Re: Grand Apagon - Electricity (not) in Spain

On 2/05/2025 8:03 pm, Martin Brown wrote:

On 01/05/2025 18:41, Bill Sloman wrote:

On 2/05/2025 2:21 am, Liz Tuddenham wrote:

Bill Sloman <bill.sloman@ieee.org> wrote:
>

On 30/04/2025 7:59 pm, Liz Tuddenham wrote:

Bill Sloman <bill.sloman@ieee.org> wrote:

<snip>

So it is completely passive. A big battery isn't a primary source but it can provide enough DC current to let your grid scale inverter generate exactly the AC output that you need.

 There is a surprising amount of kinetic energy that can be stored in a flywheel or other rotating piece of big heavy machinery.

https://en.wikipedia.org/wiki/Mark_Oliphant
His homopolar generator, finally built in Canberra, is a spectacular example.
"In 1955, Oliphant initiated the design and construction of a 500 megajoule homopolar generator (HPG), the world's largest. This massive machine contained three discs 3.5 metres (11 ft) in diameter and weighing 38 tonnes (37 long tons). He obtained £40,000 (equivalent to A$3,000,000 in 2022) initial funding from the Australian Atomic Energy Commission.[82] Completed in 1963, the HPG was intended to be the power source for a synchrotron, but this was not built.[83] Instead, it was used to power the LT-4 Tokamak and a large-scale railgun that was used as a scientific instrument for experiments with plasma physics. It was decommissioned in 1985.
It started off with sodium-potassium liquid metal brushes, but after an unfortunate explosion they get replaced with big carbon brushes that worked fine.

The grid has  adopted large scale solar PV and wind farms with some very flaky inverter technology whose interractions are not at all well

 > understood.
Which is to say that the engineers who designed them didn't know as much about what they doing as they should have done.
The 2017 Hornsdale Reserve grid scale battery seems to have been better engineered. About half it's capacity is devoted to maintaining the cycle by cycle stability of the South Australian grid, and it hasn't fallen over yet.

One of the internal reports I was reading recently mentioned that they were thinking about funding a PhD to look into some of the complexities. It is pretty clear that the system is not well thought out.

That might be an overkill, but it would be a cheap way to get a decent literature search. A bit hard on the poor graduate student who got stuck with doing it - researching the hell out of problem that has been solved elsewhere isn't a royal road to publishable research results.

Why futz around with the rotating metal? It may entertain tourists, but that's really all that it is good for.

 Because it was always just there and now that it isn't the replacement inverters on many of the big installations are nowhere near good enough at simulating the required behaviour. They are too inclined to drop off and save themselves (much like nuclear plant also does). I suspect that Spain doesn't have a great deal of battery storage or pumped water.

Dropping out and saving themselves may be an easy design choice, but the designer should be able to do better. Whoever designed the Hornsdale reserve hardware does seem to have done better.

Based on the time it went tits up it seems likely that it failed due to too much power being forced into the network and not enough load of last resort or exports to France down the one puny cable they do have.

Grid scale batteries can soak up a lot of power - at least for a short while.

UK's intermittent loads of last resort are also diminishing as steel works closed although it is never really sunny enough here to matter and wind turbines can be easily feathered (and paid handsomely to do SFA). There is really only the chloralkali plants at Runcorn left now.
 Silly electricity prices based on the wholesale price for gas have pretty much destroyed aluminium and steel making in the UK. Scotland has a couple hanging on by their fingernails hoping for a reprieve.

Intermittent power sources demand grid scale storage. The UK has had
https://en.wikipedia.org/wiki/Dinorwig_Power_Station
since 1984. The wikipedia page talks about planned follow ups, but it's all a bit too complicated for the UK civil service.
--
Bill Sloman, Sydney