Industrial heat, vital for making things like glass and concrete, has been lumped in with the “hard problems” of decarbonization.
There's a roadmap to decarbonize the electric grid and ground transportation. The pathway is not so clear for tasks like air travel, long-distance shipping and energy-intensive industrial processes.
Serial entrepreneur Bill Gross decided to tackle the heat problem, not by inventing a new heating technology, but improving one that already exists. Concentrated solar power (CSP) plants reflect sunshine into a small area that reaches high heat; they can produce steam, but have not reached sufficient heat for many high-value industrial applications.
Gross' new company, Heliogen, brought in machine vision to crank things up a notch. By attaching a camera rig to a CSP plant and using visual feedback to fine-tune the angles on a field of mirrors in real time, Heliogen produced temperatures of more than 1,000 degrees Celsius at a demonstration plant in California two weeks ago.
“By achieving more than 1,000 degrees Celsius, we open up a whole range of industrial processes that were previously not easily decarbonizable,” Gross said in an interview Monday. “We really wanted to make that impossible possible.”
That promise won investment from venture capital firm Neotribe and three prominent billionaires: Microsoft founder Bill Gates, AOL founder Steve Case and cancer drug entrepreneur Patrick Soon-Shiong (who also invests in energy storage). With money to grow, Heliogen now must sell its unconventional, clean process to heavy industry.
Software eats solar heat
Traditionally, CSP plants use thousands of mirrored, motorized heliostats to reflect sunlight at a receiver on top of a tower. A lot of engineering work has gone into making those mirrors sturdy and resilient, so they point where they're supposed to point.
But the whole framework governing the tracking could use some improvement, Gross said.
“It’s all open-loop; it's all tracking by prediction of where the sun is and prediction of where the mirror should be,” he said.
As a result, new CSP plants can take around nine months to calibrate, and then have to deal with the elements shifting around them and throwing off the fine-tuning. Slight deviations from perfect aim give the beam a fuzzy focus and diminish the heat it generates.
Heliogen turned to machine vision, a technique for processing vast amounts of visual data very quickly. Another Bill Gross-backed startup, Energy Vault, uses machine vision to automate a six-armed crane as it stacks and lowers giant blocks at high speed to store renewable electricity. For solar thermal, the idea was that cameras on the tower could assess how well aimed the mirrors were and adjust them to perfection.
Success with this concept, however, grapples with a pyrotechnic limitation.
“The problem is the camera would melt because the camera would get to 1000 degrees,” Gross explained.
So the company iterated from there, tweaking the placement and design of the camera rig until, some four dozen versions later, they got one that worked.
Heliogen mounts four cameras around the high-temperature receiver, set back enough to avoid the fiery blast. These cameras track not the sun itself, but the halo of light around the celestial orb. When the cameras see the halo perfectly reflected in each of the mirrors, it means the sun itself is bouncing straight into the receiver. The system assesses the image of the field at a rate of 30 frames per second, following the sun through its daily migration and signaling the mirrors to move if they are out of line.
This technique relies on simple ingredients from the mainstream tech industry: a graphics processing unit of the sort developed for high-end video gaming, and a $1,000 computer that processes data onsite. With those modest means, Heliogen flipped the switch on its self-funded demonstration plant in Lancaster, California, two weeks ago.
“It hit 1,000 degrees Celsius immediately,” Gross said. “We were jumping for joy.”
Gross's energy ideas have a way of seeming too clean and simple to possibly work. The energy industry operates by incrementally optimizing its equipment over years and decades; showing up with a software-inflected breakthrough defies the normal order of business.
Now it's on Heliogen to prove that this successful demonstration can turn into a sustainable business model.
“We really want to be the operating system for solar concentration,” Gross said. “We can go to every existing CSP plant and offer better focus.”
Specifically, Heliogen would be the technology supplier, and partner with engineering, procurement and construction firms to do the building. It already signed up the Parsons Corporation as one such partner.
The deeper question is whether industrial customers are as excited about this as Gross is.
The target market is facilities that burn natural gas, coal or even trash to produce heat for making things like cement, steel and glass. They would need to have factories in dry, sunny regions where the CSP can work best, and space to erect a hot tower with a field of mirrors.
These companies also need to approach intermittency with an open mind. The initial offer would only operate during the eight or so hours a day that the sun shines. Customers are still excited about that, Gross said, noting that even the limited run eliminates 25 to 33 percent of a factory's carbon emissions from heat production. Down the road, Heliogen will equip its plants with ceramic thermal storage to run around the clock.
Given the limitations, the product will need customers with serious drive to reduce greenhouse gas emissions, or it will need to promise substantial cost reductions versus the status quo.
“Our goal is to make our heat cheaper than burning fuel, and then the carbon benefit is just gravy on top,” Gross said. “I’m not relying on the carbon credit to make money.”
Either way, the proof will come if this splashy unveiling leads to firm contracts.
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