The Story Behind One Solar Robot

I am peering through the glass window of a refrigerator-sized machine. The machine is named Endurance, if you go by the printing on its side, or Lucy, if you go by what Leila Madrone calls it. I’m watching some plastic get tortured.

It’s going through the equivalent of 100 years of life in a harsh desert climate: It’s been exposed to extreme heat and cold, and UV radiation. It’s been sandblasted. It’s been shaken around a whole lot. It suffers, because it needs to last 30 years without anyone having to fix it. Better for it to fail now, in the lab, than later, at a solar installation in some far-flung desert.

The building, in the former industrial sector of San Francisco’s Mission District, is older than it looks: it was used to make custom mining equipment during California’s silver rush in the early 1900s. Ideally, the plastic would last as long as this building. Maybe it will. If you have a problem with plastic, Madrone tells me while we peer through the glass, if you have a problem with the way that it sticks around in the environment, you just need to use it for what it’s good for — use it for something that’s supposed to last forever.

This plastic is part of the answer to a question that Madrone found herself asking back in 2008. By that point, she had built a lot of cool robots. Her thesis in electrical engineering at MIT was a set of motorized laser guides to help people play the theremin. After years of designing precision robots for biotech, she had fulfilled the life goal of her 7-year-old self and worked with NASA — leading an engineering team working on the Gigapan, a commercial version of the robot that lived on the Mars Rover and took panoramic shots of the places it visited. But Madrone still wondered: What was the most useful robot she could build?


Madrone settled on solar trackers — mechanical systems that move solar panels in order to help them follow the path of the sun. The concept isn’t new; solar-tech historian John Perlin found a description of a simple solar tracker dated 1699. (It was a slab that grapevines grew along the side of, that could be tilted throughout the day with a series of pegs and tracks to maximize sunlight.) Plants had come up with the concept even earlier.

But for someone with Madrone’s skills in automation and robotics, solar tracking looked like the right problem: It took a proven renewable technology and made it even better. Trackers in general could already boost the energy production of a solar panel by 20 percent or more. With the right breakthroughs, they could be the thing that tipped the balance and made solar the lowest-cost energy source out there.

Madrone read everything she could find about solar — in academic journals,  on the internet. She interviewed people working in the field. She began working for a solar startup called GreenVolts, which was developing equipment for concentrated solar: small, high-tech power plants whose modest footprints made it easier for them to locate near cities. GreenVolts’ technology was far out; the arrays looked sort of like a field of robotic flowers, with panels that branched out from a central column like petals. The panels, and the trunk, were actually a huge precision robot that could track and concentrate sunlight much more efficiently than old-school photovoltaic solar.


It was really cool. It also came with a lot of bells and whistles — it was, as one business reporter put it, “bling-heavy.”

In 2008, the price of ordinary, non-high tech photovoltaic solar panels began to fall, sharply. It kept on falling. This was partly due to the recession, partly due to (successful) efforts by Chinese solar companies to seize the day and drive their competitors around the world out of business by selling photovoltaic panels at below cost. There was no bling that could outcompete that kind of bargain, especially when the bargain was a proven technology that everyone in the industry knew how to install and maintain.

GreenVolts was toast, though it would take a few more years to figure that out, and Madrone was disillusioned. She left the company and spent five months traveling through Europe, Asia, the Middle East, and Mexico. She visited islands where the only power source was expensive and dirty generators, and cities like Kathmandu, where the electrical grid was so non-functional that blackouts were a daily occurrence. The more that she saw, the more she became convinced that any solar technology that would have an impact needed to be so cheap and easy to manufacture that it could be deployed anywhere.

When she returned, Madrone began collaborating with an old friend at MIT, Saul Griffith. Griffith was the sort of inventor who came up with new devices and companies at the same clip that other people might, say, take out the trash, or do the nightly dishes (he’s best known for founding Instructables). At that time, he found himself increasingly preoccupied with climate change — and the problem of inventing tools to fight climate change that people actually used.

Among the projects he worked on: a road that is also a solar panel (turns out you expend more energy building it than you ever get back from using it). A wind-energy device called Makani Power, which is like the lovechild of a windmill and a kite (bought by Google X in 2012, where it has remained perpetually in the testing stage ever since). A cargo-hauling tricycle with electrical pedal assist (cool, but the battery alone costs $1,000, so not practical to bring to market). A website called WattzOn that catalogues tools to help people, cities, and utilities reduce their personal energy consumption (popular with a geeky subset of people, cities, and utilities interested in doing this, but otherwise under the radar).

Griffith had recently founded Otherlab, a research and development company that Madrone describes as part startup, part academic lab. Griffith and another Otherlab co-founder, James McBride, had also written a concept paper two years earlier, hypothesizing that mass-manufactured, plastic parts could dramatically bring down the cost of a solar tracker. Madrone moved into Otherlab and started building prototypes in a corner of the building.

Concentrated solar power (CSP) was still desperate for good trackers, so Madrone and Griffith started a new company — Sunfolding — and decided their niche would be designing a solar tracker that could work with any concentrated solar project. “We started with concentrated solar, thinking if we can do this, we can do anything,” says Madrone. CSP trackers were the hardest to build; they needed to be extremely precise while operating in harsh conditions.

What they came up with was a collection of small, inexpensive mirrors that tilted using pneumatic pressure. The whole setup had much less wind drag and fewer moving parts than a traditional steel-and-glass heliostat. In November 2012, the project won $2.6 million from the Advanced Research Projects Agency-Energy (ARPA-E), a government agency designed to fund risky but interesting energy technology, in the tradition of the Pentagon’s DARPA.

But the price of photovoltaic solar continued to fall, which made even believers in concentrated solar (which relies on an entirely different technology) balk at building new $3 billion plants. And the technology kept changing, making investors risk-shy: No one wanted to install a huge solar array, only to have to rip it out and start over a few years later because the technology didn’t work out. “There’s a lot of really neat innovations you can come up with related to energy,” says Madrone, “but they’re not necessarily what the industry needs or wants.”

What the industry needs and wants, Madrone and her colleagues hope, is huffing pneumatically a few feet away from where I’m sitting to interview Madrone, in an empty workshop on the third floor of Sunfolding HQ. It’s just around the block from Otherlab HQ, where the plastic is being tortured. This building, also old, was erected by a German-American pipe organ company that’s almost as old as the silver mining equipment company, but that proved much more long-lived. Schoenstein & Co., the pipe organ manufacturer, outgrew the space a few years ago and moved its operations to Benicia, Calif. Outside the door to the workshop is a huge room where, from 1928 until 2004, pipe organs were built. The list of each organ made on site, and its destination, still hangs from one wall.

Christopher Michel

Today, heavy-duty engineering texts like Uhlig’s Corrosion Handbook (third edition) are scattered around the upstairs workshop. Under normal circumstances, the ping pong-table-sized solar panel in the corner of the workshop would not be moving this fast, but right now it is rapidly tilting, fast-forwarding its way through a sequence of pre-programmed days. One of the things Madrone and Griffith found is that it’s easier to program a field of solar panels with pre-existing algorithms describing the sun’s movements than it is to fuss with a sensor that follows the path of the sun in real time — but would also be one more part that could break.

Standard-issue solar tracking devices for PV are designed, in Madrone’s words, “the way you would expect an industrial machine to look like.” They’re made of motors and gear boxes and bearings, which have a lot of surfaces that rub against each other and wear out. They have to be assembled by hand in a factory somewhere. The panels are moved by a torque tube that runs along the length of 20 or 40 solar panels, so that it can move all the panels at once when it rotates. This is efficient, and doesn’t use much energy, but has the unintended effect of forcing every large-scale solar installation that wants to use tracking to become a giant, flat rectangle — no matter how many nice, oddly slanted or shaped spots are nearby.

Sunfolding’s approach is different. The only hardware that moves Madrone and Griffith’s test panel is a set of chunky, accordion-pleated tubes, about the size of a liter bottle of soda. They are linked via a series of tubes to an air compressor off to the side, and as air moves in and out of the tubes, they expand and contract, and the panel tilts. The tubes are made out of black automotive plastic; as they expand and contract, the effect is part inchworm, part Muppet.

I ask Madrone if, compared to all the other robots she’s built, this one might not be just a little boring. “I’m glad that you see it’s a robot,” she says. “Because it runs autonomous systems. It runs presumably for decades without anyone telling it what to do. It responds to the sun. If there’s bad weather it does something to protect itself. For all intents and purposes, it is a robot.

“It’s not a fast-moving robot. It doesn’t move any faster than the sun moves. But a lot of the things you have to solve for this tracking system are really interesting problems. There are things we are doing with our controls that no one else can do.

“It’s really easy to build something that works for a day,” Madrone adds. “It’s a whole other piece of work to build something that can go for a week. Every time you increase that without someone coming in and poking it and replacing things, it becomes harder and harder.”

It has not escaped Madrone’s attention that when she graduated, many of her fellow engineering students at MIT worked on hardware projects. Now, more and more of them work on software. Even with the much-hyped “internet of things,” and the tsunami of venture capital flowing through the Bay Area, the field for hardware projects is small. Companies that can invent new hardware and actually bring it all the way to market are rare. Venture capitalists may come in at the late stages of a product’s development, but they aren’t going to fund research and development for hardware when software, immaterial and scalable, is so much more tempting.

Only five years passed between Madrone’s decision to build a cheap way to move solar panels around and her actually releasing a product to market. That’s an eternity in internet years, but a pretty short one for hardware that is supposed to make it to 2045 before it needs repairing.

Getting to this point took more than building a better mousetrap. It took learning the ins and outs of an industry that was changing fast, yet skittish about changing any further. It meant leaving cool ideas by the wayside if they interfered with cost and reliability. It meant building something most individuals will never see in action (since building codes have a hard enough time permitting rooftop solar that stays perfectly still).   It meant signing on to a funding mechanism that involved spending a long, eight-hour day every three months talking technology and strategy with a government agency, ARPA-E, that was both a champion and an enforcer. (Madrone sees this as a good thing: “A lot of startups don’t have that experience where they have someone scrutinizing them and making sure they are doing everything technically correctly.”)

The tech industry, as a whole, is prone to big visions and big ideas — with good reason, since big ideas are the language of venture capital. That’s not the language that Madrone speaks.

“We have to get away from this hero mentality,” she says, as we leave the 100-year-old pipe organ factory and step out into the sunshine. “We don’t need someone to create a magical box that means we can do whatever we want all the time and use all the energy we want. We need to get really smart about our energy use and really smart about how we create energy.

“The only way we can do that is by creating an ecosystem where there are a lot of ideas working together. And we need to start valuing that kind of community of ideas instead of the one hero that is going to save us all. ”


Meet the YIMBYS

Originally published at Grist.

The first time I heard of Sonja Trauss, she was mobilizing San Franciscans to support new apartment construction. This was not a campaign that went over well in the Mission District, a formerly working-class neighborhood that was in the middle of a full-on freakout over how many people seemed to want to build luxury condos there. One night, when I was walking down 24th Street, I saw that someone had taped up fliers to telephone poles with pictures of Trauss on them. Her eyes had been whited out and replaced by dollar signs.

Based on this backstory, I assumed Trauss must be one of the numerous young real estate professionals who come to the Bay Area to seek their fortunes. I was surprised, when we met up last week, to realize that she actually belongs to a species I’d thought almost extinct in the Bay Area: the bona fide, deeply eccentric city-government nerd. Even stranger, Trauss had just turned around and done something that seemed to delight even her more vociferous opponents — she was trying to sue a suburban municipality to build more affordable housing.

Here is how Trauss’s thinking goes: We need more housing units, and the market-rate units we build now will become tomorrow’s middle-income apartments. Her theory is based on her experience working for a neighborhood advisory committee in a rapidly gentrifying part of Philadelphia right before the mid-2000s housing bubble burst. “When the market crashed,” Trauss told me, “all those projects we had approved went on sale for a third of the price they would have, while all the projects we gummed up were never built. We lost the opportunity to create more units.”

Trauss’s enthusiasm for building has brought out the critics. They say that, at best, she just doesn’t know her local history (when the mid-2000s housing bubble burst, the Mission was relatively unaffected); at worst, she’s a tool of the real estate lobby, hoping for a payout.

Neither view could be easily squared with Trauss’s latest move — organizing a lawsuit against the East Bay suburb of Lafayette, arguing that the city has wrongly blocked builders from putting up new housing. The lawsuit would be based on the 1982 Housing Accountability Act — an obscure California law intended to help affordable housing projects from having to compromise on density in order to win approval from local planning commissions. In 2011, a court ruled that the act applied to all housing, not just affordable housing. In 2014, a developer in the Mission used the act to fend off an effort to scale down a 12-unit apartment building that they had been trying to build for years on the site of a former Kentucky Fried Chicken.

But Trauss’s new effort seems to be unprecedented — it would be the first time that actual people, rather than developers, were using the law. And if her campaign succeeds, the implications could be huge. Suburbs like Lafayette are historically allergic to allowing more housing density, yet denser communities, many urban environmentalists believe, are the key to kicking our climate-wrecking carbon habit. Trauss’s suit could upend the tidy universe of California suburbia: Google employees living in San Francisco and commuting down the peninsula by tech bus could potentially could sue Mountain View for its refusal to approve three-quarters of the proposed housing around the Google campus. Speculators could ride BART and Caltrain all over the Bay Area, looking for locations around transit hubs where community organizations had blocked development.

Here’s how Trauss came to Lafayette: In August, she read a news article about the well-to-do suburb located east of San Francisco, over the hills from Oakland. Average income in Lafayette is about $130,000 — double the state average. It has an excellent school system and its own BART stop, and, like many similar communities, is determined to stay suburban. The Bay Area may have acquired 270,000 new residents in the last five years, but that doesn’t mean Lafayette is working to make room for them.

In 2010, Lafayette tried to rezone a Christmas tree lot that had been zoned for apartments in the 1940s, down from 35 units per acre to one home per five acres. The rezoning never went through. Then in 2011, a developer came up with a plan to build 315 apartments on the land (about 15 units per acre). The plan was to rent the finished units out, starting at $1,500 per month for a one bedroom — a price that, by Bay Area standards for new construction, was fairly modest, especially for an area with a good school district.

Neighborhood backlash was swift: “This development project will significantly impact traffic, threaten the safety of children crossing the street on their way to school, and decrease property values of hundreds of homes,” one petition read. The city refused to approve the project. The developer threatened to sue Lafayette under the Housing Accountability Act, but backed down when Lafayette offered to buy half of the land and turn it into a 10-acre city park. The developer drew up plans to build 44 more expensive single-family detached homes on the property instead.

But because of a quirk in the Housing Accountability Act, the developer wasn’t the only person who could sue Lafayette. Any person who could make a case that they would have lived in one of those 315 apartments, had they been built, could sue the City of Lafayette for standing in their way.

Right now, Trauss has a legal team and 15 plaintiffs lined up. She’s looking for more. The group also plans to host a panel discussion at the Lafayette Public Library titled: “Why are we suing you?”

Trauss has been obsessed with local politics since the days when she started writing the newsletter for her neighborhood organization in Philadelphia. She can rattle off the permit history of every major housing development that has gone up in the Bay Area in the last three years. “When we’re all there at a deep-level city meeting all night,” says Trauss, “I feel like I have more in common with the other people at the meeting than with anyone not at the meeting, even if we’re on opposite sides of an issue, because we’re all the type of people who think this is a good way for us to spend our lives.”

When Trauss moved to the San Francisco Bay Area four years ago, she first lived in El Cerrito with a relative whom she helped get through chemo. (“It’s a country club model moving here,” she said. “Either you have to pay a huge up-front fee, or you need to know someone.”) She found work quickly, teaching math at a private high school. But finding a place to live was an ordeal.

“I was just sick of ranting with my friends about how hard it is to find a place,” she says. “My four friends and I could go to the Planning Commission every Thursday and make our same speeches that we make at the bar about how we need to build more, build faster, build everything someone wants to build — and we might actually do some good. Local politics is where it’s at. People say ‘Oh, I’m so disconnected from politics. Nothing I say or do matters.’ That’s only because they’re paying attention to national politics. Local politics? You can take it over. If you’re bored with going to the bar every night and getting drunk, you can just take over your town. If you feel like it.”

Trauss and her friends decided to call themselves the San Francisco Bay Area Renters Federation — or, for short, SFBARF. The acronym was deliberate; Trauss’s roommate insisted that you couldn’t buy branding like BARF, and no one would ever confuse them with anyone else. (The current lawsuit is organized under a new, less creatively acronymable name: the California Renters Legal Advocacy & Education Fund.)

The ultimate goal is not to torment Lafayette so much as to fire a warning shot across the bow of all the Bay Area suburbs who have failed to take on their share of new residents. “I talked to Sam Altman, the head of Y Combinator,” Trauss says. “He told me that Y Combinator alone creates 10,000 new jobs a year in the Bay Area. That means we need 5,000 new homes. At least.”

That said, Lafayette Terraces, the 315-unit complex that inspired the lawsuit, is far from a poster child for smart growth. Those 315 apartments were going to come with over 500 parking spaces, made necessary because the development is a nearly 40-minute walk away from the Lafayette BART station. A high density building’s environmental value vanishes if the people who live densely still drive everywhere. Many of the things that Lafayette residents objected to about the project — increased pollution from traffic near the complex, in particular — made sense.

That’s the argument that the mayor of Lafayette — attorney and former Ecology Law Review editor Brandt Andersson — made when he debated SFBARF member Brian Hanlon on television station KTVU. Andersson felt SFBARF’s pain, he said. He himself had a kid in his 20s who was still living in the home. But in its enthusiasm to find a test case, Andersson argued, the group had ignored the specifics of Lafayette as a city.

For one thing, since the city had never formally turned down the development, SFBARF didn’t have much of a case. For another thing, Lafayette had drawn up a plan, made three years ago, to keep multi-unit housing downtown, near the BART station. “We don’t want high-rises,” Andersson said — the plan called for a maximum of three stories in height, and 35 units per acre. But over the last few years the city had approved several apartment complexes downtown, and had optioned a city-owned parking lot to a developer to build 24 units of workforce housing.

All fine and good, said Hanlon, but still not enough — between 2007 and 2013 Lafayette had only signed off on permits for 10 percent of the amount of low-income and moderate-income housing that the Association of Bay Area Governments recommended built to keep up with population increase in the area. (Overall, though, Lafayette built 65 percent of the recommended number of units, which is a higher percentage than San Francisco.)

Trauss objects to Andersson’s characterization of the development as too far out of town. An ordinary person could walk the 1.7 miles to downtown, she responded, and a not very in-shape person could bike. Plus, she adds, “It’s almost always true that new development doesn’t have the transportation infrastructure (this includes walking friendly roads, not just buses and whatnot) it needs at the time it’s developed. That’s because we don’t build transportation (or really do anything) unless there are people asking for it. So if we let ‘not enough transportation’ be a reason to not build (and often we do), almost nothing will get built.”

That said, this case has always been about something bigger than Lafayette. “It’s not just a lawsuit,” says Trauss. “It’s a political exercise. Most people would be very uncomfortable tearing down 315 houses. But they don’t have a similar objection to never building them in the first place, even though I feel they’re morally equivalent. Those people show up anyway. They get born anyway. They get a job in the area anyway. What do they do? They live in an overcrowded situation, they pay too much rent, they have a commute that’s too long. Or maybe they outbid someone else, and someone else is displaced.”

“It’s easy to see the problem when you’re tearing down someone’s home. But when you’re not building, it’s hard to see whose home it is.”