Biofuels are a waste of time

[Zor]

Let's compare two methods of energy: Biofuels and Photovoltaic cells. Both systems are in the end solar power, converting sunlight into energy that we can use for various functions.

To get solar power we make and set up a bunch of these...

...which collects the sun's energy, converts it into electrical energy at 40% efficiency nowadays (and they're improving) which we can send anywhere we need it via cables. Be it to power our computers, lightbulbs, vacuum cleaners, LED bulbs, fridges, fedora factories, electric cars and railways and other such nice things all nice and clean without carbon emissions or any of that unpleasantness.

On the flip-side you got biofuels. The process starts by growing plants who use photosynthesis to make solar power. This process works at 1% to 2% efficiency so basically for every square meter you dedicate to solar panels you'd have to put down 20 square meters of plants. They also require fertilizers and irrigation.

These plants use said solar energy mostly to make cellulose, the polysaccharide that wood is made out of. There is a decent amount of energy in cellulose which you get out by burning it in a fire but doing so is very clunky and inefficient. If you want to make fuel out of a chemical that's more usable you'd best go with sugars, which are much easier to process into fuels. You're best option for this is sugar cane...

...which is full of sugar and grows rapidly. The only problem is that it's firmly a tropical plant with no frost resistance whatsoever and needs a lot of water. In more temperate latitudes the main alternative for biofuels is corn...

...of which only the ear has the sugar content required to make biofuel, which is a small part of the plant. Either way harvest time comes, the sugarcane and corn gets harvested by a combine harvester, put on a truck and trucked off to the biofuel factory. There they get mulched and refined into biofuels. For every one joule of energy spent refining sugar cane into biofuel you get eight joules worth of biofuel. For corn for every joule you spend in refining (after decades of R&D have been put into making the process as efficient as possible) you get 1.5 joules worth of biofuels. This can be used to power internal combustion engines and used in narrow fields as an inferior substitute for gasoline while still creating carbon emissions.

This is leaving aside the fact that we need arible land to grow crops for food to eat.

In short, biofuels are a dead end as far as energy policy goes. They're horribly inefficient, generate pollution and there are an all around better methods for making sunlight into usable energy which exists right now.

Zor

[LaCroix]

Small nitpick - biofuels are only releasing the carbon they consumed while growing. If the energy used in production is also solely generated from biofuels or alternative energy, it is carbon neutral, e.g non-polluting.

The most efficient way would be to use biofuels as an energy storage, by using excess solar power to convert exess corn or other crop (which can be stored and processed at the rate the energy available allows for - it doesn't need to be fresh from the field to be useful) to biofuel.

[Guardsman Bass]

There are a few applications where we don't have batteries with enough energy density to replace liquid fuel. We can definitely do electric cars, but so far we aren't able to build electric passenger jets. You can run the jets off hydrogen, but that requires redesigning the entire plane for it - it's easier just to switch them over to a carbon-neutral biofuel.

[mr friendly guy]

Aren't biofuels as a general rule used to power different things than solar? I mean solar powers hot water systems, household appliances etc. Biofuels are used for cars and jets. Now you could say, lets build more electric cars so that they now compete for powering the same things. Ok, there is still the problem that for now, electric cars rely on lithium of which it is going to be difficult to supply that many cars.

The other thing biofuels can be used for, albeit indirectly is soil purification. That is you use plants to suck up the heavy metal from polluted soil. To get some of your money back, the plants are used to make biofuels.

[Borgholio]

Biofuels are only used because they are generally compatible with the infrastructure set in place in the early 20th century...petroleum powered automobiles and powerplants and such. Due to the power of car and oil lobbies, they'd rather push for biofuel because it lets them continue using their existing tech instead of investing in better battery tech which would cost them money.

[LaCroix]

Biofuels are only used because they are generally compatible with the infrastructure set in place in the early 20th century...petroleum powered automobiles and powerplants and such. Due to the power of car and oil lobbies, they'd rather push for biofuel because it lets them continue using their existing tech instead of investing in better battery tech which would cost them money.

No.
Just... no.

Take one little look at the table of energy densities at wikipedia, and you will realize that we have like 20(Methanol) to 80 times (regular fuels) more energy density in fuels than in lithium batteries. And >200x if you include hydrogen.

It is most likely not possible to achieve similar energy densities to fuels with batteries. They are not at therir optimum, yet, but pretty much a dead end in the long run. It would be more feasible to disregard them, and start using power to create hydrogen from water and use fuel cells to convert it back to electricity. That would allow for high charges at low weight, fast recharge by simply refilling the hydrogen tank, and would not harm the environment.

[Grumman]

The other thing biofuels can be used for, albeit indirectly is soil purification. That is you use plants to suck up the heavy metal from polluted soil. To get some of your money back, the plants are used to make biofuels.

What happens to the heavy metals in that scenario? Are they concentrated in the parts of the plant not used for biofuel and/or extracted during processing?

[mr friendly guy]

The other thing biofuels can be used for, albeit indirectly is soil purification. That is you use plants to suck up the heavy metal from polluted soil. To get some of your money back, the plants are used to make biofuels.

What happens to the heavy metals in that scenario? Are they concentrated in the parts of the plant not used for biofuel and/or extracted during processing?

http://www.abc.net.au/news/2010-10-29/g ... gy/2316830

This article is the one I am referring to. To best answer your questions

1. Heavy metal doesn't volatise according to the article. So if they are burnt it could end up in the car, which brings me to the next point.

2. This particular plant (which actually grows on non arable land, so doesn't compete with food production) is known as napier grass or elephant grass. According to the article the grass takes the heavy metals and accumulates that in "the upper parts of the grass." This plant is used as a biofuel because we can get ethanol from a fermentation process.

Now this article describes how they got ethanol from the "stocks and leaves" of this plant. So presumably we can get away with using only the bottom parts of the plant as the heavy metal accumulates in the top.

Going on, a quick google search shows ethanol base solutions are used to help get rid of heavy metals from waste water, so I guess if we need to we can get rid of the heavy metals from the ethanol, although I am not sure how cost effective it will be. However the idea of using biofuels in my scenario is mainly to decontaminate land first, and the biofuels is just a bonus.

[Zeropoint]

Wow. I mean, holy crap. I had NO idea that compressed hydrogen was THAT far beyond all other chemical fuels. We should definitely get on that!

[Darmalus]

Wow. I mean, holy crap. I had NO idea that compressed hydrogen was THAT far beyond all other chemical fuels. We should definitely get on that!

Don't just look at MJ/kg, look at MJ/L, where hydrogen's performance is rather poor. Great for rockets where mass is king, bad for cars where volume is sharply limited.

[Grumman]

http://www.abc.net.au/news/2010-10-29/g ... gy/2316830

This article is the one I am referring to.

They are clearly aware that this is something they need to keep an eye on, which is reassuring. I just thought it needed to be brought up, since cleaning up lead-contaminated soil isn't so awesome if the cost was bringing back leaded petrol.

[His Divine Shadow]

We're using biofuels successfully in Finland through our vast forests. I mean they're gonna grow regardles what we do about it. The harvested biomass can be used for heating fuel with minimal processing, solving urgent heating issues and making us more self reliant. In a place where sunshine is a rarity half the year or more.

In my county they opened up a new heating facility that runs on wood pulp and it provides district heating for homes and public facilities within several km of it. In Vaasa they're burning trash for heating as well, and putting biological waste in bioreactors to provide biogas for heating and also plans to power public traffic in Vaasa with it.

Biofuels are more than just farming and then turning stuff into ethanol.

[Lord Revan]

my elder brother has been working on using dried up manure for heating/power purposes as well and from what I've heard from him the results have been promising.

[LaCroix]

my elder brother has been working on using dried up manure for heating/power purposes as well and from what I've heard from him the results have been promising.

Yeah, I am thinking of installins such a stove in my home (horse ranch) after the remodeling is done. I certainly have more than enough of that stuff.

[Lord Revan]

my elder brother has been working on using dried up manure for heating/power purposes as well and from what I've heard from him the results have been promising.

Yeah, I am thinking of installins such a stove in my home (horse ranch) after the remodeling is done. I certainly have more than enough of that stuff.

Though my brother is working to do this nationwide not just for himself as he works for one the major power companies here in Finland.

You could say that work my brother is doing is total horseshit

[Me2005]

Let's compare two methods of energy: Biofuels and Photovoltaic cells. Both systems are in the end solar power, converting sunlight into energy that we can use for various functions.

...which collects the sun's energy, converts it into electrical energy at 40% efficiency nowadays (and they're improving)...

Eh, not quite. While the bleeding-edge tech is into the mid 40% range, commercially viable cells (the ones you can get and put on your house or business) continue to hover around 20% efficiency. They'll probably get there someday, but that day is not now. You've also got lifespan issues: PV cells are better than they used to be, but still require replacing every few decades, and it isn't exactly a clean process to make them. No question there's room for improvement all around, however.

Wow. I mean, holy crap. I had NO idea that compressed hydrogen was THAT far beyond all other chemical fuels. We should definitely get on that!

Also relevant:

[aerius]

Take one little look at the table of energy densities at wikipedia, and you will realize that we have like 20(Methanol) to 80 times (regular fuels) more energy density in fuels than in lithium batteries. And >200x if you include hydrogen.

It is most likely not possible to achieve similar energy densities to fuels with batteries. They are not at therir optimum, yet, but pretty much a dead end in the long run.

Actually it's impossible, period, with one exception. All batteries work on a series of redox reactions, we know what the reactions are and we can calculate the maximum theoretical energy density for any given battery. For commercially available lithium ion we're at roughly half the theoretical max, which is totally a dead end. It'll be nice if my laptop ran for 8 hours instead of 4, but it ain't gonna get a plane off the ground.

The one exception is an aluminum-air battery, which in theory can get around the same energy density as hydrocarbon fuels. It basically takes aluminum and turns it back into aluminum ore, and when the charge runs out you plop in a new battery and send the old one out to be recycled back into aluminum. Considering how energy intensive making aluminum is, you might as build a nuke plant and run Fischer–Tropsch to make gasoline or diesel.

[NoXion]

Also relevant:

Isn't this energy density, amazing as it is, offset somewhat by the need to reprocess fuel elements (which costs energy)?

Granted I'm of the opinion that nuclear fission should be part of any sustainable energy solution worth pursuing, but I think that overstating the case is a mistake.

[jwl]

Let's compare two methods of energy: Biofuels and Photovoltaic cells. Both systems are in the end solar power, converting sunlight into energy that we can use for various functions.

...which collects the sun's energy, converts it into electrical energy at 40% efficiency nowadays (and they're improving)...

Eh, not quite. While the bleeding-edge tech is into the mid 40% range, commercially viable cells (the ones you can get and put on your house or business) continue to hover around 20% efficiency. They'll probably get there someday, but that day is not now. You've also got lifespan issues: PV cells are better than they used to be, but still require replacing every few decades, and it isn't exactly a clean process to make them. No question there's room for improvement all around, however.

Wow. I mean, holy crap. I had NO idea that compressed hydrogen was THAT far beyond all other chemical fuels. We should definitely get on that!

Also relevant:

Relevant in the sense that you are suggesting putting a nuclear fission reactor in a car?

[Me2005]

Also relevant:

Isn't this energy density, amazing as it is, offset somewhat by the need to reprocess fuel elements (which costs energy)?

Probably, but I'd expect not so much that it's wiped out even in part. You're talking about an energy density 1.6 million times greater than gasoline. You can spend 99.9% of the energy gained on processing it, you're still netting a return 1,600 times greater than gasoline (and that's not knowing what it costs in energy to get gasoline).

Relevant in the sense that you are suggesting putting a nuclear fission reactor in a car?

Possibly, but more that we're talking energy density: hydrogen being 2.5x the density of gasoline is still ~1/640,000 the density of uranium. If we're reaching for something significantly better than gasoline, which hydrogen may be, uranium is stunningly better than that. So there are higher stars to reach for - 6.3 lbs (1 gallon) of gasoline makes my ~1.5 ton car go ~30 miles. 6.3 lbs of hydrogen could make that 90 miles. 6.3 lbs of uranium could make that 48,000,000 miles, or 240x the longest I'd imagine my car could last, and enough fuel for 3,200 years of daily driving, which is 32x longer than the longest I'd probably live.

I've seen proposals that took less weight in urainum than that and used a car as a mode of transportation and a home-energy source.

Now, how feasible it is to make a reactor that small, I have no clue. I know that NASA makes nuclear batteries, so maybe something like that, but I've heard NASA's have shortish lifespans (~20 years) and don't actually provide much power (w, not Kw).

[madd0ct0r]

My notes in ((brackets))

Let's compare two methods of energy: Biofuels and Photovoltaic cells. B&;oth systems are in the end solar power, converting sunlight into energy that we can use for various functions.

To get solar power we make and set up a bunch of these...
[ig]http://www.exide.com/Media/images/Mantl ... oltaic.jpg[/ img]
...which collects the sun's energy, converts it into electrical energy at 40% ((citation needed -pteferably outside lab)) efficiency nowadays (and they're improving) which we can send anywhere we need it via cables. Be it to power our computers, lightbulbs, vacuum cleaners, LED bulbs, fridges, fedora factories, electric cars and railways and other such nice things all nice and clean without carbon emissions or any of that unpleasantness. ((Area needed is still to be demonstrated. Sunk energy from refining and manufacturing is still to be accounted for. Night time power storage is still to demonstrated in this post))

On the flip-side you got biofuels. The process starts by growing plants who use photosynthesis to make solar power. This process works at 1% to 2% efficiency so basically for every square meter you dedicate to solar panels you'd have to put down 20 square meters of plants. ((You need to look at the different types of photosynthesis. C4 type is more effecient. Most alage are more effeviebt.))They also require fertilizers and irrigation. ((Not accounted for in this thread. Neither have you looked at wet or dry pyrolysis, closed loop algae thermal with ccs or hydrogen injection into sludge digestors ))

These plants use said solar energy mostly to make cellulose, the polysaccharide that wood is made out of. There is a decent amount of energy in cellulose which you get out by burning it in a fire but doing so is very clunky and inefficient ((more efficient then even your claimed 40% for solar plus cracking cellose options are also pretty effeviebtr)) . If you want to make fuel out of a chemical that's more usable you'd best go with sugars, which are much easier to process into fuels. ((Not really unless you are after hugh quality liquid fuels.. This is becomibg a straw man))You're best option for this is sugar cane...
[mg]http://cenblog.org/cleantech-chemistry/ ... 605581.jpg[/i]
...which is full of sugar and grows rapidly. The only problem is that it's firmly a tropical plant with no frost resistance whatsoever and needs a lot of water. In more temperate latitudes the main alternative for biofuels is corn...(( NO. Temperate equivalent is sugar beet. Which you don't mention but is common though out Europe and Asia. Corn is a stupid as funk biofuel, used only in America because of the farm policy))

...of which only the ear has the sugar content required to make biofuel, which is a small part of the plant.((citation needed. I can send you papers of you want. Sugar cane is also a a c4 type plant and the bag case is already digested for energy and fertilizer in Brazil.))@ Either way harvest time comes, the sugarcane and corn gets harvested by a combine harvester, put on a truck and trucked off to the biofuel factory. There they get mulched and refined into biofuels. For every one joule of energy spent refining sugar cane into biofuel you get eight joules worth of biofuel. ((citation needed))For corn for every joule you spend in refining (after decades of R&D have been put into making the process as efficient as possible) you get 1.5 joules worth of biofuels ((Yes. Corn is a shit option. As anyone in this industry knows)). This can be used to power internal combustion engines and used in narrow fields as an inferior substitute for gasoline while still creating carbon emissions. ((Totally unlike solar panel production right?))

This is leaving aside the fact that we need arible land to grow crops for food to eat (( well, there's a bunch of different fuels you've not discussed that don't conflict that in the same way. Willow, lemme minor, agroforestry , Jatropha, and combined cropping like oil seed rape which also suplies cattle fodder which can also be turned into captured energy. Also you need a lot of desert in your country before solar supply doesn't start competing with land used currently for food))

In short, biofuels are a dead end as far as energy policy goes. They're horribly inefficient, generate pollution and there are an all around better methods for making sunlight into usable energy which exists right now. (( unless you need ccs, concentrated liquid fuels, low temperature fuels, winter heating fuel or we run out of lithium before organic solar film tough end up enough for outside deployment ))

Zor

I love solar and biofuels cannot supply the sheer energy we need. That's a fact. But they have their use in a sensible energy policy and they deserve a real write-up not this sloppy number less rubbish.

[Simon_Jester]

Probably, but I'd expect not so much that it's wiped out even in part. You're talking about an energy density 1.6 million times greater than gasoline. You can spend 99.9% of the energy gained on processing it, you're still netting a return 1,600 times greater than gasoline (and that's not knowing what it costs in energy to get gasoline).

The flip side of this is, the estimated world reserves of uranium are on the order of several million tons.

The estimated world reserves of petroleum are in excess of a trillion barrels, or somewhere upwards of a hundred billion tons.

And that's before we count coal and natural gas, or the potentially nigh-limitless reserves of biofuels, or things like ammonia and hydrogen that can be produced using fully sustainable energy.

Nuclear power is a good idea- but it's not a 'forever solution.'

Moreover, as noted, nuclear power being energy-dense is useless for the main purpose we use liquid fuels for in real life: small, compact, high-density power supplies for mobile vehicles. It isn't practical to build a car or airplane powered by a nuclear reactor. There's no point in fixating on the energy yielded by a kilogram of uranium, when we're talking about a car and the reactor infrastructure required to extract the energy from the uranium would weigh twenty times more than the car itself does.

Now, how feasible it is to make a reactor that small, I have no clue. I know that NASA makes nuclear batteries, so maybe something like that, but I've heard NASA's have shortish lifespans (~20 years) and don't actually provide much power (w, not Kw).

"Nuclear batteries" are radioactive thermal generators, which use a totally different mechanism to provide power, in that they are powered by passive radioactive decay of an unstable isotope. They are vastly lighter and more compact than any nuclear reactor could ever be. Moreover, the isotopes they're made of don't occur in nature (they'd have decayed long since). Therefore you have to manufacture them in very energy-inefficient ways.

[Arthur_Tuxedo]

No.
Just... no.

Take one little look at the table of energy densities at wikipedia, and you will realize that we have like 20(Methanol) to 80 times (regular fuels) more energy density in fuels than in lithium batteries. And >200x if you include hydrogen.

It is most likely not possible to achieve similar energy densities to fuels with batteries. They are not at therir optimum, yet, but pretty much a dead end in the long run. It would be more feasible to disregard them, and start using power to create hydrogen from water and use fuel cells to convert it back to electricity. That would allow for high charges at low weight, fast recharge by simply refilling the hydrogen tank, and would not harm the environment.

Energy density is not the be-all end-all of car propulsion. The best efficiency we can achieve with the internal combustion engine is in the new Prius which achieves 40%, with most gas cars closer to 25%. Electric engines are already in the 90% range, which is to say 7x more efficient (10% waste vs 75%). Granted, this still puts gasoline at 10x the effective density, but that only means that electric cars will be a few hundred lbs heavier, which is nothing close to a deal-breaker.

Home charging eliminates 13 wasted hours every year assuming a person fuels up their gas car once per week and it only takes 15 minutes to drive to the station, fuel, and drive back. Electric cars are also much quieter and deliver far greater torque off the line, which causes them to feel subjectively more powerful. Hydrogen cars, OTOH, are far less efficient over the full cycle and retain the disadvantage of gas cars that can't be refueled at home and thus don't start with a full charge every morning.

To compare FCVs to EVs, the upcoming crop of 200-mile electrics like the Chevy Bolt and Tesla Model 3 mean that only people who cannot own a parking space with a plug or who frequently drive long distances will need a vehicle that is refueled at a station. Once EV range is up to 400 miles in the ~2025 timeframe, even those customers might consider one if the price is competitive. I can't see a similar path to mass adoption of hydrogen cars either economically or ecologically since converting energy to make liquid hydrogen and then converting it back to power the car introduces 2 extra layers of efficiency loss compared to EVs and liquid hydrogen isn't something you can just pump out of the ground.

Compared to gas cars, the Prius Two Eco is now at 56 MPG and the most efficient gas cars could hit 65-70 MPG in the next 10 years with refinements in hybrid systems and increased use of turbochargers tuned for efficiency. It probably won't make sense to build a whole new infrastructure of hydrogen fueling stations that won't be any cheaper or better for the environment in order to sell expensive FCV cars that have all the disadvantages of both gas cars and EVs, particularly when you can have all the advantages of both with something like the 2016 Chevy Volt, which spends the vast majority of its miles in EV mode but can still be driven cross-country using the existing refueling infrastructure. Whichever existing tech you compare them to, FCVs lose.

[Borgholio]

It probably won't make sense to build a whole new infrastructure of hydrogen fueling stations that won't be any cheaper or better for the environment in order to sell expensive FCV cars that have all the disadvantages of both gas cars and EVs, particularly when you can have all the advantages of both with something like the 2016 Chevy Volt, which spends the vast majority of its miles in EV mode but can still be driven cross-country using the existing refueling infrastructure. Whichever existing tech you compare them to, FCVs lose.

This is pretty much my stance on it. Despite all the downsides of gasoline, the fueling stations are everywhere. You can't go anywhere in the country without having at least one or two gas stations within range. Electric cars are getting there as well, with charging stations all over (including Tesla Superchargers), and of course the ability to charge up at home or at work. But hydrogen? Here are the numbers I got from a bit of googling.

Number of Gas Stations in the US - 168,000
Number of EV Charging Stations in the US - 12,000 - 32,000 (depending on source)
Number of Tesla Supercharger Stations in the US - 602
Number of Hydrogen filling stations - 21

Yeah...fuel cell vehicles aren't going to be useful for a very long time.

[Grumman]

Electric cars are getting there as well, with charging stations all over (including Tesla Superchargers), and of course the ability to charge up at home or at work.

This summer I was rather surprised to find they'd installed one in my home town. It's only got 2,000 people in it, but it's also got an electric charging station in the central car park.