Live data from Hacker News

U.S. corn-based ethanol worse for the climate than gasoline, study finds

reuters.com

31–40 of 264 posts

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#31
post #15

Earlier quoted context omitted.

More energy in the form of diesel and fossil fuel derived fertilizer went into corn ethanol than you get out in usable fuel

I think that the post was saying that it doesn’t require us to take carbon out from deep within earth and put it into the atmosphere.

It's an irrelevant point. Carbon emissions include logistics and manufacturing operations.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#32
post #22

Gasoline unlocks carbon that was buried underground. If we can avoid that surely its better?

On a first approximation, food production (including corn) is just channeling natural gas into fertilizers through Haber–Bosch.

If the produced food isn't actually being eaten, it's just a highly inefficient energy conversion Rube Goldberg machine.

Now to answer your question, food production unlocks plenty of carbon underground through natural gas.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#35
post #15
post #13

Intuitively this seems wrong. The explanation in the article doesn't seem convincing. Any form of synthetic fuel that doesn't take more carbon out of the Earth should be better, no?

More energy in the form of diesel and fossil fuel derived fertilizer went into corn ethanol than you get out in usable fuel

Compared to the alternative, though? The corn will be grown either way.

It's not hard to see 100 bushel per acre swings in corn yield between growing years even within normal growing parameters, never mind times of crop catastrophes. While everyone hopes for a good year every year, you can't plan for a good year. As such, there will always be times where there is way more corn than we can handle.

Which is what happened in 2006. A lot of corn, having busted the bins and having no home, was left out to rot. Ethanol subsidies were introduced in 2007 to build out more ethanol plants to provide a greater buffer in excess times when the regular corn market can't absorb it all so that we aren't both burning gasoline and letting the corn rot away to nothing.

I don't recall ethanol ever being considered better for the climate in a vacuum. It was only ever thought to be when you take reality into account.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#36
post #19
post #4

I think this has been well established for years. I remember seeing some studies circa 2008 showing that more energy in the form of diesel and fossil fuel derived fertilizer went into corn ethanol than you get out in usable fuel. It has always been an agricultural subsidy.

The ethanol is required as an anti-knock additive. The past alternative was tetraethyllead, which had catastrophic environmental impact. https://en.wikipedia.org/wiki/Tetraethyllead#Antiknock_agent

Octane on its own is an anti-knock additive. And ethanol actually makes your mileage go down because it is less energy dense.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#37
As others mentioned, this is not a new finding. There is a lot of academic and industrial/economic analysis on this subject. Ethanol from corn was never a good idea economically for anyone other than corn farmers. It is also bad environmentally and places additional competitive demand on our food supply (choice and competition between corn going into food or fuel supply).

Similar analysis has been done on other crop feed-stocks (switch grass, etc.) and none of the analysis has shown that crop derived ethanol is a good idea.

I'm not a leading expert on this subject by any means, but I am a PhD chemical engineer and did a lot of research into alternative fuels science and economics about ten years ago. I'm not up on the latest research and analysis but the fundamental thermodynamics and carbon cycles of crop-based ethanol have not changed much in the past ten years or so.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#39
post #6

And it generally gets much worse MPG compared to regular gasoline!

I wonder if this doesn't need to be the case. With the higher octane rating couldn't you in theory run a much more efficient and higher compression engine?

It's a simple case of it's energy density. The energy content of ethanol is about 33% less than pure gasoline. Higher octane doesn't even necessary equate to higher gas mileage. As soon as octane is high enough for your engine tuning, there's no mileage benefit.

Re: U.S. corn-based ethanol worse for the climate than gasoline, study finds

#40
post #19
post #4

I think this has been well established for years. I remember seeing some studies circa 2008 showing that more energy in the form of diesel and fossil fuel derived fertilizer went into corn ethanol than you get out in usable fuel. It has always been an agricultural subsidy.

The ethanol is required as an anti-knock additive. The past alternative was tetraethyllead, which had catastrophic environmental impact. https://en.wikipedia.org/wiki/Tetraethyllead#Antiknock_agent

It’s a hand out to Iowa because of how presidential caucusing occurs. It should go away as gasoline consumption declines and EV uptake ramps.

https://www.reuters.com/article/us-usa-election-iowa-biofuel...

Post reply on HN