Energy Matters Global and Domestic

[bobins]

It's not quite that simple, unfortunately. There are still issues with the widespread use of battery storage to prop up the system at the moment. It gets horrendously complicated but a lot of it is down to the need for 'inertia' on the system and a stable controllable energy supply, and also the fact that wind / solar / battery require inverters, and those inverters are still showing issues on occasions - the inverters are what might be the root cause of the Iberian problem.
I think I remember reading somewhere before that the inverters require a grid supply to sync to, but they've been known to mis-read that sync and start doing their own thing...... which is less than ideal when you're feeding into the national grid

A quote from the article I linked to:
"In just five seconds, Spain lost approximately 15 GW of capacity, equivalent to 60% of its national electricity demand. The remaining generation was insufficient to meet demand, thus triggering a cascading failure across the entire grid."
........There ain't enough batteries to contain that magnitude of loss.

[thorter]

The trouble is that current large scale battery storage can only hold up the grid for seconds, then needs to be quickly recharged somehow. Much excess solar? In a largely wind plus solar scenario it would need days of storage to cover periods of low wind. This would need batteries amounting to many terawatt hours of capacity. In the UK, generation over a typical day is roughly 0.7 terawatt hours (700,000 MWh), and could double if universal home heating and charging 20 million electric cars is achieved. The largest current grid scale batteries are about 1,000 MWh, so many thousands would be needed.

On prices, don’t be fooled by current selective (cross) subsidies. Once everyone gets a cross subsidy, then no one will get any benefit. Also, at present, batteries seem to be dedicated to gaming the market, not holding an essential reserve.

[bobins]

Your last point highlights the bit so often overlooked !
The battery storage industry isn't really interested in having large scale installations sitting there waiting for that day / time when they're needed. The business model revolves around topping them up with cheap electricity, and then emptying them out when the sell price is higher - this selling can involve selling the power abroad via the overseas interconnects (probably actually quite a rare occurrence) or selling via a pre-arranged contract. The battery capacity might not be there in the quantities expected just when the grid needs it most
If you want to have sufficient battery capacity sitting there 'waiting for that day', then that will cost. A lot !!!

[thorter]

If you want a tacit admission that the whole thing is difficult or impossible, look no further than Milliband`s dedication to carbon capture and storage. If renewables were really the solution, then I am sure he would not be desperate to find a way to retain hated fossil fuelled generation at huge additional cost.

[bobins]

I think it'd just be easier to reclassify the fossil fuelled energy generation as 'green', much like they've done with Drax. IIRC, more carbon comes out the chimney at Drax with them burning wood pellets than would come out with a comparable coal fired power station. It's a funny old world......

[thorter]

Yes indeed. They would have you to take their word for it that these things achieve what is asserted. Somehow, what you know about it says otherwise.

Net zero by 2050, but it takes 80 years to regrow hardwood back to the original size, not to mention emissions from transporting it a quarter way round the earth.

[bobins]

......"A pessimist is seldom disapointed"

[thorter]

Aye, a pessimist, and much to be pessimistic about!

[mickthemaverick]

An interesting video in its own right but much food for thought for the electrical engineers among us!

[bobins]

The idea of grid forming inverters being useful and a good thing is entirely accurate and they are in use in some cases, but as ever with 'Just have a think', his stock-in-trade is based on idealism. It would be entirely possible to have a wholly 'green' based energy generation system to which the GFI's are attached and we'll all be happy, but then the public might object to the costs and the massive amount of land taken up with wind and solar and all of the disruption caused by installing another HV transmission system to link up these decentralised generation sites.

IIRC, the maths says you'd need to install somewhere like 3 times what the UK actually needs in energy generation capacity (for wind and solar) in order to guarantee meeting needs all of the time. For some of the time two thirds of output won't be required.... but the owners of the wind and solar sites will still want their income otherwise it's not worth building them if there's no prospect of a good return on their investment.... so they'll only build them if there are subsidies and income guarantees. The end result will be that you won't get cheap electricity out of this 'free' wind and solar.
Wind and solar have their uses, but it's a balancing act between using just enough of them against just enough of the dispatchable generation to ensure a stable grid for all.

On a point of order - Mr Just Have A Think says that the Tesla Big Battery in Aus has enough capacity "to meet 15% of the State's inertia needs without burning a drop of fuel". That's a somewhat meaningless statement designed to distract the gullible. How long can it supply this 15% of inertia for before it's exhausted ? A millisecond ? 2 hours ? Or somewhere in between ? A conventional spinning generator will provide 'inertia' for as long as you feed it with steam or gas (or water etc).

[thorter]

Indeed, power electronics have become ever more capable over the last fifty years, and may well be able to produce enough synthesised inertia to stabilise a 100% renewables grid - at a price.

The unsolved problem is what can be done about intermittency. A quick look at the UK Elexon grid data shows that a lot more storage than one month would be required to fill in the wind famines, at several times the current overall cost of the grid. Still, if there is no electricity generated, then no need to worry about grid stability!

[myglaren]

[myglaren]

It's rather long but has some interesting points.




Have viewed this in bite-sized bits and it all seems like common sense.
Note that it gets political toward the end.
Not that I disagree with him.

[mickthemaverick]

I found this a bit irritating from the narration point of view but brilliant for the content!!

[bobins]

The only problem I have with the above video, is that I'm struggling to find evidence that it actually took place......