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Can Powerwall be configured to reduce demand charges?
Can powerwall be configured to lower demand charges? For example, when load exceeds 10kW can powerwall kick in to keep the utility load to 10kW?
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However the energy for your loads should be supplied by the solar panels, whatever the panels cannot cover is supplied by the Powerwall, and whatever the Powerwall cannot covered is supplied by the utility. So that 10kW load could largely or entirely be supplied by a combination of Solar + Powerwall(s).
A single Powerwall supplies 5kW of continuous power. So you may need two powerwalls for a 10 kW load.
But in places where there is net metering, demand charges, and/or TOU plans, there are much better algorithms to optimize ROI.
Related question - when grid goes down, does the standard installation have the PW power a subset of circuits, or is that something the installer would have to do external to the PW?
By default, the PW-2 is installed either as a whole home or partial (critical circuits) backup. Essentially, the PW-2 connects to grid, solar and the home, solar powers the home, charges the battery and exports to the grid if the battery is full and there is excess. During lower light on solar, power is provided from battery and/or solar. Obviously at night, power is from battery and/or grid.
If the grid fails, the PW-2 acts as a UPS and is limited to 5 kW continuous power so this aspect should be considered as part of a whole home backup or just critical circuits. PW's can be combined in parallel to increase this limit.
There are more detailed descriptions of function elsewhere in the forums.
Cheers,
Harry E.
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With advanced time-based controls added last year however, from my experience, the PowerWall can work well to manage demand if you have an appropriately sized system (PV kW + # of batteries) so that you can configure the entire system for zero net usage for your entire peak period.
After two months of PowerWall operation with solar, my maximum demand during peak periods (that include several hours past sunset and an hour or so before sunrise) has been 200W even with a 4kW air conditioner running periodically (day and night). I'm in the Phoenix area and my utility is SRP.
How many PW do you have and what Kw solar panels you got.?
I’m in the process of getting the panels. They’re suggesting a 4kw and my srp 1 year without solar is 13000kw. I’m worried about that srp on demand periods, will a PW help or do I need 2.
With Tesla’s active battery management system, you should measure the life of your batteries like a car’s odometer: “total kWh charged over lifetime of batteries”.
Home battery usage is far gentler than in a car, where the batteries regularly have to output full power during acceleration and than rapidly recharged during regenerative braking. Causing sudden temperature changes. Powerwalls should last far longer than Tesla car batteries.