As my three meters/transformers approach capacity, I am contemplating adding a 4th. But, I will wait for a good rate to be assured for another year. That happens in August or September.
I will estimate how much more PV production I might be able to add to my existing three meters/transformers.
The Pool/BigBarn meter is on "net metering" meaning I can use the grid as storage for a billing period. The downside to net metering is that I get paid only about $.03/kwh for excess production. The other two meters are on a "buy it immediately" or "sell it immediately" rate schedule. Buy it for $.10/kwh, sell for ~$.06/kwh.
The Pool/BigBarn has a 15kw (15kva) transformer which limits production to 15kw. The House has a 37.5kw and AcrossTheRoad has 50kw.
The Pool/BigBarn has had recent observed excess production as high as 125kwh per day. It is not optimized for energy production which means relatively few paired East and West facing panels. So, I estimate that I might get ~10% more energy/day by reworking to all E/W facing panels. I do believe I am now producing at the limit of the transformer.
AcrossTheRoad has some room for increased production. The observed daily sales have reached 255kwh. That transformer should have a capacity 3 times that of Pool/BigBarn. So, total production on that meter might reach 375kwh/day. 120kwh/day more than current.
House also has some room for increased production. Observed daily sales have reached slightly more than 200kwh. With only a 37.5kw transformer, the head room would be only a bit more than twice that of Pool/BigBarn or 250+kwh/day. About 50kwh/day more than current.
SO! I should have growth capacity of 170-200 kwh/day without adding or upgrading transformers. That would be peak days of 375+250= 625kwh on the two not net metering meters. That's compared to 455kwh current. I can hope to increase my monthly credits to 625/455 = 1.37. 37% more than current. Notice the shift from peak daily sales to average over a month. Peak monthly credit so far has been $680. So, with current rates and with no transformer upgrades, I can look forward to monthly credits around $935 as I build out to fill current capacities. I will not likely reach $1k/month unless I increase capacity.
Adding a 4th 50kw meter/transformer might add an additional 375kwh of peak day production or an estimated $500/month.
Feel free to critique my estimates.
Maybe figure out a scheme to feed power into the grid through the Pool/BigBarn transformer at night by charging the Jack Rickard battery during the day, and using your microinverter scheme to feed power into the grid at night? (Golf cart can also add some...)
ReplyDeleteMaybe add a grid-tied windmill to the AcrossTheRoad transformer to feed in power during the day/night when the wind blows. Are the tax incentives for wind different than for solar?
Just brainstorming ideas to get more power through existing transformers. Especially since they are not doing much during the other 16 hours of each sunny day.
I think the wind incentives are the same as PV. But, soon to expire. We are in a poor wind area but I'm up for trying it anyway. The prospect of generating more energy while PV production is low is enticing.
DeleteI am set up now so I can sell $.0645/kwh power at night through battery storage and grid tie inverters. But, I would have no financial incentive other than working around my sometime day limit on power through the transformer. My financial incentive for using the PowerWall at night to avoid paying $.10/kwh is about $.03/kwh. At a maximum of 12kwh per night that is an incentive of about $.40 per night. That goes to pay the $13k PW cost which has a life expectancy of 10 years, less than 4000 days or a maximum of $1600. So, unless time of use rates are forced on us, I see no future in using batteries for time shifting.