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> the seasonal natural balancing between wind and solar

Yep, this is important as storage of energy over seasonal time scales is hard. One can match and mix wind and solar to follow the annual load cycle.

...but not just the seasonal cycle: wind and sun anti-correlate also on the synoptic time scale, with high pressures being sunny and low pressures windy.

by mustakissa on Fri Oct 5th, 2012 at 09:01:38 AM EST
[ Parent ]
Big dams are your friend. :)

Peak oil is not an energy crisis. It is a liquid fuel crisis.
by Starvid on Fri Oct 5th, 2012 at 09:11:33 AM EST
[ Parent ]
Unless you live downstream from this one.

It is rightly acknowledged that people of faith have no monopoly of virtue - Queen Elizabeth II
by eurogreen on Fri Oct 5th, 2012 at 10:46:42 AM EST
[ Parent ]
Certainly, but they also have their limitations. And you only find them in certain countries...

You can, e.g., store quite huge amounts of energy in the Norwegian mountains. But getting it out quickly enough when you need it may be a problem. Even after installing all the necessary extra turbines and high-voltage lines -- where do you put all the water downstream of the dam?

by mustakissa on Fri Oct 5th, 2012 at 12:12:31 PM EST
[ Parent ]
In the river, where it is collected by the next dam.

There is also the option of pumped hydro, which would become far more attractive with access to sovereign credit.

Peak oil is not an energy crisis. It is a liquid fuel crisis.

by Starvid on Fri Oct 5th, 2012 at 05:44:15 PM EST
[ Parent ]
In the river, where it is collected by the next dam.

Eh, I'm talking GW, not TWh. Where do you put a huge amount of water all at once in a small river, with picturesque, small Norwegian villages lining the shores?

by mustakissa on Sat Oct 6th, 2012 at 04:53:18 AM EST
[ Parent ]
Naturally there are limits. In Sweden it is regulated in Vattendomar that sets highs and lows and a ton of other things. Regulated rivers are precisely that from a legal standpoint.

Have no idea what the order of maximum effect is with relation to water flows. Should not be much lower then total maximum effect though, not much point in installing more effect then the Vattendom allows water flow, though there is probably an effect on each others maximum allowed flow in the case of rivers running together. Total installed hydro capacity in Sweden is about 16 GW in Sweden.

Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se

by A swedish kind of death on Sat Oct 6th, 2012 at 05:29:21 PM EST
[ Parent ]
Yep, and in Norway 29 GW. And that's the rub. Read the title of the article: 100 GW wind installed and growing. And total consumption in Europe somewhere in the 400 GW range, and that should grow too, if we want to electrify our other energy uses, like transport, space heating, process industry, metallurgy. Electrifying those is the only way to get around the lousy Carnot efficiency of burning stuff...

So, currently Scandinavian hydro can produce only a tenth or so of total electric power consumed in Europe. If it is to serve as intermittency back-up, it should be much larger than that. As it is, it may serve Scandinavia, Scotland, the North of Germany, and that's about it. And that will require substantial investment, in HVDC lines and turbines. So, it's part of a solution at best. Alpine hydro will be another part.

Whether a hydro plant can be upgraded will depend on what's downstream: another big reservoir, a fjord, or the sea: good. And no, you don't actually need pumped hydro if the reservoir is big enough: you can "store" energy by holding back the flow, for a while at least. And the good news is that the reservoirs are lowest towards spring, when in winter there are good winds over Northern Europe.

Some reading stuff from Norway here:

http://www.cedren.no/Publications.aspx

esp. the first article.

by mustakissa on Sun Oct 7th, 2012 at 07:48:47 AM EST
[ Parent ]
You're neglecting scheduled load-following. If all the wind in Europe is offline at the same time, we will know about it at least a day in advance. Dedicated peakers only need to cover the forecast errors and unexpected plant shutdowns.

Suppose you have a sustainable grid in which the baseload is wind, solar, and run-of-river hydro (and wave and tidal); scheduled load-following power is wood pellet, biochar, and large industrial consumers being paid to shift energy-intensive production around to other parts of the day/week; and peak load is hydro, pumped hydro and biogas.

Suppose further that European total consumption is on the order of 1 TW at the daily and seasonal peak, and 0.65 TW at the trough. If the largest single point of failure is 10 GW, with an 0.3 % probability of failing during any given day, and the largest forecast error for consumption in any given day has a standard deviation on the order of 20 GW, or about 2 % of peak power.

Now assume that we want to have enough peaker capacity to make blackouts only happen once every 1800 days (approximately five years) on average, and keep enough peaker power online at all time that we only need to bleed off scheduled power about once a year. That means you need about six or seven standard deviations plus the largest single point of failure. Call it 150 GW of dedicated peaker power. For all of Europe, in a fully sustainable grid. So 50 GW of peaker power from Scandinavia alone is very definitely in the right ballpark.

The real challenge is going to be coming up with sustainable scheduled load-following.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Sun Oct 7th, 2012 at 09:07:07 AM EST
[ Parent ]
Being able to predict it doesn't absolve you from having to provide it! As you said it,

The real challenge is going to be coming up with sustainable scheduled load-following.

I think you misread me: I'm not implying that the mechanics of load following would be a problem of consequence even at ~100% renewable penetration. That meme is nonsense. But we do need load-following power above and beyond hydro.

I don't think using bio-fuels for this is a good idea: they are limited in availability, and it would be better to reserve them, e.g., for transport, where they are hard to replace completely. One solution on the longer run would be hydrogen fuel, generated by electrolysis from peak wind/solar. This is already being studied. Besides being burned in power plants, hydrogen has some direct uses, e.g., in steel making (one example of a user that could switch off on request and use stored fuel).

This would require the installed capacity of renewables to be more than 100% of average electric power load, e.g., 150%. A tall order, but the North Sea is large enough for a big chunk of that.

by mustakissa on Sun Oct 7th, 2012 at 10:03:04 AM EST
[ Parent ]
"...implying that the mechanics of load following would be a problem of consequence even at ~100% renewable penetration. That meme is nonsense."

I would not bet the farm on that.

by asdf on Mon Oct 8th, 2012 at 12:11:33 AM EST
[ Parent ]
The economic characteristics of the market interact with the physical characteristics of the power system, and the two must be considered as a whole...not so easy to do...

http://arxiv.org/abs/1106.1401

by asdf on Mon Oct 8th, 2012 at 12:43:43 AM EST
[ Parent ]
Yep, there are folks that study this for a living. Still, no show-stopper...
by mustakissa on Mon Oct 8th, 2012 at 06:39:50 AM EST
[ Parent ]

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