2 ms·

You can do reactive power with some batteries since they are all behind inverters that can be designed to do that. The Tesla grid batteries (the big ones, don't

by ok_dad 5y ago

You can do reactive power with some batteries since they are all behind inverters that can be designed to do that. The Tesla grid batteries (the big ones, don't know about power walls) can certainly do it via API commands (you can specify real and reactive power components, and frequency control, I'm not sure if they can all 3 be run at once though). I'm not sure if all battery companies have this feature though. I used to control several dozen sites with Tesla batteries via their battery control API, though we never used reactive power or frequency control. We still need storage solutions like this for long term storage, though, as batteries are mainly used for load shifting and short term arbitrage right now, at 6 hours of discharge and less.

ggm 5y ago
That's good. Condensers and like appeal to my steampunk sensibility but they aren't magic or instant. If batteries can do reactive quickly and as well as they do FCAS then it's a huge plus. Getting more than 6 hours is a good point too. I'm sure battery tech is going to include scaling to meet that, this kind of heat storage might just be about time to market.
- namibj 5y ago
  Inverters are far better than anything rotating-mass-based for control over waveform. At least if you want to, that is. You just take a (possibly GPS-disciplined) quartz oscillator and have no issues hitting 50ppm frequency stability at lower phase noise than can get through the system at 50/60Hz. They can essentially do this instantly, i.e., substantially sub-wavelength of your line frequency (a PWM of 10 kHz isn't even high for an inverter, and 100 kHz is well within what's feasible for large systems operating at a couple hundred volts; 10 kHz would equate a light-speed delay of 30km, 100 kHz of just 3km, which gets into the territory of relativistic w.r.t. medium voltage rings in cities).

by ok_dad 5y ago

ggm 5y ago

That's good. Condensers and like appeal to my steampunk sensibility but they aren't magic or instant. If batteries can do reactive quickly and as well as they do FCAS then it's a huge plus. Getting more than 6 hours is a good point too. I'm sure battery tech is going to include scaling to meet that, this kind of heat storage might just be about time to market.

namibj 5y ago
Inverters are far better than anything rotating-mass-based for control over waveform. At least if you want to, that is. You just take a (possibly GPS-disciplined) quartz oscillator and have no issues hitting 50ppm frequency stability at lower phase noise than can get through the system at 50/60Hz. They can essentially do this instantly, i.e., substantially sub-wavelength of your line frequency (a PWM of 10 kHz isn't even high for an inverter, and 100 kHz is well within what's feasible for large systems operating at a couple hundred volts; 10 kHz would equate a light-speed delay of 30km, 100 kHz of just 3km, which gets into the territory of relativistic w.r.t. medium voltage rings in cities).