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Comment by xp84 | Hacker News Reader

Whenever I hear about biofuels, I’m always very skeptical. For instance, our massive boondoggle of planting corn to turn into ethanol for automotive fuel is very provably pointless, since more energy needs to be consumed in the cultivation of the corn than will be extracted from the ethanol.

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One part of shifting from fossil fuels to, well, anything else is that the energy math looks worse because we’ve gotta account for all the stuff that we got for free before by burying the raw materials for a million years.

Realistically, though, transportation fuels have two sets of criteria for viability - the net energy produced, yes, but also then everything that makes a transportation fuel useable: density, transportability, safety, ease of loading, ease of getting the energy out, etc. They’re really closer to a battery than an energy source: how much energy did we put into this system, and how much can we get back out. You want that ratio to be as close to 100% as possible, but the fact that it takes more energy to produce than what you get back doesn’t automatically make it a bad transportation energy source if it has a variety of other useful factors.

Granted that Corn generally is particularly bad for this (I once heard a joke that the only thing corn was especially good for producing was lobbyists), but biofuels generally can still be viable even if the energy net is negative if they meet our other needs.

I could be persuaded if the corn was grown using energy that was free or at least not portable, but given the corn is grown literally using petroleum though (fertilizers, fuel for machinery), can we just skip the pork for Iowa voters and just burn the petroleum as the fuel? We’d come out ahead, including both in terms of basic economic math, and by carbon emissions.

The Brazilian ethanol from sugarcane program is better both economically and ecologically than US ethanol from corn. The program has not been replicated elsewhere in the global south.

There are a few breakthroughs that the industry wants:

(1) biodiesel production products large amounts of glycerine since the biodiesel process basically breaks off the three hydrocarbon chains attached to a triglyceride. If people figure out how to make some valuable from glycerine the industry could grow to a larger scale. (e.g. a big picture book about Brazil's agriculture industry boasts that thanks to biodiesel everybody can afford high-quality soap)

(2) Ethanol from cellulosic biomass is second only to the fast breeder reactor (and maybe pyrolysis) as an energy El Dorado. You can break down cellulose into sugar with enzymes or harsh chemicals. Trouble is the enzymes cost more than the fuel is worth and it's been that way for 100 years

On #1, biodiesel competes directly with food, so I'm not sure it's a good thing to grow the industry into a much larger scale.

There is the idea of growing algae that produce non-edible fats.

(1) Maybe nitrate it and sell it to the arms industry?

It's not really competitive with modern explosives as a shell filling in terms of explosive power, ease of handling, etc.

That seems hard to believe.

Are you thinking of the refining process?

https://www.reuters.com/business/environment/us-corn-based-e...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320919/

https://en.wikipedia.org/wiki/Corn_ethanol#Greenhouse_gas_em...

Ethanol replaced MTBE, which was good (MTBE is terrible comparitively), but now it's turned into a 43 million acre per year ag subsidy program. There is no political will to remove the subsidy, due to the folks who receive these subsidies having outsized political influence, so demand destruction will be a function of EV uptake (destroying overall blended gasoline demand over time). Agrivoltaics would also be a great alternative if you could convince enough folks to buy in.

From the last time the "ethanol is worse than gasoline" story did the rounds, I seem to remember that the entire argument boiled down to a gigantic one-time land use adjustment term that swamped the benefits. What was that about?

Anyone know if gasoline demand in the US is still rising?

https://www.eia.gov/petroleum/weekly/gasoline.php

https://www.reuters.com/business/energy/bumpy-road-ahead-us-...

https://www.reuters.com/business/energy/weak-us-gasoline-dem...

https://wolfstreet.com/2024/03/07/gasoline-demand-has-a-long...

https://electrek.co/2024/03/02/1-in-5-new-car-sales-globally...

https://www.coxautoinc.com/market-insights/q2-2024-ev-sales/

https://www.energy.ca.gov/news/2024-05/zero-emission-vehicle...

The fuel used for turning the soil, planting the seeds, spraying harvesting, drying. The energy used to make the fertilizer. Water and energy to irrigate. Then the refining and transportation of the alchohol.

Corn takes a lot of input energy. I believe that sugarcane is closer to break even as it requires less upkeep.

See https://www.intechopen.com/chapters/84069

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