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Charged my Model S with cow manure today

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deonb

Active Member
Mar 4, 2013
4,062
4,363
Redmond, WA
EcoDairy in Abbotsford, BC (Canada) has a Chademo charger that they run from an anaerobic digester, 'fed' by cow manure from the same farm.

The owner came up and spoke to me - apparently we were the first to ever charge a Tesla there. He wasn't aware that Tesla's can use Chademo. Actually a really nice place for a stop with picnic tables etc. Smells a little bit at first... for obvious reasons, but you get quickly used to it.

Chademo.jpg


Tesla Chademo.jpg
 
Did he say anything about what the manure to power ratio was? I'm curious how many pounds of manure it would take to charge a Model S

The website states (on the 'Did you know' callout):
"Manure from 50 cows can generate 12 kW-hr of electricity! The typical household consumes between 0.5 and 2 kW per hour!"


So to answer your question, a 85kWh Model S will need about 354 cows worth of manure, each generating 64 lbs of manure per day. So you would need 22'656 lbs of manure to recharge a Model S.


Put another way, each cow can supply about 240wh per day. So we're talking about 0.8 miles per cow :).
 
The website states (on the 'Did you know' callout):
"Manure from 50 cows can generate 12 kW-hr of electricity! The typical household consumes between 0.5 and 2 kW per hour!"


So to answer your question, a 85kWh Model S will need about 354 cows worth of manure, each generating 64 lbs of manure per day. So you would need 22'656 lbs of manure to recharge a Model S.


Put another way, each cow can supply about 240wh per day. So we're talking about 0.8 miles per cow :).

Well sheet! My backyard isn't big enough for that many cows
 
The website states (on the 'Did you know' callout):
"Manure from 50 cows can generate 12 kW-hr of electricity! The typical household consumes between 0.5 and 2 kW per hour!"


So to answer your question, a 85kWh Model S will need about 354 cows worth of manure, each generating 64 lbs of manure per day. So you would need 22'656 lbs of manure to recharge a Model S.


Put another way, each cow can supply about 240wh per day. So we're talking about 0.8 miles per cow :).

Thanks for sharing this -- very interesting.
I noticed that they have some grass growing on some of the building's roof area.

Two questions:
** I wonder if any other dairy or cow farms (Harris Ranch??) are using anaerobic digesters to generate electricity?

** Second big question: since this is an Eco-farm, I wonder if they sell or are able to sell real (raw) milk. They are not under jurisdiction of USDA/FDA since they are in Canada. There are grass-roots movement for pasture-fed unprocessed full-fat milk, typically for sale only through a co-op.
 
Put another way, each cow can supply about 240wh per day. So we're talking about 0.8 miles per cow :).

A small correction on your units: That would be 0.8 rated miles per cow per day. :rolleyes:

With 80 cows, I could charge 64 rated miles per day. I spoke with a rancher near Branson, CO last week, who had finished an analysis that it took 71 acres of range land per cow in his area. That means with about 9 square miles of SE Colorado range land, I could charge 64 rated miles per day.

I'll go Solar PV after that analysis. One 265 Watt panel will give me 3-4 rated miles per average day with much less mess than the cattle route...
 
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Two questions:
** I wonder if any other dairy or cow farms (Harris Ranch??) are using anaerobic digesters to generate electricity?

** Second big question: since this is an Eco-farm, I wonder if they sell or are able to sell real (raw) milk. They are not under jurisdiction of USDA/FDA since they are in Canada. There are grass-roots movement for pasture-fed unprocessed full-fat milk, typically for sale only through a co-op.
There are a number of places in California's Central Valley that have agricultural anaerobic digesters. I don't know if any of them are near Harris Ranch.

There is one list here and the Energy Commision site that describes the process and an agricultural system that has been operating since 1982.
 
Right, for more-or-less obvious reasons (my alias translates to "Moocow") this thread is both amusing and highly interesting to me.

I'm curious about their numbers: 50 cows generate 12 kW-hr - does that mean they provide a continous power output of 12 kW? If so, we're looking at 5,76 kWh/day per cow, which seems like a lot. Let's crunch some numbers:

According to what was linked earlier, a single cow produces 64lb, or 29kg of manure per day. According to Wikipedia, 1 ton of cow dung is good for 45 m³ of Biogas, which can be treated and refined into something 99% close to natural gas. The efficency of that process of that I don't know, let's ignore it for now. So that's 29kg/1000kg * 45m³ = 1.305m³ of biogas per cow, per day. Natural gas contains about 10 kWh worth of heat energy per 1 m³, and gas turbine power plants can have efficencies of around 39%. Let us assume 35%, as a small generator near a cow farm might not be the most efficient in the world.
Which means: 1.305 m³ /day * 10 kWh / m³ * 35% = 4.5675 kWh /day. Per Cow, so you would need 18.6 cows (let's make that 19 cows) to recharge your Model S once per day. Now, we have ignored some losses.

How big are they?

According to this (German) site: biogas.fnr.de: Faustzahlen the amount of electrical energy you can expect from one dairy cow is 1095 kWh/year, or about 3 kWh/day. Which means the above calculation isn't that far off and the missing efficiency number is around 66% (Slightly less, since they assume 38% efficiency vs. my 35%). That brings the amount of dairy cows needed to power a Model S to 28,3, but that's to charge it from empty-to-full, which is not realistic for most people.
It also means that the amount of manure required to fully charge the Model S is 820,7 kg, or 1809.33 pounds, not 22k as stated above.

All that said, the overall efficency of a Sunlight - grass - cow - dung - electricity is still far less than Sunlight - PV - electricity. But PVs don't give milk (yet)

Edit: As to their 12 kW number per cow, that might include heat energy and then that's a pretty reasonable number. If it's just for electricity, they might have discovered some secret in the secretion.
 
deon, the lengths you will go to ... I KNOW you will bring this up over in the vegan discussion.

impressive.

Well, I WOULD have brought it up over in the vegan discussion, but lately that thread has devolved into constructive discussion about how to improve the Shareholder meetings. What's the fun in that!!

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Right, for more-or-less obvious reasons (my alias translates to "Moocow") this thread is both amusing and highly interesting to me.

I'm curious about their numbers: 50 cows generate 12 kW-hr - does that mean they provide a continous power output of 12 kW?

There's no reason to think that it's 12 kW continuous (i.e. 12 kWh / hour). I think one can read their statement as either 12 kWh per day per 50 cows (not 12kWh per cow), or 12 kWh over the lifetime of 50 cows. The former is probably more realistic. But that means they're not getting 3 kWh/day - more like 240 wh/day/cow. It's a come-explore-and-learn farm - not a real large-scale operation, so it's possible.


If it's just for electricity, they might have discovered some secret in the secretion.

Taco Bell?
 
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...
** I wonder if any other dairy or cow farms (Harris Ranch??) are using anaerobic digesters to generate electricity?

Here in VT we have a number of methane generators that have been installed on large dairy farms by our utility. The irony is that this is another form of fossil fuel. The cow feed is basically a product of commercial fertilizer which is fossil fuel derived. It's certainly not renewable or sustainable.