Install a Bellagio-style water feature on your property. If you design it right, it can also be used to clean the PV, thus saving you physical labor. =)
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Plan: Off grid solar with a Model S battery pack at the heart
- Thread starter wk057
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Install a Bellagio-style water feature on your property. If you design it right, it can also be used to clean the PV, thus saving you physical labor. =)
beeeerock
Active Member
Those death-ray contraptions always look like they draw plenty of power. Whip one up and use it to take pot shots at the passing ICE cars...?
Apparently enphase is working on a solution for batteries. I assume it uses another inverter, but I do not know. I was surprised solaredge was 10-15% more expensive.
Tedkidd
Member
For those interested in where the utilities are headed, you might enjoy this - http://event.on24.com/wcc/r/1130756/0684A1DA70A1922F0958278D26B7B970
I also really admire Richard Kauffman, NY's "Energy Czar" - Columbia | SIPA Center on Global Energy Policy | Reforming the Energy Vision (2/18/16)
Here's a presentation I attended - States Reshaping the Energy Landscape - YouTube in which he explains why utilities are going to be VERY different in 10 years.
I also really admire Richard Kauffman, NY's "Energy Czar" - Columbia | SIPA Center on Global Energy Policy | Reforming the Energy Vision (2/18/16)
Here's a presentation I attended - States Reshaping the Energy Landscape - YouTube in which he explains why utilities are going to be VERY different in 10 years.
Will be adding a bunch more stats to wk057.solar soon, including nifty net usage graphs like this one:
Work in progress (red power from batteries, green batteries charging, grey line DC load, blue line inverted PV power). Will probably change it a bit, and release them on a delay vs real time since there are some privacy concerns with real time usage data.
The major overhaul to TMC has me taking a bit of a step back until, hopefully, some lost functionality can be restored. So, keep an eye on wk057.solar if you don't see many updates here. Also follow me on twitter @wk057. I might start actually using it since I have a bunch of followers now.
Work in progress (red power from batteries, green batteries charging, grey line DC load, blue line inverted PV power). Will probably change it a bit, and release them on a delay vs real time since there are some privacy concerns with real time usage data.
The major overhaul to TMC has me taking a bit of a step back until, hopefully, some lost functionality can be restored. So, keep an eye on wk057.solar if you don't see many updates here. Also follow me on twitter @wk057. I might start actually using it since I have a bunch of followers now.
dhanson865
Well-Known Member
Will be adding a bunch more stats to wk057.solar soon, including nifty net usage graphs like this one:
Work in progress (red power from batteries, green batteries charging, grey line DC load, blue line inverted PV power). Will probably change it a bit, and release them on a delay vs real time since there are some privacy concerns with real time usage data.
The major overhaul to TMC has me taking a bit of a step back until, hopefully, some lost functionality can be restored. So, keep an eye on wk057.solar if you don't see many updates here. Also follow me on twitter @wk057. I might start actually using it since I have a bunch of followers now.
fwiw my work proxy blocks wk057.solar "Your request was denied because of its content categorization: "none""
I can get to a direct image like http://wk057.solar/productiongraphs/2016-03-01.png but I can't get to any of the HTML.
oh and http://wk057.solar/usagetest3.png doesn't work, so something about shorter URLs or top level of your domain the proxy blocks but longer URLs or subdirectories are allowed?
anyway I just have to go there from my cell phone or from my home connection to avoid the work connection issue.
Awesome setup, wk -- this thread is inspiring. The wife and I want to do something similar this summer, although we're thinking a 30KW system of roughly 96 330W panels installed in five rows and elevated 35 feet up using some kind of stand alone support structure that we'd build above and just behind a large greenhouse. That's about 5000 pounds of electronics, not including the frame, to mount 35 feet up so that will be an interesting projection. Elevation will keep us from having to cut down too many trees though. We're thinking DC optimizers, a charge controller, no grid tie at all (don't want to pay to have the lines installed on our property) and of course the battery bank. After the solar array, we'll start building the house
We would love to do as you've done, building your own battery bank, but we're not sure how to go about buying those individual batteries, or how to wire them together. Are there any resources you can point me toward, to start learning how to replicate a smaller version of your battery bank? I've seen videos from this guy, but not much else.
We would love to do as you've done, building your own battery bank, but we're not sure how to go about buying those individual batteries, or how to wire them together. Are there any resources you can point me toward, to start learning how to replicate a smaller version of your battery bank? I've seen videos from this guy, but not much else.
nwdiver
Well-Known Member
How much would a grid connection cost? In Seattle you're looking at a HUGE difference in solar insolation between summer and winter of over 10:1.
Without a grid connection you'll either have an enormous deficit in the winter or enormous waste in the summer.
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How much would a grid connection cost? In Seattle you're looking at a HUGE difference in solar insolation between summer and winter of over 10:1.
Without a grid connection you'll either have an enormous deficit in the winter or enormous waste in the summer.
Not sure how much the connection would cost, but I'm guessing it would be a bit pricey. It would have to go through an easement and then several hundreds of feet to the build site of our property. Based on the PVWatts report we ran through helioscope using the Seattle location, our array would produce 888.8 KWh in December which would be our lowest month of production. That's about 30KWh a day, national average, so IF that report is accurate and its weather model is good (and we did it correctly--definitely an assumption) then we should be good to go. 96x330W panels facing due solar south at an 18 degree angle or so (optimum for winter).
Of course I don't know what I don't know...and that's a lot of things, so if I'm wrong thanks for pointing it out.
nwdiver
Well-Known Member
Considering the amount of curtailment you would experience in June to achieve 800kWh in December even if it costs $40k to connect it would probably be cost effective. WA has a lot of hydro and a very strong net metering policy. You could easily achieve the same level of energy independence with half as much solar installed with a grid connection. Even WK's large array can't cover his needs 100% of the time... you would either need the grid or a generator.
omgwtfbyobbq
Active Member
Going with only a generator for a back-up may not be cost effective, but some DSM, battery storage, and co-generation (Micro combined heat and power - Wikipedia, the free encyclopedia) might be. It depends on the specifics...
Tedkidd
Member
Do you think that PVWatts data I'm using is off, or are you suggesting that if I built half the system that my array wouldn't meet all the needs? With the 30KW system we've got planned, we're showing 30KWh a day (national average usage) in December with the weather. We've sized the array for the worst case scenario of winter sunlight. Using the full array, and if our data is correct, I think our structure will easily work on much less than the national average usage of electricity (and I think Wk's usage is much higher than the national average) because we're going to build our home with energy efficiency in mind (R value of 60) and the climate in Seattle is temperate so it won't be difficult to get away without air conditioning and minimal heating. Of course that number is just an average so there will be days with less or perhaps no energy production from the array. Maybe even weeks. In that case, we're thinking about using a propane generator to make up for what the battery bank can't supply. But our energy needs should be pretty modest.
The grid seems like more trouble than its worth and I share Wk's view that in the future it will be less worth it.
But of course I could be on a fool's errand. I'm far from technically savvy.
We have a small stream but we can't use it for hydro given local laws (and it makes sense). I did briefly look into rainwater collection to see if gravity fed water would be useful, but the power production comes nowhere close to what solar can provide.
nwdiver
Well-Known Member
No... I have no doubt that a 30kW system can meet 95% of your needs if you only use 800kWh per month... but that last ~5% is the tricky part... what happens when there's a week of really bad weather? Plus... if you only use ~800kWh/mo with a 30kW system you're going to produce nearly 5000kWh in June... that's ~20MWh of wasted energy every year.
I agree that the grid will be less valuable in the future... but that doesn't mean it still won't have value. Those periods of cloudy weather generally mean Low pressure systems which generally means wind... Wind and Solar make a great team but unlike solar... wind doesn't scale down very well... Importing wind from a wind farm to help fill that last 5% when there's not enough sun is a great solution but you need a grid connection. Wind and Hydro are cleaner and cheaper than stored solar... WA has both in abundance.
If the choice is between 10kW and a grid connection or 30kW and no grid connection the first option makes A LOT more sense.
The point that seems to get lost in the on-grid vs off-grid discussion is displacement. I have the batteries to be grid independent if I need them but I don't use them... Why? Because I can displace more fossil fuels by exporting during the day and importing at night. I'm more concerned with making my net consumption as negative as possible than having a gross consumption near zero. There will come a time when it won't be possible to export during most of the day but exporting when there's demand will always be more efficient than storing it.
adiggs
Well-Known Member
I don't know your particular situation (panel facing, shade, etc..), or anything else that might be specific to your situation rather than national average. However, I do have a 10 kw system and am located in the Portland area. The challenge with solar and going off-grid in the Pacific Northwest is the big swing between the peaks in the summer, and the troughs in the winter. To go off-grid, you need to handle those troughs.
Using single days, we had a couple of days last summer that cleared 70 kwh for the day. On the worst days in the winter though, we won't get 5 kwh (this year, Dec 1 - 18, we produced 3-6 kwh a day, or about 90 kwh over 18 days: how would that work out at your house, with your consumption, even with 3x the panels?).
At a monthly scale, our best month last year was June at 1626 kwh. Our worst was December for 180 and January for 250. If you triple those numbers, then December is 540 for you, and January would be 750 kwh. At the very least, be sure you have heat that doesn't need electricity to generate or distribute it
I expect that being further north, your swings will be slightly stronger than ours (bigger summers, lower winters). But you're not that much further north.
Or more simply, to go off-grid and be reliant on your own power production, the averages are only a starting point. You need to be able to handle your individual days, and the stretch of cloudy days you get at your location. Also - summer time and A/C won't be a problem. Your problem with a 30 kw system is you'll be wasting power over the summer. Crank up the AC - turn your house into a refrigerator - you'll have the power for that
One idea for getting started - get some kind of a system installed and run it for a couple of years - see what the power production is like in December and January, and see if you can get through it comfortably. All you need is one winter with no sun for a month, and things are going to be dicey.
Tedkidd
Member
Jason is a fair bit further south than you, and even with his huge production and huge storage he's a long way from being able to permanently disconnect.
I love this thread for a litany of reasons. One is I used to try explaining how hard it is to go off grid and I'd get that blank stare. Now I have a powerful case study to point to.
I love this thread for a litany of reasons. One is I used to try explaining how hard it is to go off grid and I'd get that blank stare. Now I have a powerful case study to point to.
nwdiver
Well-Known Member
Perhaps a good analogy would be having every electrical appliance in your house be independent or connected to a central battery/inverter. It should be intuitively obvious that a central battery/inverter would be the preferred method.
If every home was independent then every home would need a 20kW inverter + >100kWh of batteries. Sharing resources significantly reduces that requirement and makes the system more dynamic. There's a 50KVA transformer in my backyard that feeds 4 houses even though my house alone is capable of pulling 48KVA but we've never had a problem since it's very unlikely that every house on that circuit will try to pull that much power simultaneously. It would be a tremendous waste of resources to equip every house with the ability to handle its own peak load. In the future if every home was equipped with a small inverter (5kW) and battery bank (7kWh) that same 50KVA transformer could easily serve 10 homes with a managed smart grid.
Commercial wind power is ~$0.02/kWh... it's unlikely that it will ever be cheaper to cycle a battery than import wind energy. Batteries will be a necessity but they should only be used when cheaper resources aren't available.
