Blue Apple wrote:
1) it doesn't maintain 3x the average load, extreme variations are handled by energy souces with a high fraction of regulating power (gas turbines, hydro...)
In other words there is the CAPACITY to deal with them. And the ratio of worst-case east-coast load to average is about 2, today. See here for the NY ISO data, page 14. www.nyiso.com/public/.../media.../power ... _final.pdf
2) unused capacity is "cheap" as it only implies overdiminsioning plants (capital costs) and running out of optimal range during peak periods. As long as the extra capacity is not needed, there are no associated fuel costs because the power is simply not produced.
Duh. You must pay the excess capital costs associated with maintaining the over-capacity, this is hardly cheap. At 2X, this means twice the capital one would otherwise need.
The study assumes no transport losses and perfect connection between all points.
So of course it doesn't require the grid to be rebuilt, it starts with an imaginary one.
No it doesn't assume that at all, although just exactly what it does imply would be a complex secondary study. The proposed solution has a LOT of storage. What isn't clear from the prose of the study is how much of the temporal variability is handled by the storage vs handled by transmission within the region.
The decorrelation ranges for wind and solar are both shorter east to west than north to south for the obvious reason of the mean winds and storm tracks. The atlantic region is fairly narrow east-to-west. This is WHY the proposed solution uses so much storage.
The atlantic region transmits substantial power as it is (again, see the NY ISO study and use some common sense), and it pays the transmission losses to do so. It's certainly not obvious that the proposed alternative would lose more power to transmission.
It also assumes that existing fossile fuel generators will be the same as today even if they are only used a couple of hours a year.
WTF you mean "the same?" But in any event it certainly does not! For starters, only a small fraction of them would be kept, once the scenario had been built out as stated.
You appear to think that there will be cases where today's worst-case peak loads would need to be met by backup generation because there would be ZERO wind or solar available at that moment. This is nuts. Peak loads are always daytime, and they are also highly correlated with solar availability BECAUSE the peak loads are driven by AC demand.
The paper doesn't show the distribution of system under-supply; the "tail" of that plus some margin would be the required backup / peaking capacity. Other studies I've seen haven't had this much storage, because they have been for areas with better resource. I'm hesitant to guess what the backup / peaking capacity need would be here, but with this much storage it will be smaller than the backup /peaking capacities imputed by other studies ... which have tended to be on the order of 20 - 30% of average
demand at 90% PV+ solar penetration (fraction of total WH).
Because current generating capacity is about 2x average demand in the NE, this would imply that about 10 - 15% of the existing fossil capacity would need to be kept ... or something less due to the high storage.
Jeez same damn "people" who tell the existing producers that they can only sell half or less of their capacity much of the time: the power-pool ISO and the auction.
As to your second point, no it doesn't change either, because the US is committed now to rational power-pools by fair auction.
Who is gonna tell a producer that they can only sell 1/3 of their
capacity at a given time?
Failure to understand these basic facts makes me question your claims of knowledge here.
Who is going to manage the huge power storage installations?
Probably the owners of the wind+solar. By controlling it they get to bid more attractively into the auctions than if they didn't. This is happening right now, incidentally.
Who is going to build the 3x more transmission lines needed to connect all this storage and distant generating fields?
This is nonsense. There is NOT 3x of the power of today's peak loads being transmitted -- DUH! The storage will be located/associated with the generation so that this is not so.
You are conflating capacity margin with transmission requirements. I think you are FURTHER conflating peak-capacities, which are stated for the wind and solar renewables, with their mean outputs. Wind power capacity factors can be up to 0.4 at really favorable sites (And to some extent depending on the turbine name-plate rating. The modern trend in turbines is to design and rate them for maximum power output at somewhat lower wind speeds, which has the effect of making the achieved capacity factors at any site look better) but more typically runs 0.3 to 0.35. These days sites with capacity factors below 0.3 are losers ... but some turbines do get foolishly sited. And in the past a lot more got badly sited. They are smarter about it now.
Solar capacity factors in the NE suck, relative to other parts of the country. I don't know of anyplace in NY or MA with capacity factors for PV above 0.16 ... and 0.13 is a better estimating number for residential solar in most cases.
As I said the interesting part of the article is about the spatial and temporal averaging needed to achieve high availability wind power. The economic part is either trivial or unrealistic.
The "economic part" is simplified, but your counter-claims don't impugn it, and you admit the substance of the paper.