Best time to use/conserve energy with solar on PG&E E-6 plan?

[195]

First post! I recently got solar installed on my roof. I am on PG&E's E-6 plan and am in NEM 1.0. (For those tracking the NEM 1.0 cap, I installed solar at the end of August and got my permission to operate on September 8th. There is still a little cap space left for those who are on the fence about solar).

Anyways, now that it's all set up, I can see my usage dip below 0 in the middle of the day and go back above 0 in the evenings and mornings. I would still like to conserve at the appropriate times and optimize the value of my solar investment. So with PG&E's E-6 plan, what is the rule of thumb as far as conservation goes? Also, when would be the best time to use energy? During the middle of the day or during off-peak hours? For reference, I am using a 4.25kW system that was designed for about 85% of my annual usage.

[inetdog]

You get the best economic return if you do not run major appliances during peak rate hours even when the sun is shining. Instead sell that power to POCO and buy it back at cheaper rates later in the day or early in the morning.

The only exception, which basically does not apply to residential customers, would be if your rate plan had a penalty for high demand (energy consumption during the worst case 15 minute period).
In that case it might make sense to always run your biggest loads only when the panels were producing.

In the entirely different situation of off grid PV using batteries, you want to run your loads during peak solar production so that you put the least possible cycling on the battery bank.
Grid tie with Net Metering is different because in the worst case the battery is free and it the best case you sell power for less than you pay to get it back again.

[foo1bar]

Search for "E-6 rate plan" and you'll see:

Summer (service from May 1 through October 31):
Peak: 1:00 p.m. to 7:00 p.m. Monday through Friday
Partial-Peak: 10:00 a.m. to 1:00 p.m. AND 7:00 p.m. to 9:00 p.m. Monday through Friday Plus 5:00 p.m. to 8:00 p.m. Saturday and Sunday
Off-Peak: All other times including Holidays.

Winter (service from November 1 through April 30):
Partial-Peak: 5:00 p.m. to 8:00 p.m. Monday through Friday
Off-Peak: All other times including Holidays.


And they also provide the $/kwh for each of those - so you can decide whether it's worthwhile to wait until after 9PM or just go ahead and start that dishwasher (or whatever) at 7PM.

[195]

Thanks for the quick response and I appreciate you listing the scenarios. I don't run batteries and there doesn't appear to be any penalties as you described under this plan. So I'll stick with my same conservation tactics I had before solar.

Thanks!

[inetdog]

S
And they also provide the $/kwh for each of those - so you can decide whether it's worthwhile to wait until after 9PM or just go ahead and start that dishwasher (or whatever) at 7PM.

My dishwasher has a delay setting of up to 8 hours, so I can load it up and turn it on in the afternoon or evening and have it run after 1AM. Unfortunately my water heating is tankless on-demand using propane, so I really do not save much on power except the electricity required to superheat the water.

An electric dryer with delayed start would be great, but I suspect that would violate some safety rules.

[foo1bar]

Thanks for the quick response and I appreciate you listing the scenarios. I don't run batteries and there doesn't appear to be any penalties as you described under this plan. So I'll stick with my same conservation tactics I had before solar.

Thanks!

Correct - there is no demand charge for E-6.
(As an aside, the common TOU rate for small/medium businesses with solar in PG&E is A-6. That also doesn't have a demand charge. )

Back to you though - If you haven't been trying to time shift your usage to non-peak times, you should try to do that.
You can run your dishwasher for about half the cost at 9PM as it will cost you at 4PM
(Or electric drier, or washing machine or EV charger or ...)

The more you can shift to off-peak times, the better off you are financially. (At least up to where you're generating more on a dollar basis than your consuming on a $ basis)

[cebury]

Ditto what was said above. Much better to sell as much solar kWh as possible during peak and use during any other part/off peak periods. Bets are there won't be any residential demand charges before 2019, if ever, as long as gubernatorial green policies stay what they are in CA.

[J.P.M.]

Just like the stock market: Buy low - sell high. Doesn't get more simple.