VIII.3. The Electric Farm Pt. 3 – Exchange with Phil Timmons
(originally published April 7, 2008)
I wanted to alert readers of this blog to an interesting exchange I had a few weeks back with Phil Timmons on my posts on the Electric Farm from last November. I appreciate Phil’s expertise in this area and willingness to think out of the box about the practical equipment requirements that face farmers (and miners). Given the ongoing price spikes in food and oil, I am hoping that the Electric Farm concept gets some more attention. If interest grows among farmers, engineers and tinkerers we might be able to get more minds working on the problem of developing a sustainable but machine-assisted agriculture, where farmers can either generate their own energy for machines on the farm or draw energy from a increasingly clean grid.
I’m reposting the exchange below:
Read this story after finding a link to the earlier first part. Thought the first was an excellent overview.
I am an EE working on utility scale RE projects, and from prior life experience, electric farming is of particular interest.
Just as observation — it seems this follow-on story falls in the Electric Vehicle “battery trap.”
Why the assumption that it would be needed or desired to operate the equipment on batteries? That tends to be very lossy — first in charging the battery, and then in recovery of the energy from the battery.
Electricity tends to be dynamic and likes to be used as it is generated. Have you began any studies into non-battery farming applications, or have any interest in that?
Thanks for your efforts, I think you are doing very good work.
By: Phil Timmons on March 11, 2008
at 7:40 pm
The point of the Electric Farm concept and the Renewable Electron Economy idea is that you are using batteries to power devices for a number of reasons outlined below. The Electric Farm wouldn’t be electric without batteries, though I suppose that a PHEV or multifuel tractor are suitable transitional vehicles.
The 15% round-trip loss of batteries charging and discharging I don’t consider to be very significant in comparison to the energy losses associated with competing fuel cycles. With biofuels or petrodiesel you lose 70% of your energy to heat in the engine which doesn’t even include the highly inefficient process of turning sunlight into biofuels via plants (as well as all the other issues associated therewith) which contains perhaps 0.5% of the original solar energy in it. The hydrogen fuel cycle loses 65-75% of the original energy of the renewable electricity and hydrogen has its storage problems as well.
So if we are to create a sustainable, affordable, mechanized agriculture, we will either need to prioritize and subsidize the use of petroleum in ag until the point when batteries and RE comes down a lot in price, or certain brave souls and companies will start pioneering the use of electric drive tractors fueled by renewable electricity. It will help if there emerges a discipline called “agro-ergonomy” which studies and reduces the amount of mechanical work per unit crop output, thereby reducing the amount of mechanical energy required to produce food (no- and low-till organic ag would be starts). It could be that we become so clever in our use of mechanical energy to farm and biofuels progress to the point where we won’t need much of them to cultivate food. But you will still be able to do many times more work with less of an ecological footprint with electric tractors and renewably generated electricity, stored in batteries that will be more energy dense than the current crop.
By: Michael Hoexter on March 11, 2008
at 9:57 pm
I guess I am still lost on the MUST-HAVE-BATTERIES dogma. (or bio-fuel for that matter).
Sorry, but I did not see any reasoned connection between converting available electric power to battery stored power and then converting it back to electric power just to use the electric power that was present to begin with. Does doing that make sense to you?
Not only are the losses (already mentioned present), but the start-up costs are much higher for including those batteries, as well as long term maintenance and replacement as they are limited life equipment.
Like I said, I think you started hard on the right track with citing the local generation of renewable energy to power equipment. That is great. But to not just use the power directly while it is there does not make sense. To borrow an old farming phrase — Make hay while the sun shines.
Your targeted numbers — 250 kW for example — is an excellent farm scaled application. (btw, while the exact math may say that is over 300 hp, in practice we do not budget much more than 1 hp per kW.) 250 kW / 250 HP is a reasonable output from an acre of solar thermal electric generation — which already is cheaper than coal — not talking PV, but rather solar thermal.
So sitting one acre aside can run all the power consumed by 100’s of acres. If this is roof mounted, a couple of large barns, as well as housing and garages can be placed under this.
So that 250 HP can easily run irrigation during solar prime time, as well as most other equipment during other times.
Maybe the battery thinking is from being sort of stuck on a model of equipment that goes round and round and back and forth across a field? As you may know center pivots (irrigation) and linear irrigation already do that with electric drive and no batteries.
Further, large scale electric equipment does not need batteries by virtue of its size, either. I have worked with 1500 hp draglines (large shovel cranes that could eat a whole farm in a day) and these use no batteries — just cord connections from line power.
While I can see the use of some battery vehicles to zip hither and yon (have put an forklift drive motor on a small tractor, myself, and run it both by cord and batteries), to do the mass grunt work with batteries is not real sensible to me when straight up direct power (DC or AC) is available.
Maybe this is a concept conversion thing we are stuck on? Sort of like a farmer of old looking over a modern tractor to figure out where the hay and oats go in? (still thinking in “horse” mode).
Electric farming would not need or probably even want to have equipment that was designed and optimized around petrol in a post-oil world, any more than one would want or need a harness or whip to drive a tractor.
But if you are interested in doing an exploratory essay on methods for profitable post-oil, all electric farming without batteries, I would be happy to help.
By: Phil Timmons on March 12, 2008
at 6:22 am
Thank you for your out of the box thinking. It may very well be that electric farming implements or vehicles will be able to remain plugged in as they do their work. I have seen pictures of old Soviet farm equipment that uses trolleybus style poles on overhead wires.
Staying plugged in may be an option for some farms or types of farming but in other settings it may soon require too much electrical infrastructure built around some fields.
Also, I think commercial farmers would have a lot to say about the inability to use energy when the sun ISN’T shining. Our agriculture has evolved both under animal and now fossil fuel energy inputs to be able to work at night or under poor light conditions. At harvest or planting time, some farmers will work around the clock. There are so many timing issues involved that I wouldn’t want to dictate to farmers when they would have to use energy. There are going to be a lot of crop losses if farmers can’t use their machines whenever they need them.
Batteries (or a grid connection if the implements /vehicles can remain plugged in) will be well worth the investment. As I point out in my essay, the extra weight of batteries can be used as ballast for pulling heavy loads: now tractor operators need to add weights when they need extra traction. Plus having a stack of batteries connected to the grid will give farmers an additional source of income to help stabilize the grid (selling ancillary services) or store cheap nighttime wind power from neighboring wind farms. So, while I can see that you engaging in a thought experiment, my sense of the future indicates lots of electric energy storage. On the other hand, experimenting with different task requirements with different energy requirements will continue to occur, perhaps minimizing the need for storage.
So, I don’t see the emphasis on batteries as a lack of imagination or a fixation: the functionality they offer is well worth the 10-15% charge-discharge energy loss they represent.
Still, you may well yet invent the grid-tied farming systems of the future, I would assume in close collaboration with commercial farmers!
By: Michael Hoexter on March 13, 2008
at 6:06 am
Phil Timmons responds:
Hey Michael, interesting discussion, thanks.
Used to do commercial farming back a life-time ago. Corn, wheat and soybeans.
Can’t remotely take credit for any invention in this regard, just observation of another industry that tends to use non-battery electric power day or night, in 24 hour operations, year around, with all sorts of weather (far more demanding than farming).
Typically mining operation have far more material moved, are far more remote than most farms, and much larger footprints. (all challenges to full electric power). But the typical mine operation uses almost all electric — either self-grid or commercial grid operations.
Electric mine cars trains for underground, dragline shovels above ground, and conveyors and electric trains above ground. Even the typical large Terex dump trucks (diesel) that we tend to associate in popular culture with mining (sort of like tractors are associated with farming) are used less and less, and now only until the conveyor(s) (all electric) get built.
Like I was mentioning above, a solar thermal electric system (and again NOT PV) of about one acre produces power to more than cover the heaviest use by most farming applications. Most of the year would just be sending power up to the grid. During times of heavy operation or off-hours the farm can draw from the grid. But when looking at electric power sales versus electric power costs, that should be a net money maker for the farm, as well.
I know the following is not your issue, but for other readers, I probably need to jump into some myth busting at this point . . .
There is no electricity shortage in the US. At most there is a time of use issue. Only during times of “peak” use do we come close to using what is available. Peak in the market I design for – Texas and the West – only happens in the middle of Summer, in the middle to late afternoon. Everyone has on the Air Conditioning. And that is it. We turn on all the Gas plants and hydro in addition to the base load coal and nuke plants and run them into early evening while the day cools down.
Most of the time, there is so much base-load power available that entire coal plants are shut down and taken off line for rebuilds in the Spring and Fall, when electric power use drops.
The sham “need to build more nukes” you hear from folks with no knowledge of the power industry is ALL marketing hype being mindless repeated. The proposals for building of new nukes are that it would 80% government funding. Not only costs more, but takes years and years to build. This is a huge welfare program for the contractors/builders. Costs more to operate and then leaves a mess to clean up, as well. Build, operate and then clean up – all losses.
There are lots (and LOTS) of surplus electricity on the grid. Base load power is cheap to buy and there are large discounts to use it off-peak. Solar thermal electricity produces best during the peak use – the methods discussed here would put MORE power on the grid during peak and only consume from the grid during off peak.
With that out of the way . . . back towards what drives all the tractor and energy use on the typical crop farm . . .
Creation of the seedbed.
The need for a good seed bed is what drives the use of a plow. A mold board plow flips the dirt like a slow motion wave breaking along a sea shore. This places weeds and organics at the bottom of the wave to compost, and fresh dirt to the top. For tmi — http://en.wikipedia.org/wiki/Plow
The entire mold-board plow system is what created the need for the high pulling power for the high traction and high power tractor. Often a tractor is described in draw bar horse power – which is essentially its pulling power. An interesting aside — the “traction” portion of the word Tractor is now what we now totally associate with farming just as somewhere around 100 years ago, draft horses would have been totally associated with pulling plows (hence “horse power”).
The rest of the seedbed creation — After the mold board plow turns over the soil, a disk harrow is pulled over it to break up the clumps, and then a wide “drag” is pulled to smooth the soil to plant seeds. So that is typically four passes across the field just to get the seeds in the ground.
The “lite” version uses what is called a chisel plow that is a one pass plow to break up the top of the soil, followed by a drag and then planting. Again that is covered in the wiki article.
But in al that, it is the high traction / pulling power tractor is needed for plowing that is driving the methods – which are modeled after the horse methods they replaced. The other implements are made wider and wider to attempt to efficiently use all that horse power available.
There are a couple of alternatives to using this method to create a seedbed. Like you mentioned the Soviets did have some creativity. Even using surplus Army tanks (high power and high traction) to pull plows.
One alternative to tractors I have seen from the Soviet era was a cable pulling method that would drag a plow across a field to a stationary winch. The winch was moved down the edge of the field, so the motive device was required to only be mobile in one dimension. A present day electric grid application of this may be to run a power line down the edge of the field to power the winch and pick the power from the line as the winch moved along.
Current US farming does something like the cable pull method in a system called “travelers” for irrigation. An anchored cable is pulled onto a winch on a mobile wagon-mounted irrigation water gun. The power of the pumped water pulls the cable onto the wagon, moving it across the field while dragging a large water hose behind. These are often electric (grid) powered via a motor and pump which provides the water pressure that makes the whole system work.
A method that I am looking at for total electric (non battery) creation of seed bed is use of tiller/cultivator methods – and yes, this is typical small garden method, but there are commercial farm tractor methods of using tillers – here is an example — http://www.riouxinc.com/BushHogTiller.htm
As these require mostly rotational power – and not traction power, like a plow – they are well suited to be turned by electric motors. As they churn and pass through the soil they create a seed bed that is suitable for planting, and a planter can pass along behind in the same travel. This does the entire 4 pass (plow, disk, drag and plant) in one pass.
I am looking at mounting large scale electric motor powered tillers on a frame like a center pivot, with electric motor wheels – again like a center pivot. So all this could be done while using no batteries, hydrocarbon based fuel, nor bio-fuel, just electric line power, either produced at the site or from the grid, with the power coming down the frame.
After planting comes fertilizing, irrigation and cultivating (mechanical removal of weeds) if desired. As you are probably familiar center pivots and other style irrigators, you can probably see that using liquid fertilizer can directly deliver fertilizer to the field without use of petrol, bio-fuel or batteries. Again just line power driving the pump and drive wheels.
Mechanical cultivation is one area I can see use of small battery power tractors such as you are discussing, however, with current planting methods and weed herbicides, this is not often done in commodity grain crops anymore.
And then finally getting the crop out of the field. The largest challenge with a combine/harvester is tire floatation – or bearing of the weight — on the soft field surface – not really a power or traction issue. Adding battery weight to this would not be a good thing.
It is often the weight of the grain being collected on board that bumps the limits of design capacity. A 300 bushel grain tank holds 9 tons. (300 bu. X 60 lbs/bu = 18,000 lbs = 9 tons).
I recall one Thanksgiving Day some years ago — working 23 hours straight as a Canadian blizzard was bearing down on us. Only stopping to refuel and grab some turkey and keep going. What forced the situation were wet fields and the weight of the combine would sink and get stuck in the mud. We had to wait until the ground froze and then beat the snow. Finished the last hour as snow was blowing in about horizontal in a 40 mph wind.
But what drove all that fun was the equipment and the methods used – which is still about the same today — 25 years later.
A method I am pondering for this is again using the center pivot style frame with small grain heads (the front end of a combine) attached, feeding a cylinder (the part of the combine that breaks the grain from the shell or cob) and then vacuum/blowing the grain back to a central collection point down the structural pipe that would normally be used to provide water out along the irrigator. Again, no petrol, bio-fuels, or batteries required. This keeps the weight of the collected grain back at central storage area, rather than being hauled around the field.
If folks really really wanted to use the conventional tractor methods, I have considered some options for that as well – one could take an old Steiger and put a 200 to 400 HP industrial electric motor in it in place of the diesel and have a super tractor for about 1/5 the cost of a new diesel. Run it from dragline cable – like the mine shovels discussed above, and off you go. That would last for decades and save its cost many times over in the (non) use of fuel.