Here's an even harsher assessment of plant-derived ethanols from Dr. Tad Patzek, chairman of the Department of Petroleum & Geosystems Engineering at The University of Texas at Austin:
Basically, [corn] ethanol is obtained from burning methane, coal, diesel fuel, gasoline, corn kernels, soil and environment. We destroy perhaps as many as 7 units of free energy in the environment and human economy to produce 1 unit of free energy as corn ethanol, and make a few clueless environmentalists happier and a few super rich corporations richer. The story is even worse for switchgrass ethanol.
Almost everything on TheOildrum.com is not a mainstream view, some of the minority views are right many are not.
An ethanol plant has more outputs than ethanol. Distillers Grain is a major output stream, which is a useful lifestock feed.
The paper, which I have read, counts as energy inputs all the energy required to make ALL of the inputs and takes every step possible to make the largest energy input amount possible.
Ethanol isn't the most efficent process, but the tech is being pushed ahead and the end output is a liquid high energy density fuel which is more useful that some of the energy input into the system.
As an energy economist would you mind commenting on Elon Musk's assertion that the best case with a perfect plant for making biofuel, the efficiency per unit of land used is still 2 orders of magnitude less than capturing energy with solar cells?
He also claimed that for most nuclear power plants, if you covered them and their exclusion zones with solar cells, you'd generate more energy than the plant itself generates.
(Both assertions seem pretty strong. Both were made during the interview at Oxford that was put online yesterday.)
Regarding Elon Musk, I think it is irrelevant if you get more energy out of solar panels vs. biofuels as that is simply the wrong question because you’re getting two very different types of energy out of each. Solar produces electric power which needs to be moved across a large capital intensive grid and also has to have supply and demand balance in realtime, solar has problems producing power when it is needed. Biofuels are high density portable energy sources that work with a trillion dollar base of invested infrastructure.
The portability/infrastructure view can be seen by a market based approach.
One MMBTU of natural gas delivered at Henry Hub, sells for $3.50
A Barrel of Brent oil sells for $110 a barrel
6 mmbtu’s of Natural gas has the same energy content of a barrel of Brent, or you could buy the energy content of a barrel of oil for $21 with natural gas. The FORM that a unit of energy comes in matters a lot.
Regarding Elon Musk’s claim on nuclear power plants I think there must be an assumption he’s made that I’m not aware of. On it’s face I don’t believe this is true, there likely is an important assumption missing like perhaps every single inch of the site is covered. Also even if the absolute outputs of energy are the same because solar isn’t going to always deliver a steady planed amount of power output, peaker power plants are going to be needed when days are shady etc. changing the economics.
The FORM of energy matters, Nuclear power plants run for months at full capacity and when they need to be out of service that is planned ahead of time to occur during times of the year when demand is lower. My job at Enron was to know everything about every Nuclear power plant in the country because there was a lot of money to be made in predicting if one wouldn’t be able to produce.
The compressed air storage investment that PG recently made is all about the timing and form of energy, being able to shift those has a LOT of economics value.
PG
Musk's assertion regarding biofuels was correct, but I think it was made within the context of using them as fuel. He didn't discuss many side-products that are generated during the production of biofuels.
The problem with counting "side effect" products is nobody ever takes into account the supply/demand for that product. Sure making enough biofuel for the entire US produces 100 tons of X. But if the worldwide demand for X is 5 tons, then you've now generated 95 tons of waste that needs to be disposed of.
However, the major side product of corn based biofules is distillers grain which is animal feed for Cows/pigs. There is enough demand there to actually consume all of the distillers grain produced.
He also claimed that for most nuclear power plants, if you covered them and their exclusion zones with solar cells, you'd generate more energy than the plant itself generates.
He's talking about corn. Generalizing this to "plant-derived ethanols" is a stretch
But yes, Corn ethanol is not good for a series of reasons. Other plant based ethanols may not suffer from the same problems.
Ok, I read the article, typical "only oil is good" atitude.
And by the way: efficiency with respect to sunlight doesn't matter because sunlight is free. (enough) free * anything -> free (It matters in respect to other processes)
Sunlight is free. But efficiency with respect to sunlight translates to efficiency with respect to land use. And land use is emphatically not free.
According to Elon Musk, even if you assume perfectly ideal biofuel production through photosynthesis (which no existing plant is), the amount of land that you'd need to devote to biofuel production to meet current energy needs is similar to what is currently devoted to human agriculture.
I'm not sure I understand this. Solar power could power the US with a 100 mile square area, and it seems like 'perfectly ideal' biofuel production would be just as efficient. Of course, solar panels are around 30% efficient right now (perhaps more for solar-thermal, etc) while biofuels are at negative efficiency - but that's what science is for.
Why would a perfectly ideal biofuel production be just as efficient? Commercial electric cells are close to 20% efficient. From that form to useful work is typically over 90% efficient.
By contrast from what I'm reading on Wikipedia the reaction that drives photosynthesis has a theoretical max of 25%. But you only get that efficiency at 1/4 of normal sunlight levels during the day (the rest of the light has to be wasted). We're already well below solar. And then you've got to give some of the energy to the plant for growing. Then you lose energy in the chemical reactions that make a biofuel. And the biofuel goes into an engine. Every one of these steps has a maximum theoretical efficiency that is fairly low. (For instance a gasoline car engine's maximum efficiency is in the 25-30% range.)
If I remember correctly, Elon claimed that biofuel production had a theoretical max of about 0.5% of incident sunlight energy being converted in the end to useful work. (We're a long ways away from this maximum in practice today.)
Sunlight is not free. In order to collect it you must use some land, and that incurs the opportunity cost of not doing something else with that land, such as growing plants for food.
That's not what he means. A solar energy harvester with 0.1% efficiency might still be worth it if the costs are low, it doesn't matter that you "wasted" the other 99.9% since it's unlimited.
It does matter when it comes to CO2 fixation though... if you only get 0.1% efficiency in fixing CO2 with biofuel production, but would get 1% with normal forestation, then there is a quantifiable difference.
I assure you that it would be madness to try to grow food in the places where solar cells are most effective.
Try looking for the "Desertec" project.
The main cost of solar cells are the resources you need to built them and the chemical waste that gets produced
In the process.
There are still problems with any plant-based biofuels, but they're problems with scaling, crop rotation, pesticides, and the current state of the art of ag in countries where sugarcane is grown.
But the energy return of sugarcane ethanol is high enough to make it non-silly.
Compared to solar, they're all silly. You live the glow a giant nuclear reactor, so large it is contained only by its own gravity. A .01% yield on the energy incident on earth would power everything we ever need.
A .01% yield on the energy incident on earth would power everything we ever need.
I can never understand why people trot out this sentiment. Humans are a biological species subject to normal ecological principles. One of those principles is that, in the absence of a limiting factor in our environment, we will grow. If energy availability is removed as a limiting factor, we will grow ("gettin' larger in waist and taste") until it is again. Anyone who pretends otherwise has not stepped outside to notice all the millions/billions of people clamouring for food, clean water, jobs, holidays, new computers, clothes, homes, education, etc etc. Imagining that, unlike every time in the past where human societies have chafed against resource limits and hoped that just a little more would fix everything, this time human needs will finally be satisfied, is the oldest fallacy in the book. It's just not how life works.
You live in a valley full of aurochs, horses, and boars, more than any man could eat. Taking just a fraction of these bountiful riches would give us all the food we could ever need.
I'm not sure it's broad ecological principal - humans are not simple animals - however I do think if we had "limitless" energy, we would all start flying around in personal aircraft, terraforming deserts, creating subsea buildings, and doing all sorts of wasteful things - until energy somehow became a problem again. In doing so, we would likely find other ways to disrupt our environment - just because energy is cheap and clean, doesn't mean using it has no effect.
Every time I buy a new laptop, I can't imagine how I'll fill up the drive, but I know I will.
Humans don't eat electricity or oil. Sure, they may be used to increase yields of harvests, but the limitation is still how fast plants grow and how much area they need.
Effectively we do eat oil. We replenish soil fertility with fertilisers made with oil energy, we farm large areas with machines powered by oil, etc. etc. We grow more plants faster, with shorter turn-over times, and use less human effort to do so, thanks to oil. There might be a few intermediaries but the end result is that energy from oil ends up converted into human biomass. I can guarantee you if we had never discovered oil there would be far fewer people, with far slimmer waistlines.
"is that energy from oil ends up converted into human biomass"
No, that's the whole point!
Humans surely cater to farming using oil, and we would be a lot worse without it.
But in the end food came from two sources: energy from the sunlight and CO2 (matter) from the atmosphere. (Well, then we could say we're eating car emissions).
Unless you're converting oil directly into food (let's say carbohydrates), no, all energy from plants comes from solar energy. You could of course have a giant oil powered lamp that produces light and shine that over the crop.
Water? With unlimited ultra cheap energy, there is plenty of sweet water in the oceans.
On the other hand: what is stopping us now from combining salt evaporation ponds with sweet water production in e.g. the coastal regions of the Sahara?
Except for nuclear, geothermal and tidal wave generation (and other lesser used energy sources) all energy in planet Earth is solar, accumulated during different time frames.
Sure, solar is great, except current technology is really bad at using it.
Solar has one really great aspect, it can be installed easily at the point of use. Tranporting power on the grid results in a lot of loss, by being at the point of demand solar gets an instant bump in terms of value.
>A .01% yield on the energy incident on earth would power everything we ever need.
This sounds like the Chinese soda analogy [1] in a different form. The fact that we only need 0.01% doesn't indicate the ease of capturing 0.01% in the form of usable energy.
Guy Kawasaki: "If a company can get just 1% of the people in China to drink its soda, it'll be selling a ton of soda. This is true. At the same time, it glosses over the difficulty of getting 1% of any market to use a particular product".
We destroy perhaps as many as 7 units of free energy in the environment and human economy to produce 1 unit of free energy as corn ethanol
And yet they still make a profit, and it is still highly rational to do so. Because it turns out 1 Joule of liquid hydrocarbons is more valuable than 7 Joules of methane or coal or sunshine.
This is why a tax on carbon is better than subsidies. Then that 7 fossile fuel Joules to 1 biofuel Joule would be a huge loss. Incentivize what you actually want to optimize.
A comment below mentions subsidies - that's certainly part of the answer. In addition, for mobile applications, not all energy sources are equal. Transportability (stability, energy density, etc.) also contribute to liquid hydrocarbon Joules being more valuable than methane, coal or sunshine.
Tangent- we have LPG, and from what I understand it's actually very successful in niche applications. Have we tried liquefied methane gas? We have many more sources of methane than propane.
Generally, it hasn't been very economical to do so, although I wonder what the numbers are now that we've got so much natural gas production in the US.
Comments
Here's an even harsher assessment of plant-derived ethanols from Dr. Tad Patzek, chairman of the Department of Petroleum & Geosystems Engineering at The University of Texas at Austin:
Basically, [corn] ethanol is obtained from burning methane, coal, diesel fuel, gasoline, corn kernels, soil and environment. We destroy perhaps as many as 7 units of free energy in the environment and human economy to produce 1 unit of free energy as corn ethanol, and make a few clueless environmentalists happier and a few super rich corporations richer. The story is even worse for switchgrass ethanol.
(As quoted from http://www.theoildrum.com/node/9619 )
Almost everything on TheOildrum.com is not a mainstream view, some of the minority views are right many are not.
An ethanol plant has more outputs than ethanol. Distillers Grain is a major output stream, which is a useful lifestock feed.
The paper, which I have read, counts as energy inputs all the energy required to make ALL of the inputs and takes every step possible to make the largest energy input amount possible.
Ethanol isn't the most efficent process, but the tech is being pushed ahead and the end output is a liquid high energy density fuel which is more useful that some of the energy input into the system.
And yes, I am energy economist iaee.org
As an energy economist would you mind commenting on Elon Musk's assertion that the best case with a perfect plant for making biofuel, the efficiency per unit of land used is still 2 orders of magnitude less than capturing energy with solar cells?
He also claimed that for most nuclear power plants, if you covered them and their exclusion zones with solar cells, you'd generate more energy than the plant itself generates.
(Both assertions seem pretty strong. Both were made during the interview at Oxford that was put online yesterday.)
Regarding Elon Musk, I think it is irrelevant if you get more energy out of solar panels vs. biofuels as that is simply the wrong question because you’re getting two very different types of energy out of each. Solar produces electric power which needs to be moved across a large capital intensive grid and also has to have supply and demand balance in realtime, solar has problems producing power when it is needed. Biofuels are high density portable energy sources that work with a trillion dollar base of invested infrastructure.
The portability/infrastructure view can be seen by a market based approach. One MMBTU of natural gas delivered at Henry Hub, sells for $3.50 A Barrel of Brent oil sells for $110 a barrel 6 mmbtu’s of Natural gas has the same energy content of a barrel of Brent, or you could buy the energy content of a barrel of oil for $21 with natural gas. The FORM that a unit of energy comes in matters a lot.
Regarding Elon Musk’s claim on nuclear power plants I think there must be an assumption he’s made that I’m not aware of. On it’s face I don’t believe this is true, there likely is an important assumption missing like perhaps every single inch of the site is covered. Also even if the absolute outputs of energy are the same because solar isn’t going to always deliver a steady planed amount of power output, peaker power plants are going to be needed when days are shady etc. changing the economics. The FORM of energy matters, Nuclear power plants run for months at full capacity and when they need to be out of service that is planned ahead of time to occur during times of the year when demand is lower. My job at Enron was to know everything about every Nuclear power plant in the country because there was a lot of money to be made in predicting if one wouldn’t be able to produce.
The compressed air storage investment that PG recently made is all about the timing and form of energy, being able to shift those has a LOT of economics value. PG
Musk's assertion regarding biofuels was correct, but I think it was made within the context of using them as fuel. He didn't discuss many side-products that are generated during the production of biofuels.
The problem with counting "side effect" products is nobody ever takes into account the supply/demand for that product. Sure making enough biofuel for the entire US produces 100 tons of X. But if the worldwide demand for X is 5 tons, then you've now generated 95 tons of waste that needs to be disposed of.
Your point is exactly correct.
However, the major side product of corn based biofules is distillers grain which is animal feed for Cows/pigs. There is enough demand there to actually consume all of the distillers grain produced.
He also claimed that for most nuclear power plants, if you covered them and their exclusion zones with solar cells, you'd generate more energy than the plant itself generates.
Not at night.
Or in Finland.
http://en.wikipedia.org/wiki/Nuclear_power_in_Finland
He's talking about corn. Generalizing this to "plant-derived ethanols" is a stretch
But yes, Corn ethanol is not good for a series of reasons. Other plant based ethanols may not suffer from the same problems.
Ok, I read the article, typical "only oil is good" atitude.
And by the way: efficiency with respect to sunlight doesn't matter because sunlight is free. (enough) free * anything -> free (It matters in respect to other processes)
Sunlight is free. But efficiency with respect to sunlight translates to efficiency with respect to land use. And land use is emphatically not free.
According to Elon Musk, even if you assume perfectly ideal biofuel production through photosynthesis (which no existing plant is), the amount of land that you'd need to devote to biofuel production to meet current energy needs is similar to what is currently devoted to human agriculture.
I'm not sure I understand this. Solar power could power the US with a 100 mile square area, and it seems like 'perfectly ideal' biofuel production would be just as efficient. Of course, solar panels are around 30% efficient right now (perhaps more for solar-thermal, etc) while biofuels are at negative efficiency - but that's what science is for.
Why would a perfectly ideal biofuel production be just as efficient? Commercial electric cells are close to 20% efficient. From that form to useful work is typically over 90% efficient.
By contrast from what I'm reading on Wikipedia the reaction that drives photosynthesis has a theoretical max of 25%. But you only get that efficiency at 1/4 of normal sunlight levels during the day (the rest of the light has to be wasted). We're already well below solar. And then you've got to give some of the energy to the plant for growing. Then you lose energy in the chemical reactions that make a biofuel. And the biofuel goes into an engine. Every one of these steps has a maximum theoretical efficiency that is fairly low. (For instance a gasoline car engine's maximum efficiency is in the 25-30% range.)
If I remember correctly, Elon claimed that biofuel production had a theoretical max of about 0.5% of incident sunlight energy being converted in the end to useful work. (We're a long ways away from this maximum in practice today.)
0.5% looks like what you get from corn, really
Soil area to absorption of energy is small, from leaf area to absorption of energy it looks ok.
Efficiency is overrated! Sure, you need soil, etc, but you can have two crops at the same area (or just some kind of grass or other vegetable cover)
And funny how the land usage argument disappears when it's the oil industry that's using arable land http://www.greenpeace.org/canada/en/campaigns/Energy/tarsand...
Sunlight is not free. In order to collect it you must use some land, and that incurs the opportunity cost of not doing something else with that land, such as growing plants for food.
That's not what he means. A solar energy harvester with 0.1% efficiency might still be worth it if the costs are low, it doesn't matter that you "wasted" the other 99.9% since it's unlimited.
It does matter when it comes to CO2 fixation though... if you only get 0.1% efficiency in fixing CO2 with biofuel production, but would get 1% with normal forestation, then there is a quantifiable difference.
But suddenly when it's the oil industry that uses vasts swathes of forest and arable land then it's ok and it's free http://www.greenpeace.org/canada/en/campaigns/Energy/tarsand...
I assure you that it would be madness to try to grow food in the places where solar cells are most effective. Try looking for the "Desertec" project. The main cost of solar cells are the resources you need to built them and the chemical waste that gets produced In the process.
Sent from my phone
He also mentions switchgrass as a problematic source. What other plant sources of ethanol should be considered that would offer a better tradeoff?
Sugarcane.
There are still problems with any plant-based biofuels, but they're problems with scaling, crop rotation, pesticides, and the current state of the art of ag in countries where sugarcane is grown.
But the energy return of sugarcane ethanol is high enough to make it non-silly.
Compared to solar, they're all silly. You live the glow a giant nuclear reactor, so large it is contained only by its own gravity. A .01% yield on the energy incident on earth would power everything we ever need.
A .01% yield on the energy incident on earth would power everything we ever need.
I can never understand why people trot out this sentiment. Humans are a biological species subject to normal ecological principles. One of those principles is that, in the absence of a limiting factor in our environment, we will grow. If energy availability is removed as a limiting factor, we will grow ("gettin' larger in waist and taste") until it is again. Anyone who pretends otherwise has not stepped outside to notice all the millions/billions of people clamouring for food, clean water, jobs, holidays, new computers, clothes, homes, education, etc etc. Imagining that, unlike every time in the past where human societies have chafed against resource limits and hoped that just a little more would fix everything, this time human needs will finally be satisfied, is the oldest fallacy in the book. It's just not how life works.
You live in a valley full of aurochs, horses, and boars, more than any man could eat. Taking just a fraction of these bountiful riches would give us all the food we could ever need.
I'm not sure it's broad ecological principal - humans are not simple animals - however I do think if we had "limitless" energy, we would all start flying around in personal aircraft, terraforming deserts, creating subsea buildings, and doing all sorts of wasteful things - until energy somehow became a problem again. In doing so, we would likely find other ways to disrupt our environment - just because energy is cheap and clean, doesn't mean using it has no effect.
Every time I buy a new laptop, I can't imagine how I'll fill up the drive, but I know I will.
Humans don't eat electricity or oil. Sure, they may be used to increase yields of harvests, but the limitation is still how fast plants grow and how much area they need.
Effectively we do eat oil. We replenish soil fertility with fertilisers made with oil energy, we farm large areas with machines powered by oil, etc. etc. We grow more plants faster, with shorter turn-over times, and use less human effort to do so, thanks to oil. There might be a few intermediaries but the end result is that energy from oil ends up converted into human biomass. I can guarantee you if we had never discovered oil there would be far fewer people, with far slimmer waistlines.
"is that energy from oil ends up converted into human biomass"
No, that's the whole point!
Humans surely cater to farming using oil, and we would be a lot worse without it.
But in the end food came from two sources: energy from the sunlight and CO2 (matter) from the atmosphere. (Well, then we could say we're eating car emissions).
Unless you're converting oil directly into food (let's say carbohydrates), no, all energy from plants comes from solar energy. You could of course have a giant oil powered lamp that produces light and shine that over the crop.
Crowding and water could constrain is before solar energy does.
Water? With unlimited ultra cheap energy, there is plenty of sweet water in the oceans.
On the other hand: what is stopping us now from combining salt evaporation ponds with sweet water production in e.g. the coastal regions of the Sahara?
I think we'd all be better off if energy, rather than space or water, were the limiting factor.
Except for nuclear, geothermal and tidal wave generation (and other lesser used energy sources) all energy in planet Earth is solar, accumulated during different time frames.
Sure, solar is great, except current technology is really bad at using it.
Solar has one really great aspect, it can be installed easily at the point of use. Tranporting power on the grid results in a lot of loss, by being at the point of demand solar gets an instant bump in terms of value.
An obvious distinction is between accumulated past stored solar, which is finite, vs ongoing rate of harvesting new solar.
>A .01% yield on the energy incident on earth would power everything we ever need.
This sounds like the Chinese soda analogy [1] in a different form. The fact that we only need 0.01% doesn't indicate the ease of capturing 0.01% in the form of usable energy.
[1] http://lake.blogs.com/my_weblog/2006/05/the_chinese_sod.html
That site appears broken.
Guy Kawasaki: "If a company can get just 1% of the people in China to drink its soda, it'll be selling a ton of soda. This is true. At the same time, it glosses over the difficulty of getting 1% of any market to use a particular product".
We destroy perhaps as many as 7 units of free energy in the environment and human economy to produce 1 unit of free energy as corn ethanol
And yet they still make a profit, and it is still highly rational to do so. Because it turns out 1 Joule of liquid hydrocarbons is more valuable than 7 Joules of methane or coal or sunshine.
But would they make a profit without government subsidies and set-asides for corn-derived fuels? That's what is at issue.
This is why a tax on carbon is better than subsidies. Then that 7 fossile fuel Joules to 1 biofuel Joule would be a huge loss. Incentivize what you actually want to optimize.
A comment below mentions subsidies - that's certainly part of the answer. In addition, for mobile applications, not all energy sources are equal. Transportability (stability, energy density, etc.) also contribute to liquid hydrocarbon Joules being more valuable than methane, coal or sunshine.
Tangent- we have LPG, and from what I understand it's actually very successful in niche applications. Have we tried liquefied methane gas? We have many more sources of methane than propane.
Natural gas is increasingly being shipped on the oceans:
http://en.m.wikipedia.org/wiki/LNG_carrier
When used as a portable fuel it is usually just compressed.
Methane has a much lower boiling point (-182 C) than propane (-42 C), so liquefying methane (and keeping it liquid) is substantially harder.
Can you not simply roughly double the pressure you store it at? Or is LPG already stored at borderline risky pressures.
Vapor pressure is exponentially related to temperature; you really need to keep it cold.
If you really want to produce a liquid transportation fuel from methane, the usual approach is F-T synthesis:
http://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process
Generally, it hasn't been very economical to do so, although I wonder what the numbers are now that we've got so much natural gas production in the US.