Note that what he said is that the solar roof plus the electricity that it generates is cheaper than a conventional roof. The up-front cost is higher for the solar roof.
So, yes, there are assumptions in there: how much power can be generated, how valuable will it be 10 years from now, etc.
This is big. My roof cost nearly double what my solar installs did, and getting the tax credit on the roof might have paid for the additional cost of the solar tiles over standing seam metal. (Not that I don't love the metal; it's awesome.)
Solar panel roofing tiles have been around for a long time. I wonder what this will do different? Pricing? Or perhaps they are relying on brand strength alone.
Edit: I understand the urge to downvote because I'm not singing praise, but I promise I'm not trying to be overly pessimistic or critical of what Tesla is doing. Fact of the matter is, solar tiles have been done before, and failed miserably.
From my research they have never really been competitive to the point of getting any traction in their installation. They cost a lot more and provided a lot less power compared to standard panels. This seems promising especially if it is available so that it can be installed directly by home owners.
CIGS solar roofing tiles are (or were, not sure you can still get them) about 6% efficient. These are, according to what was in the TechCrunch article are over 20% efficient[1].
DOW's CIGS was pretty garbage compared to Certainteed's Apollo II system, which achieved 13.2% efficiency. [1]
There are also up-and-coming competitors such as SunTegra that hit 14.6% [2].
It seems like asthetic options and possibly efficiency improvements is what will set this apart from previous stumblings in this space. We'll see how this looks in the real world!
Marketing and business model, primarily. Previous solar tiles were more expensive than conventional solar and so are these. The difference here is that Tesla and SolarCity are marketing it as no more expensive upfront than a conventional roof replacement by keeping ownership of the roof and having buyers sign a contract committing them to buying power from it at ever-increasing prices.
There also seems to be some efficiency and aesthetic improvements over previous tiles, but those alone wouldn't be enough to make it viable.
And from that, hopefully, scale. Solar tiles have always seemed to be a very poor relation of solar panels. The approximately 1x1.5m panel is a sort of informal global standard, and that's meant that solar tiles have been much more fragmented, much lower scale, and much more expensive.
On the other hand in theory these solar integrated building materials should greatly reduce the associated costs of installing panels - labour is usually something like half the cost of installing rooftop solar, but if you can install a solar roof without much more effort than a normal roof, those extra labour costs are massively reduced.
If you can leverage this labour cost advantage to ramp up scale of the tiles, and get them close to the per watt cost of traditional panels, this is how you can really make rooftop solar competitive. These labour costs are why rooftop solar is so much more expensive than utility solar. If you can greatly reduce them, total costs are much more tied to the cost of the tiles themselves, the inverter, and so on, where there is enormous leeway for ongoing reductions. Very exciting.
>but I promise I'm not trying to be overly pessimistic or critical of what Tesla is doing
The fact that you have to apologize for this on HN nowadays is hilarious. I agree. Both solar panels (and to a lesser extent solar roofing tiles) and the powerwall are have a lot of competition.
The idea looks good, though. I didn't catch pricing details in the presentation?
I have no particular desire to sign up just to watch the video, but I hope that the Powerwall 2 is compelling enough to beat out the LG Chem RESU.
For reference, the RESU is a wall-mounted Li-ion battery meant to be connected to a solar inverter. It seems to beat the Powerwall in basically every respect. It's a bit cheaper, it has a better warranty, and it has slightly lower advertised capacity but higher warranted capacity under basically all advertised conditions. But it's not cool and doesn't have a shiny video.
I suppose the main reason for the inverter is to go from DC -> AC.
The Powerwall 1 required an external inverter. What did that inverter do? Converted from the DC -> AC? The Powerwall 1 had DC input? I guess not, otherwise you wouldn't need the external inverter.
So this powerwall converts internally from DC - > AC -> DC (battery)?
> But it's not cool and doesn't have a shiny video.
If no one knows about it, doesn't really matter what the specs are. If you can't market a product it might as well not exist. I mean, congratulations on the engineering I guess.
the cool thing is that they look good... they look like a normal roof at the angle you would see from the street in front of the house, but from above... from the angle of the sun they are transparent and you can see the solar cells.
I know some rich people that want solar but their neighborhood associations won't allow it, but I don't think they would not have an objection to these roofs. they look really nice....
I have been curious how they were going to compete with cheap chinese solar. this seems like a good strategy but one that may be easily copied.
Just imagine if they wrote encyclopedias in your communication style.
Completely fictional example:
From Ye Great Book of All Scottish things, 856 year of the Lord, page 17:
- yepswatter : a very commonly used household object, just ask anybody around to show you one.
Here in the UK we have "planning permission" which is basically the same thing. Round our way it's been used recently e.g. to stop people extending their houses over their off-street parking, which would necessitate them parking on the road - if everyone did it the street would be impassable, so it's fair to enforce that no-one does it.
Planning permission is granted or refused by the council though, based on the need and impact on surrounding areas. A HOA can stop you hanging your laundry out to dry on a line, force you to water your lawn x times a week, prevent you painting your house a particular colour, prevent you installing a fence, determine they type of vehicle you are allowed and whether it can be parked on your drive or if it must be in a garage. It is not really comparable to planning permission which is really only required for significant construction work or change of use ie. Shop to residential or vice versa.
Plus if the HOA members don't like you they can make your life difficult. Planning permission affects everyone equally. If a neighbour can extend a property then more than likely you can too, if you are refused it is likely all similar applications would be refused, you don't know the planning officer and they don't know you so no bias can be involved which make the whole process much fairer.
This product strategy certainly seems easy to copy, I agree. That's good for humanity and bad for Elon financially (I think that's the point for him, I don't think he cares about money outside of more commas).
Honestly though, he is freaking Elon Musk. If you don't think he can make the best version of this you are way underestimating what he has accomplished already.
Its all about fundamentals and he believe he can have a fundamental edge here.
The product itself might be easy to copy, but im not so sure about the product *strategy". Solarcity does the full stack, from the solar panels to the installation to the management and storage. That's going to be hard for a Chinese factory to reproduce.
I don't think he cares about copies. Tesla is poised to be a battery company, so copies will probably buy his batteries. At least long enough for Tesla to move up the value chain.
Unless the HOA rules have a stipulation about your roof shingles exactly matching the other roofs in the neighborhood, which is common. And boring a shit to look at. I hate HOAs so much.
If all they did was protect property values by keeping people from doing outrageous things, I might be okay with them, but they go way beyond that to the point where it diminishes the value of buying property (since you can't adapt it as you see fit). Municipal codes usually take care of the worst behavior, anyhow. Which is why if I ever buy land and/or a house, it will be in a more rural area. Then I can put a damn Tesla solar roof on it, build a shed with a different roof and paint it all purple with green stripes if I feel like it.
I lived in an HOA that took their rules way too far. Here is an example - paraphrased so your head doesn't explode: "You can't have any wireless devices without written permission, except a garage door opener and TV remote."
Right. Nice try. I joked with neighbors that we should all send one letter to them on the same day. A letter for each cell phone, wifi router, satellite dish, bluetooth speaker, etc.
This was in an area where many people were on wireless ISPs, there were a handful of ham radio antennas, etc. I asked someone on the HOA board why they didn't update or remove the garbage about wireless devices. The answer - it would cost to much to update the documents, so they don't try to enforce it. It is still crazy that they ever put it in there.
This HOA says no solar, but now that it is popular they also ignoring that.
That was my question as well, this from the Techcrunch article:
"The current versions of the tiles actually have a two percent loss on efficiency, so 98 percent of what you’d normally get from a traditional solar panel, according to Elon Musk. But the company is working with 3M on improved coatings that have the potential to possibly go above normal efficiency, since it could trap the light within, leading to it bouncing around and resulting in less energy loss overall before it’s fully diffused."
Which suggests that on a square footage basis it is similar. The difference being that on a manufactured panel the cells are all exactly next to each other with no seams, and with the Tesla roof they appear to have a moat around them that varies a bit with roof tile style.
That said, assuming you cover your entire roof which will include both "ideal" south facing (or north facing in the southern hemisphere) and "non-ideal" north facing parts of the roof you may get enough additional generation from the extra tiles to push it over a more 'traditional' solar install.To be honest I'm thinking about replacing my perfectly fine (if nearly 15 year old) solar panel set up with those roof tiles. That and a couple of power walls and I just might be able to go 'gas only' with PG&E.
replacing my perfectly fine (if nearly 15 year old) solar panel
I wish someone near me would do this, boy would I snap up those second hand panels.
When I was in my early twenties I put together a solar panel + charge regulator + inverter + laptop and run a web server serving a page detailing the setup it was running on.
The entertaining things I could get up to with 1kW or more of cheap second hand panels.
Are the solar cells and powerwall shielded by any kind of solar storm? I couldnt find any detailed information confirming or denying it. I would not like for any of us to be in a situation where the 1st solar outtage is our most damaging, and thats what causes any producer of electronics to adopt labeling and marketing for it.
Solar storms don't reach the earth, one of the jobs of our atmosphere and magnetosphere is to protect us from it. So there's no point in making protections against it for solar panels on the planet.
Not to mention that coronal mass ejections (CME) happen so often that you'd expect to have already heard of such power outages if one were possible.
Musk & co changing the world one step at a time. I used to be a Tesla sceptic. Not anymore, having owned one and witnessed the relentless improvement in battery tech.
Correct me if I am wrong, it estimates 12,000$ for a single day of energy backup of your home? For 12,000$ I dont mind staying one day without electricity.
But my electric bill is like $30-40/month, Why would I want to shell out $12,000 for something that will become old tech in couple of years like the 1 powerwall.
30-40$ is probably a very small apartment. A house (2 levels) in Quebec during winter can go easily around 500$ because of the constant heating required.
Cooling a house during the summer in Texas can easily cost the same amount if not more, and you get a ton of sun during that time. The point is that for single family homes electricity does not usually cost $40/month.
But the price for the equal amount of power walls needed for a bigger house vs a small 1 bedroom raises too, according to the calculator on their site it will cost $30k+ to install it for 4 bedroom house.
It will take most people 20-30 years to recoup this in terms of an investment over wholesale energy costs at current rates. It is, for the present a gimmic.
I cannot imagine what preparation they could be making. Surely the default process is to charge the powerwall at all times if feasible. What extra operation could it do in the event of a bad weather forecast? Other than tell you about it.
Sometimes you discharge. You may decide to not discharge ahead of a storm. If it were just backup, it would be easy, but sometimes you want to consume your storage to save money, or sell back to grid, if you have time of use pricing, or get paid for grid service.
To get better lifetime out of the cells, you don't fully charge them. I bet when bad weather is occurring soon, it charges to maximum storage capacity, not to max cycle level.
This lets you have best of both worlds, with a minor tradeoff in unpredictable outages you have slightly reduced runtimes.
For $3000 this would be easy to justify just to keep my computer and network operating. I work at home and our power goes out too frequently. Is usually just for 10-20 seconds and my UPS takes care of that. But sometimes it is out for several hours - I'll say several times per year. If I can't work, I can't bill.
Where are you seeing $3000? When I set it to 1 Powerwall it tells me:
One 14 kWh Powerwall battery $5,500
Installation and supporting hardware starts at $1,000
Total estimate $6,500
Requires $500 deposit for each Powerwall
Which still ties you to the 'grid' insofar as you need the natgas supply chain, even if you have a huge reservoir you'll eventually run out. Having said that, batteries and solar panels don't have an unlimited life span either.
I'm looking at buying a petrol powered generator for reasons other than home power generation, but it will be reassuring to know we have backup power at home, but I don't think I'm allowed to store any more than 25L in one container on my suburban property. I guess that would be 25L plus each of our two cars with full tanks.
It would be fairly trivial to convert a petrol powered generator to run on propane from the barbecue gas cylinder, I've had experience installing gas kits on carburettor engines in cars.
"Which still ties you to the 'grid' insofar as you need the natgas supply chain, even if you have a huge reservoir you'll eventually run out. Having said that, batteries and solar panels don't have an unlimited life span either."
That is my thought - however, a previous comment in this thread indicates that the powerwall batteries are cloud connected and remote controlled by tesla ... so I am not sure how that pans out when you lose power and network connectivity at the same time (as happens where I live several times throughout the winter, sometimes for 24+ hours).
Good points. But for me, I live on 80 acres and it happens that the county natural gas pipeline runs under it. The easement (signed in the 60's) included the right to connect to the pipeline at will. When we built the house, we exercised that right.
So even though I am rural, I don't have to buy liquid propane to heat my house. I'm tapped into a 100,000 home supply line. Its been depressurized maybe twice for maintenance in 50 years.
Not a solution for everybody. But a pretty good one for me! And everybody else on the line.
Nice setup! How much did connecting to the pipeline cost? Making an individual connection to something so large sounds expensive, but obviously I have no actual clue.
Fortunately there was a hairpin(?) connection across the road, so I agreed to connect there. That means they didn't have to depressurize just for me. Cost nothing (easement terms). However they charged me for the pipe to run the 200' from there to the house! I could have negotiated that better.
3 of my 4 adjacent neighbors have natural-gas generators. That gives you an indication of the power reliability here. Note that I don't blame the utility, and I'm not in some backwater ($1M+ homes around me). It's just that we really like our trees here, and sometimes a branch will break in a storm and take out the neighborhood.
My gripe with the generators is they are noisy. A Powerwall would be silent and would handle the typical outage situation. But so probably would a 3000VA UPS, which would only cost $1500.
Some places even managed to get entire sewer systems buried. Granted, that happened on a very different level of urgency (you really want shit to flow, and it only flows downward), but it gives the appropriate perspective on any excuses that are based on the natural scale of infrastructure.
The point is that for sewers there was no choice so we just swallowed the cost and got on with it. For power there was so we went for the cheaper less reliable option.
It's just a big battery that you can plug things into full time. When power goes out it instantly switches to battery power. It recharges when the power comes back.
A UPS will require a battery replacement every 10 years or so, regardless of whether you ever have to go on battery power or not. The UPS should automatically sense the status of the battery and warn you when a replacement is needed.
Pick a model from one of the major manufacturers and look up the replacement battery costs to get an idea of what it will cost.
As much as I like the idea after reading about the Note 7 and then a battery fire at DARPA I'm not fond of a giant battery lithium-ion battery in my house.
The problems with those batteries are that cell phones pushed the limit such that they were dangerous due to thin walls between part of the battery(ies), and hoverboards didn't keep batteries from overcharging, which causes a chemical reaction forming spikes that penetrate the thin walls between the parts of the batteries that cause fires. The batteries tech itself is not a problem; it's the design around it.
And if you think this is bad, just wait until batteries get more powerful and there are problems. Be thankful that it only starts a small fire!
Lithium-Ion technology is pretty well-understood at this point.
Just remember that there are 10s or 100s of Billions of Li-Ion batteries around the world, and having a single one fail catastrophically is still enough to make headlines...
Tesla has lots of experience packing cells with their vehicles. I would trust them to get it right. Also they have much more space to work with versus a phone.
Any idea why the solar cells aren't packed more densely? It looks like there's a lot of wasted space on due to a square cell centered on a rectangular tile.
From when I was reading more about solar cells I recall there being something about the distance from the conductor (the two stripes visible equidistant from the midline of the cell) being a problem especially with monocrystalline cells, which these appear to be. I think this was more a problem for cells that had the conductor fixed to the back of the cell.
Google image search for monocrystalline solar cell and you'll see they are all square. I had a brief go at searching for anything to back up my claim but lost interest.
I might simply be that the silicon ingot they are cut from is cast round, see this[1] picture and it's less wasteful to cut a square with chamfered corners than to cut a rectangle, which would necessitate an ingot with an elliptical cross section, which would probably be harder to cast due to uneven cooling, maybe.
I'm not sure you can even make a mono crystalline ingot eliptical. The process heavily relies on spinning the ingot while pulling it out of a silicon puddle which results in the round shape.
I've had a few moments recently where I've thought "how can it be I haven't thought to look this up on YouTube before now", and here we are.
I found this[1] video that explains how to grow a monocrystalline silicon ingot that weighs 440 pounds, and you're right it is spun as it's extracted from molten silicon.
That's not really how it looks in the pictures on their site. It looks more like they are butted together with no overlap. Also, I'd think you'd want just as much overlap on the long side for weatherproofing. This does raise an interesting question; how are they weatherproofing this installation?
I signed up for the original powerwall and as it turns out it's not Tesla - it's solarcity (I get it, they are the same now). Oh and by the way you have to have the solarcity solar panels installed and running for the powerwall to be installed, which has a cost of it's own.
My guess is that this isn't any different given this text:
Powerwall 2 is a battery for homes and small businesses that stores the sun’s energy and delivers clean, reliable electricity when the sun isn’t shining.
Powerwall makes a whole bunch more sense for solar storage.
If you're just using it for backup power off the grid, you have to convert AC -> DC -> AC again for use. I don't know the all up efficiency of that system, but it's far from great. Probably <70%
Someone posted a link about Boston.gov being released as an open sourced project on GitHub. I'd like to take a moment to point out that this Tesla website is built on Drupal 7 too. The big thing that both websites get out of the box is i18n support for translation on top of all the tools required from content management. I wouldn't recommend it for websites and services that need many people to constantly update content but to build static pages that are cached is pretty awesome stuff.
I haven't looked into it yet, but I'm curious about using utilizing my Teslas in case of emergency for power. With 75kwh+ each (leased so no concern about cycles) I don't think I'd need a powerwall at home.
Musk and JB got asked about this (I think at the 2016 AGM?). Their response was basically "yeah we get asked this a lot; No, because of the make up of the cells makes them inappropriate for the number of cycles."
If you're concerned about emergencies: for $38 you get a self-contained LED camping lantern that lasts for 30 days on a single charge [1] at the lowest brightness, or 2 days (off at night) on full brightness. For a tiny fraction of the price of a Tesla-based emergency power solution, you could buy two of those for every room, plus an RV cooking gas burner and a big propane tank that covers heating, making food and hot water for washing. Hell, even a big diesel generator would be cheaper (not to mention it's readily available).
The main thing I'd really like to be able to backup is my (oil) furnace in the winter so that it could continue to operate in a power outage. Though,truth be told, I could get a bigger propane tank and either run some backup heat off that or a generator for a couple of my circuits.
Pretty much everything else can go out. Obviously food could spoil in an extended outage, but that's a fairly modest cost in the grand scheme of things.
How about installing a wood-burning fireplace? Super cozy also in daily life, probably adds to the resale value of your house, and you can keep firewood indefinitely as long as it's dry.
As for food: stock canned goods for a week. (There's a reason preppers have rooms full of the stuff.) You probably also want to stock bottled water for a week, just in case.
I have both a wood stove and a wood burning fireplace. The backup was part of my justification for getting the stove. I don't know if it would be sufficient if I lost power for an extended period of time in really cold weather to keep pipes from freezing but you can't guard against every eventuality. (I also worry about what can happen when I'm not around.)
As for the food, I'm close enough to civilization that I'm not too worried. Worst case I get snowed in for a couple of days. I won't starve.
Can you explain to me your economic thinking behind leasing two Teslas? Are you super rich or do you have some other thinking that went into that decision?
It's actually not a bad financial decision at all relative to other cars. Reasonably specced Model S montly lease costs after tax benefits come out to well under $1000/month. That's on par with a mid-high spec E-class or 5-series. Now factor in fuel savings and small business lease write off. Plus access to carpool lanes during peak hours and prime parkin spots.
Your better bet would be buying a $1000 2000W generator. 4 gallons of gas will give you 24 hours of peak output. About 2 gallons for less than peak output for 24 hours. They're pretty quiet, too, and smaller than a carry-on suit case.
The thing is cloud-connected, remote-controlled by Tesla. That presents a problem. Will the cloud service behind it last the life of the system? Most cloud services evaporate within five years.
"The thing is cloud-connected, remote-controlled by Tesla. "
If your use-case is backup power in case of utility failure, how does that work ? If utilities fail, the network connection to the battery may also fail, right ?
Right, so you won't be able to use an app to monitor your Powerwall while it's offline... the battery's still going to work. Backup and off-grid are advertised use cases. Tesla's cars have the "cloud-connected, remote-controlled" stuff too, but they don't stop in the middle of the road if you leave cell phone coverage.
The nominal product life is 5,000 charge/discharge cycles, or 13-14 years if solar powered. Maintenance monitoring, including battery deterioration, is remote, from Tesla's end. Will that service still be running in 2030?
There will have to be onsite maintenance for battery/invertor swaps long before any battery power product, let alone energy backup, reaches 5000 cycles of lifespan.
Interesting to see Tesla of all people estimating energy consumption on the basis solely of how many bedrooms your house has, and not adding on how many electric cars you need to charge...
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[ 3.8 ms ] story [ 276 ms ] threadedit: even with the cost savings from power generation, the roof itself needs to last forever.
So, yes, there are assumptions in there: how much power can be generated, how valuable will it be 10 years from now, etc.
Edit: I understand the urge to downvote because I'm not singing praise, but I promise I'm not trying to be overly pessimistic or critical of what Tesla is doing. Fact of the matter is, solar tiles have been done before, and failed miserably.
[0] http://blogs-images.forbes.com/peterdiamandis/files/2014/09/...
http://i.imgur.com/GCy6EVx.jpg
[1] I got there by taking the '98% as efficient as regular solar' from https://techcrunch.com/2016/10/28/these-are-teslas-stunning-... and the current 22% number advertised by Sunpower here : https://www.greentechmedia.com/articles/read/SunPower-Breaks...
There are also up-and-coming competitors such as SunTegra that hit 14.6% [2].
It seems like asthetic options and possibly efficiency improvements is what will set this apart from previous stumblings in this space. We'll see how this looks in the real world!
[1]http://www.solarelectricsupply.com/apollo-ii-solar-roofing-s...
[2]http://www.suntegrasolar.com/suntegra-tiles
There also seems to be some efficiency and aesthetic improvements over previous tiles, but those alone wouldn't be enough to make it viable.
And from that, hopefully, scale. Solar tiles have always seemed to be a very poor relation of solar panels. The approximately 1x1.5m panel is a sort of informal global standard, and that's meant that solar tiles have been much more fragmented, much lower scale, and much more expensive.
On the other hand in theory these solar integrated building materials should greatly reduce the associated costs of installing panels - labour is usually something like half the cost of installing rooftop solar, but if you can install a solar roof without much more effort than a normal roof, those extra labour costs are massively reduced.
If you can leverage this labour cost advantage to ramp up scale of the tiles, and get them close to the per watt cost of traditional panels, this is how you can really make rooftop solar competitive. These labour costs are why rooftop solar is so much more expensive than utility solar. If you can greatly reduce them, total costs are much more tied to the cost of the tiles themselves, the inverter, and so on, where there is enormous leeway for ongoing reductions. Very exciting.
The fact that you have to apologize for this on HN nowadays is hilarious. I agree. Both solar panels (and to a lesser extent solar roofing tiles) and the powerwall are have a lot of competition.
The idea looks good, though. I didn't catch pricing details in the presentation?
http://www.solarcity.com/
For reference, the RESU is a wall-mounted Li-ion battery meant to be connected to a solar inverter. It seems to beat the Powerwall in basically every respect. It's a bit cheaper, it has a better warranty, and it has slightly lower advertised capacity but higher warranted capacity under basically all advertised conditions. But it's not cool and doesn't have a shiny video.
One 14 kWh Powerwall battery $5,500 Installation and supporting hardware starts at $1,000
I suppose the main reason for the inverter is to go from DC -> AC.
The Powerwall 1 required an external inverter. What did that inverter do? Converted from the DC -> AC? The Powerwall 1 had DC input? I guess not, otherwise you wouldn't need the external inverter.
So this powerwall converts internally from DC - > AC -> DC (battery)?
It's all very confusing!
Nobody is going to buy this for the "cool"ness and "shiny video", they're going to buy it for the higher capacity.
You need to skip ahead to the 46 min. mark to get started.
If no one knows about it, doesn't really matter what the specs are. If you can't market a product it might as well not exist. I mean, congratulations on the engineering I guess.
I know some rich people that want solar but their neighborhood associations won't allow it, but I don't think they would not have an objection to these roofs. they look really nice....
I have been curious how they were going to compete with cheap chinese solar. this seems like a good strategy but one that may be easily copied.
From Ye Great Book of All Scottish things, 856 year of the Lord, page 17: - yepswatter : a very commonly used household object, just ask anybody around to show you one.
Plus if the HOA members don't like you they can make your life difficult. Planning permission affects everyone equally. If a neighbour can extend a property then more than likely you can too, if you are refused it is likely all similar applications would be refused, you don't know the planning officer and they don't know you so no bias can be involved which make the whole process much fairer.
Its all about fundamentals and he believe he can have a fundamental edge here.
Unless the HOA rules have a stipulation about your roof shingles exactly matching the other roofs in the neighborhood, which is common. And boring a shit to look at. I hate HOAs so much.
If all they did was protect property values by keeping people from doing outrageous things, I might be okay with them, but they go way beyond that to the point where it diminishes the value of buying property (since you can't adapt it as you see fit). Municipal codes usually take care of the worst behavior, anyhow. Which is why if I ever buy land and/or a house, it will be in a more rural area. Then I can put a damn Tesla solar roof on it, build a shed with a different roof and paint it all purple with green stripes if I feel like it.
Right. Nice try. I joked with neighbors that we should all send one letter to them on the same day. A letter for each cell phone, wifi router, satellite dish, bluetooth speaker, etc.
This was in an area where many people were on wireless ISPs, there were a handful of ham radio antennas, etc. I asked someone on the HOA board why they didn't update or remove the garbage about wireless devices. The answer - it would cost to much to update the documents, so they don't try to enforce it. It is still crazy that they ever put it in there.
This HOA says no solar, but now that it is popular they also ignoring that.
http://pastebin.com/raw/YeNr726v
"The current versions of the tiles actually have a two percent loss on efficiency, so 98 percent of what you’d normally get from a traditional solar panel, according to Elon Musk. But the company is working with 3M on improved coatings that have the potential to possibly go above normal efficiency, since it could trap the light within, leading to it bouncing around and resulting in less energy loss overall before it’s fully diffused."
Which suggests that on a square footage basis it is similar. The difference being that on a manufactured panel the cells are all exactly next to each other with no seams, and with the Tesla roof they appear to have a moat around them that varies a bit with roof tile style.
That said, assuming you cover your entire roof which will include both "ideal" south facing (or north facing in the southern hemisphere) and "non-ideal" north facing parts of the roof you may get enough additional generation from the extra tiles to push it over a more 'traditional' solar install.To be honest I'm thinking about replacing my perfectly fine (if nearly 15 year old) solar panel set up with those roof tiles. That and a couple of power walls and I just might be able to go 'gas only' with PG&E.
I wish someone near me would do this, boy would I snap up those second hand panels.
When I was in my early twenties I put together a solar panel + charge regulator + inverter + laptop and run a web server serving a page detailing the setup it was running on.
The entertaining things I could get up to with 1kW or more of cheap second hand panels.
1. Are not in the visible spectrum
2. Do not reach the earth surface in appreciable amounts
Not to mention that coronal mass ejections (CME) happen so often that you'd expect to have already heard of such power outages if one were possible.
You can have multiple days. But normally you would use this to arbitrage electricity prices, especially if you don't have net metering.
The funny thing about solar... it's not constant. Half the day is night... then clouds/rain/etc. 24/hours of electricity is for those dry periods.
Where I live, nobody would do that - due to cost. More popular solutions are natural gas or water heat pumps.
My parents in Australia have almost paid back their 10Kw system, in less than 5 years.
EDIT: This is a baller feature:
"Always Connected: Monitor your solar energy use in real-time and receive alerts when Powerwall is preparing for cloudy or severe weather."
They're performing weather forecasting, and then ensuring the Powerwall has charged up for a possible outage event. Brilliant.
This lets you have best of both worlds, with a minor tradeoff in unpredictable outages you have slightly reduced runtimes.
One 14 kWh Powerwall battery $5,500 Installation and supporting hardware starts at $1,000 Total estimate $6,500 Requires $500 deposit for each Powerwall
I'm looking at buying a petrol powered generator for reasons other than home power generation, but it will be reassuring to know we have backup power at home, but I don't think I'm allowed to store any more than 25L in one container on my suburban property. I guess that would be 25L plus each of our two cars with full tanks.
It would be fairly trivial to convert a petrol powered generator to run on propane from the barbecue gas cylinder, I've had experience installing gas kits on carburettor engines in cars.
That is my thought - however, a previous comment in this thread indicates that the powerwall batteries are cloud connected and remote controlled by tesla ... so I am not sure how that pans out when you lose power and network connectivity at the same time (as happens where I live several times throughout the winter, sometimes for 24+ hours).
So even though I am rural, I don't have to buy liquid propane to heat my house. I'm tapped into a 100,000 home supply line. Its been depressurized maybe twice for maintenance in 50 years.
Not a solution for everybody. But a pretty good one for me! And everybody else on the line.
A $1000 generator will provide plenty of power to run everything other than HVAC.
Neither will get you off grid, but neither will a Powerwall until you spend a lot more on solar.
My gripe with the generators is they are noisy. A Powerwall would be silent and would handle the typical outage situation. But so probably would a 3000VA UPS, which would only cost $1500.
Sydney alone has 63,000 kilometres[1] of overhead power lines. One estimate puts the cost at $23.37 billion.[2]
1. http://www.smh.com.au/articles/2002/07/29/1027926858231.html
2. https://www.ipart.nsw.gov.au/files/7b5531d9-cf65-4b1b-ae7b-9...
Or you can buy a huge ups for a lot less than 3000 and power a desktop machine too.
A UPS will require a battery replacement every 10 years or so, regardless of whether you ever have to go on battery power or not. The UPS should automatically sense the status of the battery and warn you when a replacement is needed.
Pick a model from one of the major manufacturers and look up the replacement battery costs to get an idea of what it will cost.
And if you think this is bad, just wait until batteries get more powerful and there are problems. Be thankful that it only starts a small fire!
Just remember that there are 10s or 100s of Billions of Li-Ion batteries around the world, and having a single one fail catastrophically is still enough to make headlines...
I wonder how the safety of this will compare to gas: http://bloximages.chicago2.vip.townnews.com/qctimes.com/cont...
Google image search for monocrystalline solar cell and you'll see they are all square. I had a brief go at searching for anything to back up my claim but lost interest.
I might simply be that the silicon ingot they are cut from is cast round, see this[1] picture and it's less wasteful to cut a square with chamfered corners than to cut a rectangle, which would necessitate an ingot with an elliptical cross section, which would probably be harder to cast due to uneven cooling, maybe.
1. http://www.tindosolar.com.au/learn-more/poly-vs-mono-crystal...
I found this[1] video that explains how to grow a monocrystalline silicon ingot that weighs 440 pounds, and you're right it is spun as it's extracted from molten silicon.
1. https://www.youtube.com/watch?v=aWVywhzuHnQ
My guess is that this isn't any different given this text:
Powerwall 2 is a battery for homes and small businesses that stores the sun’s energy and delivers clean, reliable electricity when the sun isn’t shining.
If you're just using it for backup power off the grid, you have to convert AC -> DC -> AC again for use. I don't know the all up efficiency of that system, but it's far from great. Probably <70%
[1] https://www.amazon.com/Ultimate-Survival-Technologies-30-Day...
Pretty much everything else can go out. Obviously food could spoil in an extended outage, but that's a fairly modest cost in the grand scheme of things.
As for food: stock canned goods for a week. (There's a reason preppers have rooms full of the stuff.) You probably also want to stock bottled water for a week, just in case.
As for the food, I'm close enough to civilization that I'm not too worried. Worst case I get snowed in for a couple of days. I won't starve.
If your use-case is backup power in case of utility failure, how does that work ? If utilities fail, the network connection to the battery may also fail, right ?
There was some IoT dog feeder that didn't have sane defaults posted here a while back.
I know I know "but Tesla". Sure, maybe they'd be different. Or maybe not.
Almost nothing behaves like this - even if it claims to.
A good example is the sonos music system. They claim that it will work properly (with your local music source) without Internet access. That is false.
This whole thread is based on speculation -- the details are not yet known.
...additionally, who's to say a Model S isn't a bedroom in your garage? /s