A little off topic, but is no one else concerned about all of this optimization, regardless of the raw source of the power.
Once upon a time all generation was local, and had to be sized for peak loads. Inefficient, but lots of inherent excess capacity almost all of the time. Made a pretty robust system.
Then we started grids and sharing power over regions. Allowed for statistical reduction in peak capacity. It didn't really cut load peaks too much, just by the slope of the daily curve over the east-west extent of the grid, but did help a lot with the somewhat random fluctuations and allowed more resistance to single generator failures.
Now we are talking about avoiding need for more generation by using storage to precisely level out the daily swings. Raw generation capacity need only be equal to average demand, with some argument about the duration of storage and the length of the average.
The resultant system seems brittle to me. If something gets a little behind it can never catch up.
The theory is that it will never get behind, mothballed plants will be brought online quickly (weeks to months) if the market price starts rising because supply is getting scarce. But the current UK grid lacks storage for peaking with only 1.6GW of hydro against a peak demand of around 60GW, compare this to the Australian installed base of 7.8GW against a peak demand of around 50GW. You can see how the hydro and gas plants are used for peaking from their energy contribution compared to their installed capacity share:
https://www.aer.gov.au/wholesale-markets/wholesale-statistics/generation-capacity-and-output-by-fuel-source
The general trend is you need to introduce more "excess" capacity for peaking/reliability, and even more again if there are intermittent renewables dumping their low cost energy into the grid. Right now the only plants that have the ability to sit idle and deliver stored power quickly are gas and hydro, oil is slower, and coal slower again, nuclear is uneconomic to run at anything other than a constant load.
The peak, measured in GW, is not a fundamentally important factor since renewables output is fairly predictable in the short term (hours). Certainly the UK's hydro is sufficient in that respect.
What is more important and difficult to achieve is storage, measured in GWh. The UK's hydro is completely insufficient for that - and will be for the foreseeable future. A noticable proportion of it has to be reserved for "black start" capability.
The peak alone is critical to this discussion about robustness,
No. The instantaneous peak (measured in Watts) is merely
one of the factors; the
duration of the peak is just as fundamental. That's most sensibly measured in power-over-time, i.e. energy i.e. Watt-hours.
The UK has perfectly adequate short term (tens of minutes) pumped storage capacity, but nowhere near sufficient for the troughs related to intermittent renewables.
whatever sources of energy are chosen the available capacity needs to exceed the peak at all times for energy security, this is the stupid reductionist argument that the grid cannot be 100% renewable generators only as they have a chance of not being available and their available capacity is 0 (while they still manage to generate a 25-30% load factor annually). The peak to trough is important also, you can't take out the fast slewing plants and replace them with nuclear reactors (unless you accept they will be running load dumps routinely, which are possibly better than negative energy prices but at least they send a message to the market). You could have any mixture of generators coupled with storage that can deliver the peak power, then its a matter of sizing the energy storage and energy production to match the expected delivery.
And the latter is subject to - and largely determined by - practicality and economics.
If the hydro was emptied and then there is inadequate energy available over winter then the hydro plants were operated sub optimally from a market perspective, they will generate the most money when the market is on the brink of collapse and are the only options available.
Heaven preserve us from people that
think they understand how markets work.
Let's consider a very simple example from a different domain, the supply of Christmas Crackers or bananas (which are the same as PCs in the sense that if either are on the shelf too long, they begin to smell).
The worst thing that can happen to a retailer is that they order too many crackers/bananas/PCs and are left with them on the shelves after Christmas or when they are rotting. If there's a 10% margin on each product, then if 10% are left over that's the whole profit from the entire 100% gone down the drain. The normal response is to order slightly
fewer than they think they could sell, say 90%. Then they have reduced the risk of losing 100% profit to not gaining 10% of the profit. Don't take analogies too far, but similar phenomena do occur in many markets.
In other cases, a valid market strategy is to squeeze as much profit out of consumers for a limited time, and then simply exit the market. Bugger the consumers; they are then somebody else's problem. That repeatedly happens here in transport and healthcare industries.
Anybody that puts all their trust in "market forces" is simply ignorant of history and economics. Even Adam Smith recognised that!
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