[Oeva-list] my first solar year with Leaf EV, solar PV, and TOU

charlesbonville at comcast.net charlesbonville at comcast.net
Tue Apr 16 15:55:37 PDT 2013


Eric and all, 


Be cautious in moving to TOU rate. The power company generally advises that it only works well for people that are not on a normal schedule, such as households with workers that work a swing shift from 3 PM to 11 PM. In those households, they are generally not at home or are still asleep during the Peak rate hours. 


That said, the larger your PV array, the more likely you are to avoid using the grid during Peak hours, which tend to coincide, not surprisingly, with most homes' highest daily electricity consumption hours. A 5 to 9.5 KW system has a higher probability of benefiting from TOU than a system 4K or less. 


Here's my gut feeling: If your PV system is not putting at least 1/2 of it's generation into the grid, you are not going to offset enough peak usage to benefit from TOU. The winter months could get expensive on TOU unless you make radical changes in your use patterns to minimize use during Peak rate. 


I can't claim to be an expert on this, but I have done some ballpark calculations and was left with the above impressions. 




One other note: I have the impression, possibly mistaken, that Pacific Power requires Net Metering for grid-tied PV systems, but does not offer TOU with Net Metering. Perhaps this is only true if the PV system is a Feed-In Tariff participant? I'd love some clarification on this if anyone on this list knows. 




Lastly, thanks for the numbers, Gary. I'd love to see the spreadsheet you used to calculate it all. 


-Charles 

----- Original Message -----
From: "Eric Cha" <ericc at xenopi.com> 
To: "Gary Graunke" <gary at whitecape.org> 
Cc: Oeva-list at oeva.org 
Sent: Tuesday, April 16, 2013 3:34:46 PM 
Subject: Re: [Oeva-list] my first solar year with Leaf EV, solar PV, and TOU 

Hey Gary, 

Thanks for sharing that info. I've had a grid-tied 4kw PV system(and a 
Solar Hot water system which is tied in with our nat gas water heater) 
for about 7 years now, and we just leased a Leaf last November. For all 
that time, we've been using basic (flat) rate billing. After reading 
your report, I decided to switch over to TOU rates as well and just did 
so. (Portland General Electric makes it very easy to do online). We'll 
see how it goes! 

Cheers, 

Eric 
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