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Power efficiency exporting / importing from Grid

Tim-in-CA

Member
Apr 23, 2018
334
149
SoCal
Hi ... tried to search to see if this question had been answered, but my Google-fu did not find what I was looking for. Is it known what the efficiency is for exporting solar to grid and reimporting? For example, for every kWh exported to grid, what is the estimated round trip loss? I'm trying to maximize my power generation and would like to charge my Tesla with excess solar once the Powerwalls have fully charged. There has to be some sort of loss during the roundtrip to/from the grid. I also REALLY wish Tesla had better integration to allow you to utilize solar generation in this manner. I have a Wallbox that lets me change the charge rate in the app from 6~40Amp real time - so I can easily adjust charge rate on the fly based on excess generation. I believe the next release of vehicle FW is going to allow this type of setting as well from the Tesla App. Thanks!
 
Upvote 0

power.saver

Grid Specialist
Supporting Member
Mar 4, 2018
639
672
Arcadia, CA
There is no efficiency loss for exporting to the grid and re-importing from the grid. The only import/export efficiency loss is in the Powerwall (it's about 90% efficient).

Any grid export/import is subject to your tariff so you may end up paying more or less to charge an EV based on the rate when the solar was produced and the rate when you charged the EV. If you have a tariff with NBCs, these apply to imports too.
 

Tim-in-CA

Member
Apr 23, 2018
334
149
SoCal
There is no efficiency loss for exporting to the grid and re-importing from the grid. The only import/export efficiency loss is in the Powerwall (it's about 90% efficient).

Any grid export/import is subject to your tariff so you may end up paying more or less to charge an EV based on the rate when the solar was produced and the rate when you charged the EV. If you have a tariff with NBCs, these apply to imports too.
Thanks, yes, I'm on SCE TOUD-4-9PM plan so definitely there are variances in per kWh costs. I would have thought that there would have been some sort of minimal loss (5%-ish or so), but good to know that there isn't a loss in the round trip.
 

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