BillHolz wrote:I have looked at TOU and adding solar but have not done either yet. In your situation, it looks like you are considering schedule 1 or 1s based on your descriptions. Schedule 1ev has a larger set of TOU categories which could be a favorable option if it is allowed with RE net metering. Another option you may want to look at is Schedule 1 plus schedule ev, which is a separate meter, generally after your s1 meter that just your EVSE is hooked up to. I considered doing the s1 + ev but I tend to do free public charging a mile from work often enough that it did not make much of a difference for me.
Bottom line, you need to get a decent idea of how much you are producing or using during each time period that a possible TOU rate covers and just compare each option in a spreadsheet.
Congratulations!golfcart wrote:We had been considering solar for a while and a local co-op brought prices down to what I consider a reasonable payback range so we finally pulled the trigger on a grid-connected PV array for our roof. Our house has electric everything and based on last years usage and the installers estimates (confirmed by PV watts within 5%) the array should offset roughly 50% of our annual power requirements.
golfcart wrote:A simple subtraction in excel shows our estimated net use but the demand TOU rate schedule from Dominion is so convoluted with riders and demand charges that I can't predict what our exact rate will be for a given window. But given the fact that over 50% of our electricity use is the leaf and the water heater, both of which are on a timer, I think it could probably work for us.
RegGuheert wrote:Congratulations!golfcart wrote:We had been considering solar for a while and a local co-op brought prices down to what I consider a reasonable payback range so we finally pulled the trigger on a grid-connected PV array for our roof. Our house has electric everything and based on last years usage and the installers estimates (confirmed by PV watts within 5%) the array should offset roughly 50% of our annual power requirements.
I will note here that my system typically outperforms PVWatts by about 25%. Of course, that depends a bit on your assumptions.
I'm in VA, but our part of the grid was sold to a small co-op about ten years back. We do not have "real" TOU here.
Here are some thoughts:
- Are you willing to share a year's worth of hourly usage data with me for my new spreadsheet? In return, I will add your house data into the spreadsheet which will allow you to play what-ifs including various amounts of solar, EVs and batteries. I'm also willing to explore the possibility of adding some TOU calculation capabilities into the spreadsheet if I can figure out a way to implement it. We can then adjust as your actual data comes in.
- If you go with a TOU plan initially, you will be able to easily compare your results with a flat-rate plan later. OTOH, if you go with a flat-rate plan now, you will never *really* know if you would have saved money with the TOU plan (unless Dominion Power provides a calculator that you can trust).
- If you do not have a heat-pump water heater, I recommend that the next time you make a replacement. It can save as much as 4 MWh/year.
- Your daytime consumption due to air conditioning is likely to be very low because when you need air conditioning is often the same time the sun is shining. (Evening is a different matter.)
- If you are installing an Enphase system, please let me know the location of your system's website so I can add it to the MTBF spreadsheet.
- I think the following statement that you made typifies the real issues with TOU metering. I have come to believe that TOU rates are designed to induce customers to better match the power company's production curve WITHOUT ACTUALLY PAYING THEM TO DO SO. This is accomplished by obfuscating the details to the point where the benefit is much smaller than it appears or even ends up costing more.golfcart wrote:A simple subtraction in excel shows our estimated net use but the demand TOU rate schedule from Dominion is so convoluted with riders and demand charges that I can't predict what our exact rate will be for a given window. But given the fact that over 50% of our electricity use is the leaf and the water heater, both of which are on a timer, I think it could probably work for us.
BillHolz wrote:If you already have a dedicated EVSE circuit, adding a schedule ev meter that is subtracted from your schedule 1 net metered house would only cost the price of the meter base, the permit, and a small amount of additional wire. No need for an electrician if you are at all handy with wiring.
The combined base charge is less than on 1s and gives you the benefit of TOU on the big controllable usage, charging your car.
Thanks! I'll PM you next week when I get back to that project. BTW, how many kWh does your house consume in a year?golfcart wrote:I have no issue sharing my usage data if you think it has some value.
Yeah, it's not too difficult. The main thrust of my sheet is to allow you to see the impact of batteries for the eventual day when net metering goes away in VA. Perhaps I'll take a look at Dominion's website to see what your TOU rates look like.golfcart wrote:I appreciate the offer with your sheet but I really don't need a sheet to implement TOU scenarios I am confident I can handle that myself either with excel or with Python. I already basically did it in excel I just can't anticipate all of Dominions riders or when Dominion is gonna add on a demand surcharge ahead of time so I'd just have to take educated guesses.
Solar Edge should perform similarly to Enphase. I'm guessing you didn't get the new HD Wave inverter because it appears those only go up to 3.68 kVA currently. Does your inverter have a plug to allow you to get some AC power when the sun is shining, or is that only on the HD Wave?golfcart wrote:Good to hear about you outperforming PVWATTS. Our system uses a solar edge inverter and optimizers with axitec panels.
Agreed. Mine are at 30 degree tilt and 194 degrees azimuth. In other words, optimized for about 1:00 PM, which works very well. Yours are optimized at about 2:15 PM, which should also work very well. The flat angle means your production will be outstanding in summertime. Here is a good website to see how close you are to optimum pointing: Solmetric. I put in "Newport News" and it appears you are within 5% of the optimum production for your location.golfcart wrote:5.83 kW system at 215 degrees and a 20 degree tilt. Should be oriented well for the TOU plan in the summer which puts a premium on afternoon demand.
Yes, it's pretty addictive! (I think my wife thought it would wear off eventually! )golfcart wrote:We've been up and running for a week. The last few days have been great I'm averaging about 33kWh a day with the cold weather and clear skies. At this rate we will cover all of my transportation needs easily with the panels, even on cloudy days I've been getting 15kWh out of it. I am addicted to monitoring the output of the panels with my mobile app...