Maryland Pepco Solar question - confused on whether to go RTM or R

[eryeal]

Howdy,

We recently had solar installed (13.8kWp system), where we expect it to generate about 90% of our yearly use. I'm confused over what billing system would be better with Pepco - the time metered system, or the regular system. The cost difference in terms of the monthly customer charge for distribution is $8 more for RTM - so right away RTM is costing about $100 more a year just in fees. As far as rate differences - the difference between RTM and R rates used to be much further apart, but aren't so much anymore.

The rate for R is .0793.

The rates for RTM are: Peak .083, Intermediate .081, and Off-Peak .0772

I'm thinking the payout for peak generation probably won't exceed the $100 in fees for RTM billing, so I'm better off just doing the regular rate billing.

Anyone have any thoughts on this?

[J.P.M.]

Estimating a bill when subject to a T.O.U. (time of use) tariff is less precise than when on a fixed or quantity tariff. With T.O.U, some estimate of hourly use pattern is needed. Sometimes or commonly, some historical use info is available from the POCO (power company), as is monthly or billing period info. In either case, the accurate but PITA (pain in the ass) method is to get the tariff structure for both scenarios, use a spreadsheet, and calculate a set of monthly bills for each scenario for your "typical" usage with and without the estimated PV system output, and choose as your best estimate shows.

[azdave]

My POCO banked my off-peak and on-peak excess generation separately and they were never able to be combined in any manner. I had a bunch of off peak energy I could not possibly use up and hardly any on-peak in reserve for when I needed it most. We also have a significant difference between on and off peak rates. I generate nearly all of the energy I need so a flat rate basic plan is by far my best choice. Forget all the timers and training the family members when it is better to use power. I now have all the excess generation in one bank and use it as needed.

If you generate less than 80%-85% of your power (my guesstimate) then you might look at a TOU plan and what it could save you. The splits between your TOU rates is small and don't seem worth the trouble to me. I would probably choose the basic plan with what I know about your situation at this point. I assume you can only change plans once a year?

[eryeal]

My POCO banked my off-peak and on-peak excess generation separately and they were never able to be combined in any manner. I had a bunch of off peak energy I could not possibly use up and hardly any on-peak in reserve for when I needed it most. We also have a significant difference between on and off peak rates. I generate nearly all of the energy I need so a flat rate basic plan is by far my best choice. Forget all the timers and training the family members when it is better to use power. I now have all the excess generation in one bank and use it as needed.

If you generate less than 80%-85% of your power (my guesstimate) then you might look at a TOU plan and what it could save you. The splits between your TOU rates is small and don't seem worth the trouble to me. I would probably choose the basic plan with what I know about your situation at this point. I assume you can only change plans once a year?

I'm thinking along the same lines - going with the flat rate especially due to the $100/year extra customer charge for TOU. Although my experience is different - since on-peak is during the day, that is what is being banked the most. I also had a different line of thinking in terms of generation - I figured the more power you generate, the better TOU will be - versus what you are saying in that lesser generation may be better TOU wise. I figure more generation is better for TOU because you will be getting paid more for your on-peak generation that is happening during the day when payout time comes (Pepco has a yearly payout).

I figured from a basic math standpoint (I understand this isn't nearly exact at all, but is just my line of thinking), peak is generating .004 more revenue per kWh than the flat rate as shown in my original post. That means in order to make up the $100 customer charge for a year, that would be 25,000 kWh's. Due to the rates being so close (flat vs peak), that's really what makes it more desirable in my case to go with flat. If there was a bigger difference, it may make more sense to go with TOU due to the extra payout the peak hours would have.

[J.P.M.]

I'm thinking along the same lines - going with the flat rate especially due to the $100/year extra customer charge for TOU. Although my experience is different - since on-peak is during the day, that is what is being banked the most. I also had a different line of thinking in terms of generation - I figured the more power you generate, the better TOU will be - versus what you are saying in that lesser generation may be better TOU wise. I figure more generation is better for TOU because you will be getting paid more for your on-peak generation that is happening during the day when payout time comes (Pepco has a yearly payout).

I figured from a basic math standpoint (I understand this isn't nearly exact at all, but is just my line of thinking), peak is generating .004 more revenue per kWh than the flat rate as shown in my original post. That means in order to make up the $100 customer charge for a year, that would be 25,000 kWh's. Due to the rates being so close (flat vs peak), that's really what makes it more desirable in my case to go with flat. If there was a bigger difference, it may make more sense to go with TOU due to the extra payout the peak hours would have.

A better guesstimate is possible, but for a lot of the time not deemed worth the effort for the information or perhaps the perceived $$ benefit achieved in lower bills. I've no idea of your tariff situation, Still, I bet it's possible, but perhaps not worth the effort.