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Comment: Re:Gamechanger (Score 1) 499

by amorsen (#49602415) Attached to: Tesla Announces Home Battery System

Plus those installations can provide a shedload of REACTIVE power, very, very useful for grid stabilization.

They can, but are they? I have only seen residential solar which reacted to grid overload/underload situations (i.e. situations which should never occur in an ideal world), not any which reacted to constant requirements for reactive power. Do you know of any which take part in the standard grid stabilization in normal use, outside of grid emergencies?

Comment: Re:Gamechanger (Score 1) 499

by amorsen (#49597421) Attached to: Tesla Announces Home Battery System

When electricity is cheap, it is because the marginal cost of producing it is low. The marginal cost is low because it does not take very much extra fuel to produce it. In other words, when electricity is cheap, its production is also less environmentally harmful. (This only holds as long as the power stations are unchanged of course.)

The Economist regularly gets this wrong by saying that electric cars are polluting more if they charge at night rather than during the day. They base this on the average pollution per kWh being higher at night. However, the average pollution does not matter. It is the marginal pollution which matters, and that is very low at night. This is really the kind of thing that economists should be specializing in getting right; I do not understand how you can be an economist and get it wrong.

Comment: Re:Try again... 4? (Score 1) 222

by jfengel (#49595835) Attached to: Grooveshark Shuts Down

Pandora makes it pretty clear that music at least costs attention. It has a *lot* of ads, both audio and on the screen. They tell you that you can make the ads go away, for a price.

People still don't quite connect that attention is being used as money, and they do still think of things as "free" even when they're paying in attention. But of all the ad-supported mechanisms I've seen, Pandora most specifically seems to make clear that you're paying one way or another.

Comment: Re:39/100 is the new passing grade. (Score 1) 170

That's a really good summary of the situation.

I do think that there's one more important factor. The flip side of reproducibility is utility. The whole reason that we care about reproducibility is that it means that we can put things to use. We demand falsifiability because if it can't be put to the test, then it's not so much "wrong" as "worthless", i.e. Not Even Wrong. If it can be reproduced but never is, what did it matter in the first place?

That's not the same kind of epistemological issue that falsifiability is, but it's a bit more immediate. If this research isn't being put to use, why are we bothering doing it at all? Wouldn't our time and money be better spent on other things?

It seems as if a lot of these studies weren't worth having done. Not just because they couldn't be reproduced, but because nobody wanted to. It's the sociology of science, the dynamics of funding and defining a new field. It's a field full of questions that we want answers to, but the questions themselves are ill-posed because we don't have a solid theory in which to ask them. We're going to have to grope towards an answer, and that's going to mean a lot of missteps.

I wish we had better answers, but it does seem to me as if this hints at a need for the field to clean itself up. Rather than performing so many disconnected studies, maybe we need to stop pushing for papers that nobody apparently has an use for even if they were valid. I know that's easier said than done; it hints at completely revamping the way funding is done. But the money is being spent, and it appears that much of it is not being spent well.

Comment: Re:Show me the math on the Tesla. (Score 1) 278

by amorsen (#49589397) Attached to: New Study Suggests Flying Is Greener Than Driving

Coal plants are certainly capable of throttling their output and using less coal. But if what you say was true, my point would only be reinforced: Marginal CO2 emissions by using an extra kWh at night would be zero, because the grid would otherwise have to stabilize by dumping electricity in resistors.

Comment: Re:Masstransit is more energy efficient than perso (Score 1) 278

by amorsen (#49589299) Attached to: New Study Suggests Flying Is Greener Than Driving

DSB (Danish Railways) has a table on http://www.dsb.dk/om-dsb/dsbs-... saying that their long-distance trains do 33g CO2 per person km. Regional trains are considerably worse. Modern cars should hopefully do better than 133g per km.

Urban trains do better because people are standing up, which significantly lowers the train weight per person.

Now, Denmark is admittedly a bit of a developing country when it comes to trains. Obviously a pure electrified system running on hydro power would do a lot better. DSB's long distance trains use 0.12kWh per person km. A Tesla uses about 0.35kWh per km, which comes to 0.09kWh per person km with 4 people.

Comment: Re:Subs as aircraft carriers (Score 1) 74

Cruise missiles work great for blowing stuff up, but there are a great many operations that call for extraction of soldiers or intelligence. Submarine-based aircraft could do this very well.

Some security strategists have proposed the florida-man-piloted-gyrocopter was allowed to land safely on the capitol lawn in order to give the North Koreans a false sense of confidence in their secret submarine-based gyrocopter assault project currently under development near PoonYang.

Comment: Re:to drive (Score 1) 278

by jfengel (#49586937) Attached to: New Study Suggests Flying Is Greener Than Driving

Averages are clearer when the correct number of significant figures is used. It's not meaningful to give four significant figures for an average that's supposed to stand in for a wide range of values. At best it's really just an order of magnitude.

And while I don't doubt the number, it does imply that they're not careful with their methodology, which makes it harder to put a lot of weight on it. It would have been better with just one or two digits of precision, or (if they wanted to spend the extra space on it) with a description of the range.

Comment: Re:Show me the math on the Tesla. (Score 2) 278

by amorsen (#49586837) Attached to: New Study Suggests Flying Is Greener Than Driving

That would be pointless because practically no one uses oil to produce electricity. Electric cars tend to charge at night where the coal plants are running at very low power and low efficiency. An idling coal plant has a very high average pollution per kWh produced but a very low marginal pollution per extra kWh.

Of course if it is a windy night the coal plants might just give up and shut down overnight, and then you really get your zero emissions.

If Machiavelli were a hacker, he'd have worked for the CSSG. -- Phil Lapsley

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