Yes. Sure, we all know that electricity is cheaper at night, but would it make overall sense for the engineers to do their work at night for this reason?

First, they don't have to use the energy when they draw it from the grid. Charge an EV at night and test it all day.

Second, it only costs a couple bucks to charge an EV car even at peak rates. Surely the engineer's time and schedule is more important.

Depends on what type of work they are doing there. If it's light manufacturing, given the discussion of wobbly sheet metal and the like, you really wouldn't have many engineers there on shift, you'd have machinists who like working second shift/graveyard. Plus, given the location and security presence, it makes it a lot easier to chase curious people away while people are working.

All the machinery they are using to build and test the cars most likely do not run on batteries.

Why should apple care about that? The cost of salary utterly dwarfs energy cost so much that even thinking about the slightly cheaper rates at night is a joke.

Apple is not a process manufacturer where energy is a large part of the budget.

Unless they're melting their own aluminum. =)

Note the article doesn't really mention electric-type humming.

One neighbor described the sounds he hears at night as "sheets of metal slamming, clanking, almost a grinding sound."

This idea they're running large amounts of electricity to charge EVs seems far-fetched. And if a charger is making that much noise to wake the neighbors then, well, they have larger technology issues to handle.

Also: when you're a large industrial electricity consumer and you pull megawatts for your work, the utility usually wants you to run at night so you don't brown out the grid for everyone else during the day. Just another data point.

I realise you're joking, but one doesn't turn an aluminium electrolysis cell on and off at a whim (as in off in the day, on in the night). Shutdown and restart is bloody expensive, dangerous, and hard work to boot.

I'm half-joking. If this plant is pulling large amounts of current, no matter what they're doing, the utility might be asking them to do it at night.

Sure. That's why you don't build an electrolysis cell in a location where electricity is (sometimes) scarce.

I'm half thinking that this is all shadow games, Apple having two guys running around and making mechanic-sounding noises to stir up the rumor mill. Mainly because a) making cars isn't really something that produces a lot of noise and b) because you don't put your real skunk works in a residential area. But you do put a fake one there.

It would be interesting if someone with a thermal imaging camera could have a look at that plant during day/night. If they're pulling loads of 'leccy only during the night, the plant should show anomalous cooling behavior.

Lockheed Martin might have OPSEC needs that require building a fake skunkworks, but Apple certainly does not. One imagines they put it in the suburbs because it was an area which is convenient to commute to, which was a boon to recruitment.

They might not need it for OPSEC, but they do have a stock price to worry about. Financial analysts are making increasingly frequent statements that Apple needs a new market to be the game-changer in if they are to sustain their growth, and Cook has said that anything car-related and groundbreaking will, if it exists, be relatively far into the future. Thus the need to stoke the rumor mill.

While I find that claim much more credible, if I were Apple, I'd focus on breaking into new markets, instead.

I'm suggesting they're doing both, breaking into new markets as a long term strategy, increasing buzz/rumors as a short term strategy.

Doesn't California also have some the most expensive electricity in the US?

We're talking about a company with $200 billion in cash lying around. They could build a few large nuclear plants without making a significant dent in that pile of money.

If only Apple could afford their PG&E bill.

Residential rates appear to be reasonably high (9th highest if I read this right: http://www.eia.gov/electricity/state/) but (a) presumably they're not exactly smelting aluminum and (b) don't they have a giant money pit that Tim Cook dives in Scrooge McDuck-style.