Anyway, short answer, no it's not 900x for half the power. Power stations are generally measured in capacity, often without mentioning the capacity factor. e.g. you could build a damn that can produce 1000 MW of power, but it is not connected to a river and relies on pumped storage, and have only storage for 1 hour of generating. The net energy generation of that facility is actually negative, a small cost for energy storage. You can't compare that to another installation which actually generates energy for 10 hours a day. They're completely different yet both carry a power rating which is not meaningful for comparing them in the way you'd want to.
I've got no clue whether that's the case for the dam you're mentioning, just giving an example where comparisons can go wrong. I can guarantee it's not 900x for 0.5x though, what it is exactly I don't know but perhaps you can name me the dam.
(in other news, the Guardian article is pretty shitty because it barely specifies any of the variables itself, like say a capacity factor. Read it as a general announcement, not a tech spec.)
That having been said, it IS a relatively more expensive project regardless. But one mustn't forget it includes a storage solution, too.
Hmmmm, yes. I have made an error in my logic by looking at peak production thanks for pointing that out.
Upon some digging I found that the Wanapum Dam in Washington (The one I was referencing) generates around 4 million MWh, or 4000 GWh per annum. Though the wiki is a little vague, not sure if that's max capacity or average. And looking on the Grant County website, it says that the dams construction cost was around $90 million, so a bit more than I previously stated.
On the other hand, the Quarzazate solar station will produce an expected 370 GWh per annum, according to the wiki. So, 10 times less power. Correct me if I'm wrong, but I think that the ratios still stay the same?
Edit: I was reading the wrong section of the wiki, phase 1 is 370 GWh. 2 and 3 add 1100 more. 1470 total.
The per-annum value is the total amount of energy generated over the course of the year. The Wannapum dam is rated at 1,400 MW; if it generated that 24x365, it would generate 12.3 million MWh. Since it actually generates 4 million MWH, it is running at about 30% capacity.
That said, a $90M dam in the 1950s would be a lot more expensive today. Partly due to inflation, but also for extra effort to preserve river ecology, etc. that nobody cared too much about back then.
So a few comments to make to explain some of the difference.
1) Damns aren't generally comparable to other renewable projects in cost, because they're dependent on a natural resource that doesn't scale. i.e. a sizeable river and geography that can act as a natural reservoir for water. Hydro can't really scale, even in Canada, a gigantic country with a relatively tiny population and a relatively huge hydro industry, can't really find new hydro projects that make economic sense because they've exhausted the opportunities already.
Imagine instead of energy, you'd be looking for a source of drinkable water for your goats. You can either build a pipeline to a nearby source of fresh water, or you can build a desalination factory. Of course the former is cheaper. But you can hardly compare its cost to another region that has no fresh water, and needs to build a desalination factory, and then say 'the price difference is huge!'. It's expected to be, particularly for very old hydro projects, which are usually the hydro projects that were the lowest hanging fruit and the easiest to exploit (unlike e.g. today's potential hydro projects in Canada, which are 10x more expensive than some of the old ones from decades ago. That cost differential is not really a function of technology)
2) Even disregarding the above, $10 in 1959 is not $10 today. In fact, it's ±$80 today. In fact, the project cost roughly $765m in today's dollars. I mean hell, in 2014 there was a crack that cost $69m to repair alone, almost as much as building it you'd almost think :p Citing a $93m cost is unintentionally misleading.
3) So about 11 more expensive, not 900x.
4) You're now referencing the 370 Gwh per annum figure, but that's for only the first part of the project that has 160 MW of capacity (which has a significantly lower cost than the $9b figure you're using). The $9b project has a capacity of 580 MW, so roughly 1350 Gwh per annum, so about 2/3rds less, not 10x less.
So you're off by a LOT with some of the numbers. Regardless, the point still stands that this is an expensive project, but then I refer to point 1) which is that you can't compare them. A better comparison would be to look at what it'd cost to build a new dam in Morocco, and there's not really much potential there that hasn't already been exhausted by the existing hydro stations in Morocco. Hydro would definitely be a more expensive venture, for sure, as would wind and fossil. As expensive as this may be, it beats what they currently have, which is importing 95% of their fossil fuels, which is a financial huge burden on a country that doesn't have a hard currency.
Anyway, short answer, no it's not 900x for half the power. Power stations are generally measured in capacity, often without mentioning the capacity factor. e.g. you could build a damn that can produce 1000 MW of power, but it is not connected to a river and relies on pumped storage, and have only storage for 1 hour of generating. The net energy generation of that facility is actually negative, a small cost for energy storage. You can't compare that to another installation which actually generates energy for 10 hours a day. They're completely different yet both carry a power rating which is not meaningful for comparing them in the way you'd want to.
I've got no clue whether that's the case for the dam you're mentioning, just giving an example where comparisons can go wrong. I can guarantee it's not 900x for 0.5x though, what it is exactly I don't know but perhaps you can name me the dam.
(in other news, the Guardian article is pretty shitty because it barely specifies any of the variables itself, like say a capacity factor. Read it as a general announcement, not a tech spec.)
That having been said, it IS a relatively more expensive project regardless. But one mustn't forget it includes a storage solution, too.