5 ms·
It’s not really watts as there is no real power output. It’s an accident that the units are homogeneous but the output is in Wh/y, where Wh is a convenient way
by SnowHill9902 4y ago
It’s not really watts as there is no real power output. It’s an accident that the units are homogeneous but the output is in Wh/y, where Wh is a convenient way of describing the capacity of a battery (under standardized conditions) and not real energy outputted.
- osrec 4y agoCould you elaborate please? Why is there no real power output?
- SnowHill9902 4y agoWhen you purchase a battery are you interested in the energy that they contain or in their capacity to store and output energy repetitively?
- osrec 4y agoInteresting. I think I would still be interested in the total energy held by the battery, plus the amount it is expected to degrade year on year. I'm still not sure why you say Wh/y would be a more appropriate unit, given that it would change as the battery degrades.
- atwood22 4y agoWatt hour is a unit of energy. Energy is the capacity to do work. When the batter leaves the factory, it is empty. It has no energy, but it can hold energy if you give it some. It's like if you produced gallon-sized plastic water jugs. Let's say you made 1000 a day. Would it be accurate to say you produced 1000 gallons of water a day? No, you produced 1000 empty jugs.
- jupp0r 4y agoBatteries are charged when they leave the factory. Besides that 1000 gal/d of storage capacity in your example is a valid unit for specifying factory output, is it not?
- atwood22 4y agoYes, "1000 gal/d of storage capacity" is valid. "1000 gal/d" is not. Even if you used 1000 gal/d colloquially, you would have been talking about the capacity of the bottles. The misconception you're having here is that "GWh of storage" is the volume of the bottle. You're interpreting it as "GWh", which in the bottle example would be like saying "They produce 1000 gallons of water / d".
- epistasis 4y agoBoth?
- ajmurmann 4y agoThanks for adding the "/y" which is what was missing for me.
- jupp0r 4y agoThat’s like saying that battery capacity isn’t really kWh because there’s no real energy storage when they are empty. The unit for energy capacity output is still Watt (or horse power seconds per year or any other unit). Besides that, those battery cells are charged as part of the production process (though not completely), so I could argue that actual energy is leaving the factory.
- SnowHill9902 4y agokWh as capacity of a battery is similar to ml as capacity of a bottle.