# Solar in Oregon, does POWERWALL make sense?



## Collier007 (Dec 26, 2018)

I took the plunge and placed an order today. Anyone else in Oregon dealt with the Tesla energy team before? One thing I have to figure out is if my south facing roof can handle enough panels to produce excess energy to justify a powerwall. It doesn't seem to make sense to get a battery backup if you only have enough sunlight to charge it 3 months of the year or so.


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## MelindaV (Apr 2, 2016)

I don't think they will size the system to over produce beyond your current needs/usage (in order to fill a powerwall). 
are you on a time-of-use electricity plan? if so, that is when a powerwall may make sense - so you have excess to pull from during peak hours instead of going to the grid. If you don't have a time-of-use plan, then it doesn't really make sense.


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## Collier007 (Dec 26, 2018)

I have a time of use plan right now (mainly because of model 3 charging), but need to consider their net metering plan once the solar panels gets installed.

In regards to sizing, I am pretty sure that the amount of panels they will be able to put on my south facing roof will not cover all of my energy usage, but we will see what the advisor says.


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## Collier007 (Dec 26, 2018)

From Google Project Sunroof


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## MelindaV (Apr 2, 2016)

I have a small roof with only East/west exposure, and they were able (barely) to find enough room between existing vents to make it work, but just not as ideally as if it were south facing.


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## Herewego (Sep 21, 2018)

I have solar and a battery back up as well. I like it as the 'just in case' scenario. So far, battery is great, I usually use it in the evening and drains to a certain percentage, then switches to the grid for power. I've had it about a year or so now and got it before the solar rebates ended... So that helped a bunch. I wish I had two batteries to get away from the grid but I also have a smaller roof but it doesn't have a problem charging and putting electricity back to the grid on summer days...


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## Collier007 (Dec 26, 2018)

So I got a small system with a Powerwall. Super happy with having solar, but a bit disappointed that the Powerwall has such a large vampire drain. Power outages seem to be more likely in the winter, when there is not a lot of sun, and that means that the usage as a safety backup is reduced if power is constantly being lost. Just an FYI for anyone else considering a plan and running the ROI on the Powerwall.


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## garsh (Apr 4, 2016)

Collier007 said:


> but a bit disappointed that the Powerwall has such a large vampire drain.


Can you give us some idea of the drain rate?


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## Collier007 (Dec 26, 2018)

garsh said:


> Can you give us some idea of the drain rate?


I just ran an test last night and it lost 5-6% .


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## Bigriver (Jan 26, 2018)

Collier007 said:


> a bit disappointed that the Powerwall has such a large vampire drain


I too was initially a bit disappointment to realize that more energy goes into the powerwalls than comes out of it, and just like the Tesla car battery, it can lose charge just sitting there.


Collier007 said:


> I just ran an test last night and it lost 5-6% .


I've been tracking the delta of what goes in vs what goes out of the powerwalls since ours were installed in April. We have 2, for a total capacity of 27 kWh. The attached picture shows the average loss per day for each month, based on the Tesla app data.

It goes from as high as 6.4% to as low as 1.9% per day (average). I believe the difference is that the higher "loss" is just the charging inefficiency, which all batteries have. The higher Powerwalls energy loss occurred when they were getting cycled daily. Now, in January, they are solely in backup mode and not ever providing power to the house, so this is truly phantom drain, but less than 2%.

Ever since we got our solar panels, kWh have a heightened value to us, which is often disproportionate. When I can see a kWh spent on something, I'm probably too aware of what else that kWh could have done. But I forever bring it back to dollars and cents (and sense) and to me it's worth the 5 to 15 cents a day to have the powerwalls in my home.


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## Collier007 (Dec 26, 2018)

Follow up post. Now that the system is completely up and running I do not see the phantom drain overnight. I have also found it very insightful to learn how much energy certain appliances use based on the app. Happy customer thus far.


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## pdx_m3s (Aug 1, 2019)

I'm also considering Tesla solar here in Portland. I think we will need their Large system to get close to net-zero. How did the rebate process go for you (Energy Trust / PGE)?


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## Collier007 (Dec 26, 2018)

Tesla handled everything and I believe the rebate came off the price before purchase. I’m on the time of use net metering plan and really enjoy watching the app on sunny days. On a sunny day it will charge from a set 50% floor to 100% by noon and then usually power the house and sell the excess until sunset (outside of major spike from dryer or oven). At peak time all of the energy comes from the Powerwall and then I charge my car at night when off-peak rates are .04c/kw.


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## Collier007 (Dec 26, 2018)

A visual of my solar with power battery utilization yesterday. It was a warm day and the AC must have come on at night a couple of times. Also, my car is not needing to charge since I am not going anywhere. So far I am a very happy Tesla Solar customer.


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