
Your Home Doesn't Matter for Tesla's Dream of a Battery-Powered Planet - europa
http://www.bloomberg.com/news/articles/2015-05-21/your-home-doesn-t-matter-for-tesla-s-dream-of-a-battery-powered-planet
======
crdoconnor
>For the average U.S. home to rely solely on solar panels and Tesla's new
batteries, the complete system would cost roughly $98,000, according to
analysis by Bloomberg New Energy Finance. Even that glum assessment assumes a
house in a sunny region such as Southern California.

927 kwh / month off grid solar system :
[http://www.wholesalesolar.com/solarpowersystems/large-
home-7...](http://www.wholesalesolar.com/solarpowersystems/large-home-7-off-
grid-solar-power-system.html)

Cost : $20,172

Two of Elon's batteries: $7k

Total cost = $27,172

How the hell did they get $98k?

I think they intentionally tried to make that number look ridiculous. I wonder
if this is more of ALEC's anti-solar bullshit.

~~~
vonmoltke
Look at the link you posted. The recommended battery pack for that system is
62kWh (1284Ah * 48VDC). That is the equivalent of 6 10kWh Powerwall batteries.

Furthermore, the 10kWh Powerwall is not for solar or other daily applications;
it's for backup.[1] A PV system needs to use the 7kWh batteries, thus
requiring 9 for this system. That is $27,000 in batteries.

Now, on to the panels. The sizing of the system you posted indicates it
assumes 5 Sun hours per day. Most of the US gets less than that; from the map
on the site it looks like 4.3 is a good average for the US. Next, as the site
clearly says when you run their off-grid calculator, you need to discount the
Sun hours if you plan on using the system in the winter; they recommend
knocking 1.5 off your yearly average. That drops most of the US to 2.8. That
means the median house would need twice the number of solar panels in that set
to cover all times of year.

Combined with the actual cost of Powerwall batteries, we are at $67,344. If
you want to use the Pacific Northwest as your baseline (which someone opposed
to solar would try to do) you approach the $98,000 for an off-grid system.

[1]
[http://www.teslamotors.com/powerwall](http://www.teslamotors.com/powerwall)

~~~
crdoconnor
>Look at the link you posted. The recommended battery pack for that system is
62kWh (1284Ah * 48VDC)

Oh look. It's $8k. So the total price is $28k.

62 kwh is over two full day's worth of electricity usage for the average US
home. I actually think that's probably quite a bit more than you need. Two of
Elon's batteries is 20kwh, which is about 2/3 of an average day's usage -
enough to last most people the night, right?

>Now, on to the panels. The sizing of the system you posted indicates it
assumes 5 Sun hours per day. Most of the US gets less than that

$98k was in California right? According to this, Los Angeles gets 5.62.
Manhattan gets 4.57.

[http://www.bigfrogmountain.com/SunHoursPerDay.html](http://www.bigfrogmountain.com/SunHoursPerDay.html)

>it looks like 4.3 is a good average for the US

Why not pick 3.9 and assume that everybody gets as much as Fairbanks, Alaska?

~~~
vonmoltke
> Oh look. It's $8k. So the total price is $28k.

Yes, and the sentence you quoted specifically said the $98,000 figure was
using _Tesla 's_ batteries.

> 62 kwh is over two full day's worth of electricity usage for the average US
> home. I actually think that's probably quite a bit more than you need. Two
> of Elon's batteries is 20kwh, which is about 2/3 of an average day's usage -
> enough to last most people the night, right?

Wrong. An off-grid PV system requires a buffer to supply power during days
with little to no sun. Two days is about right for most of the country; in
some places I would size it larger because they are prone to multiple days of
overcast conditions at certain times of year.

Furthermore, you completely ignored that I stated, supported by the link I
provided to the Tesla page, that you are not supposed to use the 10kWh
batteries for daily drain applications.

> $98k was in California right? According to this, Los Angeles gets 5.62.
> Manhattan gets 4.57.

I didn't look into where the $98,000 was supposed to be located. I assumed
they took the least-favorable location in the country.

> Why not pick 3.9 and assume that everybody gets as much as Fairbanks,
> Alaska?

Because the vast majority of the US gets in the range of 4.2 - 4.5? I could
have used 4.5, but that would only move the total cost down by about $4,000.
Still, that is the average. An off-grid system needs to be designed for the
low on that chart, or there will be times of year you have little or no power.

~~~
crdoconnor
>Yes, and the sentence you quoted specifically said the $98,000 figure was
using Tesla's batteries.

Ok, so assuming that you really do need ~60kwh and you _must_ use Tesla's
expensive batteries rather than the $8k package, that's still 21 + 3 * 8
batteries = $45k for a house in California. What is the other $53k spent on?
Postage?

>I didn't look into where the $98,000 was supposed to be located. I assumed
they took the least-favorable location in the country.

In California. It's right there in my first post.

Maybe they assumed that the average American lives in Alaska and use their air
conditioning 24/7.

------
scott_s
Something this article doesn't address is the potential impact batteries
everywhere could have. This quote in particular tells me the author, and the
speaker, don't see it this way:

 _“The battery-in-every-home idea—not only do I think it doesn’t make economic
sense, I don’t think it’s necessary,” said Brian Warshay, an analyst at
Bloomberg New Energy Finance. “Having a centralized grid is incredibly useful
and incredibly efficient.”_

The difficulty with our current power infrastructure is that there is no
buffering at the consumption side. Because there is no buffering at the
consumption side, the overall grid must be able to handle peak demand. That
is, we must over-provision. With batteries everywhere, this isn't necessarily
the case. In theory, we could all have generators, but we don't because
they're noisy, smelly, and a maintenance hassle. But sticking a giant battery
on the wall? I can see everyone having one, and big institutions having large
arrays of them. I think that has the potential to fundamentally change our
power grid.

~~~
dragontamer
Erm... or centralized storage mechanisms could be built.

[https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...](https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station)

Do you have any idea how many Li-Ion batteries would be needed to match the 30
GIGAWATT-hours of storage potential in the Bath County pumped storage plant?

The problem is that California didn't build enough of these 20 years ago.
California has a couple of pumped-storage plants coming in... and as soon as
they're built then net-metering will be even _better_ for consumers.

In general, centralized storage at the utility-level will benefit from scale.
Redox batteries will probably be cheaper and more efficient than Li-Ion
batteries that Tesla is putting out.

And Pumped-Hydro is _already_ much much cheaper, and has existed since the
60s.

~~~
dredmorbius
I ran some back-of-the-envelope calculations based on Tom "Do the Math"
Murphy's nation-sized battery, 336 TWh, sufficient for two weeks' reserve
power.

Tesla's Superfactory could produce that. In about 12,000 years.

Even if the capacity's excessive by a few orders of magnitude, that's a hell
of a lot of battery.

[http://physics.ucsd.edu/do-the-math/2011/08/nation-sized-
bat...](http://physics.ucsd.edu/do-the-math/2011/08/nation-sized-battery/)

Assuming 56 kWh Tesla batteries. Half a million battery packs is 28 GWh of
total storage capacity. That's the energy equivalent of 16,000 barrels of oil.
Assuming a modest 30% Carnot thermal generation efficiency, you'd need 55,000
bbl of oil to actually generate that electricity.

Yeah, batteries are a hard sell.

If each battery is 2m x 3m or 6m in area, the Nation Sized Tesla Battery would
cover 36,000 km^2, or an area 190 km on a side. Maybe we'll stack them.

(The actual measurements are smaller, around 1.5 x 2.5 m or so, so that's an
overstatement.)

A buddy of mine working at ORNL claims there's interesting stuff on the
storage front that's competitive with pumped storage, but can't say just what
yet. I'm highly curious myself.

~~~
dragontamer
> A buddy of mine working at ORNL claims there's interesting stuff on the
> storage front that's competitive with pumped storage, but can't say just
> what yet. I'm highly curious myself.

[http://prod.sandia.gov/techlib/access-
control.cgi/2011/11273...](http://prod.sandia.gov/techlib/access-
control.cgi/2011/112730.pdf)

"Table 4" is probably what you want to look at. As you can see, only
Compressed Air is competitive with Pumped Hydro as far as energy storage
(w-hrs).

It looks like Compressed Air is going to be the golden standard a few years
from now. There was a relatively cheap compressed-air plant created out of
abandoned mine tunnels that was hundreds-of-Megawatts in scale. I don't quite
remember the name of it however.

Also, Compressed Air doesn't require you to empty a lake (and refill it) every
day. So California's low-water situation may prefer compressed air storage
systems.

Redox Flow batteries look to be the most promising technology at utility-scale
chemical. Chemical solutions are needed for their versatility... but "long-
term" energy storage (such as day-night load balancing) will likely be handled
by Compressed Air and/or Pumped Hydro.

Currently, over 95% of the US's energy storage capacity is in pumped hydro.

~~~
dredmorbius
Doesn't CAES require gas or other fuel for reheat on expansion?

~~~
dragontamer
Early designs did. But CAES has begun to store the excess heat that is made
during compression.

For example:
[http://sigmaenergystorage.com/?page_id=447&lang=en](http://sigmaenergystorage.com/?page_id=447&lang=en)

Advances are being made at _all_ energy storage solutions. Frankly, CAES is
the most promising, now that they've figured out how to store excess heat
during compression.

------
breischl
This is the second article I've seen from Bloomberg that ignores two-thirds of
what Tesla actually said and thus massively misses the point. I'm starting to
think it's intentional.

No kidding this isn't (currently) attractive for North American homes. If I
recall correctly, they basically said that in the press conference, though I
can't find the link now. They were expecting it to be more useful in places
with lots of solar and dodgy electric grids, such as Australia.

Bloomberg also goes on and on about utility scale storage. They apparently
didn't read the press kit, where Tesla talked about how they're doing just
that.

Press Kit -
[http://www.teslamotors.com/presskit](http://www.teslamotors.com/presskit)

~~~
dba7dba
_I 'm starting to think it's intentional._

It IS intentional. Pretty much everything said (and NOT said) on MSM is
intentional.

------
Htsthbjig
Long time ago I visited the home of a young entrepreneur that had spent all
his money installing optical fiber all around his home.

I remember what I thought: How stupid someone could be. It does not make
financial sense at all when it was so expensive.

Turn out I was the stupid one. This man created a company doing exactly what
he had done in his house but for others and made a ton of money.

In some way he paid a cost for living in the future, and he understood the
practical shortcomings and advantages of the new technology much better than
anyone else, which made him succeed when others failed.

------
gwbas1c
Net metering doesn't make sense. About half of the cost of residential
electricity goes to running the grid.

That being said, electric companies aren't stupid. If / when solar power and
batteries become ridiculously cheap, they will just switch over to solar and
batteries.

Residential off-the-grid solar power will make sense in two markets: \- Highly
rural areas where it's very expensive to maintain power lines. \- "Be
prepared" cultures like Utah where people take pride in preparing themselves
for Armageddon.

~~~
hliyan
Don't forget line losses [1,2] -- closer the point of generation and the point
of consumption, the lesser they are.

[1] [http://www.greentechmedia.com/articles/read/1.2-Trillion-
Met...](http://www.greentechmedia.com/articles/read/1.2-Trillion-Metric-Tons-
of-CO2-in-Line-Losses)

[2]
[http://data.worldbank.org/indicator/EG.ELC.LOSS.ZS](http://data.worldbank.org/indicator/EG.ELC.LOSS.ZS)

------
ghshephard
First, this is the opening price. The economics are going to get better from
here, and the early adopters always pay a bit more for the privilege of
experiencing the technology - and _someone_ has to be first to get the ball
rolling.

Next - If I have a $500K+ house (modest, by Northern California standards),
and for $10K I could get this sleek, hi technology, 10 year warranty battery
that lets me more efficiently leverage my solar panels, plus potentially
giving me some insurance against a grid outage? Hell, I'm first in line.

Now, does the Tesla Battery make sense, for 100% of the US Population, today?
Of course not - but I don't think anyone has suggested that.

But this is where we start, and we improve from here.

~~~
dragontamer
Except decentralized power are an expensive luxury product. If you build a 1GW
pumped hydro plant with 10-hours of storage (10GW-hr plants cost roughly $3
Billion), then _everyone_ benefits, including those in poverty who are unable
to buy batteries for themselves.

Net-Metering from those who can afford rooftop panels can then store the
energy centrally, and then offset the costs for the non-solar users in the
rest of the neighborhood.

~~~
ghshephard
Just a pedantic note - I don't think you would price Hydro Plants power stores
based on GW-Hr capacity (that's just the size of the lakes/water reservoirs,
which might store petawatt-hours of capacity depending on the geography), but
on the rate/number of pumps, right?

~~~
dragontamer
Yes, due to Pumped Hydro's benefits... the major cost is the size of the
generators.

A single 100MW turbine can store weeks-and-weeks of power if drawing from any
small lake. But for it to be useful to a lot of people, you probably need to
build a gigawatt scale turbine.

With that said, the Bath County generator is the largest in the world, and is
close to 30 GW-hr of capacity (3GW of power. Yes, it can empty the lake in 10
hours, and refill it in another 10 hours)

~~~
ghshephard
I just lost 45 minutes reading about the Bath County generator - that has 50%
more generation than Hoover Dam. Amazing.

In terms of Storage Capacity of a Dam, I checked:
[http://www.nps.gov/lake/learn/nature/storage-capacity-of-
lak...](http://www.nps.gov/lake/learn/nature/storage-capacity-of-lake-
mead.htm)

The water available for power generation starts at 1050 feet, and goes to
1221.4

The Capacity goes from 11,474,857 acre feet to 31,141,756 acre feet. So Hoover
Dam has an operational storage of 19,666,899 foot acres

The Turbines have a capacity of 2,080 MW. From:
[http://www.usbr.gov/lc/region/pao/brochures/faq.html#capc](http://www.usbr.gov/lc/region/pao/brochures/faq.html#capc)
we discover

 _What is the maximum capacity of these works?

About 118,000 cubic feet per second: 32,000 cubic feet per second for power
generation and 86,000 cubic feet per second of valve discharge. One cubic foot
per second of water equals nearly 7 gallons passing a given point in one
second._

So, dividing 19666899 foot acres / 118000 cubic feet/second =
6,408,487,134,720 gallons / 882,701.2987 gallons/second = 7,260,085.76644
seconds = 2,016.69049 hours (only 12 weeks)

So, the operational storage capacity of Hoover dam is 2 GW * 2000 Hours = 4
Terawatt Hours. I realize these are entirely different projects, but it's
interesting to get a gut sense of how incredibly large the Bath County
generators are - not only do they generate power going _down_ \- they can also
pump that water up.

Incredible - wonder of the world.

------
Aqueous
"So defection from the electrical grid will remain well out of reach for most
Americans, and even those who manage the feat will waste a lot of capacity
thanks to solar panels and batteries that are rarely used to their full
potential."

Once again a news outlet (deliberately) fails to see the long-term strategy
for the sake of a click-baity nay-saying headline. Just like the Tesla vehicle
itself, which is still outside the reach of 99% of Americans, the point is to
aim for the luxury market first and through scale and process optimization
gradually lower the price so that it is within the reach of most Americans.

The luxury market is why Tesla is now able to develop a mass market vehicle,
why solar panels are reaching an inflection point where in many parts of the
world it will no longer make financial sense _not_ to have them, and why home
batteries will eventually be in the reach of everybody.

~~~
fredkbloggs
I love how the echo chamber keeps talking about the Powerwall as if it were
the first battery system ever made.

You can buy batteries for your home, today, at a retail price half that of the
Powerwall. With equal or greater energy storage, power output, and lifetime.
There's no need to wait for Li-ion to become "within reach". It's a needlessly
expensive technology and product attempting to displace cheaper, more capable
solutions that have been available for years.

Their marketing sure is clever, though; they're already the only battery
system that 98% of Americans have ever heard of! This is going to be a
fascinating B-school case study in a year or two. It's one thing for Apple to
convince people to pay a huge premium for its design, another entirely to
convince people to pay twice as much for a noninteractive energy-storage
device that sits in a basement or closet. I'm in awe. Luxury product indeed.

~~~
Aqueous
Sure - and plenty of MP3 players existed before the iPod, some of which, on
paper, were better than the iPod (longer battery life, bigger capacity, more
formats, better platform compatibility). But it took somebody who cared about
user experience and design to make it a popular consumer product.

~~~
fredkbloggs
That's exactly my point: there IS no user experience. It's a piece of utility
infrastructure: it sits there and does its job; you don't interact with it at
all. You're paying for a Tesla nameplate on a device you will probably never
even look at. Do you know who made the backflow preventer valve assembly that
sits between your house/apartment and the street? Would you pay twice as much
for one if it were sheathed in white plastic and had an Apple or Tesla logo?

~~~
schiffern
>it sits there and does its job; you don't interact with it at all.

This is more than can be said for the "half price" lead-acid batteries, which
need to be periodically checked for corrosion and cleaned. Non-sealed
batteries need to be topped off with distilled water annually. All PbA
batteries (flooded and AGM!) require the hydrogen vent be checked for
obstructions and maintained. That vent is an extra wall penetration for mice,
insects, heat loss, etc. The entire battery bank also needs to be equalized
every ~6 months, which may or may not be done automatically.

Sounds like the Powerwall's "no interaction" model is already better than the
competition.

[http://rimstar.org/renewnrg/off_grid_solar_battery_maintenan...](http://rimstar.org/renewnrg/off_grid_solar_battery_maintenance.htm)

~~~
fredkbloggs
AGM and gel type batteries are collectively known as valve-regulated lead-acid
or VRLA types. The maintenance procedures you described are for flooded
batteries (FLA) and are neither required nor even possible with VRLA
batteries.

You can save even more money by using FLA if you're willing to do the
maintenance. If you're not, the direct comparison is with VRLA. VRLA is much
cheaper than the Powerwall on an apples-to-apples basis.

It's hard to point to a specific source describing maintenance procedures that
don't exist. For example, a common manufacturer's manual may be found at
[http://rollsbattery.com/public/docs/user_manual/Rolls_Batter...](http://rollsbattery.com/public/docs/user_manual/Rolls_Battery_Manual.pdf).
Note the difference between FLA and AGM (VRLA) maintenance procedures.
Specifically, there are none for the latter.

------
Spooky23
Typical NYC based media people not getting it.

There are many many people who spend money right now on generators as
emergency power sources.

My parents are a great example of a perfect use case for this product. They
live in the country, and have 5-6 significant power outages a year, usually in
winter. They need a way to automatically deliver power to critical house
systems: furnace, well pump, fridge, freezer. Right now they use a large
portable generator, but that requires maintenance and a manual engagement. You
also cannot leave it unattended for long periods of time. That basically ties
them to their house in the winter months, making vacations difficult.

Lots of other markets for this type of thing too. If you have a horse or hobby
farm, one of these things keeps the heat on in the barn when the power goes
out.

~~~
dba7dba
That is a great use of Tesla Powerwall that I didn't think of. Looks like most
people are thinking Powerwall would be useful only in Sun drenched
ares/season. But from your case, Powerwall would be very useful everywhere
even in areas without much sun.

------
higherpurpose
The article is much more negative than it _should be_. There is some truth in
there, but the rest of it seems short-sighted. It's like saying "why in the
world would anyone buy a $5,000 4k TV with an OLED screen?" Yet people buy
them and that's how the technology becomes cheaper.

It's a _little_ different with batteries because they don't improve at the
same rate tech products do, but they still improve and I think once Tesla gets
a couple of those Gigafactories going the batteries will become more appealing
to a wider range of customers.

It's also the same with electric cars - 95% of the people still _don 't want_
one, even if they had the money for it, because they don't want the range
anxiety. Also aren't solar panels still more expensive than buying coal-
produced electricity? Or it least it was in the past few years, yet people
still installed solar panels.

The bottom line is Tesla only needs some "early adopter" customers to hold it
over until the product is cheap/good enough for the mainstream market. And by
the looks of it, whether it's in electric cars, solar panels or batteries,
that seems to have worked pretty well.

~~~
dragontamer
I don't understand why people feel the need to be an "early adopter" of
something like this.

How many people out there want to be an early adopter of a Lennox Air
Conditioning unit? Or of a New, more efficient furnace? Or more efficient
windows?

The fact remains: the Tesla Powerwall is a "home appliance". The process for
buying a new home appliance is the same as any other. You run the
calculations, you determine if the appliance saves you money in the long term,
and if it does... you go for it.

------
bsbechtel
I seem to remember a lot of very similar articles arguing the economics of the
iPhone didn't make any sense when it first arrived as well. Not trying to say
the result here will be the same, just running hard numbers doesn't always
tell the whole story.

------
jakozaur
The article omit use as alternative to UPS + diesel engine. In that use case
it is competitive.

Moreover, any modern invention could be dismissed as toy/limited use for rich.
E.g. Computers, mobile phones, cars... Next generation should be even more
competitive.

~~~
hoopism
Problem with Net Metering (at least for the people I know int he northeast who
have solar) is that when the lights go out they are in the same boat as
everyone else... where I live we have had multiple week+ outages. They, like
everyone else, have to have a generator to keep things going (despite solar up
on the roof). A battery would replace the generator and UPS in that case.

Of course, the week+ outage is usually due to ungodly amounts of snow...
sooooo solar may not be your friend then...

~~~
ceejayoz
> Of course, the week+ outage is usually due to ungodly amounts of snow...
> sooooo solar may not be your friend then...

[https://www.youtube.com/watch?v=YuQhlENQoIE](https://www.youtube.com/watch?v=YuQhlENQoIE)

------
gnoway
I'm confused about why 'net metering exists' is a good argument against these
batteries. As I understand it this is a mandated buy of excess home-generated
solar at retail prices - is this correct? If so, does everyone really think
this is sustainable if rooftop solar really takes off? Even if it technically
is I expect to see widespread lobbying to end it (like in Hawaii) and expect
most of the lobbying to succeed.

I don't think the Tesla batteries are a good way to lower your home energy
costs, but I don't think I would factor in net metering as a reason why, at
least not looking 5-10 years out.

------
sunstone
If I recall correctly about 80% of Tesla's battery pre-orders by dollar value
were in the commercial and utility categories rather than residential.

This article makes a big point that in the residential/solar panel market the
battery is marginal at the moment in most of the US where grid electricity is
cheap. Ok, but so what?

------
dba7dba
Imagine the world where only acts that make financial sense are done.

1\. No kids would be born. They do not make financial sense at all.

2\. We all would be living in some nasty environment. Caring for the
environment doesn't make much sense for companies.

3\. Caring weak, vulnerable people doesn't make any financial sense at all.

------
andrewtbham
> No matter how cheap prices get, batteries won't be the easiest or the
> cheapest way to take advantage of solar power.

that seems like it can't possibly be true.

~~~
bryanlarsen
That statement is true as long as net metering is in effect. Net metering
means you sell back to the grid for the same price as you buy from the grid.
So you can treat the grid as a giant, perfectly efficient battery. Put $X of
electricity in during the day and pull out $X at night. With a battery, you'd
only be pulling out ~0.9X due to efficiency losses, not to mention the cost of
the battery itself.

