Writer George Monbiot’s recent Peak Oil article entitled “If Nothing Else, Save Farming” included this comment:
There are no obvious barriers to the mass production of electric tractors and combine harvesters: the weight of the batteries and an electric vehicle’s low-end torque are both advantages for tractors.
I read this and immediately tweeted the question “Where are the electric tractors?”
Well, scientist-turned-farmer John Hewson has responded to Monbiot’s assertion with an explanation that lacks Monbiot’s, shall we say, sanguinary spirit:
[T]o anyone who has worked with farm machinery, especially on smaller and poorer farms, the idea of electric tractors will seem ridiculous. So far, electric traction has been developed only for transport, and most successfully in railway trains. The development of batteries and control systems has been directed at the needs of passenger cars, which do not have to pull heavy loads at low speeds for long periods.
Electric tractors do exist, but are light machines similar to ride-on lawn mowers, with power outputs of around 40kW. Typical farm tractors have outputs of 100kW-200kW, and no currently available batteries could provide anything like this amount of energy, or anything approaching the working life of a diesel engine.
The best lithium-ion electric car batteries and motors work at high voltages (500V for example). As an engineer, I would blench at the idea of maintaining a 100KW, 500V system in a damp and muddy farmyard, let alone carrying out running repairs in the middle of a 50-hectare field, in the rain.
As far as I know, electric traction for farm machines has not yet been even considered as an option. If it ever reaches the stage of production, it will be very expensive indeed – far beyond the budgets of even large farms.
But here’s the good news. Hewson appears to be, to a large extent, wrong! It didn’t take much digging for me to find an article singing the praises of electric tractors as perfectly suited for small-scale agriculture at least. It comes from a 2003 issue [PDF] of the Northeast Organic Farm Association’s Natural Farmer newsletter, republished here. Yes, it’s true, says the author, electric tractors are designed for mowing and light work. But people have also been converting diesel tractors to electric for real farm use with great results:
Ron Khosla, a small-scale organic farmer in New York state has converted an Allis Chalmers G to electric and told me “Our electric ‘G’ is absolutely the most important tractor on the farm. It has three times the power of the original ‘G’ which is huge and [has] enough battery life to do everything we need to on our diversified 8-acre farm… It’s totally silent. You can creep along MUCH more slowly than we could with gas. It’s silent. It doesn’t smell. It’s NO MAINTENANCE…
“It also has changed the way we operate the tractor. This is a psychological thing, but it’s real. With the gas tractor, we were less likely to stop in the middle of the row to adjust things, or clean a shoe, or whatever. With the [electric] tractor… somehow there is psychologically less inertia… And we stop ALL THE TIME to make final adjustments which has resulted in a better job. When you stop, you are stopped. No engine running. It’s just quiet and silent, no cloud of white smoke drifting over your head… nothing… Perfect silence. THIS is what sustainable farming is supposed to be about!”
His initial conversion was fairly simple, using a common series wound DC motor, golf cart controller, and regular lead-acid batteries. After learning the hard way how to care for the batteries, he has added meters, deep-cycle golf-cart batteries, and a better charger. He is planning to do a second conversion as part of SARE grant, which will include documenting the process via a web site.
Allis Chalmers Model G tractorPhoto: cwalker71 via FlickrMaybe Hewson’s concern about muddy mid-field electric tractor maintenance is a bit misplaced. An important element in all this (and overlooked by Hewson) is this fact that weight and low torque are advantages for tractors. In practice that appears to mean that heavy, low-voltage “old-fashioned” lead acid batteries will do just fine. No need for high-end, high voltage and pricey lithium ion batteries after all. Anyway, it does indeed appear that a small farm can manage with an electric tractor.
That said, even the Natural Farmer piece suggests that electric drivetrains aren’t [yet] suitable for industrial scale tractors or combine harvesters. And here we get to modern farming’s elephant in the field. Most of the “innovations” in industrial agriculture, from diesel tractors to pesticides to GMOs, have been about getting people (and animals) off the farm. But even the International Energy Agency, the group charged with estimating the world’s oil reserves (and the one recently accused of inflating these estimates on orders from nations like the U.S.) admits the possibility of oil production plateauing perhaps as early as 2020. In an environment of flat oil production, biodiesel will likely be prohibitively expensive as well—liquid fuel of any kind will be hard to come by. But the harvest will still need to come in—in a depopulated rural America, how will we manage that?
It may turn out that the only replacement for the workhorses of industrial ag like the large tractor and the combine harvester will be ... workhorses—the four-legged kind. Wouldn’t that be something.
Granted, a return to real horsepower is unlikely to come to pass. But what may happen is that as those enormous thousand acre corporate farms become unmanageable, they get broken down into smaller holdings that more modestly-sized electric tractors can handle. Wouldn’t that be something.
Whatever we do, it will take creativity and commitment to come up with a replacement for diesel fuel on the farm—in Monbiot’s bit of anecdata, a farmer who’s been trying since the 70s has only managed a fuel-use reduction of 25 percent—and the stakes couldn’t be higher. Though perhaps we don’t have to reach quite as far back into time as the horse (or the human hand, for that matter) to save farming. According to the Natural Farmer article, farms in Latin America experimented in the late 19th century with stringing catenary, i.e. overhead wires, above fields to power tractors. Given that buses, not to mention high-speed trains, still run that way, maybe large tractors and combines could manage it. Old-time streetcar technology saving production agriculture? Well, that would be something, too.
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Comments
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Hearty Roots Farm Posted 2:18 pm
30 Nov 2009
But the fuel used in tractors on many farms is not necessarily a big contributor to the farm's climate-change footprint. On our veggie farm, we use a couple of old inefficient diesel tractors for heavy tillage (our electric tractor couldn't come close to handling that job). Even so, we don't use as much fuel per week for those tractors as we do delivering our produce locally (even though it's all staying within 90 miles of our farm).
On many organic farms, nitrous oxide from manure inputs is the biggest greenhouse gas culprit; just as on many conventional farms chemical nitrogen fertilizers have a bigger climate impact than the tractors that apply them.
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Tom Laskawy Posted 2:52 pm
30 Nov 2009
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Hearty Roots Farm Posted 4:06 pm
30 Nov 2009
Yield of biodiesel per acre ranges from 50 - 100 gallons per acre (for rapeseed/soy, i.e. crops I can grow-- 500 gal. per acre palm oil is not an option in the northeast). That would mean setting aside 10 to 20% of my land to grow my own tractor fuel. It wouldn't mean the end of farming, but it definitely could make a transition to all electric tractors (or draft horses) more plausible.
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Farmertim Posted 5:55 pm
30 Nov 2009
It had a DC 110 frame(no pun intended) and about if I remember right about 38 horsepower.
Just a whole line of batteries where the engine was and this was a production model not a farm shop creation.
Don't now what happend to it though,..cheap gas I guess.
Tim
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Farmertim Posted 6:16 pm
30 Nov 2009
propelled by a motor created by Allis Chalmers but weighed 75% more than its 45 Hp counterpart.
New Holland(Ford tractors) just began tests on a hydrogen tractor the NH/H2 that runs the transmision,all operating gears, 4X4, PTO ect on electric motors and resistors to set speeds.
98 horsepower...not bad.
15 hours reserve fuel capacity..no price yet.
Tim
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Craig Allen Posted 6:28 pm
30 Nov 2009
Before the recession everyone was griping about the costs of diesel and how it was going to send everyone broke. Now the price has dropped and everyone is back to purchasing every bigger equipment. When/if we come out of the recession and peak oil really starts to cut in, Australian agriculture is in deep trouble. (Not to mention the DROUGHT!)
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amazingdrx Posted 1:39 am
01 Dec 2009
Especially the nitrous oxide (300 times the GHG effect of CO2) from manure obsertvation. It is a huge GHG effect that can be avoided. Biodigesting the manure first, and extracting valuable biogas, uses the nitrous oxide for fuel thus turning it into CO2.
The organic fertilizer left over after biodigestion can then be added to soil or compost.
Biogas can power a tractor too, it would be really efficient in a fuel cell/turbine backup generator on a battery powered tractor.
But think about it. With no till and cover crop or mulch weed suppresion why would we need tractors powerful enough to plow or even cultivate.
I'm thinking that plugin battery powered robots could do almost everything tractors and irrigation systems do now, and even more. Pinpoint soil testing and water and organic fertilizer injection, drill planting of seeds or seedlings with soil ammendment added in the hole, weeding and insect control, between rows cover crop planting and harvesting, these are things that can't be done with tractors.
I still think that large harvesting equipment would be useful for corn, grain, forage, and soy crops, but these could be adapted to plugin hybrid technology with farm biogas as the fuel. This is what the future of organic ag looks like to me. The US ought to lead the charge and the R and D and manufacturing.
This sort of ag on a global scale could actually remove GHG from the atmosphere and sequester it in the soil, real living soil that exceeds the productivity of chemical ag. And no more imported fertilizer (ammonia fertilizer is brought in on tankers from Russia now) or toxic oil-based chemicals. That cuts the over head that is killing family farms and the trade deficit that is killing our economy.
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Biodiversivist Posted 9:01 am
01 Dec 2009
http://green.autoblog.com/2009/11/29/zero-emission-sowing-farming-goes-better-than-carbon-neutral-in/
An Australian farmer is planning to have the first carbon negative farm. Hopes people will pay a lot more for his wool.
He's using Chinese manufactured Thunder Sky batteries:
http://en.wikipedia.org/wiki/ThunderSky
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dbaker Posted 9:21 pm
01 Dec 2009
This will go big
Dennis
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delweld Posted 5:29 am
02 Dec 2009
. The most interesting being Caterpillars D-7 size tractor suitable for farm work.
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cooter Posted 5:50 pm
02 Dec 2009
Today's standard is not much better, for real production on a farm the machine has to be able to pull full horsepower for 8 to 12 hours per day for up to 20 days. That horsepower in reality is near to 350hp, the day of the sub-100hp tractor went by some two decades ago.
Planters are up to 40 row, some wheat drills are 40' wide and the harvesting machines are no smaller with some grain heads on combines reaching 38' as a normal. Cultivation equipment if used range in the need of 250hp to no less than 400hp, the no-till planting equipment requires the same.
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Clifford Wells Posted 6:36 pm
02 Dec 2009
As Cooter notes, if you're into big-time field production where 40-foot wide implements are used, well, better stick with diesel for now. If you just need a work buggy such as for working fences or planting strawberry seeds, hey, electricity sounds great.
There is absolutely no limit on the break-out forces for an electric motor, and indeed the largest cranes in the world are all electric. However, these huge cranes use two extension cords about 6 inches around, and batteries are out of the question.
My thinking is that batteries are useless for most mobile applications, and does anyone think about replacing those every 3 to 6 years after they're fried? That's some expensive stuff. I remember there was a 'Green Goat' hybrid locomotive (peak 850 kW) that had a failure and the switching company had to spend $300,000 on new batteries. Whoa. I bet they're glad they didn't have four or five of them.
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dbaker Posted 8:35 pm
02 Dec 2009
this idea is going somewhere
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cooter Posted 7:28 pm
05 Dec 2009
Modern farming is fast becoming corporation level with many small farms as ours being pushed out to pasture.
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nedruod Posted 11:41 pm
13 Dec 2009
Two trends, one short term and one long term are going to reverse that trend. In the short term it's the surplus labor available and the declining economics and sustainability of petroleum necessary to drive that system.
But those are short term trends (as in less than 20 years). The long term trend (20-50 years) in farming that will lead to smaller, is computers, networks and nanotechnology.
Smaller, self-contained, and autonomous (at least in the sense of not needing direct human control) farming tools are the next wave. Not only will they be more energy efficient than gigantic combines, they'll be more land efficient too. They'll do this by being capable of dealing with situations huge machines are very difficult to build for.
For example, two symbiotic crops can be planted in alternating rows, or even in a hatch pattern so that each crop shares the nutrient benefit of it's symbiotic neighbor. Currently farmers are limited to taking advantage of symbiotic relationships between crops by rotation because it'd be very hard to have the combine collect the corn which is mature, but leave the soybeans which aren't. In fact, surely some corn is mature before it's neighbors?
On top of all that, it will be more labor efficient, which in the end will result in larger farms with smaller pieces of equipment yielding greater amounts of food.
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Avelhingst Posted 8:05 am
14 Dec 2009
However, even highly mechanized agriculture is a gamble in several variables; when it comes time to harvest, chance must be minimized. Unless there is some breakthrough in battery charging technology, there really is no replacement yet for actual transportable fuels. Something that is energy dense and easy to store, transport, exchange, and use - something almost as good as hydrocarbons. I am a believer that hydrogen could really step in to power massive machines where battery power is no appropriate (yet).
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dbaker Posted 8:20 am
14 Dec 2009
electric tractors is an excellent and financially viable idea!
get er done dude
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