The Oil Drum | Global Land Use

61 comments on Global Land Use

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MicroHydro on June 2, 2006 - 7:36am

This is a good place to continue my quantitative analysis of the absurdity of using biofuels - not to save human lives - but to save the 700 million private automobiles that are the dominant lifeform on this planet and other forms of unecessary high energy consumption.

The best case wet tropical environments have a net primary productivity of 9000kcal/year with yielded an estimate of 160m2 to grow a barrel of oil. I was asked for a more realistic case. Well, the best case palm oil plantations are said to produce 7250 litres/hectare/year. (No, I don't know how much fossil fuel fertilizers and chemicals are needed in the process) This is close to a limiting case where almost 3/4ths of the net primary productivity goes into palm oil production. So allowing for a few roads and barracks you could grow replacement for fossil fuels on "only" 15 million km2.

The trouble is that this exceeds 10% of the land area of the planet, and only wet tropical land will grow palm oil. In fact it is nearly double the entire area of Brazil. So only by destroying the entire tropical belt ecosystem (goodbye Amazon, Congo, Borneo) and genocide of the native populations (in excess of the slaves needed to work the palm oil plantations) would it be even in rough theory possible to grow even one crop of biofuels equivalent to fossil fuel use. I don't know what soil fertility of a palm oil plantation is like after years of harvesting this monocrop, but doubt it improves over time.

Rich baby boomers can relax, they should be able to get petrol enough to drive their 200 horsepower cars (think about that, this implies that your car should need 200 times as much land to grow food as a horse does!) until they retire. But please don't delude yourselves that your grandchildren will be able to do the same with biofuels. Here is the future of biofueled personal transportation: bicycle (maybe with small motor assist) for most folks, oxcarts on the farm, and for the rich folks a horse carriage to go into town

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MicroHydro on June 2, 2006 - 7:42am

EDIT 9000kcal/m2/year is best net primary productivity - (I left out the m2)

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Engineer-Poet on June 2, 2006 - 8:02am

It's better than that; we should be able to run plug-in hybrids indefinitely. If we take the billion-ton biomass (per year) claim at face value and postulate that we can get between 50 and 80 gallons of ethanol per ton, that's 50 to 80 billion gallons of ethanol per year. The US currently burns about 200 billion gallons of motor fuel per year; plug-in hybrids appear to be able to cut liquid-fuel needs by as much as 80%, so that plus ethanol from biomass put us in the neighborhood of indefinite sustainability.

However, there is NOTHING we can do if we allowed continued population growth through immigration. And that includes not just transportation, but food production, housing, land preservation and everything else.

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gregorach on June 2, 2006 - 10:07am

But if you harvest biomass at anything like that sort of rate, the ecosystem collapses fairly rapidly. You need to recycle a lot of it in order to preserve soil fertility, and leave lots more of it in place to stop the soil from eroding. Take too much and you end up with the Oklahoma dustbowl, but on a global scale, and with nowhere else to migrate to.

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Engineer-Poet on June 2, 2006 - 8:12pm

We're already harvesting a great deal of that (municipal green waste, etc.) but not using it effectively. Further, a lot of what isn't technically harvested (crop wastes) contributes little or nothing to soil tilth because it rots on the surface and never penetrates.

We have examples of processes which turn waste biomass into charcoal and fuel gas (which could feed Clostridium cultures to make liquid fuel), and we also have existence proofs of long-term sequestration of carbon and enhancement of soil properties by addition of charcoal to soil. We can get energy from biomass, enhance soil fertility and pull carbon out of the atmosphere; they are not mutually exclusive.

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IowaBoy on June 2, 2006 - 4:35pm

Where will you get the additional electricity for your plug-in hybrid? That'a a lot. Coal? only if you're willing to accelerate Global warming and further degrade air and water. Wind? A little. Solar? A little? Nuclear? Better start building pretty soon, because it takes a long time to develop that much additional capacity. We will need to do a lot simply to replace the electricity and space heating we now get from natural gas and space heating from oil.

Don't misunderstand. I am in favor of plug-in hybrids at an indvidual level. (I want one, and I plan to build a home/farm wind-power station.) But it doesn't create any new energy. If we move as much weight as many miles, we'll need a LOT more electricity to do it.

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solarfan on June 2, 2006 - 9:37pm

It doesn't create any new energy but it allows you to do the same thing with a lot less.

Here's a paper that compares the relative "door to door" efficiency of gasoline vs. electricity:

http://www.evadc.org/pwrplnt.pdf

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Engineer-Poet on June 2, 2006 - 9:56pm

Where will you get the additional electricity for your plug-in hybrid? That'a a lot.

Not really. Depending on the efficiency of current vehicles, we might get by with as little as 81 GW of power delivered to the wheels (assuming 15% tank-to-wheels efficiency and no improvements in vehicle energy requirements... which are certainly going to happen if prices stay high). Solar PV through batteries is roughly competitive with gasoline now; cheaper solar (better PV or alternate tech like Stirlings) and better batteries will make it pay to convert. The great thing is that anything which makes more clean electricity helps, no matter what it is.

Annual US gasoline consumption is about 140 billion gallons; if we assume 22 MPG average, that's 3.08 trillion vehicle-miles. If we can drive 80% of that on electricity at 350 Wh/mile average, we'd need 862 billion kWh/year or around 22% of current US electric consumption; call it 98 GW average. If we added wind capacity at 20 GW/year and got 30% capacity factor, we'd add 6 GW/year average from wind. Wind would fill the electric demand from vehicles after about 17 years, which just happens to be the average lifespan of passenger cars in the US.

Note that the available wind power on the US continent is around 1.2 terawatts.

There are some issues which would have to be resolved to make this actually work minute-by-minute, but the broad level details of how much energy is available and so forth lead inevitably to the conclusion that this can be done. You can have your Hummer as long as it runs on Li-ion cells.

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alan on June 3, 2006 - 4:35pm

Where will you get the additional electricity for your plug-in hybrid?

How about starting with the corn current going into ethanol production? One bushel of corn is used to produce 2.6 gallons of ethanol at 77000 BTU per gallon generates about 200000 BTUs. That corn contained ~400000 BTUs. If instead you took the corn to a power plant and used it to generate electricity you could power two plug-in hybrids with the corn used to power one E85 vehicle.

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MicroHydro on June 2, 2006 - 5:11pm

"However, there is NOTHING we can do if we allowed continued population growth through immigration."

Unless one believes in gray aliens from Zeta Reticuli, there is no immigration. The earth is a spherical system which can be considered closed except that it absorbs sunlight and emits infrared. Climate change, peak oil and overpopulation are not easily contained by political barriers.

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GreenEngineer on June 2, 2006 - 5:41pm

Immigration from where? Are these new folks coming from off planet, or something? Or are you seriously proposing that we in American should (or can) preserve our way of life while the rest of the world collapses into chaos?

Peak energy, peak food, peak water: these are global problems. The solutions will be global over the long term, or they won't be solutions at all.

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Engineer-Poet on June 2, 2006 - 8:10pm

Are these new folks coming from off planet, or something?

I'm sure many, including lots of Christians, would say yes. ;-)

They're coming via the same route that we all did: they were born. But we can't force other regions of the world to make the changes to deal with their own overpopulation if we keep taking it off their hands. "Think globally, act locally."

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smekhovo on June 2, 2006 - 10:23pm

The parts of the world which still have high rates of population growth send very few emigrants to the US.

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Engineer-Poet on June 3, 2006 - 12:11am

You mean, Mexico sends fewer people to the US than Sweden?

Excuse me while I roll on the floor laughing.

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Engineer-Poet on June 3, 2006 - 12:15am

You mean, Mexico sends fewer people to the US than Sweden?

Excuse me while I roll on the floor laughing.

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smekhovo on June 3, 2006 - 1:01am

Mexico's rate of population growth is no longer high by world standards. Think of sub-Saharan Africa (except the southern tip), the Middle East (except Lebanon and Israel), Pakistan and the north Indian plain. Those populations are all growing at well over 2% a year, which Mexico no longer is.

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paperhead on June 2, 2006 - 9:41am

Biodiesel from algae is 10 times better than this per area. You can use seawater on non-arable land like desert. Check into it at http://www.unh.edu/p2/biodiesel/article_alge.html
This could save the day if we get our rears in gear.

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Nate Hagens on June 2, 2006 - 1:50pm

This could save the day if we get our rears in gear.

Several thoughts:

This has not been done on anything but a very small scale
When we talk about an EROI (Energy Return on Investment), we usually assume its solely a return on Energy invested, but there are many inputs to an energy process: energy, land, water, labor, etc. So the EROEI may be very high for algae to oil but the water and land costs could be enormous making the scalability of it small
Any alternative energy that has a huge energy payoff puts us in the dangerous position of creating more energy and thus more leverage for humans to build, buy, burn and excrete more stuff. We really are running up against environmental constraints, global warming being one of the more prominent but possibly not the greatest threat (food supply, ocean health, toxicity, etc). For a 20-30:1 new energy process to replace oil and gas may seem a boon on the surface, but the externalities of such a boon must be accounted for. This doesnt make the process itself bad (algae to liquid fuel) but what we do with the net energy gain.

As Lee Corso on ESPN says...."Not so fast my friend"..
Someone else famous said "Be careful what you wish for, you might get it"

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trost on June 2, 2006 - 3:01pm

Until they address the problem of turning the desert into salt flats, I'm disinclined to take this proposal seriously. They mention that evaporation is a problem, but don't even hint out how to address it.

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