> The tried-and-true grid-scale storage option—pumped hydro [--> https://spectrum.ieee.org/a-big-hydro-project-in-big-sky-cou... ], in which water is pumped between reservoirs at different elevations—lasts for decades and can store thousands of megawatts for days.

> Media reports show renderings of domes but give widely varying storage capacities [--> https://www.bloominglobal.com/media/detail/worlds-largest-co... ]—including 100 MW and 1,000 MW.

It looks like the article text is using the wrong unit for energy capacity in these contexts. I think it should be megawatt-hours, not megawatts. If this is true, this is a big yikes for something coming out of the Institute of Electrical and Electronics Engineers.

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B1FF_PSUVM an hour ago | parent | next [-]

> big yikes for something coming out of the Institute of Electrical and Electronics Engineers.

Besides the unit flub, there's an unpleasant smell of sales flyer to the whole piece. Hard data spread all over, but couldn't find efficiency figures. Casual smears such as "even the best new grid-scale storage systems on the market—mainly lithium-ion batteries—provide only about 4 to 8 hours of storage" (huh, what, why?). I could also have used an explanation of why CO2, instead of nitrogen.

	▲	hkt 36 minutes ago \| parent [-]
		I'm sat here thinking: why not compressed or liquefied air?

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Waterluvian an hour ago | parent | prev [-]

If 1 watt is 1 joule per second then, honestly, what are we doing with watt-hours?

Why can’t battery capacity be described in joules? And then charge and discharge being a function of voltage and current, could be represented in joules per unit time. Instead its watt-hours for capacity, watts for flow rate.

Watt-hours… that’s joules / seconds * hours? This is cursed.

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B1FF_PSUVM an hour ago | parent | next [-]

It's easier to figure out for people that measure power in watts and time in hours ... 1 kW for 1 hour is 1 kWh.

That camel's nose was already in the tent with the mAh thing in phone/etc batteries, now with electric vehicles we're firmly in kWh land.

Not to mention that's what the power utilities used all along ...

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SigmundA an hour ago | parent | prev [-]

A watt of power multiplied by a second of time has an agreed upon name called joule, but a watt second is also a perfectly valid SI name.

A watt is a joule of energy divided by a second of time, this is a rate, joule per second is also a valid name similar to nautical mile per hour and knot being the same unit.

Multiplication vs division, quantity vs rate, see the relationship? Units may have different names but are equivalent, both the proper name and compound name are acceptable.

A watt hour is 3600 joules, it’s more convenient to use and matches more closely with how electrical energy is typically consumed. Kilowatt hour is again more directly relatable than 3.6 megajoules.

Newton meter and Coulomb volt are other names for the joule. In pure base units it is a kilogram-meter squared per second squared.

	▲	hunter2_ a few seconds ago \| parent [-]
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