NASA worked out how to make food out of thin air – and it could feed billions

All their news is about funding, not doing. Nor does the NASA involvement seem to be more than a query.

This sounds like a food-from-methane scheme, prettied up with hype about cracking water and CO2 using "renewable energy" to get the H and C needed. That goes into a fermentation process, like a brewery.

KnipBio was doing something like that, but using methane as the feedstock. Their web site talks about future events in 2018, so they apparently are not doing too well.[1]

Calysta is actually doing it. They bought the technology from Statoil in Norway, which had a plant 15 years ago making about 10,000 tons of animal feed a year from methane. Wasn't profitable. Calysta has a pilot plant in England making animal feed, but it's been running for several years with no scale-up.

NouriTech in the US licensed the process from Calysta and has a plant in Memphis, TN. They're working with Cargill, the big US ag company. The address for the plant shows a big place with railroad sidings, tanks, and trucks, but it's a Cargill high-fructose corn sweetener plant and doesn't match the drawings of the proposed NouriTech plant.

So it's clear that you can do this, but not clear that it makes economic sense.

[1] https://www.knipbio.com/fermentation [2] http://calysta.com/feedkind/ [3] http://nouritech.net/feedkind/

Then the company feeds the concoction to microbes, which in turn create an edible ingredient Solar Foods says is roughly 20 to 25 percent carbohydrates, 5 to 10 percent fat, and 50 percent protein.>>

Sounds like they make sugar out of CO2 and Hydrogen using renewable energy. They feed that sugar to "microbes" - either bacteria or (probably) yeast and get protein.

The first is that while plants are efficient at utilizing solar energy for their growth, we aren’t actually able to eat most of what they produce. Take the wheat plant, for example. It is widely cultivated partly because it is so good at producing calories cheaply. Even so, of the roots, the stalk, the leaves, and the seeds, we only eat part of the seeds. From the seeds, we will strip away at least the chaff and often the germ and the bran as well leaving only the endosperm to actually eat. Even that assumes that one of a dozen possible crop failure cases didn’t kill the entire plant before it could be harvested. The advantage I see to the Solein manufacturing process is that we can turn a far higher percentage of the gathered solar energy into actual consumable calories with far less land.

The second is that a portion of the carbon footprint of modern agriculture is transportation. The distance between where our food is grown and our local grocery store is often thousands of kilometers. If Solein could be produced in the same urban area that it is eaten in, then we can cut that transportation distance to dozens of kilometers or less.

Edit: my suspicion is semi-confirmed by HN user achenatx: their process starts with water electrolysis. That alone means one kg of H₂ requires a minimum of 50 kWh, costing 5 USD (at $0.10/kWh). How much Solient do they produce from 1 kg of H₂?

Notice that they compare Solein favorably to animal products, which are an order of magnitude less efficient than plant products; if you wanted to make substitute meats, you'd be comparing it head-to-head with soy and similar protein sources. Even their "meat substitute" and "cultured meat" are more processed than Solein; you'd need extra processing (i.e. energy input) to make Solein a comparable meat-substitute product.

I'll also wager that their greenhouse gas emissions models assume some sort of renewable energy source; until we're at 100% renewable energy for industrial processes, Solein production would necessitate using non-renewables for the extra energy input it requires. If you want to switch to renewable energy, and Solein ends up using enough industrial energy to require new renewable power plants (which, at global scales, it absolutely would), you'll have to also factor in the energy, material, and greenhouse gas costs of those new plants. And given that biochemical pathways in plants have had hundreds of millions of years to perfect their efficiency, it's really, really hard for me to imagine any industrial process rivaling plant-based sequestration efficiencies.

Also, I don't know about the nutritional or culinary properties of Solein, but they are starting at a tremendous disadvantage compared to natural plant-based foods that our bodies are already acclimated to. You'll need extra energy for the industrial processes creating flavors, vitamins, and other nutrients, as well as the processes required to make this glop palatable (see point above about the comparison to processed meat-substitutes).

If you're worried about CO2 production from farms, you could switch to mostly plant-based diets with non-animal meat-substitutes. Plants literally build their own solar arrays (called "leaves"), so they don't compete with other industrial power uses for still-scant renewable energy. You could use renewables for the industrial processes associated with agriculture. Some stuff, like methane production in rice paddies, is a real greenhouse gas issue, but the general approach of using plants as an integrated solar-powered carbon sequestration and food generation solution is well established and constantly improving through GMOs and farming practices.

> promote a natural fermentation process similar to the one that produces yeast and lactic acid bacteria.

It doesn't _really_ come from thin air! It's the byproduct of tiny little creatures

If we produced more wheat, potatoes, and oats, and used it all for food, we could feed several billion people just from existing US farmland.