Outside takes on clean energy
Some articles from Orca contributors over the last few months
Austin Vernon on the “Barbell" strategy in clean energy
Austin Vernon observes that there’s an emerging “barbell” strategy in energy technology. To beat fossil energy, it seems like successful new technologies segregate into two categories:
1) High-tech approaches with near-zero operating costs and vastly (>200x) better mass efficiency than coal. Solar PV, Li batteries, and other Cleantech 1.0 success stories are in this category.
2) Technologies that ‘delete everything’ in terms of complexity and expensive materials and via enormous scale just get cheaper than coal. Geology-dependent strategies like pumped hydro or enhanced geothermal are examples.
Projects in between these two extremes are challenging. A lot of aspirants for the ‘dirt cheap’ second category like water electrolysis or large grid scale batteries or most approaches to green steel or cement suffer a cost and complexity creep that pushes them towards the middle of the chart—too expensive to build, and not operationally better by a wide enough margin to be worth building.
There are a lot of other good observations in the post, on the “St Petersburg Paradox” dynamic in VC investing, the story of Nucor, and the pressures that can transform a startup founder from hero to Randian villain.
Sam Faucher on aluminum substituting for steel
There’s a big push out there to make steel electrically (molten oxide electrolysis, aqueous electrolysis, H2 direct reduction etc). But here Sam shows that at the renewable energy $/kWhr price that makes electro-steel work economically, the world might start switching to aluminum as a structural material. Aluminum is electrified already, comes from a more plentiful ore, has a better strength/weight ratio, and suffers from less corrosion (corrosion of steel costs us >1% of global GDP!)
Currently, Al production emissions are nearly five times those of steel. But if you grant the conditions that would make electro-steel viable (i.e. near-free renewable electrons) and believe Alcoa’s claims regarding the near-term viability of carbon-free anodes, then Al prices (currently ~$2000/t, 2/3 of which is electricity for the carbon-free process) will sink towards the steel price (currently ~$1000/t, mostly ore and process cost).
That sets up the surprising conclusion of Sam’s paper: for the foreseeable future, more decarbonization will happen via green aluminum than via green steel.
So if you believe in a future with cheap green electricity, a better bet than electrifying steel production might be adapting aluminum or other higher-energy materials to a broader range of construction, machinery, and transportation applications.
Sam Faucher on Muhller-Kuhne cement
Sam Faucher describes what might be the only path to decarbonized Portland cement without a green premium: burning sulfur to reduce phosphogypsum to calcium oxide, co-producing sulfuric acid as a co-product. It’s a techno-economically sound idea for decarbonized cement that would also help produce phosphate fertilizer more sustainably.[1]
But it’s almost definitely not a good startup idea. You’d have trouble raising capital—the idea ties the cement and phosphate fertilizer industries together, so you could only target about 5% of world cement demand this way. That’s an addressable market too small for the financial VCs, and a addressable carbon too small for the climate VCs. Even if you did make it through the seed stage, being a coproduct gambit would jam you into a position of codependence on both fertilizer producers and cement majors.
And your leverage over either one would be small. If you sold the fertilizer for captive market prices, your cement clinker wouldn’t be much cheaper than ordinary carbonate-derived cement. So a poor risk-adjusted return without a carbon price. In all—an interesting technical approach, and an interesting case study on why it can be hard to introduce apparently helpful new technologies in heavy industry.
Mahati Chintapalli on thermochemistry versus synthetic biology
A lot of people expect synthetic biology approaches to help us decarbonize the chemical industry.
Mahati Chintapalli looked into this topic, using a chemical complexity lens to explore whether chemistry or biology is the better tool for producing a given compound. Above a chemical complexity index of Cm ~ 60, biology tends to win. Below it, chemistry dominates. Since our chemical economy is overwhelmingly composed of low-complexity materials, Mahati's overall takeaway was that thermochemistry will probably stay more important than synthetic biology for making most simple chemicals.
Mahati's data seems to explain what we see in the startup world. There’s a long list of synbio companies that have raised 9 or 10 figures on the pitch that they’ll replace some commodity fuel or material (low Cm and margin) that have then gotten into trouble and pivoted into therapeutics (high Cm and margin). Codexis, Zymergen, Prolific Machines, Intrexon, Greenlight, Gingko, Amyris, Lygos…..probably others. But I can’t think of a single startup that has been exposed to the realities of the market and pivoted in the opposite direction.
It's true the framing does a lot of work here. If you start with the assumption that there will be a price on carbon, then by some calculations biomass could look cheaper than gH2+CO2 and the economical crossover point could decrease in synbio’s favor. If biodiversity or land use or water use were bottled into an economic constraint, then the crossover point might swing farther to the chemistry side.
Mahati explores this and some other counterintuitive observations in plain language in a note here.
Beating the drum on contrails
I still see contrails as a ‘sincerity test’ of sorts. I don’t need to read the news from COP each year—if I look up in the sky in the evening and see contrails, I’ll know the world still isn’t serious about climate change. Contrails are so visible and so cheap to avoid that if the world won’t pay to remove them, it’s unlikely anyone will shoulder any real cost ….. But that’s only a valid point of view if people know about the opportunity. To that end, Ken Caldeira and I wrote a follow up to our earlier note emphasizing that we see contrails as our best hope for near-term climate impact.
Contrails may be only a few percent of anthropogenic warming, but since they’re a short-horizon thing and so cheap to avoid, they’re the only ‘one neat trick’ that could get us about 20% of the way to Paris targets by 2050[2].
...And synthetic fats
Savor is my favorite project that we’ve launched from Orca. The dream is just so big. Food directly from air and electricity. The land you’d get back from oil-crop monocultures is like discovering a lush new continent. Like 5% more habitable land for planet earth. The prospect of feeding people no matter the location, climate, or geopolitical situation chops off tremendous tail risk for humanity. And the raw scalability of the process—connecting process steps that work at huge scale in industry already—means it will almost certainly self-fund once we can build a first commercial plant.
Footnotes
[1] This is an interesting topic by itself.
The world needs phosphorous: it’s essential for our bones, metabolism and DNA. Plants can't pull enough from the soil, so we have to add it-- phosphates are a third of all fertilizer, without them billions would starve.
Essentially all of the phosphorous that goes into fertilizer (and then into our bodies) is mined using sulfuric acid. And essentially all of that sulfuric acid is produced by burning the waste sulfur byproduct of oil refining.
So how will we get phosphorous in a net-zero world, when we won’t have so much cheap sulfur from fossil sources?
There are other sources of sulfur in the world, but they're less concentrated and would raise prices (metal sulfides, dedicated sulfur mines etc.). And there are other acids you could use to leach superphosphate rock, but they're more expensive (plus the process would be less convenient because they'd produce soluble calcium salts that you'd have to separate).
That leaves one good option: recycling phosphogypsum (the calcium sulfate byproduct of phosphate mining) back to sulfuric acid at or near the phosphate mine. That would make the process of mining phosphates circular in sulfuric acid.
Phosphogypsum stacks at phosphate mines the world over are already giant disposal problems. The material is radioactive, acidic, a nightmare where it's dumped in the ocean, a nightmare when it's left in big piles. And if you could recycle it you wouldn't need to ship in sulfur from oil-producing regions to phosphate producing regions. So you'd think a proposal like Sam's for recycling phosphogypsum back to sulfuric acid and also creating an additional value-added product would be much in demand.
But unfortunately, fossil sulfur is extremely cheap, cruel unit economics dominate commercial decision making at this scale, and getting a fossil-free phosphate supply just doesn't fit in the spreadsheet for now.
[2] This surprisingly large number comes from a line of thought that Marc Shapiro and others have articulated:
Lee et al 2021 says the contrail ERF is 57 mW/m2
Assume traffic growth ~3.6% / year from 2025 to 2050, so 2.4x growth from now until 2050.
Assume contrail ERF scales linearly with traffic, so 2050 contrail ERF = 2.4 x 57 = ~137 mW/m2
Equilibrium response (so ignoring transient earth response time - about 1-2 decades) is about 0.8C per W/m2 (CIMP6, IPCC AR6 - obviously an estimate too)
Temperature response to contrail ERF at 2050 levels => +0.11C
Today we are ~+1.5C over pre-industrial temps.
Paris says we want to limit warming to "well below +2C". So we have +.5C remaining in our budget.
So contrails in 2050 will account for 0.11C / 0.5C (~20%) of our remaining temperature budget in 2050.
(not that anybody thinks we're staying under 2ºC).