solar cells
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$100M donation powers decade-long moonshot to create solar satellites that beam power to Earth
It sounds like a plan concocted by a supervillain, if that villain’s dastardly end was to provide cheap, clean power all over the world: launch a set of three-kilometer-wide solar arrays that beam the sun’s energy to the surface of the Earth. Even the price tag seems gleaned from pop fiction: one hundred million dollars. But this is a real project at Caltech, funded for a nearly a decade largely by a single donor.
The Space-based Solar Power Project has been underway since at least 2013, when the first donation from Donald and Brigitte Bren came through. Donald Bren is the chairman of Irvine Company and on the Caltech board of trustees, and after hearing about the idea of space-based solar in Popular Science, he proposed to fund a research project at the university — and since then has given more than $100 million for the purpose. The source of the funds has been kept anonymous until this week, when Caltech made it public.
The idea emerges naturally from the current limitations of renewable energy. Solar power is ubiquitous on the surface, but of course highly dependent on the weather, season and time of day. No solar panel, even in ideal circumstances, can work at full capacity all the time, and so the problem becomes one of transferring and storing energy in a smart grid. No solar panel on Earth, that is.
A solar panel in orbit, however, may be exposed to the full light of the sun nearly all the time, and with none of the reduction in its power that comes from that light passing through the planet’s protective atmosphere and magnetosphere.
The latest prototype created by the SSPP, which collects sunlight and transmits it over microwave frequency. Image Credits: Caltech
“This ambitious project is a transformative approach to large-scale solar energy harvesting for the Earth that overcomes this intermittency and the need for energy storage,” said SSPP researcher Harry Atwater in the Caltech release.
Of course, you would need to collect enough energy that it’s worth doing in the first place, and you need a way to beam that energy down to the surface in a way that doesn’t lose most of it to the aforementioned protective layers but also doesn’t fry anything passing through its path.
These fundamental questions have been looked at systematically for the last decade, and the team is clear that without Bren’s support, this project wouldn’t have been possible. Attempting to do the work while scrounging for grants and rotating through grad students might have prevented its being done at all, but the steady funding meant they could hire long-term researchers and overcome early obstacles that might have stymied them otherwise.
The group has produced dozens of published studies and prototypes (which you can peruse here), including the lightest solar collector-transmitter made by an order of magnitude, and is now on the verge of launching its first space-based test satellite.
“[Launch] is currently expected to be Q1 2023,” co-director of the project Ali Hajimiri told TechCrunch. “It involves several demonstrators for space verification of key technologies involved in the effort, namely, wireless power transfer at distance, lightweight flexible photovoltaics and flexible deployable space structures.”
Diagram showing how tiles like the one above could be joined together to form strips, then spacecraft, then arrays of spacecraft. Image Credits: Caltech
These will be small-scale tests (about six feet across), but the vision is for something rather larger. Bigger than anything currently in space, in fact.
“The final system is envisioned to consist of multiple deployable modules in close formation flight and operating in synchronization with one another,” Hajimiri said. “Each module is several tens of meters on the side and the system can be built up by adding more modules over time.”
Image Credits: Caltech
Eventually the concept calls for a structure perhaps as large as 5-6 kilometers across. Don’t worry — it would be far enough out from Earth that you wouldn’t see a giant hexagon blocking out the stars. Power would be sent to receivers on the surface using directed, steerable microwave transmission. A few of these in orbit could beam power to any location on the planet full time.
Of course that is the vision, which is many, many years out if it is to take place at all. But don’t make the mistake of thinking of this as having that single ambitious, one might even say grandiose, goal. The pursuit of this idea has produced advances in solar cells, flexible space-based structures and wireless power transfer, each of which can be applied in other areas. The vision may be the stuff of science fiction, but the science is progressing in a very grounded way.
For his part, Bren seems to be happy just to advance the ball on what he considers an important task that might not otherwise have been attempted at all.
“I have been a student researching the possible applications of space-based solar energy for many years,” he told Caltech. “My interest in supporting the world-class scientists at Caltech is driven by my belief in harnessing the natural power of the sun for the benefit of everyone.”
We’ll check back with the SSPP ahead of launch.
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These hyper-efficient solar panels could actually live on your roof soon
The clean energy boffins in their labs are always upping the theoretical limit on how much power you can get out of sunshine, but us plebes actually installing solar cells are stuck with years-old tech that’s not half as good as what they’re seeing. This new design from Insolight could be the one that changes all that.
Insolight is a spinoff from the École Polytechnique Fédérale de Lausanne, where they’ve been working on this new approach for a few years — and it’s almost ready to hit your roof.
Usually solar cells collect sunlight on their entire surface, converting it to electricity at perhaps 15-19 percent efficiency — meaning about 85 percent of the energy is lost in the process. There are more efficient cells out there, but they’re generally expensive and special-purpose, or use some exotic material.
One place people tend to spare no expense, however, is in space. Solar cells on many satellites are more efficient but, predictably, not cheap. But that’s not a problem if you only use just a tiny amount of them and concentrate the sunlight on those; that’s the Insolight insight.
Small but very high-efficiency cells are laid down on a grid, and above that is placed a honeycomb-like lens array that takes light and bends it into a narrow beam concentrated only on the tiny cells. As the sun moves, the cell layer moves ever so slightly, keeping the beams on target. They’ve achieved as high as 37 percent efficiency in tests, and 30 percent in consumer-oriented designs. That means half again or twice the power from the same area as ordinary panels.
Certainly this adds a layer or two of complexity to the current mass-manufactured arrays that are “good enough” but far from state of the art. But the resulting panels aren’t much different in size or shape, and don’t require special placement or hardware, such as a concentrator or special platform. And a recently completed pilot test on an EPFL roof was passed with flying colors.
“Our panels were hooked up to the grid and monitored continually. They kept working without a hitch through heat waves, storms and winter weather,” said Mathiu Ackermann, the company’s CTO, in an EPFL news release. “This hybrid approach is particularly effective when it’s cloudy and the sunlight is less concentrated, since it can keep generating power even under diffuse light rays.”
The company is now in talks with solar panel manufacturers, whom they are no doubt trying to convince that it’s not that hard to integrate this tech with their existing manufacturing lines — “a few additional steps during the assembly stage,” said Ackermann. Expect Insolight panels to hit the market in 2022 — yeah, it’s still a ways off, but maybe by then we’ll all have electric cars too and this will seem like an even better deal.
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Aurora Solar’s computer-generated installation maps pull in a $20M Series A
Solar installations are becoming a no-brainer for anyone with a roof in much of the country. But getting an estimate on how much it would cost and how much juice it would generate can be complicated and time-consuming. Aurora Solar has made an automated process for doing this, and attracted $20 million in funding as a result.
A big part of the uncertainty anyone has about getting solar installed is the upfront cost and return on investment. An on-site visit may cost hundreds, or thousands for a commercial property, or that cost may be rolled up into the overall charge. But why send someone out when all the data you need can be acquired in bulk from the air?
Aurora uses lidar data for this — but not the kind of lidar where you have to fly a drone with the instrument over the house. That would hardly be less expensive and time-consuming than a normal visit. Instead they use lidar collected by small aircraft making low-altitude passes over the city.
The resulting data (you can see it above) produces detailed 3D models of the terrain and all the buildings on it; the exact size and slope of a roof can be determined with high precision. It’s actually similar in a way to how archaeologists used it to map out an ancient Mayan metropolis.
There are some programs and services out there that do virtual site visits, but many just estimate your roof area and orientation by looking at satellite imagery. That’s good for a basic estimate, but Aurora uses multiple sources of data to create a detailed 3D map of your roof, and it’s proud of its results.
“From the get-go, we have been very ambitious about the way we address the problem, probably since we faced the same issues our clients face ourselves,” said co-founder Christopher Hopper in an email to TechCrunch. That would have been in 2012, when he and co-founder Samuel Adeyemo experienced significant friction with a solar install in East Africa. The installation itself was a snap, they found, but the planning and design of the system took months.
“Aurora pioneered the concept of ‘remote site visits,’ which enables solar installers to precisely calculate how many solar panels fit on a property, and how much energy they produce without traveling to the site,” Hopper said. “We have a large dataset of LIDAR data pre-loaded in the application that’s accessible to our users. We estimate that that covers about 2/3 of the US population.”
This and other data lets Aurora create a detailed CAD model of the building in just a few minutes, and generate a basic plan for solar cell placement as well that accounts for slope, exposure, and any shade-producing obstacles like chimneys or trees nearby. (Shade reports are usually done in person, and are necessary to receive certain rebates.)
From there users can go straight into the sales and financing process, even including line diagrams for the electrical system you’ll be building. And theoretically it could all take less than an hour, which is probably how much time you’d spend on the phone trying to get a local solar installer to come out.
The A round was led by Energize Ventures, whose managing director Amy Francetic will be joining the board, with S28 and seed investor Pear also contributing.
Once nice thing about companies relying on data and automation: they scale well. So Aurora won’t need to buy a thousand new trucks to get its next few thousand customers — it needs to hire engineers, sales and support people, which is exactly what it plans to do.
“We expect to expand all of the functions in our organization,” said Hopper. “We are particularly excited about all of the things we can do on the product side and in customer success. And finally, this funding means that we are here to stay. For companies [i.e. Aurora’s clients] that rely on a software provider for their day-to-day operations this is an important factor.”
Adeyemo notes in the press release announcing the funding that “the solar professional” is the “fastest growing occupation in the U.S.” Hopefully making things easier for the customer will keep it that way for a while.
Disclosure: Former TechCruncher Rahul Nihalani now works for Aurora. Rahul’s great, but this does not affect our coverage.
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