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.
