Right, I think that's a main issue because you lose efficiency when converting back and forth and probably over time in storage unless the storage form is highly stable.

Why store electricity though?

Many large consumers (such as steelworks) have a reduced tariff on the basis that the grid can require them to shed load so many times a year at some hours' notice. Rather than storing electricity, could not a process be identified that:
1) Produces useful, storable, product
2) Can be quickly switched on and off
3) When running uses a lot of power.

As a starter, sea water electrolysis for hydrogen production might be a possibility. During periods of normal demand processing could continue as normal, but the main current could be dropped at short notice. Of course this would predicate upon there being a large baseline demand for hydrogen, but it has been talked about (for a long time) as a petrol/gasoline replacement. Who knows, it might even be possible to absorb wind farms varying output in such a manner and get some useful production out of them!

Whether hydrogen is an answer or not, multiple energy conversions are wasteful, it must be better to find an interruptible process to absorb excess and release it on a demand surge.

Yes, the alternative to storage might be consumption control. Storage is required if you have too much sustainable energy generation in your grid and too little classic generation reserve. The question is when that situation comes true.

Pumping water into high reservoirs, compressing air etc all seem to me solutions with too little capacity. Only when you have complete lakes as reservoir at your disposal with sufficient fall it might be feasible.

Production of hydrogen looks to me like creation of clean fuel which can be stored like oil or gas, and in large quantities. I don't quite understand why until now it is (almost not) being done. Is it very inefficient (energy wise) to produce, expensive hard to store, difficult to utilize?

jlinkels

That's a thing, it's sometimes easy to propose storing in some alternate form. The question does become how efficient is it to convert and then store energy as hydrogen, as well as how safe; all can be addressed. And then how useful is it to employ it when you now need to make energy from that stored medium. But a contrary argument could be that unused energy is completely unused if it's not doing something like making itself into stored energy, however inefficient that whole process may be. I've also read about storage for hydrogen in things where the structure is very small/porous such that the likelihood of explosive or uncontrolled reactivity are much lower. If you were able to convert to some form with pure excess energy, store it safely, and then re-use it at a time when you needed it, it might be one step better than doing nothing. Right now I think there's a lot of research on it, but no proposed deployments.

This is what's used at present as has been stated in earlier posts. This is one of the reasons that they "switch off" the wind turbines, (apart from too much or lack of wind!) because they don't need the power, a spinning turbine just wears out bearings, etc, so leaving it spinning when not required is not a viable proposition economically.

The grid controllers are continually monitoring the demand and adjust the supply accordingly.

As I mentioned earlier, one of the gripes here in the UK is that the Energy Companies are paid a Government subsidy, compensation if you will,for the times when they are NOT generating electricity and the wind turbines are at a standstill! We. the taxpayers, have subsidised the Energy Companies in building the wind farms then we have to pay AGAIN because they're not generating any power which the Energy Companies could have sold to consumers! I'm sure I read in some newspaper somewhere that some companies have a greater income from the turbines when they're doing nothing that when they're actually producing electricity!

Were also getting to a situation where fossil fuel stations, coal, gas and oil are being slammed with green taxes and phased out without any replacement. There's a dire need for a fresh base line supply. Nuclear power has always been the bogy man but it's clean and cheap. (OK, so you have to define "clean") There seems to be an aversion to building any new ones after the old, and I mean "old" ones have been decommissioned. Why don't we hear of anyone building Thorium Molten Salt reactors? Cheaper, can't melt down and can even be used to get rid of current nuclear waste! Sounds like win win!

Play Bonny!

A while back I was reading about some work done in Glasgow to improve low temperature electrolysis. Couple this with modern nuclear and there seems such an obvious way forward. Nuclear runs at continuous base load, switching hydrogen production on or off to absorb the excess electrical production. We power transport by fuel cells (or even adapted ICE) and leave most of the fossils underground.

The trouble is that the green lobby have got us into the position that a really bad snap or a single station going off line could trigger a collapse, there just isn't the reserve: cold, hot or spinning. The next few years may be "interesting".