It's using solar energy as input, where's the fossil fuels?

This development is exciting and hopefully spreads everywhere. Farmers being able to make their own fertilizer (at least on the nitrogen side), is a huge win.

Without commenting on the merits of this technique, composting is as old as the hills and doesn't necessarily involve fossil fuels.

Composting is to atmospheric nitrogen fixing (this type of process) as recycling is to mining.

Before people could pull nitrogen out of the atmosphere, wars were fought over guano deposits, etc.

At this point, the majority of nitrogen in human biomass comes from the Haber-Bosch process.

(I’m not arguing against composting, to be clear!)

Composting has value too -- I'm a fan of permaculture. But as noted elsewhere, this scales well and becomes one tool of many.

Its also doesent scale. Medieval farming for industrial societies gave us the atrocities of WW2 including Lebensraum.

The Industrial Revolution couldn’t have happened without the Agricultural Revolution that preceded and accompanied it, freeing up workers for industry.

In medieval times most of the population were farmers by necessity. In the UK, output per acre tripled and the proportion of the population in farming went from 60% to 20% in 1840. And the UK was still almost entirely self sufficient at this time, food imports only became substantial in the late 1800s.

Similar changes happened across Europe, though timing varied by country with the spread of industrialisation.

https://en.m.wikipedia.org/wiki/British_Agricultural_Revolut...

The biosphere seemed to scale quite a bit before we invented synthetic fertilizers. I don't think it's so much a problem of composting not scaling as much as our supply chains being wasteful and linear.

Again, not commenting on the merits of this technology, I just think it's not correct to say that composting can't scale.

WW2 could not have happened without Haber ammonia .. for explosives.

What?

The Germans pioneered modern fertilizer production in the 1890s-1910s.

Farmers have been able to do this for a very long time, but the process is very inefficient and messy when done at scale. Certainly these are good strides forward though!

This says more about the industry than about solar panels, you could say this about any product. There isn't anything inherently carbon-intensive about solar panel production.

And if you compare the distribution of these solar panels with the distribution of the equivalent amount of nitrogen produced, I bet the panels require a lot less carbon for transportation. Not to mention not relying on a nitrogen producer (Russia), and additional uses for the panels.

True, but the solar panels displace way more fossil fuels than were used to produce them, so their net consumption of fossil fuels is negative.

While that is true, it is misleading. If you can use a fixed quantity of fossil fuels to generate many decades of carbon free energy, the change to the overall lifecycle carbon requirements are very different.

Just like in algorithms, making it an O(1) rather than O(n) solution, even with a large constant factor, can make an enormous difference over time.

Your point is also true. I would contest the notion that mine is misleading, given that the parent asks, "where are the fossil fuels?"

Fair point! I don't think transportation, manufacture, or extraction ultimately require fossil fuels. Most of the energy inputs are fungible between fossil fuel or renewable. I agree with you right now but that is not a permanent role for fossil fuels. I think input processing (redox) and plastics will be the most persistent. But overall non haber-bosch ammonia is going to reduce co2 emissions and should be celebrated.

While in principle I agree fossil fuels aren't required, in practice it is much more difficult to convert transportation, manufacture and extraction than most realize

Also suspect modern agriculture's conviction that the crop is an empty vessel requiring synthetic fertilizer is long overdue for reconsideration. Organic ag can be as productive as industrial ag, at far less energy/materials cost, but it will require much more human effort. While this is a very serious tradeoff to make I would argue it is worthwhile in the long run.