Bill Gates calls it the 75% Problem.
Greenhouse gas (GHG) emissions from power plants only account for 25% of total, and electrical generation is one source of GHG emissions for which cheap renewable sources are well-suited.
If we don’t radically reduce the remaining 75% of emissions, we could carpet Arizona in wall-to-wall photovoltaic (PV) panels and still not do enough to bring down atmospheric CO2 levels.
Bird’s eye view of Heliogen’s Lancaster, CA test facility.
The trouble is that the remaining three-fourths of emissions are mostly generated through large-scale industrial and agricultural processes that lie at the core of virtually every product we enjoy in our modern lives – steel, glass, concrete, grains, beef, plastics, chemicals…the list goes on and on.
These end products or their essential inputs can only be manufactured by using very high temperatures; with current processes, the only way to generate the heat required is by burning fossil fuels.
This situation leaves us with the mother of all quandaries:
Either we destroy the capacity of the planet to sustain our complex human civilization or we give up the fruits of our complex human civilization to preserve the planet for some schmoes we will never meet.
When faced with this kind of a quandary, the only solution is to think outside the box.
I’ve got it! Why don’t we tie industrial production to a process that can scale really quickly, like Moore’s Law!
In fact, one of the most inventive, entrepreneurial engineers ever to come out of CalTech’s annual crop of incredibly inventive, entrepreneurial engineers – Bill Gross, founder of the first tech incubator, Idealab – has already followed the chain of logic above and come to the same Moore’s Law epiphany. He and the company he founded to operationalize his Eureka moment, Heliogen, is well on the way to implementing a solution that holds enormous potential for mitigating climate change.
If Gross and Heliogen are successful in their ambitious plans, we will all have a chance to continue enjoying the fruits of a modern, industrial life using heat generated solely by renewable resources.
Heliogen’s secret is the application of recent advances in computing power, imaging systems, and artificial intelligence to the field of Concentrated Solar Power (CSP).
A Brief Guide to CSP
Different CSP configurations exist; the type most analogous to Heliogen’s system has the great name of Solar Power Tower.
(See also my 2019 article about another company – GlassPoint Solar – for a look at a “trough” CSP configuration.)
CSP installations do not absorb solar energy like PV panels – instead, they concentrate the sun’s light at a specific point using mirrors. Solar power tower installations are some of the most beautiful and elegant industrial facilities I can imagine, with a meticulously arranged, dish-shaped array of large mirrors, called “heliostats,” that silently reflect the sun’s light at a focal area on the central tower.
Pipes running to the top of the tower and back allow molten salt to flow into an area at the heliostats’ focal points. The concentrated light rays heat the molten salt before moving it into an insulated tank where it can be stored until it needs to be used, for example, to create steam to run a generator.
These CSP installations operate on what engineer’s term an “open-loop control system,” just like your kitchen oven.
Your oven buzzer rings when the time you initially set runs out, whether the oven contains a 14-pound lump of turkey sashimi or if your roast is well on its way to becoming a cubic zirconia. The oven receives no information about the doneness of the dish, so can’t make adjustments to the heat or the cooking time.
Similarly, heliostats in a CSP installation are programmed to move according to precise calculations of where the sun should be in the sky, but do not receive information about how accurately their rays are hitting the tower.
In a world where there were no earthquakes, wind, dust storms, or clouds, an open-loop control system would work just fine. In the world we live in, these kinds of environmental factors mean that heliostats are never positioned exactly right; since they don’t receive feedback from the tower about where their beams are hitting, they can’t compensate for the environmental factors throwing them off.
Because the light from the heliostats is not perfectly concentrated, current CSP installations can only generate temperatures up to around 650 degrees Celsius. This is sufficient for some industrial applications, but for the really polluting activities – manufacturing steel, glass, concrete, and hydrogen – the CSP temperature ceiling is about 400-900 degrees lower than what we need.
Gross realized that by turning a CSP installation’s open-loop control system into a closed-loop one, he could concentrate the sun’s rays much more precisely and, in so doing, generate much higher temperatures.
Heliogen CSP arrays take advantage of:
- The awesome computing power now available at dirt cheap prices in the form of graphical processing units (GPUs) made by companies like NVIDIA
- The ultra-high-resolution imaging systems that are now de rigueur in every smartphone camera in the developed world
- Advances in AI that allow computers to tirelessly make tiny, real-time adjustments to a mechanical process
In other words, Gross has designed Heliogen so that its technology can ride the wave of Moore’s Law rather than being stuck on the plodding development path associated with civil engineering projects.
The efficacy of the Heliogen CSP design is evident from photos of the company’s test installation in Lancaster, California.
The Heliogen heliostats are so precisely focused using the closed-loop control system that the sunlight is concentrated in the small circle on the tower seen in the photo above. The total area at which the reflected sunlight is concentrated in a Heliogen system is about the size of a basketball hoop. Compare that to the focal area of a conventional CSP system, which is about the size of a New York City brownstone.
Heliogen’s phenomenally accurate focusing is made possible by cameras mounted on the tower that monitor the angle at which the heliostats are pointed and by a few powerful but off-the-shelf GPUs that use proprietary software to make real-time adjustments to the position of the heliostats.
Gross told me that the system hit 1,000 degrees Celsius immediately after the team flipped the switch on its first test run and that, after a bit of tweaking, the test installation is now capable of hitting 1,500 degrees Celsius – precisely the range that the most polluting industrial applications require.
While all the articles covering Heliogen I’ve seen so far talk about the potential to carry out cement manufacturing, the thing that excited me when I started researching the company was the potential to split water to manufacture hydrogen.
Cement is heavy and hard to move. Heliogen stores heat energy in stone, another medium that does not immediately bring “portability” to mind. However, hydrogen is the lightest element and is easily transportable – as long as one is careful with it. It can easily be converted into useful, energy dense chemicals as well.
Completely aside from my conversations with Gross, I have been struck by the number of reports that have crossed my desk lately opining about the hydrogen economy of the future. At present, 95% of hydrogen is produced using a process called “steam reformation” which burns copious amounts of fossil fuels. The fact that Heliogen sees a pathway to manufacture essentially unlimited amounts of hydrogen without burning a single fossil fuel molecule is an unalloyed positive for society.
This allows civilization the chance to maintain a high standard of living while getting the Keeling Curve headed in the right direction.
Next Steps for Heliogen
Heliogen’s announcement in late 2019 that it had generated temperatures of 1,000 degrees Celsius using its CSP system garnered a flood of requests from firms around the world. Gross told me that, out of this initial group, he hopes to go live with three major pilot projects within the year. The aggregate revenue potential for Heliogen when each of these pilots are built out totals billions of dollars.
I still have a few technical questions out to Gross and his team and, even though I’m excited about the wonderful potential Heliogen’s technology represents, am also conscious of the immense complexities involved in novel and ambitious engineering projects.
In addition to discussing his stunningly ambitious plans for Heliogen’s future growth, Gross and I spent time talking about the current state of climate change investing and, unsurprisingly, he had some terrific insights. I will be writing up my interview notes and publishing to this column very soon.
It’s clear that Bill Gross knows, as I do, that humanity faces a challenge of the gravest nature and that our only chance is to embark on a paradigm shift with boldness, creativity, and passion.