5 ms·

Not paying electricity for an entire year with Tesla Solar Roof [video]

43 points by teleforce 3y ago

jdjdjdhhd 3y ago
How many years before you pay off your roof and when will it need to be replaced?
- mikequinlan 3y ago
  If you watch the video, 9.6 years to payoff and 25 years to replacement in this particular case.
  - melling 3y ago
    And I imagine 25 years from now, the new solar roof be cheaper and more efficient.
    - backtoyoujim 3y ago
      Prying the old tiles off of the ruins of an post-apocalyptic wasteland can be very cost efficient.
      - wojciii 3y ago
        It also makes sense to use freely available slave labour.
  - ChemSpider 3y ago
    25 years is just what they guarantee, it probably lasts much longer. My solar roof (not Tesla, of course) is meanwhile 21 years old, and works almost like on day 1. Since I dont expect a sudden failure in 4 years, my guess it that it will last another 10-20 years.
    - itsoktocry 3y ago
      What leads you to believe a solar roof will last "much longer" than 25 years? >Since I dont expect a sudden failure in 4 years, my guess it that it will last another 10-20 years. Oh, you're just guessing.
    - PaulDavisThe1st 3y ago
      For the record, I had 4x some small panels (165W) from a reputable company that shall remain nameless. They had a 10 year warranty. Turns out that (a) the 10 year warranty actually meant "generating at least 90% of rated capacity in full sun after 10 years, but pro-rated across 10 years if not" and (b) they fell under this level after less than 5 years.
      - iforgotpassword 3y ago
        This is what I'm curious about. There seem to be really large differences between panels. Got two 150W panels for 78€ each this year. Peak output so far was around 240W, if performance stays like that for about five years I might break even in about 5 years for the full setup.
    - phyzome 3y ago
      Bear in mind that most residential roofs (of any sort) only last 10-20 years anyhow.
- trompetenaccoun 3y ago
  This question can't really be answered without knowing the location. The differences can be significant.
- technotarek 3y ago
  It really depends on where you live. Aside from the obvious electrical cost savings, you typically have state/federal incentives plus the opportunity to sell back excess power to the grid. In addition, and most importantly, there may be SREC markets that pay you to generate EVEN if you consume everything you produce. In Washington DC for example, my $30k traditional panel system should be paid off in about 5 years due to (ordered by magnitude): SREC sales, federal tax credits, excess power generation sold to the grid, electrical savings. Currently in year 3 and about 2/3 paid off.
- expertentipp 3y ago
  I'm afraid that in my location by the time the roof pays off, the roof will be so badly polluted with pollen, moss, and residue from air pollution applied by the rain, that the fall in efficiency will render the entire system inoperable.
  - gruez 3y ago
    How hard is it to rise/wash it off?
    - expertentipp 3y ago
      Depends from the flora in the region. Once lived in a city district with trees producing sticky syrup (maple?) and yellow powder (birch?). This mixture was penetrating every aperture in e.g. a car. Went to car wash, the next day car was sticky again. Spruce and pine pollen result in a moss-like layer on the roof quite quickly.
mg 3y ago
Over time, will we cover all the roofs of the world with solar panels? I would guess that a solar roof generates enough energy to cool the rooms below it, no matter how high the temperature rises on the outside. So with climate change continuing and solar roofs becoming more efficient and more affordable, it seems inevitable.
- mtsr 3y ago
  That depends. Climate change might very well (seasonally) increase cloud cover, vastly decreasing the power produced.
  - nine_zeros 3y ago
    Hypothetical
    - singularity2001 3y ago
      It is physical fact that each degree of temperature increase means the air can transport 7% more moisture and recent studies confirmed that the change in the last decades perfectly match the theoretical value. price per watt decays similar to moores law. thus cloud cover, latitude etc soon become negligible though
- Ekaros 3y ago
  Night time temperatures are also thing to consider. Not sure how viable thermal sinks cooled during sun-light hours would be...
  - blacksmith_tb 3y ago
    Sounds more difficult to implement than battery storage to keep the heating pumps running at night (given that we already have all that working well).
- spiderxxxx 3y ago
  Possible, but you're only moving heat. You're locally cooling, but the net effect of AC is more heat. If a lot of that heat can get out of the atmosphere through radiation, then we'll start to cool the planet. Greenhouse gases make that difficult.
rationalist 3y ago
[flagged]
mmmooo 3y ago
from the looks of it, his CTs are mis-reporting/double counting. A very common problem with tesla installs. My solar roof had the same issue initially, and electricians really thought it was generating more then the rating of the inverters, until I fixed it (software controlled). With 3 inverters he can't have more than ~23kw AC (assuming each is 7.8kw, which is the largest inverters tesla had at the time). My solar roof is a bit smaller (~21kw), in a similar region, but the daily peaks are slightly less than half of what he was showing.
- gruez 3y ago
  >My solar roof had the same issue initially, and electricians really thought it was generating more then the rating of the inverters, until I fixed it (software controlled). What was the software fix? Was there some config that wasn't set correctly?
  - mmmooo 3y ago
    yeah exactly, had to go into "installer mode" and configure the CT that's on a secondary powerwall, so it wouldn't count that value as part of the generation (forget the exact cryptically named option). Otherwise it considered energy pushed towards that powerwall as "additional energy in the system", and since the grid ct didn't show it was coming from there, it was assuming that the generation must be coming from solar. Or so it seemed.
AtlasBarfed 3y ago
Setup: Tesla Solar Roof (I thought it was discontinued) + 3 powerwalls + net metering 29 kilowatt array, 40 kwhr powerwall. Cost: 120k with 30k credit, projected payoff: 9.6 years Location: New Jersey Usage: Tesla car, electric AC, but gas heating (and probably gas water heating) He could probably go electric water heating too, because he is running a surplus. Full electric heating in the winter maybe, depending on insulation. He pulls from the grid in the winter, but is net-negative in all other months. The cost seems high, he says solar panels could be 19 kw total. The interesting thing is that by his viewpoint, as much solar as possible is good because as much of your appliances can be put on electric. The near-future view of this seems to be (this is not in the video, this is my personal opinion): - perovskite + silicon solar panels will increase efficiency and drop costs - 150-200 wh/kg sodium ion batteries will drop the cost of the storage arrays by 50-60%, but the utilities will continue their political war on net metering, so you'll need a bigger array - heat exchangers will drop the energy need of heat/AC so it can go electric I think the federal incentives kind of still suck. They need to make this a no-brainer option for almost all homes, be it financed zero-down or similar schemes. Right now this is a luxury feature, but that's not going to get us to low-carbon energy independence. There is also a housing crisis practically everywhere. The Feds will eventually stimulate construction to increase supply, why not make all the new supply solar enabled? Especially since the new supply is generally intended for the newer generations? I'll retire tot the corner to keep taking the hallucinogens that gave me that temporary optimism.
- p1mrx 3y ago
  > the utilities will continue their political war on net metering And they'll probably win, because it makes no economic sense for a utility to provide a valuable service (reliable energy storage) for free.
- mft_ 3y ago
  It's worth noting the delta between this price, versus buying more normal panels on the open consumer market - for similarly optimistic reasons! Based on a couple of panels I recently picked up on Aliexpress, they're running around 550-600 EUR (delivered) per kW, based on 200w panels. (You could probably go lower with more careful shopping and/or a bulk discount.) At these prices, a 29kW array (like MKB's) would cost 16-17.5k EUR, panels alone. Of course, this price is without fitting or any other required parts (noting the Powerwalls especially!), would be considerably uglier on your roof than Tesla's offering, and would likely not even fit on the same roof area (so you'd have to settle for fewer kWs) - but it's exciting how cheap solar panels have become - and looking to the future, they'll become even cheaper and more efficient over time.
lukasb 3y ago
People talk about how the grid wouldn't be able to handle everyone switching to electric cars. I wonder how residential solar (which works better in some places than others obviously) fits into that.
- IggleSniggle 3y ago
  Meanwhile I'm over here in my 100+ year old house wondering which part of my tube-and-knob cracked-rubber insulated electrical system is going to fail if I decide to use the microwave... there's plenty of interconnected pieces in an electric system that just aren't built for the transition, and there's a lot of work in getting them ready that might not be immediately obvious.
  - bobthepanda 3y ago
    That’s true for any transition. The EPA is considering declaring no safe level of lead in buildings, and that is going to fuck with a lot of older homes. https://www.nytimes.com/2023/07/12/climate/epa-lead-dust-homes.html https://www.nytimes.com/2023/07/12/climate/epa-lead-dust-hom...
trompetenaccoun 3y ago
200+ kWh per day consumption. In ~6 days this guy has used more electricity than me for an entire year. I get he also charges his electric car, which takes up a big chunk, but it still blows my mind how much electricity the average American home consumes.
- usefulcat 3y ago
  There's nothing 'average' about using 200 kWh/day in the US. Where I live in the US, the average temperature (not the high!) is in the upper 80s right now. My home is not large by US standards, but it is old and not nearly as well insulated as a newer home. The A/C runs continuously for hours on end each day, and right now we are using 35-40 kWh/day. So yeah, I'm pretty sure most of that 200 kWh/day is going to charge the car.
  - sokoloff 3y ago
    200kWh is about 700 miles of charge (and he says he doesn’t charge every day). There’s something weird going on, but it’s definitely not typical usage. I suspect an instrumentation/configuration problem before I’d suspect an average usage of almost 5x mine.
    - jackmott42 3y ago
      rich guy with a big air conditioned house?
      - nextweek2 3y ago
        Or rich guy with a heated pool.
  - trompetenaccoun 3y ago
    Edit: Sorry I made a stupid mistake. Should be 30kWh/day! That tracks much better with your own figure. Ignore the blow. --------------------------------------------------- You're right, most use less because they don't charge a car. The average seems to be about double that though at ~74 kWh/day: https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 Taking that average it would take around 2 weeks to reach my yearly consumption. Should be noted that's for something like 2.7 people, mine is a two person household.
prakhar897 3y ago
Now wait for the Electrical Companies to change the reset month to Nov. Then you have to pay Nov, Dec, Jan bill and get credits for summer months. Only for them to get reset again in Nov. An MBA will be made partner for this suggestion.
- PaulDavisThe1st 3y ago
  Depends on the company. PNM (Northern New Mexico) doesn't ever reset unless you opt to get paid cash. If you decline that, you get a (so far) endlessly available energy credit, with which you get 1 free kWh for every banked kWh, so it is a much better deal than the cash paybacks, at least if your use exceeds your generating capacity for part of the year
retrocryptid 3y ago
Meh. Tesla has been randomly changing the price of a solar roof. I can't remember the last quote they gave me, but it was slightly less than the second quote which was twice the price they initially quoted. While solar roofs are cool, I sorta need to know how much it will cost and I need that cost not to change between the time we sign a contract and the time 8 months later when Tesla decides they don't have enough local installers in my area and cancel the contract (and mysteriously deliver a an unsolicited quote for twice the original price.) So sure, if you're a YouTube influencer or Tesla employee, you can get one installed. But the rest of us schlubs will have to make due with unfashionable solar panels from reliable installers.
iforgotpassword 3y ago
Funny that he complains about the 5.75$ per month the electricity company charges. You still used the grid, so how are they going to maintain it? How to pay the guy who fixes the power lines in your street? This is actually the way it should be, and obviously not the way it's done here in Germany. We don't have net metering "because you'd be using the public power grid as your private battery then". I already pay 15€ every month as base fee, and it's not like the power grid is wearing down like a tire if you use it more. (Yes, technically it does, but practically negligible). Also if there would be more power produced in my section of the grid than gets consumed, I simply couldn't push any power back into the grid, so it's not like I'd get paid for producing power that nobody is consuming. But no, not in Germany... current prices for consuming is around 30-40ct per kWh, while you only get payed around 6-10ct per kWh depending on when you got your system installed. And that only applies to bigger setups on your roof, the smaller ones you can mount on your balcony for example, you get nothing. Energiewende made in Germany.
- sokoloff 3y ago
  Presumably, the smaller ones you mount on your balcony end up paying you the full retail rate for electricity you generated and consumed locally and that the grid never even knew about, right?
  - iforgotpassword 3y ago
    Theoretically yes, but that requires you have an old meter. Anything installed since ~2010 is either digital or at least has a mechanical blockage that stops it from running backwards. I think there is even a plan to update every single household to a digital one in the next few years
    - sokoloff 3y ago
      A small balcony unit is unlikely to surpass the electricity demand of the household. If it doesn't, your meter would never be "asked" to run backwards.

43 points by teleforce 3y ago

jdjdjdhhd 3y ago

How many years before you pay off your roof and when will it need to be replaced?

mikequinlan 3y ago
If you watch the video, 9.6 years to payoff and 25 years to replacement in this particular case.
- melling 3y ago
  And I imagine 25 years from now, the new solar roof be cheaper and more efficient.
  - backtoyoujim 3y ago
    Prying the old tiles off of the ruins of an post-apocalyptic wasteland can be very cost efficient.
    - wojciii 3y ago
      It also makes sense to use freely available slave labour.
- ChemSpider 3y ago
  25 years is just what they guarantee, it probably lasts much longer. My solar roof (not Tesla, of course) is meanwhile 21 years old, and works almost like on day 1. Since I dont expect a sudden failure in 4 years, my guess it that it will last another 10-20 years.
  - itsoktocry 3y ago
    What leads you to believe a solar roof will last "much longer" than 25 years? >Since I dont expect a sudden failure in 4 years, my guess it that it will last another 10-20 years. Oh, you're just guessing.
  - PaulDavisThe1st 3y ago
    For the record, I had 4x some small panels (165W) from a reputable company that shall remain nameless. They had a 10 year warranty. Turns out that (a) the 10 year warranty actually meant "generating at least 90% of rated capacity in full sun after 10 years, but pro-rated across 10 years if not" and (b) they fell under this level after less than 5 years.
    - iforgotpassword 3y ago
      This is what I'm curious about. There seem to be really large differences between panels. Got two 150W panels for 78€ each this year. Peak output so far was around 240W, if performance stays like that for about five years I might break even in about 5 years for the full setup.
  - phyzome 3y ago
    Bear in mind that most residential roofs (of any sort) only last 10-20 years anyhow.
trompetenaccoun 3y ago
This question can't really be answered without knowing the location. The differences can be significant.
technotarek 3y ago
It really depends on where you live. Aside from the obvious electrical cost savings, you typically have state/federal incentives plus the opportunity to sell back excess power to the grid. In addition, and most importantly, there may be SREC markets that pay you to generate EVEN if you consume everything you produce. In Washington DC for example, my $30k traditional panel system should be paid off in about 5 years due to (ordered by magnitude): SREC sales, federal tax credits, excess power generation sold to the grid, electrical savings. Currently in year 3 and about 2/3 paid off.
expertentipp 3y ago
I'm afraid that in my location by the time the roof pays off, the roof will be so badly polluted with pollen, moss, and residue from air pollution applied by the rain, that the fall in efficiency will render the entire system inoperable.
- gruez 3y ago
  How hard is it to rise/wash it off?
  - expertentipp 3y ago
    Depends from the flora in the region. Once lived in a city district with trees producing sticky syrup (maple?) and yellow powder (birch?). This mixture was penetrating every aperture in e.g. a car. Went to car wash, the next day car was sticky again. Spruce and pine pollen result in a moss-like layer on the roof quite quickly.

mg 3y ago

Over time, will we cover all the roofs of the world with solar panels? I would guess that a solar roof generates enough energy to cool the rooms below it, no matter how high the temperature rises on the outside. So with climate change continuing and solar roofs becoming more efficient and more affordable, it seems inevitable.

mtsr 3y ago
That depends. Climate change might very well (seasonally) increase cloud cover, vastly decreasing the power produced.
- nine_zeros 3y ago
  Hypothetical
  - singularity2001 3y ago
    It is physical fact that each degree of temperature increase means the air can transport 7% more moisture and recent studies confirmed that the change in the last decades perfectly match the theoretical value. price per watt decays similar to moores law. thus cloud cover, latitude etc soon become negligible though
Ekaros 3y ago
Night time temperatures are also thing to consider. Not sure how viable thermal sinks cooled during sun-light hours would be...
- blacksmith_tb 3y ago
  Sounds more difficult to implement than battery storage to keep the heating pumps running at night (given that we already have all that working well).
spiderxxxx 3y ago
Possible, but you're only moving heat. You're locally cooling, but the net effect of AC is more heat. If a lot of that heat can get out of the atmosphere through radiation, then we'll start to cool the planet. Greenhouse gases make that difficult.

rationalist 3y ago

[flagged]

mmmooo 3y ago

from the looks of it, his CTs are mis-reporting/double counting. A very common problem with tesla installs. My solar roof had the same issue initially, and electricians really thought it was generating more then the rating of the inverters, until I fixed it (software controlled). With 3 inverters he can't have more than ~23kw AC (assuming each is 7.8kw, which is the largest inverters tesla had at the time). My solar roof is a bit smaller (~21kw), in a similar region, but the daily peaks are slightly less than half of what he was showing.

gruez 3y ago
>My solar roof had the same issue initially, and electricians really thought it was generating more then the rating of the inverters, until I fixed it (software controlled). What was the software fix? Was there some config that wasn't set correctly?
- mmmooo 3y ago
  yeah exactly, had to go into "installer mode" and configure the CT that's on a secondary powerwall, so it wouldn't count that value as part of the generation (forget the exact cryptically named option). Otherwise it considered energy pushed towards that powerwall as "additional energy in the system", and since the grid ct didn't show it was coming from there, it was assuming that the generation must be coming from solar. Or so it seemed.

AtlasBarfed 3y ago

Setup: Tesla Solar Roof (I thought it was discontinued) + 3 powerwalls + net metering 29 kilowatt array, 40 kwhr powerwall. Cost: 120k with 30k credit, projected payoff: 9.6 years Location: New Jersey Usage: Tesla car, electric AC, but gas heating (and probably gas water heating) He could probably go electric water heating too, because he is running a surplus. Full electric heating in the winter maybe, depending on insulation. He pulls from the grid in the winter, but is net-negative in all other months. The cost seems high, he says solar panels could be 19 kw total. The interesting thing is that by his viewpoint, as much solar as possible is good because as much of your appliances can be put on electric. The near-future view of this seems to be (this is not in the video, this is my personal opinion): - perovskite + silicon solar panels will increase efficiency and drop costs - 150-200 wh/kg sodium ion batteries will drop the cost of the storage arrays by 50-60%, but the utilities will continue their political war on net metering, so you'll need a bigger array - heat exchangers will drop the energy need of heat/AC so it can go electric I think the federal incentives kind of still suck. They need to make this a no-brainer option for almost all homes, be it financed zero-down or similar schemes. Right now this is a luxury feature, but that's not going to get us to low-carbon energy independence. There is also a housing crisis practically everywhere. The Feds will eventually stimulate construction to increase supply, why not make all the new supply solar enabled? Especially since the new supply is generally intended for the newer generations? I'll retire tot the corner to keep taking the hallucinogens that gave me that temporary optimism.

p1mrx 3y ago
> the utilities will continue their political war on net metering And they'll probably win, because it makes no economic sense for a utility to provide a valuable service (reliable energy storage) for free.
mft_ 3y ago
It's worth noting the delta between this price, versus buying more normal panels on the open consumer market - for similarly optimistic reasons! Based on a couple of panels I recently picked up on Aliexpress, they're running around 550-600 EUR (delivered) per kW, based on 200w panels. (You could probably go lower with more careful shopping and/or a bulk discount.) At these prices, a 29kW array (like MKB's) would cost 16-17.5k EUR, panels alone. Of course, this price is without fitting or any other required parts (noting the Powerwalls especially!), would be considerably uglier on your roof than Tesla's offering, and would likely not even fit on the same roof area (so you'd have to settle for fewer kWs) - but it's exciting how cheap solar panels have become - and looking to the future, they'll become even cheaper and more efficient over time.

lukasb 3y ago

People talk about how the grid wouldn't be able to handle everyone switching to electric cars. I wonder how residential solar (which works better in some places than others obviously) fits into that.

IggleSniggle 3y ago
Meanwhile I'm over here in my 100+ year old house wondering which part of my tube-and-knob cracked-rubber insulated electrical system is going to fail if I decide to use the microwave... there's plenty of interconnected pieces in an electric system that just aren't built for the transition, and there's a lot of work in getting them ready that might not be immediately obvious.
- bobthepanda 3y ago
  That’s true for any transition. The EPA is considering declaring no safe level of lead in buildings, and that is going to fuck with a lot of older homes. https://www.nytimes.com/2023/07/12/climate/epa-lead-dust-homes.html https://www.nytimes.com/2023/07/12/climate/epa-lead-dust-hom...

trompetenaccoun 3y ago

200+ kWh per day consumption. In ~6 days this guy has used more electricity than me for an entire year. I get he also charges his electric car, which takes up a big chunk, but it still blows my mind how much electricity the average American home consumes.

usefulcat 3y ago
There's nothing 'average' about using 200 kWh/day in the US. Where I live in the US, the average temperature (not the high!) is in the upper 80s right now. My home is not large by US standards, but it is old and not nearly as well insulated as a newer home. The A/C runs continuously for hours on end each day, and right now we are using 35-40 kWh/day. So yeah, I'm pretty sure most of that 200 kWh/day is going to charge the car.
- sokoloff 3y ago
  200kWh is about 700 miles of charge (and he says he doesn’t charge every day). There’s something weird going on, but it’s definitely not typical usage. I suspect an instrumentation/configuration problem before I’d suspect an average usage of almost 5x mine.
  - jackmott42 3y ago
    rich guy with a big air conditioned house?
    - nextweek2 3y ago
      Or rich guy with a heated pool.
- trompetenaccoun 3y ago
  Edit: Sorry I made a stupid mistake. Should be 30kWh/day! That tracks much better with your own figure. Ignore the blow. --------------------------------------------------- You're right, most use less because they don't charge a car. The average seems to be about double that though at ~74 kWh/day: https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 Taking that average it would take around 2 weeks to reach my yearly consumption. Should be noted that's for something like 2.7 people, mine is a two person household.

prakhar897 3y ago

Now wait for the Electrical Companies to change the reset month to Nov. Then you have to pay Nov, Dec, Jan bill and get credits for summer months. Only for them to get reset again in Nov. An MBA will be made partner for this suggestion.

PaulDavisThe1st 3y ago
Depends on the company. PNM (Northern New Mexico) doesn't ever reset unless you opt to get paid cash. If you decline that, you get a (so far) endlessly available energy credit, with which you get 1 free kWh for every banked kWh, so it is a much better deal than the cash paybacks, at least if your use exceeds your generating capacity for part of the year

retrocryptid 3y ago

Meh. Tesla has been randomly changing the price of a solar roof. I can't remember the last quote they gave me, but it was slightly less than the second quote which was twice the price they initially quoted. While solar roofs are cool, I sorta need to know how much it will cost and I need that cost not to change between the time we sign a contract and the time 8 months later when Tesla decides they don't have enough local installers in my area and cancel the contract (and mysteriously deliver a an unsolicited quote for twice the original price.) So sure, if you're a YouTube influencer or Tesla employee, you can get one installed. But the rest of us schlubs will have to make due with unfashionable solar panels from reliable installers.

iforgotpassword 3y ago

Funny that he complains about the 5.75$ per month the electricity company charges. You still used the grid, so how are they going to maintain it? How to pay the guy who fixes the power lines in your street? This is actually the way it should be, and obviously not the way it's done here in Germany. We don't have net metering "because you'd be using the public power grid as your private battery then". I already pay 15€ every month as base fee, and it's not like the power grid is wearing down like a tire if you use it more. (Yes, technically it does, but practically negligible). Also if there would be more power produced in my section of the grid than gets consumed, I simply couldn't push any power back into the grid, so it's not like I'd get paid for producing power that nobody is consuming. But no, not in Germany... current prices for consuming is around 30-40ct per kWh, while you only get payed around 6-10ct per kWh depending on when you got your system installed. And that only applies to bigger setups on your roof, the smaller ones you can mount on your balcony for example, you get nothing. Energiewende made in Germany.

sokoloff 3y ago
Presumably, the smaller ones you mount on your balcony end up paying you the full retail rate for electricity you generated and consumed locally and that the grid never even knew about, right?
- iforgotpassword 3y ago
  Theoretically yes, but that requires you have an old meter. Anything installed since ~2010 is either digital or at least has a mechanical blockage that stops it from running backwards. I think there is even a plan to update every single household to a digital one in the next few years
  - sokoloff 3y ago
    A small balcony unit is unlikely to surpass the electricity demand of the household. If it doesn't, your meter would never be "asked" to run backwards.