts to win?

That is the existential question facing the Solar Circle and its membership. For years, the group wondered how to get celebrities and religious leaders to speak about climate change and renewable energy; in the last year it got just that, from Leonardo DiCaprio to Pope Francis (ClimateWire, Jan. 20; Greenwire, Sept. 25, 2015). Members strategized how to speed the adoption of rooftop solar; earlier this year, the U.S. surpassed a million solar installations.

Now that solar is maturing into a complex global enterprise, the horizon is filled with other questions: How will gigawatts of intermittent solar power be stored? Can home or industrial-size batteries get cheap enough to do it? Can electric cars? Can the hub-and-spoke electric grid be flattened into a mesh, making a thousand rooftop solar panels as valuable as a centralized coal power plant?

Members of the group are quick to point out that it’s still early days for solar. “When there’s solar energy on every building you look at, our job might be done then,” said Guiney. Some circle members, particularly the younger ones, think the circle could play a role in transforming the world’s energy system into one that revolves around the sun.

“In a whiteboard environment, what would we do?” Blunden asked. “We’ve got to prepare for domination.”

But before domination comes defense.

One of the solar industry’s key policy tenets, net energy metering, is under attack by climate deniers and “utilities who think they own the electricity world,” said Shaw. Nevada gutted its net-metering policy last year, arguing it is a hidden penalty on customers who don’t generate their own power. Another key policy tool, the renewable portfolio standard, seemed to be on a path toward bringing ever more renewable power to ever more states — until recently. In the last year, standards have been scrapped in Kansas and West Virginia and have stalled in Ohio and Maryland.

In other ways, solar is “so successful that we caused a new problem,” Shaw said. In California, by far the leader in integrating renewables onto the power grid, output from solar and wind farms has spiked at times of day when demand for power is the lowest — the so-called duck curve — which has caused the grid operator to shut down deliveries (EnergyWire, May 2, 2014).

The circle, founded with 30 members, now has meetings attended by between a dozen and 20 regulars. Many of the original members have stepped away, and some refer to it in the past tense. Some, like Kammen, believe the circle has been overtaken by events; he has stopped going, he said, because he can see the same people and have the same conversations at the energy and climate conferences that crowd the calendar these days.

Others find that time is overtaking them.

“I wouldn’t say it’s a social club, but it’s not as substantial or as relevant as it once was,” said Hayes. “We’re a bunch of geezers now. We’re going to start dying, and we’ll see if we get replaced and it continues to have usefulness.”

At a meeting last year, the circle mourned the passing of three spouses. One was Harwood, who was a circle member along with her husband, Aitken. He still makes it to all the meetings he can, because both the topic and the people are close to his heart.

“There is no other such group anywhere that meets regularly and has such a diverse membership,” he said. “And God, we love each other. When we meet each other, there’s hugs all around.”