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