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Plan: Off grid solar with a Model S battery pack at the heart
- Thread starter wk057
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- Energy Environment Policy
Blasphemy!
Actually, she prefers her car, believe it or not.
I actually wrote that after reading your post about how charging her car is a major load on the system, so was thinking that she could leave her car home to be charged the next day when you have excess energy.
dhanson865
Well-Known Member
I can't speak to size of individual systems but I can speak to the overall situation.
The Open PV Project - State Rankings has TN in 21st place with 22MW vs NC in 16th place with 56 MW (out of 54 places, DC, PR, and 2 others?) aka NC has more solar PV installed but it's in fewer installations (larger installations on average in NC smaller on average in TN).
OK lets see what I can find aboout residential system sizes
World's largest off-grid residential solar-plus-storage system installed in Hawaii - Solar Choice lists a 170KW PV system with 1MWh battery system at Bakken Estate in Hawaii.
This one in Southern California is 150KW but not off grid.
I can't find any list that I trust to compare to yours.
OT, but:
In my area, power companies are responsible for all costs up to the meter. They supply the meter pan, you supply the installation labor for the pan and then all the inside conductors attaching to the bottom terminals of the meter.
EcoHeliGuy
Member
Depending on situation here it can be upwards of $20k if they need to install a pole during connection
wk, now that winter is coming to an end, it would be great to have a report on how well the system fared and how many times you had to go back on-grid.
BTW - what happened on January 22? Looks like no production at all that day.
BTW - what happened on January 22? Looks like no production at all that day.
Well, the full system has only been online since the beginning of September, so I only have about 6 months of data now. There's some screw ups in there too where my control scripts flipped back over to the grid for longer than I realized, resulting in wasted power the next day or that day. Add to that the fact that I can only track fully utilized power (battery charging and/or loads) and can't track full PV power when the batteries are full.... and I'm not 100% sure how telling my stats really are about a lot of things. Recently I've added a manually activated ~8kW dump load in the form of old bitcoin miners in the attic, but when I have excess power it's usually ~30+kW worth, so, this is only making a small dent. I'm not doing to run dump loads off of the batteries, either, since that would be silly to add cycles to the pack unnecessarily.
January 22nd was the day before this: Let there be light! (Snow sliding from solar panels) - YouTube ... where my panels were completely covered in snow.
It warmed up a little on the 23rd and the roof was cleared off around ~noon on its own (avalanche!). The snow came in the night of the 21st/morning of the 22nd. The panels were completely covered by sunrise and literally completely shaded. My back roof is ~35ft from the ground, so, not much I can do about them up there. The ground array is pretty massive, and I tried sweeping off the smaller one.... but it's just too much area. It snows so seldom here that I don't think any real mitigation would be useful. A friend suggested low powered stick-on heading coils for the rear of the array to keep it above freezing when it snows... but the cost and install time and such would certainly not be worth it for the 1 day per year it will be a problem.I want to setup my site to better show some longer term stats, and I might be able to get to that this week sometime, but, maybe not. We'll see how my schedule works out with other projects.
Sounds like a database glitch of some kind. I've moved them over. If I missed any let us know.
Thanks for the update. Forgot about the snow storm that came through that week. I agree that it doesn't make any sense to really do anything about it since it almost never snows around here. Maybe a little more towards your side of the state, but certainly nothing that would make financial sense to do something about it.
Maybe your new page can have a counter on the number of bitcoins generated as well
Maybe your new page can have a counter on the number of bitcoins generated as well
nwdiver
Well-Known Member
Thanks, cloud effect!
Had some unusual cloud effect a couple days ago... first time I've seen clouds add to daily production... not just peak power.
The array faces west and there were some clouds in the west that morning... they reflected a bit of light from the rising sun and added ~3 kWh to that days production. The skies cleared before noon so clouds never shaded the array.
This is what cloudless skies look like...
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nwdiver
Well-Known Member
Yeah... 15.6kW of panels on a 11kW inverter... the clipping won't be as dramatic in the summer when the power output of the panels drops due to temperature. The ROI of a 12kW vs 11kW inverter would have been ~5 years. Oversize ratio of 1.4... the upper limit of what I think is advisable with module vs inverter prices where they are.
nwdiver
Well-Known Member
You lose ~0.5% power for every C increase in temperature. This is SE NM... not uncommon to have a string of 100F+ days... in the summer. This is even reflected in the projected production on SMAs website... you can see a slight dip in June even as the days get longer.
I expect the peak power output of the array will be ~12kW in July... there will still be some clipping... but not much... and top end power is less valuable since it's exported for $0.075/kWh vs self-consumed power which is worth $0.12/kWh. A fatter power curve is more valuable than a tall one. The projected annual curtailment is a lot lower than the graph would suggest... PV Watts estimates that only 543kWh is being lost annually. So spending $1200 more to match the array to the inverter would only generate $40/yr. Module costs are falling much faster than inverter costs... oversized arrays will likely become much more common.
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Tedkidd
Member
nwdiver
Well-Known Member
I am not sure I understand why self conumed power would be at a different rate. Are you not on a net metering arrangement?
