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California breaks 1 GW energy storage milestone

pv-magazine-usa.com

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Re: California breaks 1 GW energy storage milestone

#31

Post by vondur »

jedberg wrote: post #25

As a Californian who has been watching the CalISO web page since the 90s, what I find most interesting is that the peak usage and total generation now is pretty much the same as it was in the 90s (~50MW). Based on the energy mix, it looks like lost coal capacity has been replaced with solar and other green energy, and demand has gone down relative to population because of efficiency initiatives and rooftop solar for…

California still imports a large amount of power from other states (primarily Arizona and Utah, with some hydro from Oregon). So we essentially outsourced a lot of our power production to other states.

Re: California breaks 1 GW energy storage milestone

#32

Post by [deleted] »

cptskippy wrote: post #29
samatman wrote: post #24

Earlier quoted context omitted.

It is a bit confusing, but it isn't wrong, there are just two capacities in question. We could call them power capacity and energy capacity. This system can deliver 2000MW for four hours, or 1000MW for eight hours, but can't deliver 4000MW for two hours, because that exceeds the power capacity.

Why not call it the rate or throughput? We don't state that a car with a 100mph top speed has a 100mph capacity.

[deleted]

Re: California breaks 1 GW energy storage milestone

#33

Post by HPsquared »

pranavjoneja wrote: post #5
firebaze wrote: post #3

Earlier quoted context omitted.

"My car runs 100 miles!" instead of "My car runs 100 miles per gallon!", and almost anyone would notice something is amiss. I don't get the difference to mixing "Watts" with "Watts/hour".

Energy is not Watts per hour (Watts/hour), it's Watts times hours (Watt-hours). Sorry for pedantry, but the units are the topic of discussion here.

That's got me trying to visualise "mile-gallons", and failing because its dimensions would be "length^4".

Re: California breaks 1 GW energy storage milestone

#34

Post by vondur »

danans wrote: post #7
philipkglass wrote: post #4

Energy storage projects are typically described in terms of maximum power (megawatts) and hours of supply at peak power. Multiplying hours and megawatts gives megawatt hours, a unit of energy. Gigawatts and gigawatt hours are just different magnitude units for the same power and energy values, like meters and millimeters. Most electrical grids experience peak demand in the early evening when people come home from wor…

> Gigawatts and gigawatt hours are just different magnitude units for the same quantities, like meters and millimeters. I liken it more to distance vs speed. Power, like speed, is a rate, in particular the instantaneous rate at which energy is transferred. Expressed using the same scheme we use for speed (distance per time : power per time), power is watt-hours per hour (or 0.0036 megajoules per hour). I'm guessing w…

This is what confuses many people, especially with solar and battery storage. "I've got 400 watts of solar feeding into my 400AH of batteries with a 3000w inverter" Most people will have no idea how much usable power they get and how much energy storage they need to meet their needs. (this example is mostly from an RV perspective)

Re: California breaks 1 GW energy storage milestone

#35

Post by renewiltord »

sib wrote: post #30
samatman wrote: post #24

Earlier quoted context omitted.

It is a bit confusing, but it isn't wrong, there are just two capacities in question. We could call them power capacity and energy capacity. This system can deliver 2000MW for four hours, or 1000MW for eight hours, but can't deliver 4000MW for two hours, because that exceeds the power capacity.

But then it seems that they should say "2000MW of delivery capacity" rather than "storage capacity"

It’s not “storage capacity”, it’s “energy storage capacity”. Think of it like “sources of power”. Source 1 is nuclear, Source 2 is Hydro, Source 3 is Energy Storage.

What are our power sources available to the grid today? Nuclear, Hydro, Energy Storage.

What are the capacities?

Nuclear capacity is 1 GW

Hydro capacity is 1 GW

Energy storage capacity is 2 GW

Re: California breaks 1 GW energy storage milestone

#36

Post by HPsquared »

2Gkashmiri wrote: post #27

I got my "hybrid" inverter today. My panel size is 330w x 16. So 5.2kWh. Grid tied system. 1 year. Average production 28 kWh on a good day with no grid power cuts. Well the new hybrid inverter from phocus is supposed to use the generation when grid outside is down internally at home and that opens up a lot of possibilities. Been thinking about using solar water heating to reduce electricity consumption but that is a…

I wonder if anyone has invented a "storage heat pump" for air conditioning purposes.

Re: California breaks 1 GW energy storage milestone

#37

Post by tohmasu »

long_time_gone wrote: post #6
firebaze wrote: post #3

Earlier quoted context omitted.

"My car runs 100 miles!" instead of "My car runs 100 miles per gallon!", and almost anyone would notice something is amiss. I don't get the difference to mixing "Watts" with "Watts/hour".

Not knowing the difference in miles and miles/gallon will get you stranded in your car pretty quickly. Now knowing the difference between watts and watts/hour will have almost no appreciable effect on your life. You flip a switch, the light turns on, and you get an invoice a month later.

Sure, but people writing articles on the subject should know better than to mix units like this.

Re: California breaks 1 GW energy storage milestone

#38

Post by danans »

vondur wrote: post #34
danans wrote: post #7

Earlier quoted context omitted.

> Gigawatts and gigawatt hours are just different magnitude units for the same quantities, like meters and millimeters. I liken it more to distance vs speed. Power, like speed, is a rate, in particular the instantaneous rate at which energy is transferred. Expressed using the same scheme we use for speed (distance per time : power per time), power is watt-hours per hour (or 0.0036 megajoules per hour). I'm guessing w…

This is what confuses many people, especially with solar and battery storage. "I've got 400 watts of solar feeding into my 400AH of batteries with a 3000w inverter" Most people will have no idea how much usable power they get and how much energy storage they need to meet their needs. (this example is mostly from an RV perspective)

In general, people are not used to formally separating power and energy as concepts, much less as units of measure.

This makes perfect sense because most of the measurements of things we own or consume are counted in units like area, volume, and energy, which are inherently more tangible than an instantaneous rate like "power". Speed is a bit of an exception to this, but I think that has to do with the ubiquity of speedometers in cars.

To the extent that people broadly understand power as distinct from energy they tend to do so in a mechanical, not an electrical context, and in less precise terms ("That's a powerful truck"). However, some exceptions to this are light bulbs and electric space heaters, where people generally understand power as being proportional to brightness and heat output.

In a way, it's an incredible testament to the engineering of electrical systems that people have been able to largely ignore the difference between power and energy, or just need to flip a circuit breaker if something exceeds a limit.

Re: California breaks 1 GW energy storage milestone

#39

Post by Ajedi32 »

vondur wrote: post #34
danans wrote: post #7

Earlier quoted context omitted.

> Gigawatts and gigawatt hours are just different magnitude units for the same quantities, like meters and millimeters. I liken it more to distance vs speed. Power, like speed, is a rate, in particular the instantaneous rate at which energy is transferred. Expressed using the same scheme we use for speed (distance per time : power per time), power is watt-hours per hour (or 0.0036 megajoules per hour). I'm guessing w…

This is what confuses many people, especially with solar and battery storage. "I've got 400 watts of solar feeding into my 400AH of batteries with a 3000w inverter" Most people will have no idea how much usable power they get and how much energy storage they need to meet their needs. (this example is mostly from an RV perspective)

Amp hours is particularly annoying IMO because you can't convert it to energy without knowing the voltage.

Re: California breaks 1 GW energy storage milestone

#40

Post by toomuchtodo »

vondur wrote: post #31
jedberg wrote: post #25

As a Californian who has been watching the CalISO web page since the 90s, what I find most interesting is that the peak usage and total generation now is pretty much the same as it was in the 90s (~50MW). Based on the energy mix, it looks like lost coal capacity has been replaced with solar and other green energy, and demand has gone down relative to population because of efficiency initiatives and rooftop solar for…

California still imports a large amount of power from other states (primarily Arizona and Utah, with some hydro from Oregon). So we essentially outsourced a lot of our power production to other states.

Arizona, Nevada, and Utah have quite a bit of area for solar PV. It’s fine for California to import from there as long as they use their leverage to force a move away from coal now, and natural gas later. Clean hydro from the PNW is no different than PJM and NYISO grids importing clean nuclear and hydro from Ontario, Canada (which they do).
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