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Comment by toxik | Hacker News Reader

You can still divide GWh of capacity by a year and get GW of capacity, ie the instantaneous production rate of capacity.

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No you cannot. Watt hour is a unit for energy derived by applying power over time. That’s why when you divide by a period of time you’re left with power. The unit “GWh of storage” is a complex unit that’s not easily broken up. When you divide by time you get a new unit, “GWh of storage per unit time”

You are conflating two different concepts here. One is "unit" which is a measure of a physical quantity (ie "GWh"). The second is the physical quantity itself ("battery storage capacity"). The relationship between the two is that a unit can be used to quantitatively describe a physical quantity ("5 GWh of battery storage capacity"). Physical quantities like "battery storage capacity" can usually be quantified in different units which can be converted to each other ("5000kWh = 5GWh = 1.8 * 10^13 J"). The unit itself ("GWh") doesn't describe precisely what physical quantity is being measured. It could be mechanical energy stored in a flywheel, the total heat output of a chemical reaction, battery storage capacity, etc.

You’re fundamentally misunderstanding the units. I don’t know what else to say. “Watt hour of storage” is not the same as a Watt hour. You can’t divide by time to get power. That should be obvious.

"Watt hour of storage" is not a unit, it's the physical quantity "storage" quantified by the unit "Watt hour", ie the combination of the two.

That’s what you’re not understanding. “GWh of storage” is a unit. It’s not an SI unit, but it is a unit, i.e. a thing you can use to measure something. The production of this factory is being measured in this storage unit. Watt is also a unit, a unit to measure power. There is no way to convert a unit of power to this unit of storage.

Do you have a reference for the definition of this energy storage unit? I have never heard of it before and my attempts at searching the web seem to contradict you.

Wikipedia writes: “Storage capacity is the amount of energy extracted from an energy storage device or system; usually measured in joules or kilowatt-hours and their multiples”

https://world-nuclear.org/information-library/current-and-fu... writes: “Storage systems for electricity include battery, flywheel, compressed air, and pumped hydro storage. Any systems are limited in the total amount of energy they can store. Their energy capacity is expressed in megawatt-hours (MWh), and the power, or maximum output at a given time, is expressed in megawatts of electric power (MW or MWe).”

Both of which to my layman reading opposes your claim.

You decided all on your own that GWh of storage cannot be divided by a time unit to create another 'new' unit, GW of storage. Repeat: _You_ decided that. I can explain it simply: One GW of storage is equivalent to producing one gigajoule of storage per second.

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