ToU Billing

[fatjay]

Peco has finally decided that ToU billing is for me.

Even without solar, with batteries only, I could charge my batteries on super-off-peak, and run the house, and go from 19c/kwh to 8c/kwh.

 

[Hedges]

"Highest weekdays 2 to 6 PM"
Can you put PV in the mix?

Calculate cost of batteries (DIY or off the shelf) and inverter per kWh over their life, see how many years to break even.

Less than half sounds good, but $0.11/kWh only allows so much investment.
(can you invest your money better elsewhere?)

 

[Brucey]

$15 price difference annually per utility, peanuts but what assumptions are they making? Steady state load on the touch plan as well,?

 

[fatjay]

$15 price difference annually per utility, peanuts but what assumptions are they making? Steady state load on the touch plan as well,?

I only recently went live on my pv system. I believe it averages the entire year, where I've been running off mostly battery during the day for only a month

 

[fatjay]

"Highest weekdays 2 to 6 PM"
Can you put PV in the mix?

Calculate cost of batteries (DIY or off the shelf) and inverter per kWh over their life, see how many years to break even.

Less than half sounds good, but $0.11/kWh only allows so much investment.
(can you invest your money better elsewhere?)

I used 28,520kwh this past year. With a $0.11/kwh savings, that would be $3137. My inverters cost $3000 for 18kw and my batteries cost $4400 for 60kwh. Add in $2000 for misc, that's a 3 year payoff for having zero solar panels.

Add in 11kw of panels, pvwatts says I'll make 14,206kwh per year. I know they're a bit ambitious but it's a starting point. That would mean my 28MW would be reduced to about 14MW, that would bring my annual bill to ~$1120, or averaging less than $100/mo

 

[740GLE]

Don’t worry after a while and you started saving some coin, they’ll start jacking up the monthly flat connection fee

 

[Hedges]

I used 28,520kwh this past year. With a $0.11/kwh savings, that would be $3137.

Only if all consumption was at peak rate times.

28,520 kWh/year / 365 days/year = 78 kWh/day on average.
60 kWh batteries can shift up to 5/6th of your daily consumption (given one contiguous peak rate period per day.)
Probably sufficient for your actual on-peak consumption.

Do you know the full details of peak, off-peak, possibly part-peak rates and hours?
Mine are part-peak 3:00 to 4:00 PM and 9:00 PM to midnight.

It is only the power you were buying at times that would be higher rates where you can save.

Savings would be relative to $0.19 if that is your non TOU rate (are you charged higher due to consumption tiers?)
Consider what peak rates would be if you did draw then (shouldn't happen with that big a battery, so long as system is reliable.)

My inverters cost $3000 for 18kw and my batteries cost $4400 for 60kwh. Add in $2000 for misc, that's a 3 year payoff for having zero solar panels.

Add in 11kw of panels, pvwatts says I'll make 14,206kwh per year. I know they're a bit ambitious but it's a starting point. That would mean my 28MW would be reduced to about 14MW, that would bring my annual bill to ~$1120, or averaging less than $100/mo

You may buy 11kW of panels for $2200 +/-
Mounting hardware can be significant cost.
Do your inverters already support PV?

Do they support charging from grid at select times and discharging from battery at select times or in some way to prioritize being ready to accept PV when sun comes up? (in other words, might charge at night or might discharge at night, maybe tuned by you for hours and watts.)

I think batteries and PV can each cost just a couple pennies per kWh amortized over assumed 16 year and 20 year life. So neglecting value of your time they can compete with even $0.11, bit tighter but still savings vs. $0.08 rates.

My much higher rates makes them considerably more attractive. But minimum wage is also much higher here.

 

[Mav986]

Same here (in AZ) with APS, just switched to ToU since I installed the DiY battery pack (15kWh).
During winter months, the Super Off peak is from 10 am to 3pm. So that is when I charge the battery using help from the 4.5kW solar panels (lots of shading in the spring).
During summer months Super off Peak goes away, so I just have to make certain the battery is charged prior to 4 pm (which should be using PV only in the summer).

I have found so far that I am barely using any Off Peak and zero On Peak power. Love it.

 

[fatjay]

Only if all consumption was at peak rate times.

28,520 kWh/year / 365 days/year = 78 kWh/day on average.
60 kWh batteries can shift up to 5/6th of your daily consumption (given one contiguous peak rate period per day.)
Probably sufficient for your actual on-peak consumption.

Do you know the full details of peak, off-peak, possibly part-peak rates and hours?
Mine are part-peak 3:00 to 4:00 PM and 9:00 PM to midnight.

It is only the power you were buying at times that would be higher rates where you can save.

Savings would be relative to $0.19 if that is your non TOU rate (are you charged higher due to consumption tiers?)
Consider what peak rates would be if you did draw then (shouldn't happen with that big a battery, so long as system is reliable.)




You may buy 11kW of panels for $2200 +/-
Mounting hardware can be significant cost.
Do your inverters already support PV?

Do they support charging from grid at select times and discharging from battery at select times or in some way to prioritize being ready to accept PV when sun comes up? (in other words, might charge at night or might discharge at night, maybe tuned by you for hours and watts.)

I think batteries and PV can each cost just a couple pennies per kWh amortized over assumed 16 year and 20 year life. So neglecting value of your time they can compete with even $0.11, bit tighter but still savings vs. $0.08 rates.

My much higher rates makes them considerably more attractive. But minimum wage is also much higher here.

• Peak Weekdays: (2 p.m. – 6 p.m.)
• Off-Peak Weekdays: (6 a.m. – 2 p.m. & 6 p.m. – 12 a.m. )
• Off-Peak Weekends and Holidays: (6 a.m. – 12 a.m.)
• Super Off-Peak All Days: (12 a.m. – 6 a.m.)

I've been scheduling my inverters to flip to grid mode for the past few weeks from 12am-6am to actually see if it's viable. I only have half my solar hooked up at this point, but based on the topping off of the batteries alone, i've basically been able to shift all of my consumption from the grid to battery. If I switch to ToU billing, it should save me considerable amount.

 

[Steve777]

One other consideration, the efficiency of charging your battery from grid and then inverting that power back to AC is not 100%. It's not awful, but maybe ~90% efficiency. So that .08/kwh that you are charging your batts with may be costing you more like .09 when you actually use it.

Probably won't make a dramatic difference in your calcs/decision, but might want to keep the accounting accurate.

 

[GRMRC]

See sig below. We are on TOU with NEM2. The grid is my infinite battery. We produce more kWh than we consume. Our yearly true up is < $0.
We only charge our DC coupled batteries using solar. Buying power from the grid to charge batteries seems counter productive. Charge = AC to DC. Discharge = DC to AC. Try paying >$.40 kWh and you wouldn’t even consider charging batteries from grid to say nothing about the NBC.

 

[Steve777]

See sig below. We are on TOU with NEM2. The grid is my infinite battery. We produce more kWh than we consume. Our yearly true up is < $0.
We only charge our DC coupled batteries using solar. Buying power from the grid to charge batteries seems counter productive. Charge = AC to DC. Discharge = DC to AC. Try paying >$.40 kWh and you wouldn’t even consider charging batteries from grid to say nothing about the NBC.

Yes, I hear you. For your situation and with your system and load I'd likely do the same.

But it all depends on the balance between your likely production, rate structure, and loads. For those with very cheap or free grid power during some time period, or if your seasonal weather means you won't be able to recharge your batts from PV anytime soon, the ability to charge from the grid during a low cost/free time after it is clear PV didn't do it is important.

 

[GRMRC]

Yes, I hear you. For your situation and with your system and load I'd likely do the same.

But it all depends on the balance between your likely production, rate structure, and loads. For those with very cheap or free grid power during some time period, or if your seasonal weather means you won't be able to recharge your batts from PV anytime soon, the ability to charge from the grid during a low cost/free time after it is clear PV didn't do it is important.

I designed my system to be able to export 12 months a year which means I produce more power than I use 12 months a year.
I have a newer custom built home so I could dictate what the energy consumption would look like. The cheapest “solar” system is to reduce energy consumption first. I realize many folks are trying to retrofit older homes and have constraints that prevent them from zeroing out their energy bills.

 

[GRMRC]

I used 28,520kwh this past year. With a $0.11/kwh savings, that would be $3137. My inverters cost $3000 for 18kw and my batteries cost $4400 for 60kwh. Add in $2000 for misc, that's a 3 year payoff for having zero solar panels.

Add in 11kw of panels, pvwatts says I'll make 14,206kwh per year. I know they're a bit ambitious but it's a starting point. That would mean my 28MW would be reduced to about 14MW, that would bring my annual bill to ~$1120, or averaging less than $100/mo

Wow. I only used 11,250 kWh this past year. Heat=62F. AC=70F 24/7. Ducted Daikins. Four zones.

 

[fatjay]

I am not interested in grid tie or exporting, the regulations around that are absurd here, and I was personally insulted by the electric company, so I'm disconnecting from them as soon as I can.

We have all electric stove/ac, but heat is oil. Hopefully I'll be able to fix that eventually. My 60kwh battery will eventually be built out to 120kwh and my 11kwh will eventually become 22kwh. My wife loves electricity and despite my efforts to reduce consumption, it looks like I've bottomed out for the winter.

 

[GRMRC]

I am not interested in grid tie or exporting, the regulations around that are absurd here, and I was personally insulted by the electric company, so I'm disconnecting from them as soon as I can.

We have all electric stove/ac, but heat is oil. Hopefully I'll be able to fix that eventually. My 60kwh battery will eventually be built out to 120kwh and my 11kwh will eventually become 22kwh. My wife loves electricity and despite my efforts to reduce consumption, it looks like I've bottomed out for the winter.

That’s going to take a lot of FU money to disconnect from the grid.

 

[Dr.Jekyll]

I'm doing this now in Western PA. Charge batteries during Super Off Peak (50% of cost), then use them through the day. Half price bill... sort of. I get billed for consumption and distribution separately. The TOU only affects consumption, so its more like 33% reduction, not 50%.

However, another big benefit is that I am far more likely to export solar during peak (2x cost) hours. This will offset peak usage (both consumption and distribution), or become a credit at the end of the year (just consumption).

 

[fatjay]

That’s going to take a lot of FU money to disconnect from the grid.

I'll spend FU money to get off the grid. , it also saves me a fortune in electric.

 

[fatjay]

ToU billing has arrived! My once $500/mo electric bill went to $320 last month with solar and no ToU. I still have 2 circuits on the grid and need to get them switched. At the current rate my bill will be $200.

 

[740GLE]

ToU billing has arrived! My once $500/mo electric bill went to $320 last month with solar and no ToU. I still have 2 circuits on the grid and need to get them switched. At the current rate my bill will be $200.

That’s a solid FU!!

 

[woe]

I'm not sure if you have a system like we do in Texas, but if you can get report of your usage in 15 min intervals as well as your EFL from your rep I can put in into my spreadsheet to do a comparison of your costs. In my case I calculated of I could move 65% of my usage to the free period it would be worth it. Which I was easily able to do. Happy to give you the info if you think it will help and if you can provide your report and EFL

 

[Skypower]

Even my graph suggests an FU on a year.
When I do go to grid, Solar Assistant automation decide how much and then, only off peak.

 

[fatjay]

I'm not sure if you have a system like we do in Texas, but if you can get report of your usage in 15 min intervals as well as your EFL from your rep I can put in into my spreadsheet to do a comparison of your costs. In my case I calculated of I could move 65% of my usage to the free period it would be worth it. Which I was easily able to do. Happy to give you the info if you think it will help and if you can provide your report and EFL

That would be amazing if I could get details like that. However the image I posted is about as detailed as they provide. They have a day view that's hour by hour but it's only a chart, nothing i can export and I can only see one day at a time.

I am curious what it'll look like in the summer running ac 24/7. But I should have additional panels up by then.

Here's last august.

 

[woe]

That would be amazing if I could get details like that. However the image I posted is about as detailed as they provide. They have a day view that's hour by hour but it's only a chart, nothing i can export and I can only see one day at a time.

I am curious what it'll look like in the summer running ac 24/7. But I should have additional panels up by then.

Here's last august.

View attachment 287533

That's a bummer. Smart meter Texas gives meter readings to the 15 mins next day and it's actually what the REP uses so the numbers are exact as what you'll see on your bill. You can export it or have it emailed to you daily which is nice.

If you ever manage to get a report even if it's to the hour let me know and I'll send you the analysis.

Based on the picture can you guess by free hours? Lol

 

[adobopr]

I'll spend FU money to get off the grid. , it also saves me a fortune in electric.

If you're spending like 500 a month consistent, that's 6k a year. That's absolutely plenty to get like a 6-7 year ROI. After that it's free energy which in your case thats an extra vacation you can take a year. I think that's the biggest FU.