Tesla Gigafactory Investor Thread

[evme]

How about this, from my understanding. Battery cells need to be cycled 10-25 times for QC reasons. Can't the factory produce battery cells during the day on sun power. Then charge the cells up during the day, and then discharge the battery cells at night? Effectively use the charge/discharge QC test to act as a base load for the factory. Would this not work?

Because if you can do this, Tesla won't even need external power other than for backup purposes.

 

[austinEV]

How about this, from my understanding. Battery cells need to be cycled 10-25 times for QC reasons. Can't the factory produce battery cells during the day on sun power. Then charge the cells up during the day, and then discharge the battery cells at night? Effectively use the charge/discharge QC test to act as a base load for the factory. Would this not work?

Because if you can do this, Tesla won't even need external power other than for backup purposes.

that makes sense. I have had the thought that they would need large banks of batteries swapping power with each other for testing. easy to tweak and draw off power at night.

 

[AudubonB]

How about this:...Effectively use the charge/discharge QC test to act as a base load for the factory. Would this not work?

I think that's a very prescient insight. It effectively also would turn the gigafactory into a "breeder reactor" for batteries - using batteries to make batteries.

Jocular thought #2: QC mo betta be good....else the factory shuts down!

 

[austinEV]

I think that's a very prescient insight. It effectively also would turn the gigafactory into a "breeder reactor" for batteries - using batteries to make batteries.

Jocular thought #2: QC mo betta be good....else the factory shuts down!

you might keep banks of known good batteries, though that would consume them over time.

eventually you would accumulate cells or lots that fail spec but are otherwise OK. they could be used for a long time. even with heavy use they still keep capacity for a long time. and you accumulate them all the time. that is the clever way to handle rejects... build sophisticated stationary packs that accommodate cells of various ages and capabilities. they also flag dead cells and some intern goes around and collects them. only then do they get truly recycled for materials.

 

[techmaven]

How about this, from my understanding. Battery cells need to be cycled 10-25 times for QC reasons. Can't the factory produce battery cells during the day on sun power. Then charge the cells up during the day, and then discharge the battery cells at night? Effectively use the charge/discharge QC test to act as a base load for the factory. Would this not work?

Because if you can do this, Tesla won't even need external power other than for backup purposes.

Of course, charging isn't 100% efficient. Neither is discharging. I can see it being done to charge one batch with another + ~20% more juice. Either way, the factory will have to be grid connected for nighttime ops.

 

[evme]

I think that's a very prescient insight. It effectively also would turn the gigafactory into a "breeder reactor" for batteries - using batteries to make batteries.

Jocular thought #2: QC mo betta be good....else the factory shuts down!

If the factory is going to make 35gwh of production a year. We a are talking about 100mwh of batteries made per day. On top of that you still have wind power which is more abundant at night. If a few battery cells don't make it, that won't matter in the scheme of things.

Of course, charging isn't 100% efficient. Neither is discharging. I can see it being done to charge one batch with another + ~20% more juice. Either way, the factory will have to be grid connected for nighttime ops.

Well yes, charging isn't 100% efficient, neither is discharging. But it way over 80% efficient.

According to here:

Charging Lithium-Ion Batteries – Battery University

Lithium ion batteries have 97-99% charge efficiency

I also wonder since solar panels produce DC power, would they even need inverters? Or can they charge the batteries straight with DC.

But regardless, they would be grid connected anyways as they would want to sell power back to the grid.

One can even argue that more important then cost of electricity would be the rate the local utilities buy electricity. Having discount electricity might create complications there.

 

[austinEV]

You have many more batteries than you plan to test. Like 100x. Certainly you have to be grid tied for a while, but there is no reason they couldn't cache power for nighttime eventually, using factory-second batteries. Unless their yield is near perfect they will accumulate these anyway. And it is far better to use them than to just scrap and recycle them. People have widely speculated on TMC that car packs sent back for "recycling" could in fact be reused for stationary storage instead, and the same principle applies for factory rejects, and the factory itself would be the logical first customer of stationary storage.

 

[techmaven]

Lithium ion batteries have 97-99% charge efficiency

I also wonder since solar panels produce DC power, would they even need inverters? Or can they charge the batteries straight with DC.

Ah, yes, I forgot, it can be DC to DC with no inverter. Still, there will be some additional loss because you need a DC to DC step up (even if that is accomplished with using a higher number of batteries to source the energy).

 

[Auzie]

I also wonder since solar panels produce DC power, would they even need inverters? Or can they charge the batteries straight with DC.

That's an interesting thought. Efficiency can be gained if we get both dc and ac wiring in our homes, as we can get rid of all the wall transformers and plug directly into low voltage outlet, if available.

 

[JRP3]

There will still need to be power conversion devices between DC sources, you need to be able to regulate current flow. I expect a full pack dumping unchecked into an empty one would be a high current event.

 

[Robert.Boston]

I'm curious as to how municipal ownership enhances the ability of a utility to be rate-creative, or allowing it to offer the other advantages you mention over that of a privately-operated firm.

In all fairness, that curiosity, while genuine, also is coming from someone who views the entire concept of any grid-intertied electrical producer or distributor claiming that "you get to choose from what kind of source your electrons come" as being snake oil hooey of the worst sort.

In most states, municipal utilities are self-regulating (on the theory that the owners and the customers are one and the same). Hence, unlike investor-owned utilities, they don't have to go through elaborate rate proceedings at the state's public utility commission to establish a new rate structure or other special purpose contract.

 

[Cosmacelf]

In most states, municipal utilities are self-regulating (on the theory that the owners and the customers are one and the same). Hence, unlike investor-owned utilities, they don't have to go through elaborate rate proceedings at the state's public utility commission to establish a new rate structure or other special purpose contract.

The fact that they almost always undercut the PUC pricing by a lot helps too.

 

[tander]

How about this, from my understanding. Battery cells need to be cycled 10-25 times for QC reasons. Can't the factory produce battery cells during the day on sun power. Then charge the cells up during the day, and then discharge the battery cells at night? Effectively use the charge/discharge QC test to act as a base load for the factory. Would this not work?

Because if you can do this, Tesla won't even need external power other than for backup purposes.

If I remember correctly the original gigafactory presentation basically said that the plan was to be totally off grid (except maybe to sell energy back) which seems pretty possible if you've got a giant roof in a desert, tons of batteries, and maybe throw in some wind and other renewable options. This is part of how they intend to decrease the price of batteries...a factory that has no external electric bill regardless of output has a profound competitive advantage in any high volume industry right now, in ten years it will probably be a standard (and essential) practice for any commodity manufacturer.

 

[Benz]

The announcement of the first chosen site for the Gigafactory was going to be made in June 2014. It looks like they have delayed the announcement to July 2014.

 

[brian45011]

San Antonio does have a very high mix of solar and wind it's portfolio..

OCI not OCE? Wind perhaps, but solar? "Today, natural gas comprises 42 percent of our generation capacity, followed by coal at almost 28 percent. Nuclear energy makes up nearly 14 percent, while wind farms produce 13.5%. Energy efficiency programs, solar and landfill-generated methane gas, account for the remaining 3 percent. "

 

[ItsNotAboutTheMoney]

OCI not OCE? Wind perhaps, but solar? "Today, natural gas comprises 42 percent of our generation capacity, followed by coal at almost 28 percent. Nuclear energy makes up nearly 14 percent, while wind farms produce 13.5%. Energy efficiency programs, solar and landfill-generated methane gas, account for the remaining 3 percent. "

That raises a question: how is self-generated solar accounted? If a utility has an RPS and self-generated electricity isn't accounted for, it makes hitting the RPS harder. They mention energy efficinecy programs, so maybe they can report identifiable drops in demand under energy efficiency.

 

[Robert.Boston]

That raises a question: how is self-generated solar accounted? If a utility has an RPS and self-generated electricity isn't accounted for, it makes hitting the RPS harder. They mention energy efficinecy programs, so maybe they can report identifiable drops in demand under energy efficiency.

As I understand it, if you have two meters (one for your energy use and the second for your solar generation), then they can count the solar. But if you just have a single meter, I'm not so sure.

Efficiency programs count by using estimates. If they replace a piece of equipment with one that is twice as efficient, they do some math and attribute the delta as a savings.

Demand response programs develop a baseline usage pattern for a customer and then credits the customer for on-demand reductions from that baseline. Very error prone; a consultant here in Maine got hit with enormous fines for helping a client manipulate the baseline high to get credit for "reductions" that were really just normal usage.

 

[Cattledog]

OCI not OCE? Wind perhaps, but solar? "Today, natural gas comprises 42 percent of our generation capacity, followed by coal at almost 28 percent. Nuclear energy makes up nearly 14 percent, while wind farms produce 13.5%. Energy efficiency programs, solar and landfill-generated methane gas, account for the remaining 3 percent. "

OCI is correct. I think they have a 20% renewables target in a few years (2020?), so wind + solar + other. They do still have aggressive incentives for residential and commercial solar. OCI's deal, at the time, was one of the largest in the world. Wouldn't surprise me if they were planning the next big deal (in addition to Gigafactory).

 

[dhrivnak]

Not all solar is accounted for. If for one have one meter, it can run backwards if I generate more than I am using and it can run forward if I am using more than I make and it keeps track every 15 minute period. In my first 10 months I generated 8.6 MWh but only "sold" back 5.2 MWh. The 3.4 MWh is electricity I produced and used at the same time. There is no record of that production save my own records. The power company only sees 5.2 MWh of production.

 

[Jack6591]

June comes and goes

June comes and goes with no word on Tesla | Albuquerque Journal News