Hacker News Reader

Comment by jfoucher | Hacker News Reader

"22 gigawatts of electricity per hour" ?? WTF? As soon as I read that the credibilty of the whole post went waaay down...

But anyway, very cool.

View on HN

It's not uncommon for people in the energy business to say "gigawatts" as short hand for "gigawatt hours". In that context this sort of makes sense. At their peak (likely when the sun was just right and the clouds were parted over most of Germany), it produced 22 gigawatt hours in a one hour time period. Without the implied "gigawatt hour", saying it just hit "22 gigawatts" isn't really that impressive, because that could just be a momentary spike. Being able to sustain it, even for an hour, is impressive.

They didn't say "gigawatt hours". They said "gigawatts per hour", which would be a rate of change of power generation. For example, if the sun came up and in 6 minutes your solar power station went from producing 0 to producing 2.2 gigawatts, that would be an increase of 22 gigawatts per hour. I strongly suspect that the author of the article is just ignorant.

Yes. Gigawatt hours would be meaningless. I'm saying that the "gigawatts" was a short form of "gigawatt hours", which means what they were talking about was "gigawatt hours per hour", which is really just average gigawatts over an hour, but that is quite meaningful as compared to straight up gigawatt.

It clearly carries a certain meaning, the same meaning as if a news story referred to "the country of Africa" or "Pablo Picasso, a well-known classical composer": its meaning is that the person who uttered it is too innocent of reality to be a reliable source of information on the topic.

...or too familiar with industry jargon to realize that they aren't being clear to a wider audience.

Like I said, it isn't unusual for people to say "gigawatts" and actually mean "gigawatt hours" when it comes to the power business.

Journalists routinely confuse energy and power units. Occasionally I write to one of them about it; maybe I'll write to this guy since his email address is readily available.

But yeah, if you look for it you'll see this in maybe 70 or 80% of news stories about power generation.

Maybe they meant gigawatts-hour, a unit of energy, although a bizarre one to use in any case.

Why is it a bizarre unit? I'm billed for my electricity use in kW/h.

No, you're billed in kWh.

In SI, energy is measured in joules, and power is measured in watts. One watt is one joule per second. It's indirect to say "watt-hour", because in effect you're saying joules per second times hours when you could have just said joules.

That's true. I just think of kilowatt-hours as a single unit, like Joule. That way it's no more bizarre than saying Newtons instead of kg m/s^2

I emailed Erik Kirschbaum about his "22 gigawatts of electricity per hour" statement. I received a "was deleted without being read" response.

Reply on news.ycombinator.com