Why would you take California as example? Why not the whole US average? Using the same data in your link, US average is $1368/year for all households. This includes multifamily buildings like condos or apartments. If you consider only single family homes, their energy use profile is higher. So, $2000/year energy bill for single family homes is a fair estimate.
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Why would you take California as example? Why not the whole US average? Using the same data in your link, US average is $1368/year for all households. This includes multifamily buildings like condos or apartments. If you consider only single family homes, their energy use profile is higher. So, $2000/year energy bill for single family homes is a fair estimate.
Another anecdotal data point: Northern california, 4 bedroom house, we had $2400/year from air conditioning mostly, adding maybe another $600/year from electric vehicles (conservative estimate), so $3000/year is what I am offsetting with my 10kW system, paying for itself ($18,000 after 30% federal tax credit incentive) in 6 years of ownership, currently in year 2.
mmd
Active Member
OK, that could be. CR probably picked the average of those that consume more electricity that others, thinking they will be more willing to purchase the solar roof.
PS: As the post above says, payoff is much faster with just solar + net metering. Typically 6-7 years.
Ugh.
Some terrible assumptions being used both by CR and by some posters here regarding the solar roofs.
CR: "We'll back out $2,000/yr from our calc's as that's the average elec. bill in 3 solar states".
One poster here: "Doubt a roof can generate $2K worth of electricity", and so on.
HERE are the salient points:
* Musk's presentation was that a Powerwall could sustain a 4-br house...considering just its lights, receptacles & refrigerator. NOT a high-consumption high-end home, and he was referring to the battery bank, not the PV array.
* A 3,000 sqft roof will have some fraction of its surface oriented appropriate for solar capture. USUALLY less than half. To get all, the roof would need be a south-sloping single shed roof. Not a hugely popular style in Brentwood, best sources tell me.
* "$2K" is the utility's bill, it is not a very good representation of the # of kWhs produced. In the more appropriate avoided cost terms, an average roof in an average insolation region most definitely could pump out the appropriate # of kWhs. More to the interest of this forum's average member, if I have gauged correctly, yesyoubetnodoubtaboutit a full frontal solar-slabbed roof could power all your A/C and water heating needs AND your Tesla without any need for grid connect. Not in Alaska but certainly in Yuma and between those extremes....it depends
Would that be a cost-effective way of telling your local friendly utility monopoly to do something anatomically impossible to itself? Mebbe, mebbe not. Their rate structures, their overall rates, their reliability, your region's propensity for natural disasters, your sentiment and your pride of independence and the weight you place on diminishing fossil fuel consumption all play into answering that question.
Some terrible assumptions being used both by CR and by some posters here regarding the solar roofs.
CR: "We'll back out $2,000/yr from our calc's as that's the average elec. bill in 3 solar states".
One poster here: "Doubt a roof can generate $2K worth of electricity", and so on.
HERE are the salient points:
* Musk's presentation was that a Powerwall could sustain a 4-br house...considering just its lights, receptacles & refrigerator. NOT a high-consumption high-end home, and he was referring to the battery bank, not the PV array.
* A 3,000 sqft roof will have some fraction of its surface oriented appropriate for solar capture. USUALLY less than half. To get all, the roof would need be a south-sloping single shed roof. Not a hugely popular style in Brentwood, best sources tell me.
* "$2K" is the utility's bill, it is not a very good representation of the # of kWhs produced. In the more appropriate avoided cost terms, an average roof in an average insolation region most definitely could pump out the appropriate # of kWhs. More to the interest of this forum's average member, if I have gauged correctly, yesyoubetnodoubtaboutit a full frontal solar-slabbed roof could power all your A/C and water heating needs AND your Tesla without any need for grid connect. Not in Alaska but certainly in Yuma and between those extremes....it depends
Would that be a cost-effective way of telling your local friendly utility monopoly to do something anatomically impossible to itself? Mebbe, mebbe not. Their rate structures, their overall rates, their reliability, your region's propensity for natural disasters, your sentiment and your pride of independence and the weight you place on diminishing fossil fuel consumption all play into answering that question.
`
Well, this whole thing started off with Vlad saying the reason Octobers are not that great is because of the Tesla aspiration to deliver 3000 cars more than they produce this quarter while my counterpoint was simply that is because they are building inventory.
In 20 years the cost/price of electricity on a sunny day may approach zero most days. At worst the cost would be a couple cents plus transmission for those not self-generating. I have a hard time imagining anyone renew a lease for ancient electronics. Net metering certainly won't be extended on these system. If rooftop solar makes sense in 20 years it will likely include a very advanced battery system.
With very cheap solar modules ideal orientation may even change to east/west ( as Tesla showed on their gigafactory model, IIRC).
I see very little value past the 20 year PPA contract, especially without net metering.
With very cheap solar modules ideal orientation may even change to east/west ( as Tesla showed on their gigafactory model, IIRC).
I see very little value past the 20 year PPA contract, especially without net metering.
That may have been too coy by half to avoid answering a direct question. The 10 Q states: "Revenue recognized from the sale of regulatory credits increased by $114.7 million from three months ended September 30, 2015 to the corresponding period in 2016."
The SH letter said ZEV credits sold in 3Q16 were $139 million. Filings from 2015, show Tesla reported $39 million in ZEV credits and $16 million in CAFE/GHG credits during 3Q15..
That's $30.7 million in CAFE/GHG credits in 3Q16. Tesla has not split out CAFE/GHG credits in any filing for 2016; however for the 12 prior quarter in calendar years 2013-2015, the quarterly average was about $15 million/quarter, so the "pie in the face" quarter appears to be about double the average.
"Double the average" could be the result of Tesla bunching revenue from CAFE/CAFE credit sales that normally would be recognized in Q2 into Q3, similar to what was done for ZEV credits. In 2Q16, Tesla reported $64k in ZEV credit revenue; in 3Q16 ZEV credit revenue jumped 2171% , Q over Q, to $139 million.
The 3Q16 10 Q also states: ": Revenue recognized from the sale of regulatory credits increased by $113.9 million from the nine months ended September 30, 2015 to the corresponding period in 2016." In the first nine months of 2015, Tesla reported $104 million in ZEV credit revenue and $44 million (i.e. ~$15 miillion/quarter) in CAFE/GHG credit sales. During the first three quarters on 2016 for ZEV credit sales, Tesla reported $57 million, $64 thousand, and $139 million respectively. That leaves $48.64 million for the first nine months of 2016, so either `$16 million per quarter, or a "pie" of ~$18 million in 1H16 and $30.7 million for 3Q16
Assuming we all need new roofs within 20 years anyway; what would be your best estimate for the extra cost of a Solar glass roof 20 years from now (2036) given current cost reduction scenarios?
Given that roof will last 30-50 years from then, what would you estimate the marginal cost of electricity per kWh would be, produced (and buffered) from that roof?
I believe the Glass roof will cost less than today's comparative asphalt and will essentially be standard roofing at that time anyway built into the amortization value of the home itself- If so, the cost per kWh may well be negative and require excess sinking to ground.
According to ElonsVelvetJacket, S60 base price is increasing by $2K. Once confirmed, should provide another modest boost for margins (although likely more of an impact in Q1 2017 than Q4 2016). A further sign Tesla is production constrained.
Tesla is increasing the base price of the Model S by $2,000, source says
Tesla is increasing the base price of the Model S by $2,000, source says
Ugh.
I expect CR to actual do math rather than make a random assumption that a roof can produce $2k of electricity a year.
There are plenty of solar panel calculators there and although there are differences in orientation and roof design, they could have described several different scenarios and provide ranges.
Why not just assume it can produce $3k or $1k (about the U.S. average for electricity)? They created an average roofing cost and then just threw in how much electricity it could produce with nothing behind it.
I made that "terrible assumption" you cited since I actually have a solar system. I am getting no where near $2k in electricity per year I am happy to upgrade my system and buy a battery if I can be generating so much excess, so I will look into this more in depth. $2k a year is a lot.
In-post Mod input: Perhaps my post wasn't clear that I was rolling my eyes over that portion of the CR article. It was very sloppy; close to the point of uselessness.
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dhrivnak
Active Member
Mine was about $7500 but that was 17 years ago and included ducts. A new high efficiency unit is now about the same as we do not need to run ducts. My guess you will save some on AC as well
dennis
Model S Plaid
And in this particular quarter Tesla chose to build inventory cars early in the period because they didn't want to disappoint a lot of customers by delivering them custom ordered cars with AP1 hardware after AP2 was announced. So rather than idle the factory for 3-4 weeks instead of one week they built inventory cars instead.
As a result of this unique situation we can't really draw any conclusions from the October delivery data on whether they will make this quarter's forecast or not.
3Victoria
Active Member
In 20 years: if most houses include solar and batteries, then neighbourhoodd could do local load sharing. They neighbours on holiday might be selling power to the neighbours hosting guests and needing more power. Neighbourhoods might power share with other neighbourhoods. What role does the power company have? I am not sure how it all fits together.
dennis
Model S Plaid
In California the PUC has grandfathered net metering for 20 years from when your solar panels are put into service. Don't know about other states.
sub
Active Member
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My numbers are basically the same with my 8kw system, I have 4 bd 3000 sqft and my system will have paid for itself in ~6 years, I'm in year 5.
Edit - just received my monthly report, lots of rain in NorCal the last 3 weeks. I haven't paid for power since install.
Week Peak Power Energy Produced
10/01/2016 - 10/07/2016 7.14 kW 278 kWh
10/08/2016 - 10/14/2016 6.91 kW 243 kWh
10/15/2016 - 10/21/2016 6.86 kW 234 kWh
10/22/2016 - 10/28/2016 7.06 kW 171 kWh
10/29/2016 - 10/31/2016 7.23 kW 62.0 kWh
October 2016 Total: 989 kWh
Previous Month Total: 1.31 MWh
Year to Date: 12.1 MWh
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If the average house-hold uses between 1000-1500 kwh/ month, I don't think a solar roof will cover your needs entirely. Also, will the new Tesla battery pack have enough output to power a large AC unit + all other lights and utilities? Many large AC units require 5500 watts of continuous power. I would guess not. In addition, I doubt you'll be able to charge your Tesla and run AC unit at the same time. As I remember EM said during most recent meeting, Tesla roof and battery are an excellent way to compliment your existing utility supply, but it's not meant to replace it.
bdy0627
Active Member
Few points that need to be considered before assuming that NPV for renewals is largely illusory:
- example of efficiency improvement between 4 times to 7 times is not relevant, as at 22.5% efficiency when new current cells are much closer to the theoretical efficiency limit of 33%. Even assuming that the SQ Limit can be surpassed at some point in future, assuming even 2 times improvement might prove to be optimistic
- urge of rip down 20-year old panels upon expiration of lease to replace them with something less than 2 times more efficient is not any more likely than replacement of the house HVAC system simply because more efficient system is available on the market. Absolute majority of HVAC systems get replaced because aging system breaks and no longer operational, not because of presence of more efficient HVAC systems on the market.
- reduction of the solar system efficiency and aggregate renewal rate can be captured by properly adjusted NPV of Unlevered Project Cash Flow. The Solar City 2016 Q2 shareholder letter for example indicate
"Our Q2 2016 Value of MW Deployed was $3.62 per Watt, composed of (1) upfront Tax Equity Investment of $1.59 per Watt, (2) Upfront Cash Rebates and Prepayments of $0.06 per Watt, and (3) the NPV of Unlevered Project Cash Flow from customers and solar renewable energy credits (SRECs) after tax equity distributions of $1.97 per Watt ($1.61 per watt contracted and $0.36 per Watt from estimated renewal) at a 6% discount rate. Discount rate sensitivities are provided in the back of this letter."
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Old news. Was posted on this thread at least two times already.
Ulmo
Active Member
So, 56% cost efficiency at the renewal. What is the 6% discount rate?
Agree with rest, except that I think you're not optimistic enough on efficiency improvements of new products (at time of renewal), but even if it is higher like I suspect, they're already closer to that than they used to be, so I think your point still holds about it plateauing by a little bit, just because it's hard to imagine the efficiency getting wildly better than 20% super fast (I suppose some breakthrough could get us to the 80% level in many decades).
Regarding the efficiency improvements of the future, let's look at the current NREL (research) chart (currently shows 2016-08-12):
I see that a few years ago, Panasonic was at 25.6% in the lab, and LG at 27.5% in the lab. The top score is 46%. My prediction is that over the next few decades, we'll start to see stuff between 25% and 40% (incrementally) show up in end user products, such as car and home roofs, solar farms, commercial roofs, etc., slowly and incrementally. That is only double. It's been doubling every 20 to 25 years or so. At half of double, something that is already working would seem like it could stay there until it's no longer useful, or if it's in the way of higher use. Also, if your roof makes almost enough and you get more cars but you can cover more roofs and/or car roofs with more solar, or install a solar car port, then you have efficiently increased your solar area without having to tear out working solar panels. Also, basically all of these systems are grid connected, so you don't really have to increase your generation; you can just pull more and more from the grid as the decades pass, to compensate. At the wearout point (25 - 45 years?), one can finally replace them, with the best newest and greatest that the homeowner (customer) can afford at that time (probably all roofs will be solar roofs, then, with some exceptions like flat roofs, pole mount, etc.). Also, in 15-20 years, there may be things like solar paint, for siding, or even just solar siding, that will augment the older stuff on the roof.
Some roofs will be removed and replaced. But not all of them. I think quite a few will go until the solar panels no longer work well. Mars could even have self-sustaining humans on it before some current Solar City roofs are no longer productive (although that's right on the precipice).
Agree with rest, except that I think you're not optimistic enough on efficiency improvements of new products (at time of renewal), but even if it is higher like I suspect, they're already closer to that than they used to be, so I think your point still holds about it plateauing by a little bit, just because it's hard to imagine the efficiency getting wildly better than 20% super fast (I suppose some breakthrough could get us to the 80% level in many decades).
Regarding the efficiency improvements of the future, let's look at the current NREL (research) chart (currently shows 2016-08-12):
I see that a few years ago, Panasonic was at 25.6% in the lab, and LG at 27.5% in the lab. The top score is 46%. My prediction is that over the next few decades, we'll start to see stuff between 25% and 40% (incrementally) show up in end user products, such as car and home roofs, solar farms, commercial roofs, etc., slowly and incrementally. That is only double. It's been doubling every 20 to 25 years or so. At half of double, something that is already working would seem like it could stay there until it's no longer useful, or if it's in the way of higher use. Also, if your roof makes almost enough and you get more cars but you can cover more roofs and/or car roofs with more solar, or install a solar car port, then you have efficiently increased your solar area without having to tear out working solar panels. Also, basically all of these systems are grid connected, so you don't really have to increase your generation; you can just pull more and more from the grid as the decades pass, to compensate. At the wearout point (25 - 45 years?), one can finally replace them, with the best newest and greatest that the homeowner (customer) can afford at that time (probably all roofs will be solar roofs, then, with some exceptions like flat roofs, pole mount, etc.). Also, in 15-20 years, there may be things like solar paint, for siding, or even just solar siding, that will augment the older stuff on the roof.
Some roofs will be removed and replaced. But not all of them. I think quite a few will go until the solar panels no longer work well. Mars could even have self-sustaining humans on it before some current Solar City roofs are no longer productive (although that's right on the precipice).
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