Powerwall 2 and Integrated Solar

https://powerwall.tesla.com/?powerwall2

by ph0rque • 10 years ago

520 325 10 years ago

powerwall.tesla.com

rjdevereux• 10 years ago

Sounds great, I'd like to see the assumptions in the financial model that show how it is cheaper than conventional roofing material.

rch• 10 years ago

It's difficult to beat the cost of the usual raw materials, so they need to exceptionally long lifetimes.

edit: even with the cost savings from power generation, the roof itself needs to last forever.

greglindahl4• 10 years ago

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.

toomuchtodo6• 10 years ago

You also now get a 30 percent tax credit to replace your roof. Before, you'd be entirely out of pocket for the roof, separate from the solar install.

mrfusion11• 10 years ago

Looks amazing! I wonder how they get wired together? How are they attached to the roof?

swampthinker2• 10 years ago

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.

mrfusion11• 10 years ago

I didn't know that. I thought they were always in an r&d phase before.

robotbikes• 10 years ago

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.

chongli• 10 years ago

The price of PVs has fallen by multiple orders of magnitude in the past half century or so[0]. This is a staggering change!

[0] http://blogs-images.forbes.com/peterdiamandis/files/2014/09/...

toomuchtodo6• 10 years ago

Great comparison of solar price decline along side other fuels:

http://i.imgur.com/GCy6EVx.jpg

ChuckMcM2• 10 years ago

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].

[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...

swampthinker2• 10 years ago

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!

[1]http://www.solarelectricsupply.com/apollo-ii-solar-roofing-s...

[2]http://www.suntegrasolar.com/suntegra-tiles

makomk2• 10 years ago

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.

Brakenshire3• 10 years ago

Marketing and business model, primarily.

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.

forgetsusername• 10 years ago

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?

ifhs• 10 years ago

Brilliant. Can't wait to order one. Wonder when it will ship since I was planning on reroofing next 4 months or so.

greglindahl4• 10 years ago

Not for a while -- he said next summer, starting in California. And all 4 styles won't be available at start.

jburgess777• 10 years ago

Is there a summary for anyone that doesn't want to sign up?

andrewtbham2• 10 years ago

https://electrek.co/2016/10/28/tesla-solar-roof-powerwall-en...

sabertoothed• 10 years ago

You can also watch it on the SolarCity website (somewhere halfway down). Without registration.

http://www.solarcity.com/

amluto2• 10 years ago

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.

hyperbovine• 10 years ago

People are willing to pay a premium for nice looking stuff that works well together. cf. Apple.

givinguflac2• 10 years ago

Where is the premium here?

l33tbro• 10 years ago

You can just give a dummy email and the video will load immediately.

annerajb• 10 years ago

Tesla version integrates the inverter and has double the capacity(14kwh) for the same cost as LG Chem REsu 9kwh version

One 14 kWh Powerwall battery $5,500 Installation and supporting hardware starts at $1,000

mateus12• 10 years ago

14/9 is not double.

amluto2• 10 years ago

Is it a string inverter? Is it compatible with DC optimizers? Can it provide backup power in the event of a grid failure?

duaneb• 10 years ago

But it's not cool and doesn't have a shiny video.

Nobody is going to buy this for the "cool"ness and "shiny video", they're going to buy it for the higher capacity.

OrwellianChild• 10 years ago

Video is available directly at the Solar City website: http://www.solarcity.com/

You need to skip ahead to the 46 min. mark to get started.

erikpukinskis2• 10 years ago

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.

andrewtbham2• 10 years ago

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.

option• 10 years ago

In CA, it is illegal for HOA to block solar installations

toomuchtodo6• 10 years ago

Also in Florida, surprisingly.

iamcreasy• 10 years ago

What is HOA?

JBReefer• 10 years ago

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).

spectrum1234• 10 years ago

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.

notatoad• 10 years ago

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.

sergiosgc• 10 years ago

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.

slfnflctd• 10 years ago

they would not have an objection to these roofs

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.

twothamendment• 10 years ago

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.

revelation• 10 years ago

Direct 1080p video link:

  https://uhsakamai-a.akamaihd.net/sjc/omega/vod/sjc-566a4ba6-8cb9-4eef-9ff4-f91aa8d13adb/84771680112000/96870994920000/plain/improved/1/chunk_NUMBER_84a103284c.flv

Replace NUMBER with 1 to 190 or get the playlist:

http://pastebin.com/raw/YeNr726v

alando46• 10 years ago

Any idea how much power these things put out when compared with a conventional solar setup? 1:1? .5:1?

ChuckMcM2• 10 years ago

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.

mrfusion11• 10 years ago

Normal shingles have a lot of overlap right. Wouldn't most of that moat be the overlap?

TheSpiceIsLife8• 10 years ago

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.

donclark• 10 years ago

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.

hliyan• 10 years ago

Radiation spikes caused by solar storms

1. Are not in the visible spectrum

2. Do not reach the earth surface in appreciable amounts

cyphar• 10 years ago

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.

starchild_30012• 10 years ago

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.

starchild_30012• 10 years ago

The video: https://www.youtube.com/watch?v=dRqSkR4ENAg

usaphp4• 10 years ago

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.

yessql2• 10 years ago

You are wrong.

You can have multiple days. But normally you would use this to arbitrage electricity prices, especially if you don't have net metering.

wernercd• 10 years ago

If you generate more electricity than you use during the day, you all of a sudden don't have an electric bill... or a drastically reduced one.

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.

usaphp4• 10 years ago

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.

easytiger• 10 years ago

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.

foobarqux• 10 years ago

I thought Straubel said that the Powerwall was meant not for offpeak storage but for emergency backup.

toomuchtodo6• 10 years ago

That Powerwall was of a different chemistry, and has been discontinued.

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.

JoeAltmaier4• 10 years ago

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.

intrasight4• 10 years ago

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.

TheSpiceIsLife8• 10 years ago

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

JoeAltmaier4• 10 years ago

Hm for that price I can install a natural-gas generator. Have power for days if necessary, full power on all circuits.

intrasight4• 10 years ago

I don't see $3000 - that's my point. But for $3000 I'd buy one.

mamcx• 10 years ago

So is not possible to self-install them?

mrfusion11• 10 years ago

If you use a laptop a ups can power your router and modem for quite a long time.

Or you can buy a huge ups for a lot less than 3000 and power a desktop machine too.

celticninja5• 10 years ago

What's the running cost of a huge ups?

mrfusion11• 10 years ago

Is anyone else having trouble with the tesla website? - bunch of words are in a different language and the prices are in a foreign currency.

dghughes• 10 years ago

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.

stomato• 10 years ago

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!

kbaker• 10 years ago

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...

bluthru• 10 years ago

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.

I wonder how the safety of this will compare to gas: http://bloximages.chicago2.vip.townnews.com/qctimes.com/cont...

onesun2• 10 years ago

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.

TheSpiceIsLife8• 10 years ago

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.

1. http://www.tindosolar.com.au/learn-more/poly-vs-mono-crystal...

extrapickles2• 10 years ago

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.

anexprogrammer• 10 years ago

A little over 50% of a roof tile is covered by other tiles to provide the weatherproofing. The square solar part covers nearly all the exposed area.

onesun2• 10 years ago

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?

AndrewKemendo• 10 years ago

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.

v0rts• 10 years ago

What are your thoughts on the first gen powerwall and solarcity?

nickparker• 10 years ago

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%

n17r4m• 10 years ago

The specs list it as 90% efficiency round trip.

zappo2938• 10 years ago

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.

manav2• 10 years ago

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.

martin_bech• 10 years ago

They would have more than enough power, but you cant pull power out of a Tesla. That would make supercharging to good of a deal.

Roritharr• 10 years ago

Never thought of a Tesla as a driving bucket of electricity.

antmldr• 10 years ago

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."

jrv• 10 years ago

That, plus they said that you'll often want to use the car at the same time as someone else uses electricity in the house.

semi-extrinsic2• 10 years ago

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).

[1] https://www.amazon.com/Ultimate-Survival-Technologies-30-Day...

ghaff9• 10 years ago

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.

sfblah5• 10 years ago

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?

deagle50• 10 years ago

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.

manav2• 10 years ago

I am self-employed/own a company. They are basically business leases so written off nearly 100%.

swissoak• 10 years ago

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.

Animats2• 10 years ago

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.

conductr• 10 years ago

Same thoughts on every IoT, smart, connected, app enabled gadget

rsync3• 10 years ago

"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 ?

dangrossman2• 10 years ago

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.

beambot4• 10 years ago

It's not hard to imagine the solution: fall back to sane defaults like every other system not connected to the cloud.

jameshart• 10 years ago

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...

pizza• 10 years ago

Bedrooms generalizes better for new customers.

...additionally, who's to say a Model S isn't a bedroom in your garage? /s

seanlinmt• 10 years ago

Is the patent for Powerwall v2 available somewhere as well? As per https://www.tesla.com/blog/all-our-patent-are-belong-you? Just windering if it contains enough info for anyone to built a unit themselves.

toomuchtodo6• 10 years ago

The software is the special sauce. You could build your own PowerWall easily: it's just a battery box. The battery management system is the hard part.

davej• 10 years ago

It's not just a battery box. There's some pretty advanced liquid cooling and an inverter in there.

keyle• 10 years ago

It looks so cute with its 110kg (220lbs)...

Fej• 10 years ago

How long are the batteries going to last? With phones, we expect the battery to deteriorate after a couple of years. This is an investment. Will it need to be replaced in a few years' time?

samcheng2• 10 years ago

Tesla automotive batteries have shown pretty strong resilience over the few years they have been running, even on cars that have been driven hard.

Cars are at >90% capacity after 50,000 miles. It's not like the batteries need to be replaced frequently.

http://i.imgur.com/nWM9ZrS.gif

I wonder if these Powerwalls will have the same sophisticated battery thermal management system as the cars?

sfblah5• 10 years ago

Houses and roofs last far, far longer than cars. 50k miles is 4 years for many drivers.

mbrock• 10 years ago

Ten year warranty at least.

will_hughes3• 10 years ago

The problem with phones is that they don't have good management - the battery doesn't have active cooling, or heating when needed. They're also charged to full capacity or depleted to empty a lot of the time.

These things are what kills battery life.

Klez19932• 10 years ago

"They're also charged to full capacity or depleted to empty a lot of the time."

Does it affect battery life if I keep my phone charged even if it's at 100% ? (My phone is charging during the night, so it will be at 100% for a long time and keep charging).

If it reaches 0%, how does that impact battery life compared to reaching 20% and charging up ?

I never looked up these things but it might influence how I charge all my devices.

usrusr6• 10 years ago

Phone batteries get hot, but they have plenty of thermal connection with the environment. This is nowhere close to the magnitude of a heat problem you would have within a massive multicell pack, where the direct environment of one hot cell would be a few other hot cells. Active cooling is not something you add to a pack the size of a Tesla to make it survive a few more cycles, it needs it to survive the first cycle. But sure, once you have active cooling you might just as well try to make it powerful enough to create an environment that is even better than that of a single cell phone battery. Just don't hook overboard and have the cooling power demand cut noticeably into total cycle efficiency.

About cycle depth: Does Tesla come with an UI where you can do something along the lines of "I need to go 200 miles the day after tomorrow, do whatever you think is best for the battery in the time until then"? Or at least a setting "feel free to optimize from what you learnt about my driving patterns, except when I press the prepare-long-distance button"?

If not, most of that battery management technology will just be about not being worse than a single cell system. In that case, the difference in perceived durability mostly comes from a wildly different balance between depth of discharge and expected lifetime. Phone makers are quite happy with your batteries getting worse after two years, so they drive them over a wide voltage range, Tesla is in a market where they can't do that.

I suspect that drivers want their "fully charged" just as much as phone users, but I might underestimate Tesla/owners here. Maybe "battery wisdom" just needs some time to sink in. Sony is advertising a "top off the battery only just before the morning alarm goes off", this is the right direction (to bad that the new compact is a downgrade)

codeulike• 10 years ago

Ten year warranty.

sfblah5• 10 years ago

Yes.

newman314• 10 years ago

I'm interested in both but could not find any details what kind of output a solar roof would generate.

Also, I would be interested in know if it's possible to walk on top of a solar roof. People still need to be able to get on the roof to do work.

Tinyyy• 10 years ago

https://www.tesla.com/solar

For people like me who missed the solar roof.

whage• 10 years ago

Thanks! Can someone tell me what kind of architectural style does that house on the landing page represent?

return0• 10 years ago

Muskhaus

pseudometa• 10 years ago

Contemporary

dsr_• 10 years ago

That's a Modernist house. Flat cantilevered or overhanging roofs, large expanses of glass, right angles, no attics, rare basements. Concrete and engineered wood as preferred building materials.

It's called Modernist, but the style is nearly 100 years old.

Tyr42• 10 years ago

Oh, and if you are interested, here's a chart of them all:

http://www.blogarama.com/home-garden-blogs/320928-inspired-h...

Or one big image:

http://mentalfloss.com/sites/default/files/p-americanhouses_...

I think it almost feels like the deconstructionist modern style (bottom right)

zo1• 10 years ago

You got 4 different answers. Something just isn't right with that:

    Modernist
    Deconstructionist Modern Style
    Muskhaus
    Contemporary

andreyk• 10 years ago

His argument about the solar roof starts by equating the situation to how Tesla started out - electric cars were slow and ugly and needed to be sexy and cool to be attractive, and the same is true for solar. Except I highly doubt this is true here - do people really mind the look of typical roof-mount solar? My impression is that the upfront cost is just too high and cost recoup is just too slow. The argument for the solar roof is then 'using a solar roof in the first place = way cheaper than installing on top of existing roofs (and also it looks as good and works better)'.

Maybe? I'd like to see the quantitative argument here. Having a house pre-built with a fancy solar roof AND a powerpack seems like it would still be pretty much for rich people. Still, maybe the aim is for a similar trajectory as Tesla - start with a product for rich people, make it attractive, lower cost so everyone can have it and WANTS to have it.

Unrelated: gosh, I like the content of the video presentation but it would be nice if Musk was a slightly better presenter.

nixarn2• 10 years ago

Every time Elon presents something we have this coversation. I for one love listening to him talk compared to say the presenters at Apple and Microsofts recent event. He's genuine, doesn't feel like a salesman, talks about the reasoning and science behind it all in a great way.

davidivadavid2• 10 years ago

The content of his presentation is always interesting. The delivery is always incredibly awkward and cringy.

makomk2• 10 years ago

The reason that solar roofs aren't common is that they're more expensive than rooftop solar. As I understand it, Tesla/SolarCity's argument isn't that they're cheaper than normal solar, it's that they're the same cost as normal re-roofing once you take into account the income from the solar. From the ArsTechnica article: 'In a private conversation with journalists after the announcement, Musk declined to state a price for the roof or a price-per-square foot. He did admit "it's not gonna make sense for somebody to replace a brand new roof with a solar roof." But if your roof needs replacing anyway, he said, the cost/benefit could make sense for many families.'

More specifically, since SolarCity's business model is that they own the solar panels and you're committed to buying electricity produced by them for their lifespan, his argument is that it costs no more than conventional re-roofing + conventional electricity. There is of course the slight downside of you no longer owning the roof over your head, and having to commit to electricity purchases for the next decade or so.

anantzoid• 10 years ago

Unrelated: gosh, I like the content of the video presentation but it would be nice if Musk was a slightly better presenter.

Same goes for the audience. I heard one shouting "Save us Elon!". Where do they get these people from?

will_hughes3• 10 years ago

do people really mind the look of typical roof-mount solar

Depends on the people you're asking.

Some Home-Owners-Associations in the US forbid the installation of rooftop solar on visual grounds. Though some states have signed laws stopping HOAs from doing this.

mattmcknight• 10 years ago

One problem with solar traditional roof mounts is that they are heavy, and many houses aren't rated to carry that much additional weight. In addition, they can affect the water flow on the roof, and then when you need to replace the shingles, you've got all of these panels in the way.

However, some people do think some solar panel installs are ugly: http://www.greensunnj.com/SolarHallofShame

ghaff9• 10 years ago

do people really mind the look of typical roof-mount solar

It depends on the person and it depends on the house design. IMO, some roof-top solar installations look pretty ugly.

To your cost point, yeah, it's still hard to look at a lot of solar as something that works financially today for most people even with the price drops--if having an off-the-grid backup doesn't have a lot of value.

As various people here are quoting, $1K/year covers electricity use for a lot of people. Even if you double that to account for higher usage or price increases, it's hard to square that with a $20K or solar/battery installation even if you ignore maintenance and depreciation.

Loic2• 10 years ago

Quick question for the people living in the US (Target customers of the Powerwall). What is your yearly power usage?

On the website[0] they put for sizing 10kWh/day/BR. Which means 14600kWh/year for a 4 bedroom house. Here in Germany, working from home with a 4BR+office house, we are using 2550kWh/year. So, I suppose the Tesla sizing is to support a "peak day" usage, but still, I am surprised by the calculations. This is why this totally informal and unscientific survey :)

[0] https://www.tesla.com/powerwall

ascorbic• 10 years ago

I'd imagine it's based on a home with air conditioning. I'm assuming that being in Northern Europe you don't have AC.

Loic2• 10 years ago

Effectively, we do not have AC and our heating system is not heat pump based but using the local district heating. This means that this power usage is only for: cooking, lights and computer/tv/etc. appliances.

Yaggo2• 10 years ago

We use heat pumps as well in Northern Europe, but to transfer heat from outside to inside. You can get even five times more heat for the invested electricity compared to direct (resistive) electric heating. The best winter optimized air-to-air pumps work down to -20 °C (-4 °F) with efficiency ratio over 1. For example, I heat my entire house with a single heat pump through the year. Our average electricity bill is ~100 €/month. There are less than ten days in middle of winter when I turn on extra resistive heaters.

Unfortunately, although in Southern Scandinavia we receive about as much sunlight energy than Northern Germany per year, the peak is in summer when the need of energy is lowest and during three winter months almost no usable energy can be harvested from sunlight, meaning that solar-only powered house would need gigantic battery bank (~100 Tesla Powerwalls) to survive over three darkest months.

throwaway1974• 10 years ago

Ireland, 4 bed detached, solar water heater which works well for about 4 months of year, oil heating + wood/turf stove for rest of time. No need for air conditioning here but heat recovery thingie is on all time.

5000kWh last year, tho I have computer(s) on 24x7 due to home office, Comes to about 120€/month

Half of all the bills are just standing charges, and renewable subsidies charges and taxes, and taxes on taxes. Hence adding LED lights, low power appliances etc did little to budge the bills

flushandforget• 10 years ago

We worked out recently that we spent under £20 pcm on gas and electric over the last year. 2 people, washing machine, fridge, 2 x laptop, LED lights, 1 LED TV, and gas heating. Admittedly we only put on heating in the evening for an hour or so. Southern England (UK). Attribute to it not being cold for the last two winters here. Duvets and hot water bottles are used regularly. Yet to turn on heating this year. Not looking forward to the cold. Water bill however is shocking.

iotscale• 10 years ago

1BR+office (home office with 2 always on computers), air circulation with filtering, around 80 square meters, 2 people, also Germany, 3600kWh/Year (~90€/month)

That could probably triple if we had AC. Far worse if we had electrical heating.

dirtyaura4• 10 years ago

Interesting to compare different countries.

Helsinki, Finland here. Roughly 2100kWh/year. 2 people, a flat with 2 rooms + kitchen. We have district heating. Several laptops in the house, frequent home cooking, most lights are LED based, no sauna inside the apartment. We don't pay any attention to manually saving electricity, i.e. turning off lights etc. Our electric company provides a comparison report on their web site, according to it we are well below the average for similar household.

dabeeeenster4• 10 years ago

'no sauna inside the apartment'

Finnish problems

jacquesm3• 10 years ago

The big difference is because of air conditioning and baseboard heating, two things that are relatively rare in Europe.

j1vms• 10 years ago

The big difference is because of air conditioning and baseboard heating (...)

Which makes you wonder why there is not as much high-profile attention on A/C (and to a lesser extent electrical heating) as being a problem worthy of rethinking by Silicon Valley (perhaps even ahead of solar, in North America).

fulafel• 10 years ago

Baseboard heating, if it's the same thing as radiators, are the norm in central and north Europe IME.

elorant• 10 years ago

Athens, Greece here. 2BR house with 2 AC units and electrical heating. Around 5.500KWh/year.

olex• 10 years ago

That's a very interesting number. Here a comparison, from Germany too: I used to live with 3 flatmates for several years in a 4BR apartment (165m²), our yearly usage averaged 5500-7000 kWh. That included heating water (electric boiler), but no room heating or air conditioning.

I've recently moved out into a 1BR, 63m² apartment, and am targeting 1500-2000kWh - don't have any usage numbers yet since it hasn't been long enough, but those seem realistic to me.

snarfy• 10 years ago

It's really going to depend on the location in the US.

When I was living in the southwest, my energy bill per month was ~$500 for a 4 bedroom house. A/C eats a lot of power. After moving to the northwest, my bill is around $80/mo.

Brakenshire3• 10 years ago

To convert that to kWh, assuming a 10-15c/kWh rate, that would equate to 40,000-60,000 kWh per year in the SW and 6,400-9,600 kWh in the NE.

My figure for a 4 bed house in the UK is about 4,800 kWh per year.

tzs• 10 years ago

Over the past 12 months, 12000 kWh, in the Pacific Northwest [1]. I expect that to be lower this year, because I just had my house insulation improved. My house was originally a two bedroom house of approximately 1000 sq ft (92 m^2) built in 1964, and an additional bedroom was added in 1984, bringing it up to approximately 1400 sq ft (130 m^2). There was no insulation under the floor in the original house, and just a small layer of some kind of shredded paper-like material in the attic. The added room had decent insulation under the floor, and some real insulation in the attic, although not up to current recommendations for attics in this area. I now have a properly insulated floor, and the whole attic has been brought up to R49.

Here's a month-by-month breakdown, giving kWh for the month and average temperature.

  2015-11:  730 kWh, 54 F (12 C)
  2015-12: 1780 kWh, 42 F ( 6 C)
  2016-01: 2100 kWh, 40 F ( 4 C)
  2016-02: 1600 kWh, 43 F ( 6 C)
  2016-03: 1420 kWh, 46 F ( 8 C)
  2016-04: 1130 kWh, 48 F ( 9 C)
  2016-05:  580 kWh, 57 F (14 C)
  2016-06:  460 kWh, 59 F (15 C)
  2016-07:  490 kWh, 62 F (17 C)
  2016-08:  460 kWh, 66 F (19 C)
  2016-09:  530 kWh, 67 F (19 C)
  2016-10:  560 kWh, 59 F (15 C)

(Note: dates are the dates on the bills, which come about a week into the month, so the actual period covered is mostly in the prior month)

Rates here are $0.09/kWh for the first 600 kWh per month, and $0.11/kWh for whatever is over 600 kWh.

I don't see how you can use so little power. 2550 kWh/year is under 7 kWh/day.

During the summer months I turn my heat pump off, doing climate control by opening windows and using a couple of box fans to ensure air flow through the house. I typically have two fans running at opposite sides of the house. Figure 50 watts each, running whenever I'm home (weekends, plus one day a week working at home, plus 2/3 of the day on days I work at the office), and that comes to about 2 kWh/day average.

I usually have my entertainment system on when I'm home. If I'm using the TV, it's a total of about 100 watts. If the TV is off because I'm just listening to the streaming radio services my cable provider provides, it's about 60 watts. Call it 75 watts on average, and rounding to the nearest kWh, that's another 2 kWh/day.

My desktop computer uses 150 watts when used casually, such as reading and posting on HN, or browsing the web. Figure 4 hours a day on the computer on work days, and double that on my work at home day and weekends), and that's another kWh.

I'm up to 5 kWh/day now, just for fans, TV/stereo, and one desktop. Then there is my refrigerator, the pump for my well, my water heater, a washer and dryer, cooking appliances (stove, oven, microwave, electric griddle), and lights. Some of those use quite a bit of power. For instance, cooking baked french fries in the over (preheat to 450 F (230 C), then bake for 35 minutes) uses 3 to 4 kWh. I only do that maybe once a week, though, so it maybe contributes 0.5 kWh/day. Lights (all LED) are probably about 0.25 kWh/day (mainly two 14 watt (100 watt equivalent) Cree bulbs running 8 hours a day). All in all, these other things are going to probably average 2 to 3 kWh/day combined...and that puts me at or above your usage.

So, best case I should be able to maybe get down to your usage, during times of year when I can turn off the HVAC system and rely entirely on a couple of fans for climate control. And the best I've actually achieved is twice that...which means I've got something drawing more power than I accounted for above. My first guess is the refrigerator, as it is quite old. Time to stick the Kill A Watt meter on it and see what it is going on. The only other things I can think of that I left off are battery chargers for phone, tablet, handheld ham radio, and rechargeable batteries.

During months when I have to use the heat pump, I don't see any way I could get down to anywhere near your usage. How do you keep your house warm in winter?

I have noticed that if it is sunny out, then if I open blinds and drapes to let the sunlight in, I can reasonably heat the house that way even if the outside air temperature is low. I did that today, and got the house up to 68 F (20 C), and the insulation was good enough to keep it warm enough to keep the heat pump off for most of the night. It's now 4 AM and 43 F (6 C) outside, but the heat pump has not come on yet. Unfortunately, it is usually overcast during most of the winter around here so most days that won't work.

[1] West across Puget Sound from Seattle. Here's monthly temperature data for this general area: http://www.usclimatedata.com/climate/bremerton/washington/un...

antisthenes• 10 years ago

The reason their calculations are so high is because in the US, typical houses are made as cheaply as possible, pretty much with paper, plastic and vastly insufficient insulation.

That may have changed in the recent years, but holds true for most residential properties built before 1980.

novaleaf• 10 years ago

If you think the USA had bad standards, In Thailand it's common (even today!) to build skyscrapers out of cement and single-pane glass.

To bangkok office workers, it's pretty natural to blast the AC all day and have the office still be above 28'C

ghaff9• 10 years ago

What a sweeping generalization.

Furthermore, unless you're in an area of the country that requires the use of a lot of AC--or you have electric baseboard heat--insulation doesn't even play that much into electricity usage.

ap22213• 10 years ago

I've lived in a lot of cities through the 'rust belt', and I'd estimate that half if not more of pre-1970 houses had no insulation at all.

agumonkey• 10 years ago

Seems like Western Europe is getting up to speed with standardized insulation. People are monitoring heat leaks in buildings etc.

Two things: 1) I wonder how much energy could be "saved" with proper insulation. Per Country, per planet. 2) Insulation seems like a human sense, by that I mean, whenever I've lived in an old, stone wall house, I enjoyed the delay in temperature. It's still refreshing when the sun hits hard, and still mildly warm when cold settles.

More efficient lifestyle and better quality of life ? I'd sign.

hdctambien• 10 years ago

I used a little over 12000k Wh/h over the last 12 months in a 4bed with 2 people in Texas. I also have 2 cats and 2 dogs, so I don't turn the AC down too much during the day.

date-elec-solar

10/15-567-503

11/15-329-312

12/15-290-373

1/16-270-493

2/16-218-535

3/16-269-543

4/16-352-509

5/16-510-383

6/16-994-492

7/16-1292-514

8/16-976-401

9/16-832-???

I changed the password on my router in September and didn't update my solar controller, so I don't have data for my September solar production, but it was probably around 500 (I produced 579 last September!).

guruz• 10 years ago

It's no wonder that the EU has half co2 emission per capita than US, given the inefficiencies in US power consumption, cars etc.

https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...

tghw• 10 years ago

A lot of it has to do with geography. Europe is quite a bit further north, and doesn't experience some of the heat that the US does.

It always helps me to remember that Rome is further north than New York.

trymas• 10 years ago

It probably depends on number of electric appliances.

If you live where you have electric heating/cooling, electric water boiler, electric stove/oven, you'll burn a lot of electricity. I burn 2500-3000kW/year in 1B apartment, but except heating/cooling - everything is electricity. If I had a gas stove and hot water I'd probably use less than 1/3 of that.

Also I'd guess that in US people do not built as well insulated buildings as in Europe, thus more power for heating/cooling

pjc502• 10 years ago

I have a solar installation which makes it slightly harder to work out what I've actually used - I know what I've generated, and what I've paid for, but since the metering isn't net that doesn't quite let me work out actual usage.

I have however got a very nifty graph of my solar generation (3.8kW roof system, 56N Scotland): https://flatline.org.uk/daystats.html

What I think you can see if you poke about the graph is that solar is very variable in practice. There are days in summer when it doesn't break 500W at all, and in winter there's basically nothing for a couple of months.

I'm happy with the installation and its return in feed-in-tariffs, but I wouldn't consider going off-grid unless I had to and had space to put up a wind turbine.

Edit: my heating and cooking energy comes from mains natural gas, as well; currently this is far cheaper than electricity. Might be useful to include that in comparisons.

jackrh• 10 years ago

I don't know if this is available in the UK but in the US we can get devices like the one I got that allows us to monitor our usage and calculate usage vs generation. https://rainforestautomation.com/rfa-z109-eagle/

http://pvoutput.org/list.jsp?userid=41746 This web site collates all the data from your solar system (again, if it supports that like my enphase system) and the power company. $10 per year donation.

https://itunes.apple.com/us/app/pvoutput-pro/id994297624?mt=... And this little app adds a beautiful way to explore the data. $2 to get all the features.

This is all a bit involved to setup but the end product, that iOS app, is just brilliant. It just takes the data from pvoutput and massages it into an addicitive portable display. 1.5 years later and if the monitoring system is down for more than 12 hours my wife yells at me.

I am ignoring the powerwall because we have a sweetheart deal with net energy metering in southern california and the power delivery has been rock solid. So it would just be a minor insurance policy in case of a catastrophic event.

catawbasam• 10 years ago

Our family of 4 in a 4BR house lives in the humid SE USA. We use about 5000 kWh/year. Our efficiency report says we use roughly half as much as comparable households.

metric10• 10 years ago

They're probably factoring in a charging Tesla in the garage.

vollmond• 10 years ago

Just to add more anecdata:

* 150-year-old rowhome in central Pennsylvania, USA.

* 2 adults, 2 small children, dog/cat.

* Window unit air conditioners (2 running most of the time in summer, with a 3rd in the attic office running a lot less since I don't use it much). Hoping to install mini-split system eventually, but it's low priority

* Gas steam heat

* Gas stove/oven

* Gas water heater (I think)

* Electric baseboard heat in 2 rooms

* Electronics: tv/roku, modem/router, 2 laptops. 2 phones charged occasionally

* Lights are almost entirely CFL/LED.

My usage over the past year is just a hair under 14,000 kWh. Around 1500/mo when the A/C or baseboard heaters are on. Lowest months were April/May when both of those were off and I dipped down to 500 kWh.

If my math is right, most of the rest may be due to ceiling fans -- we have 5-6 that are left on pretty much year-round. Assuming they're each 75 watts, that's around 50 kWh/mo per fan. It never occurred to me to wonder how much power they might use.

So, if I leave A/C and baseboard heating off, and only run fans in currently-occupied rooms (bedrooms at night, living/dining/kitchen during the day), my usage would be about 4000 kWh/year.

How do you use so much less? Tiny efficient fridge? That's the only big item left in my house.

swerling• 10 years ago

I've got an 80-year-old row house in Queens, NY. Family of 4, no pets.

Our electricity usage is well below yours. We don't make a huge effort to conserve, and I don't believe our house is particularly well insulated. We have no special energy tech, unless you count the LED lights. We have a lot of electronic gizmos sipping away at any given time.

Winter: we don't have the baseboard heaters, but I work from home most days and have an infrared heater pointed at my desk for a good 8 hrs or so each day.

Summer: my wife hates A/C when she sleeps, so we only have one air-conditioned room at night (me and 1 kid in the room w/ A/C, wife and other kid in the other). No pets, so we leave the A/C off when we're out, it comes back on (by timer) about an hour before we get home. So big difference in summer.

Still, that doesn't sem to account for all of the difference. I just checked my con-ed history online. Some typical usage numbers:

  Feb: 310 kWh  
  Apr: 240 kWh
  Jul: 410 kWh
  Sep: 270 kWh

We spend anywhere from $80-$350 a month for electricity. Maybe there's a big difference between an 80-year-old row and a 150-year-old row?

We have

- 3 window A/C units.

- 3 routers, running 24/7

- 2 servers (mostly used as NAS), running 24/7

- FireTV, a few sonos devices, drawing a bit 24/7

- Many lights, mostly LED. We're pretty good about turning them off.

- ~10-15 phones/kindles/laptops/tablets/gizmos constantly being topped off

- Gas for stove, water, and household heating

EDIT: After reading more discussion below, I thought maybe I'd made a mistake, since there is a difference between our usage and most of the other US folks. I double checked, and the numbers are right. Our total usage for the last 12 months is 4340 kWh. We were gone for a few weeks in the summer, else it would have been a bit higher.

ghaff9• 10 years ago

That's quite similar to me with a 4BR in Massachusetts.

I'm in the 550-600 kWH range for most of the year. Goes up a little bit in the summer if I'm running my 1-2 window unit ACs on occasion. In the summer, I do run several fans more or less continuously.

I do have an electric oven, dishwasher, washer, dryer, and several refrigerators. I also still have a fair number of halogen or other incandescent lights although I'm slowly swapping in LEDs. On the other hand, it's mostly just me and I do a fair bit of traveling so appliances and lighting probably don't add as much as they could.

I have a little bit of baseboard heat but I rarely use either that or my space heaters. (Forced hot water heat and water heater.)

My electric company says my use is about average in the area for the size of my house (albeit their figure is a few hundred square feet too low).

ghaff9• 10 years ago

I'm guessing that would be below peak day usage for me--i.e. two window AC units running (which isn't common)--but 14600kWh/year seems pretty close as an average based on my $100 or so monthly electrical bill. That's for a 4BR house, albeit a smallish one, that uses oil heat almost exclusively in the winter and runs fans, and only sometimes AC, in the summer.

My electric company sends out a comparison statement periodically and says I'm about average for similar-sized neighbors. (Albeit, it thinks my house is a bit smaller than it is.) So I'd say Tesla's calculator is about right for the US although it's going to vary a lot based on AC and electric heat.

varjag• 10 years ago

Throw in charging a Tesla in your figure..

ph0rque2• 10 years ago

My 2300 ft^2 (210 m^2) house in NC uses 11000kWh per year. I needed less than half my roof (the southern half) to be covered in solar panels to generate almost all my electricity (I do have gas air and water heating, however).

I'd like to build my next house to PassivHous or similar standards. I think I can get the energy usage to 5000 kWH anually. With the whole roof sloping southward, I think I'd be able to generate more than what I need for the house, even accounting for electric transportation.

rsp1984• 10 years ago

Me in my 2BR apartment: 550 kWh / year. My startup office (3 developers and a lot of computers): 600 kWh / year.

Not including heating. Location: Wiesbaden, Germany.

I have a car but hardly use it. I go to work by bike every day. Guess I'm not quite the target audience for this powerwall thingy :-)

wilwade• 10 years ago

Another data point. Past 12 months we're at 22,000 kwh. Average of 60kwh a day. Older 4 br house with people almost always in it. USA, TN.

I think the main difference for us is that my wife and some of the kids are at home almost all the time and we kept the house warmer for the baby this winter.

masto• 10 years ago

I'm in the US (suburbs near NYC) and over the past 12 months we've used 15714 kWh. 5 bedroom house built in the 1950s. With all my electronic toys, our love of air conditioning in the unbearable NY summers, and the tendency for nobody to pay any attention to turning things off, I'm almost surprised it's not higher. Also, we have a Nissan Leaf (electric car) which is responsible for 2500-3000 of that usage. Total electric bills for the past year comes to $2885. I don't think we get enough light here for solar to be worth it, but occasionally I think about it.

ecopoesis• 10 years ago

14,130 kWh for a 4000 sq ft 4 bed in Boston over the last 12 months for a 150 year old house. It looks like AC is a large portion of that. Thankfully, we use gas for heat and cooking.

mpermar• 10 years ago

Spain, 4BR/200m2 house, roughly 5.500KWh/year. No A/C, heating used pretty much only in winter.

wjnc• 10 years ago

Don't forget gas for heating in Europe. One cubic meter of low caloric gas approximates 10KWh. My household (Netherlands) uses 4k KWh but also 3k m3 north sea gas. So about 34 KWh equivalent total. Suddenly a not so different ballpark. (And I have an eye opening moment. Never knew gas was so full of energy.)

alanpca• 10 years ago

I used 2400kWh in Canada last month! What are the temperature swings like where you live? We can go from -40F to +100F throughout a year.

awqrre• 10 years ago

Could it be because of the warranty? For example, those batteries in 2 years won't be able to keep half the original charge.

erikpukinskis2• 10 years ago

I live in California, 4br house with four adults. We use about 200kWh/month in the summer time which is basically just lights, electronics, and fridge (water and stove are gas), and 1000kWh/month peak in the winter time because we heat our rooms with electric space heaters.

We don't own the house so there's not much we can do about it. The windows aren't really insulating at all, and there's one old gas heater that doesn't work, although even when it did it all the heat just went straight up the stairs.

In the summer the upstairs gets extremely hot. But our rent is very cheap compared to other places in the bay area, so we are afraid to bother the landlord about these things. #freemarket

evandijk70• 10 years ago

Amsterdam, Netherlands. Around 1200 kWh/year. 1 person, flat with 1 room + kitchen. I am not home that often due to my job/hobbies, but I do have a gaming PC and a laptop. I did buy a power efficient refrigerator and washing machine when I moved in (Not terribly special or something, just bought the ones with a certain label). I also don't have a dryer and I cook using gas.

perilunar• 10 years ago

What is your yearly power usage?

Shouldn't that be 'What is your yearly _energy_ usage?' ? Or alternatively: 'What is you average power comsumption?'

2500 kWh/year = 6.85 kWh/day = 285 W, which sounds pretty reasonable

For comparison, an average male requires 8700 kJ/day = 100 W

40 kWh/day for a four bedroom house = 1.67 kW, which is huge. Maybe it includes charging a couple of Tesla cars as well.

Uptrenda2• 10 years ago

You can buy 12v 250ah deep cycle AGM batteries from China for around $5 per battery -- lets assume another $15 for world-wide shipping. These kind of batteries would have around 3kwh of storage per battery but since you shouldn't discharge them to more than 50% lets also say that you need to double the number of batteries to achieve 14kwh of usable power for 28kwh of total capacity. At that capacity level, you would need only 9 batteries for a sub total of just $180 USD (including shipping.)

Lets proceed with these calculations and say that you also want a good quality "grid-tie" "pure sine wave" inverter (to feed your stored energy back to your home grid) which will set you back any where from $100 - $1000. Your total cost for energy storage is still only going to be around $1180 (worse case.) Now consider that the life time for the Tesla batteries and standard AGM batteries seem to be very similar and I honestly have no idea what the customer is actually paying for.

Is the compact size and sleek appearance really worth the extra cost to the customer? Maybe it is. Maybe people don’t want to have a nerdy battery bank in their homes but to me the benefits all seem a little petty. (Granted, I definitely do see the benefit for tech like this in electric cars though, don’t get me wrong.)

oasisbob• 10 years ago

Source for that battery pricing? Seems WAY optimistic.

Given the weight + hazardous materials in an AGM, I can't see shipping hitting $15/unit unless you're talking about a container full.

beambot4• 10 years ago

Are you sure about those shipping costs to a residential address...? Professional installation? Process and guarantees from a reputable American OEM? Breakdowns and warranties?

I think you're missing a lot of costs beyond the raw materials...

botty_throwaway• 10 years ago

Regarding professional installation, those costs are not factored into the base price. It's an additional cost to both parent's DIY method and the Powerwall.

As for reputable warranties against breakdowns, please check out the fine print of the Powerwall warranty terms and conditions. It's a '10 year warranty' with some very special legalese baked inside that may make you reconsider the cost premium commanded by guarantees provided by a company very adept at lawyering up and navigating regulation.

The warranty (at least in North America) has provisions for voiding warranty claims in off-grid scenarios: during the entire period from installation to claim you must have constant access to the Internet for remote updates. If Tesla detects you go offline, they reserve the right to deny your claim.

In addition, if you use the Powerwall for additional applications besides self-consumption of solar power, you're capped at 18 MWh aggregate throughput before the claim is denied. Consider a 6 KWh solar installation for 5 hours daily charging, with the purpose of selling back energy to the grid (not classified as self-consumption). Now also realize that since this is aggregate throughput, all the charging, smoothing, and then discharging to the grid takes 2x the throughput. How many days warranty do you end up getting from this '10 year warranty'? 18 MWh / (6 KWh * 5 * 2) = _300 days_.

Finally, the warranty specifically says how they may choose your compensation. Could be an outdated refurbished model, but could also be cash market value of a similar system at the date of claim. Given the exponential rate of dwindling costs for energy storage, that's a gamble that in a few years your warranty may just pay out a tiny fraction of what you originally invested in you were sold a lemon.

Tying the luxury price premium to guarantees feels very reminiscent of smartphone insurance... which is almost never a good buy. I'm with parent, let's just be honest here: you're paying for luxury markup -- sexy compact design and a good story.

doikor• 10 years ago

And once your self made cheap chinese battery pack ends up catching fire and taking your whole house with them you understand why you want to pay for some actual company to do this and have some quality control/insurance.

sfblah5• 10 years ago

Yeah because Lithium Ion batteries never catch fire.

beefman• 10 years ago

Where can I get a 250ah battery for $5? I see prices in the hundreds, and weights over 150 lbs.

Edit: Though we only need 5 of them, not 9. The whole point of deep cycle batteries is that it's OK to discharge the quoted capacity every cycle.

Uptrenda2• 10 years ago

You guys do realize that most of the technology you buy is already made in China so its not like buying "American" is going to be some magical guarantee of quality. You'll find that a lot of the tech companies already have their products manufactured entirely overseas where the price is then marked up several hundred percent and sold to western consumers.

Regarding costs: I didn't factor in every possible cost but I still find it hard to believe that these high powered lithium batteries will work out to be cheaper than AGM batteries at this stage -- even factoring in things like shipping and installation costs (though I may be wrong about this, I think that this battery is likely to be like the Apple of PC components.)

By the way: If anyone is interested in suppliers have a look at companies like Guangzhou Henda Power Ltd and Guangzhou ESG New Energy Technology Co. They sell cheap AGM batteries like the ones I've mentioned. And you may even bump into one of SolarCity's suppliers if you do enough research ;)

Anyway, thanks for the downvotes for not band wagoning but none of you have any clue what you're doing.

qaq• 10 years ago

you did not factor in cost of space

nimish• 10 years ago

Arbitrage economy 7 in the uk-- halve your electricity orice. Not bad at all....

Annatar2• 10 years ago

So I used the calculator on Tesla's web site, in my case, I'd want 3 powerwalls and I'd want a solar installation to complement it: $18,000 USD.

That's still way too high: $1,800 - $2,500 would have been acceptable. That is how much I'm willing to pay for some solar panels, three batteries, and a little bit of electronics (processed sand) to control the lot.

As far as I'm concerned, this is all still hype. Prices need to go down, waaayyy down, and the profit margin and the engineering needs to be recuperated through volume. The days of fat profit margins and the early adopters amortizing the research and development have come and gone. The computer industry learned that lesson the hard way; it would be a shame if Mr. Musk repeated the same mistake, instead of learning from history.

maxerickson3• 10 years ago

A more interesting metric might be months of pay back time. $1,800-$2,500 seems like an arbitrary number you made up.

Like if your power bill averages $150 (I realize it probably doesn't) and you plan to stay in place for a few years, then something like 50*$150=$7500 is easy to consider and is much higher than the numbers you tossed out (that's just over 4 years to pay you back).

I mean, I agree with the point you are implying, that people won't be overwhelmingly excited with solar until the payback goes below 2 or 3 years, but I think it also makes sense for longer payback times.

Annatar2• 10 years ago

A more interesting metric might be months of pay back time. $1,800-$2,500 seems like an arbitrary number you made up.

It is an arbitrary number I made up!

Which part of that is how much I am willing to pay requires additional clarification?

I mean, I agree with the point you are implying, that people won't be overwhelmingly excited with solar until the payback goes below 2 or 3 years,

That's exactly right, and more: I am not willing to amortize their research and development costs outright. That's something Tesla (or any other company, for that matter) will have to do over years, at least as far as my wallet is concerned. Amortizing research & development costs outright is just pure greed; I won't support it.

dabeeeenster4• 10 years ago

"Powerwall uses an internal inverter to convert DC energy to the AC energy required for your home, lowering cost and complexity."

Does this mean that you don't need to buy a regular solar array inverter if you are deploying it with a new solar installation?

anthay• 10 years ago

I was pleasantly surprised to see prices quoted in £GBP - the Powerwall is available in the UK! But, we don't have enough sunlight here to run a typical house off-grid year-round, do we?

Brakenshire3• 10 years ago

In the UK we get about a quarter of the incident energy from sunlight in Winter than we do in Summer. You could do it by overbuilding your solar array by 4 times over what's required in Summer. That might actually be reasonable if solar prices carry on going down. Or you could do it by having some sort of micro-CHP system which produced electricity and then uses the waste heat to heat the house.

But, yeah, I think this is the major outstanding issue with renewables at the moment. Solar with battery storage looks like it will get parity with the grid anywhere near the equator, where you don't need seasonal storage. The UK needs additional solutions. I think we should be putting more money into developing micro-CHP personally. British Gas were trying out a Sterling engine system a few years back, there are also some in development using Fuel Cells.

hanoz• 10 years ago

In the UK a lot of people are on tariffs which pay them above market rate for the electricity they generate regardless of whether they feed it into the grid or use it themselves. A battery like this will allow them to both sell and use 100% of what they generate.

IanCal• 10 years ago

You could possibly also reduce your costs by using an economy7 meter and only charging the powerwall over night (assuming you can set times on it).

TillE• 10 years ago

Germany is at a similar latitude to England/Wales, and they've been investing a ton in solar.

It's certainly less efficient, but still worthwhile.

DvdGiessen• 10 years ago

For those who are looking for something similar but (being the kind of people who read HN) would like something more configurable and hackable, you might check out the products of Victron Energy[0]. They've also have an optional remote management portal[1] which allows you to set up and monitor everything remotely for years now, and most the software running locally on the devices is open source and fully modifiable (such setups are even supported!).

Full disclosure: I'm one of the developers of the mentioned Remote Management portal.

[0] https://www.victronenergy.com/ [1]: https://vrm.victronenergy.com/

gregn610• 10 years ago

X-post from reddit as it might get an answer here...

http://m.imgur.com/pgskG9q?r

This LNG ship got me wondering about a battery equivalent, charged up in a desert solar farm and shipped to a major city.

I get 16 Powerpacks per 40ft container 5100 containers per Panamax ship =81600 powerpacks per ship At 95kWh per pack = 7752MWh per ship ( based on powerpack v1)

So is that like two Hinckley C nuclear reactors worth of energy? How long would that last before having to go back for recharging? How long would it take to charge from a massive solar farm etc etc. so many questions but basically, is it remotely viable?

pjc502• 10 years ago

It's not "two Hinckley C nuclear reactors worth of energy" unless you confuse MW and MWh. 7752MWh per ship = two hours of Hinckley C.

Two9A• 10 years ago

Fully Charged interviewed the CEO of SunAmp recently: https://www.youtube.com/watch?v=9upXeTMHUqE

One of their new projects is to ship heat, stored in phase-change material, from a generation plant to central Bristol on a barge full of SunAmp cells. So it's a similar concept, shipping heat batteries instead of Powerpacks.

sfblah5• 10 years ago

Lithium Ion batteries lose charge over time, so during transport they would discharge.

Lithium Ion batteries can handle a relatively small number of recharge cycles (when compared with the number that a metal cylinder/sphere can handle when just filling it up with LNG)

mcbits• 10 years ago

Another way to approach the question is to compare the energy density of LNG to Lithium-ion batteries: https://en.wikipedia.org/wiki/Energy_density

You'd need about 10-20x more shipments of the same volume or 50-100x more shipments of the same weight to transport the same quantity of energy.

superfx• 10 years ago

Does anyone know where the video was filmed? It looks like it might be a neighborhood in the Bay Area.

crb• 10 years ago

The "Colonial Street" set at Universal Studios in Burbank, California. Most famous as the set of Desperate Housewives.

https://en.wikipedia.org/wiki/Colonial_Street

sambe• 10 years ago

I'm not following the calculations, maybe I'm sleepy. "can power a two-bedroom home for a full day". They say that is 20kWh (it doesn't change when you say sockets vs entire home...). They say the battery is 14kWh and only recommend one. Huh?

Dowwie2• 10 years ago

I'm very impressed by the solar roof shingles, especially the French slate style.

mrfusion11• 10 years ago

@elonmusk Just a thought. How about A prebuilt shed built with these shingles might make a good product.

A lot of people buy prebuilt sheds and if it only cost $x extra and you could start lowering your electric bill.

dabeeeenster4• 10 years ago

You also need the inverter etc etc. So unless it was a big shed, maybe its not viable?

mrfusion11• 10 years ago

Good point. I'd imagine you could charge an electric car without an inverter. Perhaps it could be just for that purpose. Bury a line running to your garage.

DeBraid• 10 years ago

Many Powerwall 2's can be combined to reach potentially unlimited scale. Tesla working with SCE to build an 80 mWh Powerwall 2 stack.

Utility power required to partner with local generators. Bright future for both rooftop and Big Utility.

Solar Roofs

Solar roofs superior to normal roof? Can they look better and costs less. Maybe.

Make solar panels look like roof shingles. A textured glass tile contains/covers (?) the solar cells.

Hydrographic printing allows each tile to look unique, so the roof/house looks beautiful. No two roofs will be the same.

From street-level, it looks opaque, but is transparent to Sun.

Dowwie2• 10 years ago

I suspect that Tesla will exponentially improve the capacity and performance of these Powerwall units every couple of years.

mathgeek• 10 years ago

Exactly the reason that many people are wise to hold off on installations. The long term cost savings are wasted if future products are exponentially better in the short term. Non-financial benefits aside, naturally.

Gustomaximus• 10 years ago

A bit late to thread but;

1) I'm wondering why the tiles weren't larger? Wouldn't this make laying them much cheaper in a world where labor is such a significant cost for building. Aside from the shingle look I'm surprised these dont come in 1mx1m type sizes plus some smaller sizes for edges. I cant imaging this want discussed so curious if I'm missing some obvious logic here.

2) If you didn't have a ceiling would these let light through and further reduce electricity usage?

3) The cells seems to be a small proportion of the tile. Is this something they expect to increase so they will increase power generation ability significantly over future releases?

Powerwall 2 and Integrated Solar

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