Storage can be measured in watts as well as watt-hours. Doesn't help to have a 1TWh of storage if the output is limited to 1W. You need both. Not sure what the parent post was actually referring to though.
But watts IS actually important for balancing renewables. The storage is not so much about storing energy across days, as it is about frequency regulation. An interesting thing is - you'd think hydropower would be perfect for balancing renewables, but it's actually not on its own. You really don't want to ramp power up and down every second. It wears out the hydro power plant faster. Faster changes in pressure results in more wear and tear. So counter-intuitively, you're seeing some considering putting battery-storage in hydro power plants.
> Less than a gigawatt is in battery storage
It's funny how often numbers like this are presented with the intention of making renewables/storage look bad, when they're often incredibly impressive when you consider the context. The fact that battery storage has come this far, and most of it in only the last few years, is very impressive to me. The growth is exponential, so the fact that it's almost the same order of magnitude is promising.
> This works out to a few minutes of storage - and a matter of seconds of battery storage.
I don't think the whole country needs more than a day of total short-term storage. Especially if you combine it with more HVDC power lines. So doesn't seem that bad to me. Still a looong way from reaching the goal, but no solution is going to be complete in less then two decades.
For long term storage there needs to be other solutions. For those rare days/weeks where there's somehow significantly less solar and wind for a longer period over a larger area.. it might be a good idea to just keep some gas power plants around. If you only use them a few times a year, I think we can make enough CO2-neutral fuels for them.
For winter months in colder climates, you can also look to countries like Sweden. Make trash burning power plants that use its heat to heat nearby homes. Very efficient, and you can "store" power by storing trash. Southern areas can "transfer" power to the north by sending its trash there. Modern plants are incredibly clean burning. In Oslo they also have a demonstration that combines it with CO2 capture and storage.