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Bruce Steele

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Improving EROEI numbers
« on: March 18, 2014, 02:02:51 AM »
I posed the question earlier whether producing food calories with solar cells and the power it yields should increase the EROEI numbers for solar. The question depends obviously on whether you actually do yield a net calorie gain.
 
My question was specific to gardening with a battery powered tiller powered with solar cells, but it could be expanded to pumping water, producing fertilizer or hauling the produce to market. You could expand it further to cooking or heating water with passive systems and probably much more I haven't considered, but this needs to be taken on in incremental fashion or things will quickly become unmanageable.

I have already started trying to get numbers to quantify K/cal of invested energy with K/cal of produced crops for the battery powered tiller. Since I believe even the calories used by the worker doing the gardening needs to be calculated to get to a real answer for my question, but I would like to start simple.

Anyone who has ever gardened, knows that with a shovel, a hoe and some effort you can overdose on zucchini squash. Producing food calories with very little fossil fuel inputs is not fantasy. So I would propose starting with a limited parameter (garden space) and doing as much work by hand as possible with a solar cell powered battery operated tiller as an assist. Count all inputs very carefully. The labor invested should also be tracked.

Because human time and energy is important, I also think timesaving technics that are not energy sinks should also be included. Paper mulch, scavenged cardboard paths, grafting for vigor, and trellises are all things I have included in my initial efforts and the energy costs of those need inclusion. JimD brought up fences and those would probably be a show stopper, so even fencing needs extra thought, but working to feed bunnies or deer will quickly cut into food calories produced so they do need consideration. For example, a woven willow fence might do the trick. My point is ALL inputs need tracking.

Water is a very real energy input unless you happen to live where rain is always right on time and adequate. Water will likely be reasonably equal to a conventional gardening effort, however, so initially I intend to focus on the solar tiller. To really get good EROEI results will require tricks and those take time to develop, but if I can prove up with tillers first, I think scale issues will be the next hurdle. Equipment will need to last a number of seasons, so amortizing equipment K/cal numbers will be necessary. The longer the equipment lasts, the better the resulting EROEI numbers that can be achieved.

To get a good handle on all this, I would need to run some sort of control, but honestly I don't have the energy for that. I suppose I will need to compete with traditional agriculture and their advantage of vast scale, but that is someone else's homework project. Mine is to show that a solar powered tiller can yield a positive EROEI and at the same time yield more tonnage of crops and calories produced than you can get with a shovel and hoe. Yes tonnage.

How does that sound for starters?         
« Last Edit: March 18, 2014, 11:32:44 AM by Neven »

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Re: Improving EROEI numbers
« Reply #1 on: March 18, 2014, 02:16:43 AM »
Neven,  oops . Not  exactly where I intended to place the new file but it isn't very busy down here and it has served an ancillary cause. Please move it where appropriate as that isn't in my limited skillset.

Could just delete it and recreate it elsewhere? Pretty sure the site lets you delete your posts...

Bruce Steele

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Re: Improving EROEI numbers
« Reply #2 on: March 18, 2014, 02:20:32 AM »
Ccg, will attempt . Here goes

Bruce Steele

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Re: Improving EROEI numbers
« Reply #3 on: March 18, 2014, 02:25:22 AM »
Ccg, I tried and it told me I can't remove the first page of a new file so I will wait for Neven.
Sorry Neven.

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Re: Improving EROEI numbers
« Reply #4 on: March 18, 2014, 02:58:23 AM »
Ccg, I tried and it told me I can't remove the first page of a new file so I will wait for Neven.
Sorry Neven.

Learn something new every day  :D

And for the double win, now it's "forum relevant" too...

Neven

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Re: Improving EROEI numbers
« Reply #5 on: March 18, 2014, 11:47:20 AM »
How does that sound for starters?       

For starters, this sounds great! Count me in, as soon as my wife and I get our garden up and running (should be improving from year to year).

I believe food and energy independence are the most important things to strive for, if we want to have a chance at either solving the current global predicament, or have something ready for when things start to collapse.

The more knowledge (data on EROI, nutritional value, cycles, etc) we can gather about this complex theme, especially with regards to horticulture, the more robust the foundation becomes.

What I do know, is that in all this EROI is crucial. And so I'm looking forward to reading about your endeavours, Bruce.
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Bruce Steele

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Re: Improving EROEI numbers
« Reply #6 on: March 18, 2014, 01:31:01 PM »
Neven, Thanks for fixing my post. Sometimes when I want to go back and fix a spelling error I can't ,so the word is perimeter.
 I would like to re-post this link to "Carts and Tools". There is also a electric wheel hoe that can go as fast as I can walk. There is an lithium ion battery that can perform a very large amount of work before needing a charge. I recommend it over the lead battery. Carts and Tools is working on a new 36 volt tiller also. The motor is the same as the one used in electric scooters. Part of imbedded energy is in the amount of metal used in construction so a small tool like this has much less energy imbedded than a full sized tractor .

 https://cartsandtools.com/product/tillie/

Another picture of tillie working

http://photos4.meetupstatic.com/photos/event/4/6/a/2/highres_343098082.jpeg

I will need to figure out the K/cal energy invested in building one of these things and also the
imbedded energy of an extra 24 volt battery.  The company has shown pictures of a single solar
panel they use to recharge the battery. Tillie is very quiet and you can still hear the songbirds as you work.
 The greenhouse isn't going to go into my energy calculations for starters. Call it a luxury that is focused on market production. I have plenty of land to plant beets, potatoes and high calorie foods
that don't need a greenhouse.
 Simple inventions I believe can make large differences. I wanted one of these before they were invented and I know some people have converted old tractors to electric but then you have to move all that weight around and figure the energy cost of a couple tons of steel. 



Laurent

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Re: Improving EROEI numbers
« Reply #7 on: March 18, 2014, 01:57:51 PM »
For a better EROI I would go for that kind of tool.
http://www.fermedesaintemarthe.com/A-14023-houe-maraichere-1-roue.aspx
with that option that can be useful.
http://www.fermedesaintemarthe.com/A-14039-buttoir.aspx

Can be done DIY for less money...

Go on with your calculations...very interesting.
« Last Edit: March 18, 2014, 03:48:25 PM by Laurent »

JimD

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Re: Improving EROEI numbers
« Reply #8 on: March 18, 2014, 03:34:55 PM »
Bruce

The following link should assist you if your eally want to try and calculate numbers.  There is a chart a ways down that lists embodied energy in a number of common materials.

1 MJ = 239 Kcal to help you with converting to food equivalents

I am sure we can find numbers for a lot of additional materials and entire pieces of machinery.  But one can see how hard it is to get positive EROEI when you start looking at the numbers.

steel for instance (before it is modified into a part for your tiller) = 20.1 MJ per kilo
aluminum is 155 MJ per kilo
I don't think those numbers include mining and transportation of ore, just smelting.

this one really bites

Photovoltaic (PV) Cells Type Energy MJ per m2 Carbon kg CO2 per m2
Monocrystalline (average) 4750 242
Polycrystalline (average) 4070 208
Thin film (average) 1305 67

Cars?!

Quote
Treloar, et al. have estimated the embodied energy in an average automobile in Australia as 0.27 terajoules as one component in an overall analysis of the energy involved in road transportation.[10]

And the average car there is small.
http://en.wikipedia.org/wiki/Embodied_energy
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JimD

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Re: Improving EROEI numbers
« Reply #9 on: March 18, 2014, 03:55:43 PM »
Bruce

Another link which should help you.

5 Variants
5.1 Cradle-to-grave
5.2 Cradle-to-gate
5.3 Cradle-to-cradle or closed loop production
5.4 Gate-to-gate
5.5 Well-to-wheel
5.6 Economic input–output life cycle assessment
5.7 Ecologically based LCA


http://en.wikipedia.org/wiki/Life_cycle_assessment
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wili

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Re: Improving EROEI numbers
« Reply #10 on: March 18, 2014, 04:45:06 PM »
Jim, I often have to remind myself to check dates on wiki data, since they are rarely super current.

I note in particular that the embodied energy stats for PV's is from 2006. Prices have dropped dramatically since then, so I have to assume there has also been at least some improvement in embodied energy/efficiency of production (and especially in EROEI, the really important figure here, it seems to me).

I assume they are still not great, but perhaps not quite what the wiki figures indicate.
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Bruce Steele

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Re: Improving EROEI numbers
« Reply #11 on: March 18, 2014, 05:09:17 PM »
JimD,   So steel just taking a stab at this without pulling tillie apart to weigh it

Steel.  239 times 20.1. =  4803.9 per kilo times 10 =  48039 k/cal for twenty two pounds

Aluminum. 239 times 155 = 37,045 per 2.2 pounds

Monocrystalline. 239 times 4750 = 1,135,250 time 2 m2. = 2,270,500

Total = 2,355,584 K/cal per tillie

The 24 volt battery is going to be a whopper I assume so it needs to be added

One acre potatoes.   = 3,729,040 K/cal per acre

So like I said you need to get several years out of one machine and amortize the embedded energy
costs. You do get a lot of potatoes to eat however.
My question remains. If tillie with solar cells,batteries and metal cost combined equals say
4,000,000 k/cal embedded energy costs and you get five years of use and produce 11,777,920 k/cal
of food you get  an EROEI of 2.94   The solar cells will keep producing energy while not charging your batteries and if we lowball that at an EROEI of 2 then have you improved your actual EROEI by more than double? I really don't think the solar cell EROEI is that low and tillie doesn't weigh as much as the amounts I have used. So it comes down to what the embedded cost of the batteries and charger
amount to and how long everything lasts.
 
And a lot of work. I don't want to start paying for an electric car or the solar cells it would require on potato income just yet. Figuring how many people the project might feed is also of interest but I am
just trying to improve solar EROEI for now.   
« Last Edit: March 18, 2014, 05:28:56 PM by Bruce Steele »

Bruce Steele

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Re: Improving EROEI numbers
« Reply #12 on: March 18, 2014, 05:35:59 PM »
I see I messed up the k/cal for five years of potatoes. It is 18,645,200 which changes the EROEI to
4.66. I will also need to know the numbers for the copper windings in the motor. If you can grow two ,three or four acres you'd be getting somewhere.

JimD

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Re: Improving EROEI numbers
« Reply #13 on: March 18, 2014, 05:51:57 PM »
Bruce

Don't forget you have to determine the energy costs of mining, transportation of the ore, labor for the above, turning the steel into parts, labor for that, assembly of tiller, labor, transportation again, O&M of the tiller (my farm equipment was always needing parts and maintenance), labor for O&M, transportation to get parts and the embedded energy in those parts, etc.

The same kind of process goes on with every part, battery, etc.

And to be a bit anal about it all one has to partially include all the tools used to work on the equipment and the shop and its costs as well.

My guess is that a full analysis is going to come in at about 0.2 EROEI.  But that is just a WAG.  And don't forget that you figured potatoes above which are much more calorie dense than the average vegetable.

Below is a blog post I remembered (surprised me I could do that too!) and dug up.  Comes up with a Medieval EROEI of 1.1 to 1.6.  And that is not true subsistence ag as they were already using some technology. 

http://earlywarn.blogspot.com/2010/03/net-energy-of-pre-industrial.html
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Laurent

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Re: Improving EROEI numbers
« Reply #14 on: March 18, 2014, 06:28:24 PM »
Well, well, pretty numbers. At any moment it does quantify the quantity  of CO2 released in the process, does it ?
After all energy is one thing but that releasing of CO2, is, we now it, a big part of the problem. Can you store the CO2 in the earth, can you quantify that ?

Bruce Steele

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Re: Improving EROEI numbers
« Reply #15 on: March 18, 2014, 08:46:12 PM »
O.K. I am just taking a shot at this and we all have to remember I am the beast of burden here. I think these energy issues can be quantified. I appreciate any help I can get. I went out, fed the critters and used my electric wheel hoe,an electric version of the one Laurent linked this morning. I just got back to the house and I finished 3500 square feet of soil preparation. Less than three hours and an area much larger than most people would attempt to garden for the year.I still have charge in the battery. If Laurent tried to do the same with his manual one he likely couldn't finish 3500' sq. in a whole day.
  I am suppose to be the carbon cycle guy and I can't really make even an educated guess on how much carbon my soil fixes but I doubt I have any net gain in soil carbon at the end of the year. Most of any mulch or cover crop is oxidized by the end of the year I believe ,but that is a separate issue. Since I do put in a cover every year I am probably doing a better job of cutting back on soil carbon loss than most farmers as I see very few using cover crops ,organic certified or not, actually being put in.
  I said in an earlier post I will not make claims until I get better numbers. I was just taking some
preliminary ballpark swings at it this morning. I don't feel like unbolting everything and weighing the
component parts right now. It matters very little if the equipment can't take several years of abuse.
  I know potatoes and beets give much better calorie  returns than lettuce but if you where planting for survival ,potatoes, beets and cabbage would be what I planted. This isn't a project that is going to garner many adherents anyhow so long as the $100,000 tractor is sitting in the barn and  the refrigerated semi-truck is idling in the driveway waiting to run your vegetables a thousand miles to market. This is what you do when your wife and child are hungry and the grocery store is a hollowed out shell. Getting any positive return on the energy you put in becomes a little more serious then.
I am no saint, eccentric maybe and still in pretty good shape for 60. Work helps.   

Neven

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Re: Improving EROEI numbers
« Reply #16 on: March 18, 2014, 09:22:23 PM »
Quote
I was just taking some preliminary ballpark swings at it this morning. I don't feel like unbolting everything and weighing the component parts right now.

How about asking the manufacturer?

And aren't there any EROI estimates for different materials that can be used? Or does Bruce really have to find out where every single component of his Tillie has been manufactured, and then reduce the entire chain, every machine used, every nut and bolt, every mended shoe, every unintended fart, to numerical data?
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Bruce Steele

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Re: Improving EROEI numbers
« Reply #17 on: March 18, 2014, 09:53:39 PM »
Neven, I have both a phone call and an e-mail sent with the component weight questions to the manufacture.
 Everything is relative and as a small farmer I would like to see how to reach the best energy returns.
Sidd produces bio-fuel and the Amish use horses. Seems like something someone would scientifically document and quantify? I have had farm advisors over and I just get funny looks when I broach
the subject.
 p.s. I have finally figured how to get back into overly long posts to correct spelling errors

JimD

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Re: Improving EROEI numbers
« Reply #18 on: March 18, 2014, 11:20:51 PM »
Neven I am pretty certain that no one that manufactures equipment thinks about EROEI numbers other than folks making renewable energy generation equipment as it helps them market their stuff.  But they also have a big incentive to exaggerate and it seems over time that the numbers for that stuff keeps coming down.  John Deere could care less of course.  For basic materials the links I provided have a bunch of those covered.

Bruce I am not trying to depress you.  I just was pointing out stuff that might be relevant.  I tried to do what you are doing myself and was not very satisfied with the results.

If one is just thinking about growing ones own food I think what you are doing is very instructive and useful.  But, as you know from trying to make some money farming, as long as we have dense cheap energy to access it is not possible to compete financially at the small scale with the big scale guys.  One needs hundreds to thousands of acres and lots of big equipment to maximize revenues.  It is a mess.  It won't last.

Laurent some of the links list both energy to manufacturer as well as CO2 emissions generated by the manufacturing.
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TerryM

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Re: Improving EROEI numbers
« Reply #19 on: March 18, 2014, 11:38:01 PM »
This discussion is way over my pay grade but it seems as though some/much of the raw material going into these projects will either be recycled from other uses or will itself be recycled at the end of this usage thus cutting EROI back considerably.
Copper aluminum and iron typically go through many iterations before finally ending as landfill & I'd think that approximating this reuse has to be considered.
The few farms that I've had some familiarity with all seem to have found space for a scrap heap where worn out equipment languished before being repurposed. I can't imagine that once Bruce's tiller has reach the end of it's useful life it will simply be disposed of without thoughts that the one remaining good wheel might find use on a wagon or that the surviving wiring wouldn't find use for repairing broken fencing if it was good for nothing else.

Terry

Bruce Steele

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Re: Improving EROEI numbers
« Reply #20 on: March 19, 2014, 04:35:37 AM »
JimD, Sometimes I get a little down, if that came through it wasn't anything you said. I was looking at my little tiller and thinking about a whole year of labor , a whole year just to maybe break even. You have farmed , the heat, unpredictable weather, unpredictable odds, no money and a whole year to just have the food calories add up the the energy it took to build it. I don't care about any of that much but it does stand as some proxy for our collective predicament. My friends ,my peers are a collection of men with very little in common but tenacity. That is what we respect in each other and I don't let doubt undercut the confidence that a lifetime fighting the Pacific has given me. I will push on but it doesn't mean I am unaware that long odds someday catch up.

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Re: Improving EROEI numbers
« Reply #21 on: March 19, 2014, 03:25:50 PM »
I posed the question earlier whether producing food calories with solar cells and the power it yields should increase the EROEI numbers for solar. The question depends obviously on whether you actually do yield a net calorie gain.
 
My question was specific to gardening with a battery powered tiller powered with solar cells, but it could be expanded to pumping water, producing fertilizer or hauling the produce to market. You could expand it further to cooking or heating water with passive systems and probably much more I haven't considered, but this needs to be taken on in incremental fashion or things will quickly become unmanageable.

Bruce,

If this is the thread/topic content you asked me to review (from another thread/topic)
I believe I'm the wrong person to provide any worthwhile feedback to the above.

Having spent a some years in a lifestyle of - "if you were not in school, church, or the hospital you spent virtually every waking hour (except in the dead of winter) in manual labor toward the pursuit of food production" - for family/relatives, livestock, and some crops/livestock for cash generation, doesn't relate to your solar activity/experimenting, only to your blisters and sunburns.


JimD

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Re: Improving EROEI numbers
« Reply #22 on: March 19, 2014, 04:00:04 PM »
Terry

Your point is very relevant.  This issue is one of various ones related to EROEI which cause the numbers from multiple calculations to be so different from each other when talking about the same technology.  Some doing the analysis do not include all of the factors such as recycling, costs of miming, transportation and a host of other actions.  Very strong proponents of a technology or those who have a financial interest often leave a few items out which results in higher numbers thus skewing the impression of how great the technology is.  Other times some factors are left out because they just can't figure out how to calculate them.  Some factors get guesstimated and really mess things up.

That is why I pointed out over in the renewables thread that Hall had done a rigorous analysis of Spains solar EROEI and found it much lower than was commonly thought.  Hall is one of the few who is really good at this stuff.  I give his numbers a lot of weight because he really does try and include everything.

One of the advantages farmers have is their skills set and general approach to life is oriented towards increasing EROEI just because they keep piles of worn out stuff to cannibalize and figure out how to get every little bit of life out of something (I used to pick up every bolt, washer, nut that I found on the road when out for walks and put them in my parts bins - saved me a  bunch of  money and increased my personal EROEI).  That is not something that industry is oriented towards all that much.
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JimD

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Re: Improving EROEI numbers
« Reply #23 on: March 23, 2014, 08:33:30 PM »
Bruce

Your EROEI number request from the other thread.  I don't remember where I read it (old age) but I went and looked around a bit and found some interesting stuff.

http://earlywarn.blogspot.com/2010/03/net-energy-of-pre-industrial.html

Quote
Over the last century, as the US food system mechanized and as Americans came to prefer more processed foods, the energy return of the US food system fell to the point where, as I articulate in my essay The Energy Cost of Food, it now takes 15-20 Calories of energy inputs to deliver one Calorie of food in the US once waste and spoilage are accounted for. That’s an investment of 15-20 Calories into the system to get 1 Calorie of food, a steeply negative return on investment.

That is an EROEI of 0.07 to 0.05  And then there is this

Quote
What about ‘local foods’? Maybe. I do energy audits on farms as a profession, and have audited both direct and indirect energy use on a number of small farms in the northeast, including certified organic farms. These farms are held high by the local food crowd, but from an energy standpoint their operations are often less efficient than larger-scale conventional operations. Where it takes around 4 Calories of input energy to deliver a Calorie of fruit or vegetables on a typical, large-scale farm, it’s common for smaller farms to require 15 or even 20 Calories of input energy to accomplish the same feat. If local food embraces the small-scale industrial agricultural model used on so many of the farms I audit, the link between food prices and fuel prices would get stronger, not weaker.

Some small-scale operations are more efficient than others though. I recently audited a small, certified organic, pasture-based dairy operation that delivered fluid milk at an energy return of about 1.25, meaning that every 1 Calorie of energy the farmer invests in his operation he gets 1.25 Calories of fluid milk. That’s a small but at least positive return, and likely emerges from the fact his pastures require comparatively little inputs and mechanical maintenance once established. Perhaps vegetable farms that focus on perennial vegetables would fare better than those that grow annual crops? I’m hoping I’m asked to audit a perennial vegetable or fruit operation soon so I can find out.

There is hope for you.  Do you know of anyone who runs a small commercial operation and grows perennials?  I had some (asparagus) and you have the artichoke growers.  But it is a niche market thing I would guess.
 
http://www.resilience.org/stories/2013-09-09/the-energy-return-of-energy-invested-of-US-food-production
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JimD

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Re: Improving EROEI numbers
« Reply #24 on: March 23, 2014, 08:57:29 PM »
Bruce

More goodies.  Same author.

http://www.aisthetica.com/resources/energy-cost-of-food/

I note from this link and the previous one that commercial vegetable production is approximately the same EROEI as pasture raised meat.  So it makes an interesting argument with the vegetarians about their hatred of meat consumption.  I have tried to make the point many times with those who oppose eating meat that it is the CAFO operations which need to end.  Not meat consumption as that is just as good or bad depending on your viewpoint as eating vegetables.  You can raise meat where you cannot raise vegetables. 

We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

Bruce Steele

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Re: Improving EROEI numbers
« Reply #25 on: March 23, 2014, 10:16:40 PM »
JimD, Thank you for the links and information. I will read more carefully later. Maybe I will drop the author a line and see what he has to say about my efforts and offer me some tips on how to improve.
It would really be cool to set some sort of new standard. I am going to go put in some sweat equity right now but thanks again for the help.

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Re: Improving EROEI numbers
« Reply #26 on: March 24, 2014, 02:20:08 AM »
JimD, I sent the whole EROEI page off to  eric@aisthetica.com
We will see what he thinks.

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Re: Improving EROEI numbers
« Reply #27 on: March 24, 2014, 09:24:20 PM »
JimD, I contacted the author of the paper you linked and he got right back to me. Here is his new web page and another good article on food and EROEI.

http://www.howericlives.com/resources/meat-vs-veg-an-energy-perspective/

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Re: Improving EROEI numbers
« Reply #28 on: March 25, 2014, 07:53:02 PM »
1.  In using the embedded energy contained in the equipment, one would have to use the equipment every day, all year (or growing season) with repairs as necessary until the equipment became too expensive to maintain (end of useful life)
1a.  in a tropic environment, with high quality soil (low wear and tear) the equipment would produce 100X more food than a similar crop at 45'N latitude, so the calculation is biased on conditions.
1b.  the type of crop used for the calculation will determine what the energy yield per tilled acre will be.  If you are growing sugar beets you will get a lot more calories than if you are planting lettuce.  Both are considered "food" so the application of this exercise is subjective on whether you are working to produce a "survivor scenario" (potatoes, carrots and cabbage) vs. an energy intensive one (sugar beets)

2.  If you use solar as a source then you will only use a very small portion of the daily solar production capability for the operation of the tiller.  In addition, the tiller will reach End of Useful Life (EUL) long before the panel does, and the panel will continue to produce after that  Therefore the energy investment of the solar panel should be be discounted to only include the portion of total lifetime output used by the tiller.

The variance in 1a and 1b above will yield a variance of over 1000X total energy output.

Therefore, EROEI is not a useful metric when looking at food production, it is only useful if applied to biofuel production (though I guess, kind of a fun analysis to do!)

However, given a set of boundary conditions (i.e. 35'North latitude, typical growing season, potatoes only, per acre)  you can come up with a reasonable EROEI of the food produced.

this is how I would do it.

1.  Solar source:  total energy invested in manufacture/transport times the ratio of total potential output energy divided by total energy used by the tiller during the growing season. (est. 1/200)
2.  equipment:  total energy invested in manufacture transport divided by the percentage of total useful life expended during the growing season (est. 1/40)
3.  total calories produced in the growing season. 

Now, once you found out how many calories of food you produced for the total amount of energy that was invested, assume that the energy for production of solar source and equipment was derived from renewable energy resources.

how does that feel?

« Last Edit: March 25, 2014, 08:10:26 PM by jai mitchell »
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Re: Improving EROEI numbers
« Reply #29 on: March 25, 2014, 09:21:10 PM »
Jai, If I could do even a small percentage of the EROEI you think possible I would exceed the best numbers documented by the energy consultant in earlier posts. Those numbers would also allow many third world farmers a much higher standard of living and obviate the need for coal fired power plants and transmission lines. The proof however is in the pudding as they say and tracking those inputs are important I believe.
 Thank you for your inputs and if you can find literature resources to help me out I would appreciate it. Give me some time to mull through your suggestions. I understand # 1ab&c and yes I understand different crops have different calorie counts and those are fairly easy to calculate. Survival or third world crop choices will differ from farming and economic goals for a Calif. farmer but still K/cal conversions do allow one to compare apples to apples or apples to whatever.
 I am not getting any younger so manufacture utilizing renewables is maybe part of someones future and indeed some solar panel manufactures already offset some of their energy requirements with renewables but for the next ten or fifteen years while my knees hold out I will need to perform under current manufacture constraints. This is a place where the rubber meets the road and transport once the crops leave my farm are a major energy externality but since I sell everything close to home and not a show stopper. It will be interesting to see how this turns out.
 I only get to blog during breaks in the workload, gotta go. 
 

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Re: Improving EROEI numbers
« Reply #30 on: March 25, 2014, 10:12:45 PM »
JimD, Sometimes I get a little down, if that came through it wasn't anything you said. I was looking at my little tiller and thinking about a whole year of labor , a whole year just to maybe break even.

Whether or not a year is bad or not though depends on the lifespan of the item too? If proper standards for durability were mandated, obviously that would help an EROI calculation?

I appreciate this is an aspiration in the modern context, not an actuality - but I'm thinking of the way iron used to be used historically for example. They would build tools to last - potentially across multiple generations - because of the high cost (effort and scarcity) involved in obtaining the metal.

As such they were far more sustainable (and presumably would score much better for EROI on those tools) than we are today, where we can use technology to mindlessly squander billions of tonnes of iron? (where even 1 tonne would've been great wealth to them).

Unfortunately this sort of action is rather hard for an individual to do much about without collective action (it would also no doubt destroy a significant chunk of the economy if goods were actually built to last properly).

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Re: Improving EROEI numbers
« Reply #31 on: March 26, 2014, 04:13:13 AM »
Bruce, I did not give you a specific EROEI for your thought experiment, I just said how I would do it.

A reasonable approximation to the embedded energy in equipment, solar panel production, caloric output of crop and the useful lifetime energy generation potential of the solar panel, and proportion used for one year's cultivation is necessary to determine the final EROEI.

I think that you will find that using solar as a source will significantly reduce the EROEI over conventional methods.  In addition, the UN has determined that organic farming is a significant method of natural carbon sequestration (at least until things really warm up!)

http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pdf (large file)
Trade and Environment Review 2013: Wake up before it is too late - Make Agriculture truly Sustainable now for Food Security in a Changing Climate

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Re: Improving EROEI numbers
« Reply #32 on: March 26, 2014, 05:27:43 AM »
Jai, I was looking at that 1000x difference. Now if someone only was getting .001 EROEi and someone else did 1000x better they would end up at an EROEI of 1. Not bad as far as the numbers I have read.
I do appreciate the links and the one you posted on the " Jim Hansen loves Nuclear " thread was pretty dense . Mostly over my head but some nice side by side charts on various technologies. Since I started out rather critical I do deserve the repartee.
 Not exactly a thought experiment either or it doesn't feel that way at the end of a long day.

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Re: Improving EROEI numbers
« Reply #33 on: March 26, 2014, 07:39:42 AM »
thought experiment was from my perspective   :D

what I meant to say was that if you compared a 1 acre crop of lettuce grown in Ireland and a 1 acre crop of sugar beets grown throughout the year in Hawaii you would get a difference in calorie output by over 1000X.   

that was all I was saying there. 
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Re: Improving EROEI numbers
« Reply #34 on: March 26, 2014, 06:07:29 PM »
thought experiment was from my perspective   :D

what I meant to say was that if you compared a 1 acre crop of lettuce grown in Ireland and a 1 acre crop of sugar beets grown throughout the year in Hawaii you would get a difference in calorie output by over 1000X.   

that was all I was saying there.

I took this one step further - and I'm challenging the assumption (it seemed reasonable at a glance, and then I thought about it - why would the plants have such different abilities to capture energy from conditions that are limits to either plant).

It does look as though sugar beets are more calorific than lettuce in terms of yield per acre, but not perhaps by anywhere near as much as you think - unless you can find a major flaw in my hastily done back of the envelope calculations?

Calculations:

Cal per kg sugar beet (440 calories per kg):
http://www.whfoods.com/genpage.php?tname=foodspice&dbid=49

Cal per kg lettuce (130 calories per kg):
https://www.weightlossresources.co.uk/calories-in-food/salad/Iceberg-Lettuce.htm

Yield per acre, sugar beets:
30 tons per acre
27215kg per acre

Yield per acre, lettuce (340 cwt per acre):
17272 kg per acre
http://www.nass.usda.gov/Statistics_by_State/Arizona/Publications/Bulletin/10bul/pdfs/45-lettuce-spinach-cabbage-aypv.pdf

So calories per acre:
Lettuce - kg yield x calories per kg = 2.2 million calories
Sugar beets - yield x cals/kg = 11.9 million calories


So if I did it right - sugar beets yield ~6x the calories lettuce does.

However that doesn't tell the whole EROI story of course - to do that we need to consider the energy required to plant, harvest, process - etc.

I'm guessing lettuce closes those gaps significantly if consumed immediately, as it doesn't have to be dug out of the ground to harvest and isn't usually heavily processed to make sugar. I assume it's also less nutrient hungry by virtue of lower biomass yield if nothing else but welcome corrections from people who know better.

By the way - yield per acre is just a first step. If you go to your hypothetical "harvest all year round situation" you need to consider how many yields per year you can get. Lettuce matures in 60-90 days - so can I claim 5 harvests per year, or 11 million calories per acre year?

It seems sugar beets is only 90-100 days to maturity, so shall we call that 3.7 harvests per year? That would be 44 million calories per acre year.

The slightly faster maturity time of lettuce narrows it down to a multiplier of around 4x - can we shrink that further with extra handling difficulties? Or is my assumption there wrong? Anyone?

I'll be impressed if you can get anywhere near 1000x...

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Re: Improving EROEI numbers
« Reply #35 on: March 26, 2014, 08:46:23 PM »
Bruce

This 1000X EROEI stuff is just not correct.

The basic embedded energy in the tractor in the example is the same in either case.  If in one environment you completely use the tractor up ten times faster than in another environment because you use the tractor much nearer a 100% duty cycle than the other does not change the embedded energy.  Nor does it have hardly any impact on the running and maintenance costs.  You just end up spreading that embedded energy over a different time frame.

Different crops do result in different calorie densities but it is not that simple.  As a former owner of an organic farming operation I can assure anyone that the mechanical requirements of different crops vary widely and thus this changes the EROEI calculation also.  Another point, which I am sure you know, is that to farm organically (i.e with some attempt at sustainability) one has to rotate their crops so it is impossible to always have a high calorie density crop in place.  In the sum or aggregate of things it is going to average out to almost the same number all the time for a specific farming operation depending on the mix of equipment used and the other farming methods.

A note on soils.  Tropical soils are NOT more fertile than temperate soils.  Just the opposite in fact.  In temperate soils the majority of the nutrients are stored in the soil, while in tropical soils they tend to be more contained in the vegetation.  Thus the well known problem with  clearing rain forest which remains productive for such a short time compared to temperate land converted to agriculture. 

Quote
2.  If you use solar as a source then you will only use a very small portion of the daily solar production capability for the operation of the tiller.  In addition, the tiller will reach End of Useful Life (EUL) long before the panel does, and the panel will continue to produce after that  Therefore the energy investment of the solar panel should be be discounted to only include the portion of total lifetime output used by the tiller.

While it is accurate to spread the embedded energy of an item over whatever it is used for, the assumption in this case is not valid.  One has no idea whether the panel goes first or last or at the same time.  There are far too many intangibles to make this assumption.  How well was the panel manufactured and what is its ideal working lifespan.  Since it was designed to most likely be in  a fixed location up away from the ground what impact does its use on a piece of farming equipment have. It is now exposed to much harsher conditions of vibration, dirt and such.  As any farmer can tell you this environment is harsh and one cannot expect the same life from the equipment as one might expect.  Its lifespan is almost certainly going to be shorter in this use than what it was made for.  The same issue applies to the tiller.  Was it designed for heavy use or for some part time gardener.  I have personally used tillers which were 40 years old and tractors which were made in  1950.  And one seemingly identical piece of equipment dies at half the lifespan of its twin.   What happens on a fishing vessel when you bring on a piece of equipment not designed for that work and environment?

Quote
1.  Solar source:  total energy invested in manufacture/transport times the ratio of total potential output energy divided by total energy used by the tiller during the growing season. (est. 1/200)

Since this appears to be the calculation for the solar panel its estimate is that the embedded energy in the panel is to be allocated at 1/200 per year.  This implies that the panel is good for 200 years?  If memory serves panels are not projected to last more than 1/10th that long in ideal installation conditions.  Best make this estimate based upon the embedded energy cradle to grave including any parts and maintenance and assume 10-15 years life span given the working conditions and then see what the real world delivers.  Capacity factor is not relevant in this calculation.

Quote
2.  equipment:  total energy invested in manufacture transport divided by the percentage of total useful life expended during the growing season (est. 1/40)

If the tiller being discussed was designed for rugged industrial farming use this number is probably a little high.  25 years is the norm though it is indeed the case some would last longer.  If it is a tiller designed for small scale farming use (a BCS tiller for instance) you should be able to get 15 good years out of it.  A tiller designed for home gardeners would most likely be shorter than that.

And then you need to include the many additional embedded energy inputs across the entire range of support issues for the farming operation which are necessary to grow this food as there are a host of them.

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Re: Improving EROEI numbers
« Reply #36 on: March 27, 2014, 12:07:07 AM »
cc

Agreed, I am surprised that sugar beets yield only 3X the caloric content of lettuce.  However the yield at the latitude I was talking about is 240 not 340 so that brings it down by 29.5% on the lettuce side.

Your estimate is correct, from my experience you can produce significant quantities of rootcrops in Hawaii all year around.  Perhaps cassava would be a better comparison crop.

anyways I was just trying to make the point.  there are variables that significantly change the yield.  If you only use your tiller for 1 week out of the year you are hardly getting your money's worth.  EROEI is affected.  I agree with the 4X annual yield in tropical soils.  So the difference is a factor of about 30.7 times more calories per acre-year of beets in Hawaii vs. lettuce in ireland  not 1000!  ok over exaggeration of the acre-year. . .

JimD

the 1/200 is portion of the amount of total energy generated by the solar panel during its entire useful life's output that is utilized by the tiller in a single season.  (assuming only 1 week of operation)  this is a generous assumption it should probably be about 1/600.  This represents the proportion of embedded energy for the manufacture/transport of the panel that counted toward the "energy invested" side of the equation.

The 1/40 is considering a tiller used for 1 week out of the year,  I figure it could easily last 40 years if stored properly and maintained regularly.

these assume only 1 tilling per year.

in any event, as I said before EROEI for food production is a pointless exercise unless you are worrying about peak oil. 

Unless you are worrying about peak oil.

This is simply a process of converting solar energy to biological energy.  Given the nearly unlimited amount of solar energy available, there isn't really a restriction on energy invested and only physical restrictions (water land, material resources, fertility) affect energy returned.
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Re: Improving EROEI numbers
« Reply #37 on: March 27, 2014, 02:15:30 AM »
From Walter Haugen,
Pumpkins 7,670,991 K/cal per acre
Prunes.    7,337,851 K/cal per acre
Apples.    6,365,646.        "
Beets.      5,473,010.        "
celery.     5,240,648.        "
Garlic.      4,590,422.       "
Potatoes.  3,729,040.      "
leeks.       3,309,743.       "
Basil.        2,873,152.      "
cabbage.   2,789,771.       "
Kidney
     Beans.  2,735,482.       "
rhubarb.     2,433,960.      "
Delicatas
 Squash.    1,408,719.  "
Brussel
  Sprouts.   1,369,735.      "
Carrots.      1,059,441.     "
Green Beans 999,232.   "
Purple Beans 943,256.      "
Cauliflower.   861,801.   "
Onions.          334,164.    "
tomatoes.       193,706.   "
spinach.          125,616.   "   

These are crops Walter grows and yields from his growing conditions in Oregon I believe.

My tiller will see dozens and dozens of use days this season as cultivating and weed control are the largest most repeated part of organic horticulture. The repeated nature of cultivation is one of the reasons organic doesn't even match conventional ag in most EROEI calculations. Composting and hauling compost is also energy intense .  One of the questions I have not seen in energy calculations is EROEI for the 1000 pounds of cover crop seeds I use for about five acres. Tilling them in requires horsepower my little tillers will never attain. Utilizing livestock and a fallow rotation may reduce this input but then the livestock need feeding the rest of the year. With enough land one may be able to keep rotating them for a larger portion of the year but again I need to get some simple numbers first and try to make improvements over time.
 Jai, I am worried about peak everything and enjoying what time I have left on this planet. If you follow my " carbon cycle " page you will better understand part of my motivation. These tools and technics may at present be more applicable to third world conditions but if you have spent the time I have on your hands and knees you might better understand my egerness to utilize the small technological improvements that make my workload a little easier. JimD put some time in farming also and I greatly appreciate his opinions and experience . What I am trying to do is forward thinking and maybe the most I can contribute to future generations. Maintaining smallholdings and small farm infrastructure is important in the long haul. It is important for wildlife, soil health, water quality and peace of mind. It is a beautiful thing to see when done correctly. My farm is beautiful. Pointless?

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Re: Improving EROEI numbers
« Reply #38 on: March 27, 2014, 04:15:44 AM »
haha!  no, believe you me I was very involved in a Hawaii biodynamic horticulture/school project!  I am a big fan, really!!!



Have you seen this?

he raises chickens, fish, and vegetables in a solar aquaponic greenhouse to feed himself his wife and their 3 children.  They are almost completely self-contained.

This is a reproducible system.

http://natgeotv.com.au/videos/doomsday-preppers/self-sustaining-suburbia-B172AB98.aspx
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Re: Improving EROEI numbers
« Reply #39 on: March 27, 2014, 10:35:03 AM »
Thanks for that YouTube link, Jai. That would be a good documentary to show my daughter (in German), and one of the speakers actually is doing a lot of work on humus-building just 20 miles from here. I'll have to check that out.
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Re: Improving EROEI numbers
« Reply #40 on: March 27, 2014, 05:04:21 PM »
Bruce

Yes you do have to include the energy inputs to the cover crop just like you imply.  True EROEI measures everything. 

This discussion is not about peak oil though there are clearly similarities and a great amount of the academic work in this field was initiated in relation to those concerns.  But the concept is universally relevant.

Sunlight hitting the surface of the earth is "free" in a sense.  But crude oil or natural gas in the ground is as well in the respect that we do not have to create it either.

Collecting solar energy and using it is not free.  There are hundreds activities required to collect that free energy and use it which are not free and they are part of the EROEI calculation.  Among these activities are the costs of determining what materials are needed for the equipment, the planning for the mines, transportation of ores, smelting of aluminum (far more carbon intensive than steel), the costs of feeding and housing all of the workers involved in all of the activities associated with this equipment, the suppliers to those people have a share in the costs, transportation of the parts to factories which assemble, same for their workers, designing and planning the manufacturing facilities and the materials for them and het building of them, transportation again, the trucks for transportation and the people involved and the factories for the trucks and mines for the steel, tools and machines to assemble the equipment on site, parts and labor over the equipment's life span, transportation to the waste facilities when the equipment is worn our, recycling costs and transportation of the used materials to a factory where they can be put into process again, and hundreds and hundreds more costs.  Many of these costs are highly polluting activities completely separately from carbon emissions and those costs need to be included as well.  We are decades from the point where there will be no fossil fuel sue in that chain of costs mentioned above and that needs to be considered.  I have just scratched the surface here.  When all is said and done those costs bring the 'free' number down to the EROEI number calculated for each solar energy use. 

There is no free lunch.
I have been studying the EROEI issue since about 2005 and have read dozens of reports and analysis.   Some good some not so good.  When one digs down to the rigorous cradle to grave work which is intended to capture all of the actual costs (like the ones Charles Hall performs) the absolute best EROEI number I Have ever seen is for the giant Saudi crude oil fields such as Ghawar (after 50 years still the  biggest single energy producer in the world and where for at least a couple of decades the oil shot out of the ground at over 2000psi) which come in at numbers below 100 EROEI.  Ghawar still skews the EROEI for oil higher than the practical reality.

Re: your numbers for Kcal per acre for different crops.  You should look up numbers for grains for a good comparison also.  A couple of your numbers looked different than I remembered so I looked up a few.  There are wildly different numbers out there.  For instance on potatoes you see numbers as high as 17 million an acre and as low as your 3.7 million.  This points out the need for actual calculations for your soil, fertilizer inputs, irrigation and growing conditions.  I went and dug my John Jevons How to Grow More Vegetables out of the farm books boxes - you own me a beer- (his growing methods are called Bio-Intensive - not the quasi-religious bio-dynamic stuff of Stiener) and he has collected vast amounts of actual growing data over the last 30 years and he grows mostly in California I think so it might be good for you to look at for comparison.  I based my planting densities to a great extent on his numbers when I was farming (thus my plus $30K per acre gross revenue) but if you do this there are increased costs associated with this as well so there is a balance to seek.  But here are a few numbers.  His very high numbers are also derived from very dense plantings (this is an intensive gardening technique which I adapted to small scale farming) and I tried to shoot for the lower numbers in terms of results.

His numbers come in units of Pounds per 100 Sq Ft so the conversion is a pain.  The ranges according to the book are also due to the average temperature while growing and the numbers go down with rising heat (sounds like AGW).

Bush snap beans 30 - 108
broccoli               26-53
cabbage              96-383
carrots                100-400
cauliflower           44-291
cucumbers          158-581
eggplant             54-163
potatoes            100-780
squash/zuch       160-478
squash/winter     50-350
tomatoes            100-418

corn                    11-23
rice                       8-32
wheat                   4-26

Grains are dry of course.

1 acre = 43,560 sq ft so multiply the above number you use by 436 to get pounds per acre.  I will leave the rest to you  :)

A note about Jevons work.  His methods are similar in some ways to permaculture ideas and he has collected  vast amounts of data to back his claims up.  Data is one of the big weaknesses of permaculture advocates in that they do not seem to have taken a scientific bent to prove what they claim.  Jevons has and there is enough similarity between his work and permaculture to get some idea of the productivity of their methods (my estimate is that they are significantly less productive but far more sustainable). 
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Re: Improving EROEI numbers
« Reply #41 on: March 27, 2014, 06:43:11 PM »
JimD, You said the other day that a farmer has to diversify their crops because it is both hard on soil fertility to keep planting in the same spot every year and also because plant pests and pathogen will build up otherwise. Being a market gardener also requires a little foresight into food trends or "It"
crops and that also demands introducing or taking crops out of your line-up. There are enough variables including weather to make farm to farm or season to season comparisons very difficult.
 How long any one piece of equipment will actually last is also unknowable until it breaks or becomes more expensive to repair than to just replace. Even the friability of the soil on any given farm will change the equipment you need or the amount of time and fuel it takes to get a field ready for planting.
 I understand these variables. With all the potential K/cal variability one should be very careful making projections or claims. When starting out trying to maximize EROEI you can pick and choose both crops , growing techniques , and equipment to get the best returns. Knowingly stacking the deck as it were. If you only count a small subset of your entire operation and acreage planted with some educated foreknowledge of likely results you are also kinda cheating but still the lessons learned about how exactly one can achieve very good EROEI on even a sub-set is still both educational and potentially useful. It also is vastly easier to do in the "keep it simple stupid" mindset. But that is exactly what I intend to do. Rationalizing my current operation is totally different from trying to think about what and how I might feed myself and a few friends in a tough spot. So minimizing all large equipment, planting high K/cal per acre crops, utilizing renewables, beneficial use of animals that are hardy and can help like chickens, using perennials that don't need a lot of cultivating, orchards , full utilization of plants grown, minimizing discards, planting with an eye to storage, grains and oil crops, are all free game and likely to benefit high full lifecycle EROEI. Pond culture with pigweed for duck and fish crops and passive energy projects all fall into the same category .
 That is a long list however so I am just going to run tillie with some solar and crops that likely will give me the numbers I want to see. When it comes time to make claims I just need to tell people what and why I did it and provide cautionary warnings about extrapolation.

JimD

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Re: Improving EROEI numbers
« Reply #42 on: March 27, 2014, 08:26:38 PM »
Bruce,

I support what you are doing.  I also made a lot of efforts along the line you are doing and found it extremely hard to quantify to my satisfaction.  It is sobering in light of what it tells one about sustainability and the implications for the future.  You and I could easily feed ourselves and survive (as long as we quit paying taxes I guess), but the folks in New York City have a problem.

I'm going on vacation and will not be around much for a while (I need to rest up from retirement).  Best of luck.
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

sidd

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Re: Improving EROEI numbers
« Reply #43 on: March 28, 2014, 12:30:18 AM »
Speaking of old equipment, lemme just look around the barns
Ford tractor, 30 yrs
Massey-Ferguson comping 45 yrs (neighbours)
4 row corn picker, Deere, 30 yrs
Gehl wagon, 50 yrs (designed to be horse drawn, but we haul it about with whatever is available, its got the load transporter hooks and chains coupled to the wheels)
Hay wagon 80 yrs, still works, also designed to be horse drawn

and .. ta da ... 2 scythes i just saw hanging on the wall in the top level, rusted blades need replacement,
but beautiful balance and handles ... 150 yrs judging by the age of the rest of the junk piled round it (including tools used to build the barns in 1867) That hay wagon might be older than 80 too...

probably lots more if i want to move stuff ... there is a horse drawn tiller somewhere that i swear i saw last year ...

sidd

Eric Garza

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Re: Improving EROEI numbers
« Reply #44 on: March 28, 2014, 08:06:26 PM »
Hi Bruce and others, nice to see this discussion happening. Doing energy LCAs are challenging. Regarding your attempt to estimate the embodied energy of your tiller, a simple way to do it is use estimates of embodied energy per kg finished machinery. For the articles linked above I used 85 MJ/kg of machinery, and applied this figure to all large equipment, including cars, tractors, combines, tractor implements, trailers, etc.

This is, of course, a very rough estimate, but embodied energy of machinery is usually small for an operation because you amortize it over the lifetime of equipment, which is often many years. The big energy inputs are typically liquid fuels (gasoline and diesel) and the embodied energy of consumable inputs like fertilizer, compost, pesticides, etc. These are bought and used every year, year after year.

No sense investing huge amounts of effort quantifying something that's going to be negligible...

Bruce Steele

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Re: Improving EROEI numbers
« Reply #45 on: March 28, 2014, 09:16:58 PM »
Eric, Very nice to see you here. I think an average embedded energy investment per kilogram is a great place to start. Minimizing those costs by minimizing the weight of equipment will probably get me the highest EROEI possible. I do think small equipment may have a shorter lifespan however .
?  Is the 85MJ/kg amortized over what ever life I do get out of my tiller ?
I still need to get a number for my lithium ion battery as I believe the battery may have less years of utility than the tiller or solar panels. From what I have read the lithium isn't recycled but other more expensive battery components like cobalt are. So it would be nice to know EROEI for both the battery and potentially a  recycled battery deduction.
 If you were to take a guess, a ballpark swing, what would you think might be a best case EROEI for a big garden without tractors or gas tillers run with a solar set -up?  Soil amendments with a horse manure compost , hand turned ,and sourced on the farm that grows the garden? Producing a fairly high calorie crop like potatoes ?  I won't hold you to any numbers I'd just like something to shoot for.
Figure on an acre for ease of calculations and comparisons. Maybe a five year life for the tiller.

JimD

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Re: Improving EROEI numbers
« Reply #46 on: March 29, 2014, 06:39:17 AM »
Bruce

Might help.

http://legacy.wattzon.com/stuff/items/k7claulbuzuawizd083iq2aofy/ka39mnins6b9t4be22dad2k61y

Li-Ion
Quote
Embodied Energy

88,977,340 Joules
 Total 24 g

50,000,000 Joules
 Electronics 1 g

680,000 Joules
 Metal 17 g

432,680 Joules
 Manganese 2 g

400,000 Joules
 Plastic 4 g

37,462,500 Joules
 Manufacturing

83,426 Joules
 Transportation 13,904 km

2,160 Joules

http://www.academia.edu/239998/Lithium_Battery_Sustainability_Analysis

http://www.level.org.nz/material-use/embodied-energy/
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

Bruce Steele

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Re: Improving EROEI numbers
« Reply #47 on: March 29, 2014, 09:35:23 AM »
JimD, Thanks and enjoy your vacation.I put in another three hours on the electric wheel hoe today.
Again I wore out before I ran out of battery. It is a little smoother to operate than the tiller and will probably hold up to longer use as a result. It is a pretty simple piece of machinery and if I had to I could put one together from an electric scooter and a manual wheel hoe. Mine is a 24 volt model but Carts and Tools is starting to use a 36 volt battery in their new tillers so a 36 volt wheel hoe would make things a little faster because you could push a wider blade. Having nice sandy loam makes things fairly easy for me ,rocks would really not be good and also would chip and dull the blade. Soil therefore might be a very big factor in where this technology is applicable.I am most of the way through a 200 ft. by 200 ft field now and a three 25lb bags of seed potatoes will be showing up soon. I'll be ready for them once they come.
 I have been on night watch lately for a couple sows that both decided to produce more piggies than nature gave them tits to handle. I may have to attempt heroic measures and bottle feed a couple but my vet is looking at me like I have gone bonkers.
 It is nice that Eric Garza has been willing to join us. Shows I think the reach of Internet.
 April fools is my traditional planting date and the weed control pre -plant till will start tomorrow .
I,m already starting some serious sleep deprivation and season is just about to begin in earnest.
I guess another advantage of a very small tiller is I don't have to worry about falling off and running myself over. :D     

Bruce Steele

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Re: Improving EROEI numbers
« Reply #48 on: March 31, 2014, 08:12:52 PM »
For all you DIY( do it yourself ) engineers out there check out this site. Batteries , solar panels, electric wheel hubs and all the fixings to put together a sustainable farm infrastructure. It is a dreamers paradise.

http://www.goldenmotor.com/

Bruce Steele

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Re: Improving EROEI numbers
« Reply #49 on: April 24, 2014, 08:19:21 PM »
Reducing food energy costs requires some accounting of various energy inputs for production and transport of different foods. Fishing can attain very high EROEI numbers when both fuel use per ton of production and transportation by ship to market are combined. Fishing can also produce very bad
negative EROEI numbers with inefficient fishing techniques are combined with air transport. So putting a premium on " fresh fish " could be replaced with " fresh frozen " fish premium. Knowing how much energy goes into the food you eat requires labeling food with energy input numbers. I believe Sweden has a energy labeling requirement for food and maybe someone could help educate us on how that works. Do people change their eating habits as a result?

                
 
 
One example given by Tyedmers (2008) describes the differences in the emissions due to the air transport of fresh Alaska salmon to San Francisco and the surface transport of Alaska frozen/smoked salmon to San Francisco.   The transport emissions from the fresh salmon was nearly 20 times that from the transport of frozen/smoked salmon. Tyedmers’ study also found the greenhouse gas emissions (GHG) for long haul shipping were  by far the lowest of any transport method.     In the California squid fishery, where much of the landings are transported by sea to Asia for processing and then some are returned to the US for consumption, the carbon footprint is among the lowest of global fisheries.   In contrast,  emissions from air transport of live California lobster to consumers in Asia are likely to be similar to those in the air transport of fresh Alaska salmon to San Francisco.
 
Summary:  Combining the two major sources of energy usage and carbon emission, production and transport, it is clear that California’s purse-seine fishery has extremely low energy usage for production and low energy usage for transport.    California’s trawl fisheries have average energy usage for both production and transport, while California’s lobster fishery has very high energy usage for both production and transport.  
 
 
References:
 
Pelletier, N., E. Audsley, S. Brodt, T. Garnett, P. Henriksson, A. Kendall,K. Kramer, D. Murphy,T. Nemecek, and M. Troell.  2011. Energy Intensity of Agriculture and Food Systems. Annu. Rev. Environ. Resour. 2011. 36:7.1–7.24

Philbin, C.W. 1980.  Three different delivery modes ford fresh-caught Pacific whiting, Merluccius productus.   Mar Fish Rev.  Feb 1980  30-6.
 
Tyedmers P. 2001. ‘Energy consumed by North Atlantic fisheries.’ In Fisheries impacts on North Atlantic ecosystems: catch, effort and national/regional datasets (Eds D. Zeller, R. Watson, and D. Pauly). Fisheries Centre Research Reports, 2001, vol. 9(3), pp. 12–34 (Fisheries Centre, University of British Columbia, Vancouver, British Columbia).

Tyedmers, P., 2004. Fisheries and energy use. Encyclopedia of Energy, Volume 2. Elsevier Inc. p. 683-93

Tyedmers, P. and R. Parker. 2012. Fuel consumption and greenhouse gas emissions from global tuna fisheries: A preliminary assessment. ISSF Technical Report 2012-03. International Seafood Sustainability Foundation, McLean, Virginia, USA.
Tyedmers, P., 2008.  The role of ‘food miles’ in the carbon intensity of seafood.  
Wiviott D.J., and S.B. Mathews. 1975. Energy efficiency comparison between the Washington and Japanese otter trawl fisheries in the northeast Pacific.  Mar. Fish. Rev. Vol. 37 (4): 21-24.
Woods, J., A. Williams, J.K. Hughes, M. Black, R. Murphy. 2010.  Energy and the food system.
Philos.Trans. R. Soc. B 365:2991–3006
Ziesemer, J., 2007. Energy use in organic food systems. FAO. Natural Resources Management and Environment Department Food and Agriculture Organization of the United Nations. 28p. http://www.fao.org/docs/eims/upload/233069/energy-use-oa.pdf
 

Table 1.   Fuel consumption of fishing vessels in relation to landings (gallons of fuel per metric  
               ton of fish or shellfish).
 
Country                                     Gear                      Species                              gal/mt
 
TRAWL (SHRIMP)
Canada​Trawl​shrimp​166
Norway​Trawl​shrimp​381
Iceland​Trawl​shrimp​267
                                                                                                          Average​271​
TRAWL (FISHES)                                                                                                                            
Canada  19991​Trawl​redfish, flatfish, cod​109
Norway 19981​Trawl​cod, saithe, haddock​135
Iceland  19971​Trawl​cod, redfish, saithe​131
Germany 19981​Trawl​cod, plaice, haddock​411
Japan (in USA) 19712​Trawl​rockfish, pollock, blackcod​273
Washington 19712​Trawl​rockfish, cod, hake​50
Monterey 2000-33​Trawl​rockfish, blackcod, flatfish​104
Monterey 2010-23​Trawl​flatfish, sandabs, halibut​197
​​                                Average​176    
OTHER BOTTOM GEAR
Canada  19991​Dredge​scallops​90​
Canada 19991​Long-line​cod, haddock, hake​129
Canada 19991​Gillnet​cod, saithe, halibut​378
Norway 19981​Long-line​cod, haddock, ling​126
Iceland 19971 ​Long-line​cod, haddock, dab​158
Iceland 19971​Hand-line​cod, saithe, redfish​161
​​                                Average​213
LOBSTER
Norway1​Trap ​lobster​987
California3​Trap ​lobster (Santa Cruz Is.)​689
California3​Trap​lobster (Point Loma)​474
​​                                Average​717
LARGE PELAGICS
Canada 19991​Long-line​swordfish, tuna​460
NE Pacific 1990s4​Troll​salmon​219
NE Pacific 1990s4​Purse-seine​salmon​95
Global5​Purse-seine​tuna​97
Global5​Long-line​tuna​283
Global5​Pole and line​tuna​394
​​                                Average​258
 
PELAGIC TRAWL (pelagic fishes)
Iceland `19971​Pelagic trawl​capelin, herring, whiting​21
Germany 19981​Pelagic trawl​mackerel, herring, sardine​30
USA Oregon6​Pelagic trawl​hake​9
​​                                 Average​20
PURSE SEINE (small pelagic fishes and squid)
Norway19981​Purse-seine​herring, whiting, mackerel​27
Iceland 19971​Purse-seine​herring, capelin​15
Canada 19991​Purse-seine​herring, capelin, mackerel​8
USA East Coast 19991​Purse-seine​menhaden​8
USA California3​Purse-seine​squid, sardine, mackerel​6
​​                                 Average​13
 
​​
 
COMPARATIVE FIELD CROPS AND MEAT PRODUCTION
                                                                                           
USA7​​corn​16
USA7​​soybean​24
UK8​​milling wheat​16
UK8​​potatoes​8
UK8​​carrots​11
UK8​​milk​16
UK8​​pork​108
UK8​​beef​179
​​tomato (hot-house)​787
​​
 
1Tredmers (2001); 2Wiviott and Mathews (1975); 3unpublished data; 4Tredmers (2004) 5Tyedmers and Parker (2012), 6 Philbin (1980) . 7Woods et al 2010. 8 Ziesmer 2007.