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Comment by frossie | Hacker News Reader

These are the kind of calculations that make me weep - somebody getting happy with numbers without engaging their brain as to the answer. Obviously the Tesla factory is not going to require 20,000,000 Megawatthours to operate - that is as much as the whole electricity production of the State of New Hampshire.

Assuming their input data is actually correct, I will speculate they are calculating the energy cost of the entire lithium battery production from raw materials, such as extracting lithium from mineral deposits, the majority of which would happen before the materials arrived at the Tesla factory.

I also expect Elon Musk knows what his electricity bill is. Given his investment in green technologies and his general success in delivering projects, I would be rather surprised if he advertised a solar factory if there was a chance he would be out by 4 orders of magnitude on how much power he would need.

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>Assuming their input data is actually correct, I will speculate they are calculating the energy cost of the entire lithium battery production from raw materials, such as extracting lithium from mineral deposits, the majority of which would happen before the materials arrived at the Tesla factory.

If you look at one of their sources[1], it is clear that this is the case.

[1] http://www2.epa.gov/sites/production/files/2014-01/documents... p.65

According to this study[0], it takes about 116 kWh of input energy to create a 100 kWh battery, given the materials. The majority of the total energy usage is in material production, not battery production. Assuming Tesla is not making their own materials, this deflates the required input energy substantially.

[0]: http://www.electrochem.org/dl/ma/202/pdfs/0068.PDF

> Assuming Tesla is not making their own materials, this deflates the required input energy substantially.

And also inflates that amount of greenwashing involved...... Why crow over renewable energy when your use of energy is irrelevant relative to your suppliers?

But their statement seems accurate and clear: they will operate the GigaFactory using renewable energy. They don't claim or imply that they will extract the materials using renewable's or that all their suppliers will use renewable's.

They should source their lithium from solar-powered contractors. Maybe even sell them some panels for a good price. (I realize the brine is already evaporated in the sun, but there's electrical separation after that.)

A 100Kw battery is used more than once. Making it 116kwh to store 116,000+ kWh.

So, your solar roof drops from 100% 'green' to 99.9% 'green' that's hardly a real issue.

So the statement "our factory will produce batteries while running solely on renewable power", though potentially factually accurate, is greenwashing?

Reportedly, the gigafactory will import ore from the mines directly, and process it. So, optimization might be possible, especially given that they can choose more expensive extraction processes because they don't have to compete on the cent.

Where has this been reported?

They don't have any magical technology that allows them to dramatically reduce energy needed. The obvious conclusion is that they won't make anywhere near as many batteries as assumed.

It isn't magical technology, it is simple logistics.

South America to China to California vs Nevada to Nevada to Nevada.

Transportation uses very very little energy compared to everything else that needs to be done.

You will not find your magical technology in shipping.

Additionally ocean shipping is cheap enough that it can take less energy to ship something to the other side of the world than to the other side of Nevada.

I had a dig around, you are right that transport of lithium is relatively negligible in the energy budget (back of an envelope calculations suggest around 0.5 kwh for a 1 kwh capacity battery), transport of other material such as nickel is actually more important, but even when you add them all together it is only maybe a couple of percent or so of the energy involved.

It seems that the drying process is the one to target as it accounts for around 50% of the energy budget and uses big electric ovens. Electric ovens are something that respond very well to economies of scale though, given the losses are a function of the volume versus the surface area, so you could see significant reductions there with a factory this size.

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