[ExI] A proposed replacement for oil

[Keith Henson]

Last night, I was thinking about the SolarSyngas project. It occurred to me
that the entire oil production could be replaced with synthetic fuel from
biomass processed into fuel with renewable energy. We probably would not
replace oil to this extreme, but the potential is there. In the long run,
we will have to get by on renewables and biomass. Some uses of oil, like
gasoline, can be replaced by batteries, while other uses, such as
long-distance aircraft and lubricants, are much harder. Oil also supports
the chemical industry and plastics, but those can start with syngas instead
of oil.

It would be a strange world, harvesting large sections of the world's
forests every year. But it would hold down the frequent huge forest fires
across Siberia and Canada.

ChatGPT said this:

Prompt: Considering human use of oil, how does that compare to biomass
production

It depends on whether you compare *mass*, *energy*, or *carbon*, but in all
cases, the Earth's biosphere is much larger than humanity's oil consumption.
By mass

Current world oil consumption is about *100–105 million barrels/day*.

That is approximately:

   - 16–17 billion liters/day
   - ~14 billion kg/day (oil density ~0.85 kg/L)
   - *About 5 billion metric tons of oil per year*

By comparison, global terrestrial and marine photosynthesis produces on the
order of:

   - *170–200 billion metric tons of dry biomass per year*

So by dry mass,

   - *Annual biomass production is roughly 35–40 times greater than annual
   oil consumption.*

By carbon

Dry biomass is roughly 45–50% carbon.

Thus:

   - Biomass production contains roughly *80–100 billion tons of
   carbon/year.*

Oil is about 85% carbon:

   - 5 billion tons oil/year × 0.85 ≈ *4.3 billion tons of carbon/year.*

So humanity burns carbon in oil at about

   - *4–6% of the carbon fixed annually by photosynthesis.*

Of course, humans also burn coal and natural gas. Total fossil fuel
emissions today are about *10–11 billion tons of carbon/year*, which is
roughly *10–13% of annual global photosynthetic carbon fixation*.
By energy

Oil contains roughly 42 MJ/kg.

Five billion tons therefore contain

   - ≈ *210 exajoules (EJ)*

Global net primary production (NPP) stores approximately

   - *2,000–3,000 EJ/year*

depending on the estimate.

Again, oil use is on the order of *10% of annual biological energy storage*.
Why this matters

This comparison is important for proposals like your municipal solid waste
(MSW) gasification concept.

Photosynthesis captures roughly *120 gigatons of carbon from the atmosphere
each year*, but almost all of it returns to the atmosphere through
respiration, decay, or fire within years or decades. Only a tiny fraction
becomes long-lived organic matter or fossil fuels.

Municipal solid waste represents biomass (plus plastics and other
materials) that has already been harvested and concentrated by human
activity. Recovering its chemical energy as syngas can therefore tap into a
small portion of this enormous annual biological throughput without
requiring additional cropland.

One caveat is that not all biomass is available for energy. Most annual
biomass production:

   - supports ecosystems,
   - decomposes naturally,
   - maintains soil organic matter, and
   - sustains food webs.

The fraction that humans can sustainably harvest is much smaller than total
global production.

For perspective, even if humanity replaced all current oil consumption with
freshly grown biomass, it would require harvesting only a modest fraction
of total annual global biomass production in principle. In practice,
however, land use, nutrient cycling, biodiversity, water availability, and
the diffuse nature of biomass make that substitution far more challenging
than the global totals alone suggest. This is one reason waste-derived
feedstocks, such as MSW, are attractive: the collection and transport
infrastructure already exists, and the material would otherwise require
disposal.
^^^^^
This is a gigantic proposal, but given the economic disruption caused by
the current war with Iran, it might be worth considering.

Please forward if you think of anyone who might be interested.

Keith
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