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Comment This method never fails (Score 1) 133

Here's how to calculate a 100% accurate estimate 100% of the time, when your manager asks you to predict how long it will take to implement feature X:

1. Tell your manager you'll get the estimate for them as soon as you've done the necessary research
2. Go back to your desk
3. Write down the current time
4. Implement the feature
5. Subtract the time you wrote down in step (3) from the current time. This is your 100% accurate estimate of how long it took you to implement the feature
6. Email your manager, and let them know the estimate value. If you're feeling like it, you can also let them know that the feature is now implemented (although this may make them feel like the estimate you gave them is no longer particularly useful, so treat cautiously there)

Comment Re:Not just software. (Score 1) 133

For example, if the last time you did it, it took 3 weeks, a good prediction is that this time it's going to take 3 weeks.

Hopefully it will take less, because this time I will be able to take the code I wrote last time and just re-use it, possible with some minor modifications, rather than designing and implementing it all from scratch.

(Or if I can't do that, then either it's a new task and there wasn't actually any "last time I did it", or I did a lousy job last time of designing my code to be re-usable. Software development is mainly about automating previously manual processes so they can be repeated more quickly/easily in the future; that applies to the process of writing the software itself also)

Comment Not just software. (Score 2) 133

Performance predictions have an optimistic bias.
It's known as the planning fallacy
It amazes me how people who should really know better fall for this.
For example, if the last time you did it, it took 3 weeks, a good prediction is that this time it's going to take 3 weeks.
Yet most people will predict less than 3 weeks - even if you point out the planning fallacy to them before hand.
I can almost here the rationalizing; "It's not going to take 3 weeks again, because we aren't going to make the same mistakes again."

But it's far, far, worse than just an inability to predict accurately.
Frequently schedules are determined by need rather than reality. As in, we need this done by Tuesday - make the schedule accordingly.

Comment Re:Easily impressed (Score 1) 177

When my first reaction to seeing the interior photos is "Wow this shit is fugly", the bar is immediately raised on how impressive the rest of the vehicle will have to be before I consider buying one.

I think back to when the Model S was announced; my reaction to the dashboard on that car was "Whoah, COOOL!"

Comment Re:Storage? (Score 1) 390

Advanced forms of compressed-air storage with thermal recouperation are the next-generation technology. There's a lot of talk about batteries from battery suppliers and uneducated pundits who don't know shit about city-scale power storage and can only conclude that large storage facilities are made of big, expensive parts while battery banks are made of small, cheap parts.

Think about it this way: A battery is cheap. We can just slap a battery onto a power pylon. We can space them around the city, close to point of use, so there's less loss from battery to house consuming the power. We can expand this with the grid, laying batteries out everywhere. That's obviously a cheap, cost-effective solution with many benefits.

Snipe the obvious technical problem first: Power generation has to flow from the source to the point of use, with a battery in the middle for intermediate storage. Having it close to the source means more loss to the destination; having it close to the destination means more loss from the source. Location of the generator matters; location of the storage facility doesn't, so long as it's "in between". Either way, it matters much less with high-voltage DC transmission, so "in between but a little of to the side by 20 miles" is functionally-equivalent to "right on the pole connected to my house".

A battery is cheap, blahblahblah, okay. What costs more to build, maintain, and operate: a 1,000MWh storage facility built out of $178-per-cell lithium batteries, or a 1,000MWh storage facility built out of giant tanks and piping for a recouperating compressed-air storage system that cost millions of dollars for the tanks, the pipes, pumps, turbines, and so forth?

That's the thing: batteries are cheap. They're versitile. You can throw one up on a pole--and you can drive all over the god damn place for hours to get to the widely-spread batteries, climb the pole, bring the battery down, repair it (replace bad cells), and so forth. You can put the batteries all in one place to avoid that.

Problem is a facility to store a ton of power generation for one hour of run time. I've seen $145-per-kWh cells, and a city of 80,000 homes requires 45MW. That's 45MWh to run for one hour. For each hour of stored energy, that's $6.525 million. If you built a regional storage facility for 1 million homes for 1 hour (562.5MWh), the battery cells alone (never mind any BMS circuitry, housings, or the facilities around them) would cost $81.5 million.

Texas built a 300MW-output, 30,000MWh (yes, 30GWh) CAES plant for $200 million. Not the equipment. The entire, operational facility. Again: just the lithium battery cells for a battery plant storing 45MWh cost $81.5 million. The fractional cost of that capacity in the Apex CAES is $0.3 million.

It's funny because people keep talking about batteries, largely because Tesla is talking about making a lot of money selling batteries. Lithium battery grid storage is a giant scam. Tesla makes excellent cars, end of story; grid-scale storage is not a Tesla battery problem.

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