End the Ethanol Rip-Off • Hacker News Board

Re: End the Ethanol Rip-Off

#151

Post by lutorm » Wed, Mar 11, 2015, 9:11 PM UTC

modoc wrote: post #118

lutorm wrote: post #28

Earlier quoted context omitted.

"Race gas" is commonly understood to refer to octane number. E85 is 94-96 octane, according to wikipedia, which enables you to run higher compression or higher boost. The fact that it has lower energy density just means you burn more of it, so your tank runs out faster. It has nothing to do with the power you can get out of the engine.

If E85 has ~40% less energy in it per volume/weight, then you'd need to be pushing ~40% MORE fuel in the same timeframe to break even on power, right? So you'd need the octane jump from 91/93 to to 94-96 to allow you to run enough extra boost to burn 40% more fuel per cycle. Assuming your turbo/supercharger can deliver 40% more pressure without a big drop in efficiency. And you need your fuel injectors and fuel pump…

You don't add 40% more fuel/air mixture, you make the mixture 40% richer. Fuel is such a small part of the fuel/air mixture that 40% more fuel volume has virtually no effect on the compression stroke.

Timing out the injectors is an issue if they are marginally sized, and the ECU can throw a fit because it thinks the injector timing can't possibly be as off as the lambda sensor tells it.

On my old VW Passat, you could program an offset into the ECU to account for the latter problem. I test-ran it on up to about E85 without any other changes, and got noticeably less knock retard until the injector time saturated somewhere around E60.

Re: End the Ethanol Rip-Off

#152

Post by eru » Wed, Mar 11, 2015, 10:17 PM UTC

snowwrestler wrote: post #140

eru wrote: post #66

Earlier quoted context omitted.

It's not quite as simple. Oil companies are interested in making money, not in your burning oil. If they could make more money with your burning less oil (eg by raising oil prices high enough without damaging demand too much), they'd go for it. In this case, the conclusion might still hold. But the proper argument has one more step.

You're right but that's not the effect that the RFS has. Ethanol directly supplants oil, without affecting total supply or demand for liquid fuel, so it does not allow oil companies to raise their price per volume. Again: that's why they oppose it.

Actually, it's even worse: if people are forced to consume ethanol with their oil, and ethanol makes the combination a worse product, then demand for oil will drop further than the displacement alone.

Re: End the Ethanol Rip-Off

#153

Post by joshuapants » Thu, Mar 12, 2015, 12:30 AM UTC

IgorPartola wrote: post #143

joshuapants wrote: post #131

Earlier quoted context omitted.

Correct me if I'm wrong, but if for example we only used pure ethanol as fuel, carbon would still be emitted, but it would also be offset by the carbon absorbed by growing the next round of fuel crops. It seems like such a situation would be either carbon-neutral or close to it. Especially if we develop (through GMOs or ordinary selective breeding) crops specifically for fuel purposes to make the whole process more e…

That's not correct. In a pure-ethanol economy, the total emissions will be CO2 from: - Deforestation for the creation of corn fields. This includes the process of cutting down trees (gas powered machines, transport, etc.) and loss of trees that will no longer produce O2/absorb CO2 - Planting - Fertilizers. This one is huge as creation of fertilizers is nasty business and fairly energy intensive. - Harvesting - Transp…

I'm still kind of confused on this. In all the examples of energy expenditure, we assume that the energy comes from ethanol in the first place. The plants aren't magically creating more carbon, so if you grow the same amount as you burn, that carbon should be absorbed back.

That leaves deforestation for planting, which is a problem since human energy use isn't the only source of CO2. But if deforestation is avoided (this is where GMO crops would come in, grow more fuel in a given amount of space) or we implement other methods of CO2 sequestration (impractical now, but perhaps not in the future) we could still minimize that risk.

Re: End the Ethanol Rip-Off

#154

Post by ArkyBeagle » Thu, Mar 12, 2015, 2:00 AM UTC

Inception wrote: post #142

ArkyBeagle wrote: post #111

Earlier quoted context omitted.

It's hard to say what the footprint of cattle farming really is. Each side ( and oh boy are there sides ) cherry picks their own figures. I know that in Texas, the biggest reason people let family land that could be used for cow-farming go is taxation - there are Land Trusts that allow you to keep nominal control of the land while agreeing never to use it productively again, to get a tax abatement. Also, the lyrics t…

>> It's hard to say what the footprint of cattle farming really is. It is hard to say for certain, but we can get a pretty good idea based on the inputs required to raise cattle. Water, grain, antibiotics, petroleum based fuels to plant, harvest and transport the grain, petroleum based fertilizers to aid in growing the grain, and herbicides and pesticides to kill unwanted organisms (I'm sure I missed something). Not…

But I suspect that, dependent on the land in question, those inputs may vary widely. Nothing that can make you a modern living can be done with no footprint. But I am pretty sure just from examples of relatives and friends that this will definitely vary. Does that scale? Probably not well. But people have been ranching - even dryland ranching - since before fossil fuels were a serious consideration. Ever see the "ranches" towards Laredo in South Texas? My goodness, that is some rough country. Every living thing there is somehow armed or very, very fast.

Here is why I say these things - my piano teacher's father in Northeast Oklahoma was one of the ones who reintroduced bison onto his land. Cattle are different from bison, but not that different. There's a Vast ocean of grass from the Rio Grande well into Canada, and four-legged critters eating it, making food is remarkably efficient.

I can indeed point you to the book "Cadillac Desert" which does a rough sketch, with respect to the Central Valley farmers. This doesn't make them bad people. It just means these things are messy.

We call the noodge "eat your vegetables" because it's a cliche. I eat good vegetables with great gusto these days; my taste has matured. But all things in balance.

Re: End the Ethanol Rip-Off

#155

Post by pedalpete » Thu, Mar 12, 2015, 9:56 PM UTC

toomuchtodo wrote: post #144

eastbayjake wrote: post #35

Earlier quoted context omitted.

I'm hopeful that normalized relations with Cuba will be the end of our crazy corn subsidies. If you want to make ethanol, sugarcane is 7x more energy efficient in producing ethanol compared to corn, and you can produce twice as much ethanol from an acre of sugarcane as an acre of corn[1]. And if you want to sweeten food and beverages, the same energy efficiency applies to cane sugar harvesting: you can get more sugar…

Corn subsidies will end when electric vehicles begin to put a dent in gasoline consumption in the US.

I think corn subsidies have a lot to do with food, and corn-ethanol producers are piggybacking on that subsidy rather than driving it.