Best direction and tilt for PG&E E6 rate?

[Svoad]

As it get closer to installation day I have more choices to make. I can pretty much pick the direction and tilt of my system. I'm on the PG&E E-6 rate so my solar engineer suggested that the system be pointed SW 225* at a 15* tilt. I was under the impression that dead south 180* with a much higher tilt would produce more energy. I asked him about this and he explained it was because of the time shift in the E-6 rate to 1pm to 7pm. Then said he would engineer anything I wanted.
This will be a ground mounted system. I played with pvwatts some and it shows me the yearly energy produced but with a 15* tilt I would suspect it to produce more engery during the summer months. is this the standard install for a ground mount and if not what direction/tilt should I be looking for ?

[J.P.M.]

Because of T.O.U., there is a difference between max. production and max. bill offset. Think of a PV system as a revenue producer. All other things about construction costs assumed about equal with respect to orientation and tilt , the goal then becomes to find the array orientation that produces the greatest revenue considering the E-6 tariff schedule and per kWh pricing.

It takes a bit of work w/ a spreadsheet, the tariff schedule and the hourly system output from PVWatts, but the task is not as daunting as it may seem. 4 or so hours on a Sat. A.M. will get you most of the way. As long as it's a ground mount with associated flexibility as to orientation, a few iterations w/PVWatts will usually allow a rather quick convergence to an optimum. You can then massage the final design having a better guess on the cost/benefit/penalties of tradeoffs.

FWIW, and as a SWAG, 225 deg. azimuth and a 15 deg. tilt probably isn't a bad first approx. For the time/effort involved, I'd run the analysis as described, but that's just me..

[wwu123]

A very rough rule of thumb is that every one extra kwh of summer peak generation you can produce can offset the cost of two off-peak hours in winter or at night; so you can see how shifting west somewhat can make up for some loss of overall production, as gaining peak production by shifting west offsets the loss of off/part-peak production at more than 1:1.

[ltbighorn]

Keep in mind that E-6 TOU hours will change in later years (2021 and 2022) -- getting much later in the day. Maybe a more westward orientation would help, but with peak times of 3-8pm and then 4-9pm, I'm not sure that it'll make much difference relative to the losses from being that late. Then again, part-peak will be noon-3, then 2-4, which is still better than off-peak.