Tesla to sell battery packs for home use

[Rory]

I guess you don't have to order an extra battery for your car and strip it down like in that video a few weeks back...

http://offgridquest.com/news/tesla-motors-announces-a-new-home-batter

[miguelvp]

Wall mounted, I hope people don't put nails on it to hang pictures
Of course they wouldn't do that right?

I think it's a great idea, we will have to see what the price is first

[dannyf]

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.

Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

It is hard to imagine that to be a net positive.

Not to mention the pollution created in mining, and manufacturing of such batteries.

[tom66]

I don't see people living off the grid in large numbers - not anytime soon, at least. There's not enough solar to do it, especially so if we all have EVs charging off of these panels...

But the grid storage could really help with the duck curve. One possible solution is for grid inverters to be given a price by the supplier, which is updated frequently. The price during peak solar hours would be low, so very little would be sold into the grid (pretty much only if the batteries were fully charged as the energy would otherwise go to waste.) Then, as demand increases price will increase, so inverters will be commanded to sell more into the grid to meet the demand. Inverters with greater storage will sell for longer. Those with less storage will probably wait until the price is highest (using market forecasting or guaranteed pricing from the grid supplier) to return maximum value.

This would help level demand (making nuclear more economic, for the base load) and stabilise the grid. It  could also reduce the risk of any one power plant failure crippling the system. What's not to like?

It is hard to imagine that to be a net positive. [...] Not to mention the pollution created in mining, and manufacturing of such batteries.

I have a problem with this statement.
http://www.transportation.anl.gov/pdfs/B/855.PDF (page 5, paragraph 2)

[...] Our energy assessment shows that 40.2 MJ of purchased energy, including
that associated with the production of lime, is required to produce a kg of Li2CO3. This value
corresponds to a life-cycle energy rate, including the fuel cycle of purchased fuels, of 44.7
MJ/kg. Most of the purchased energy (78%) is derived from fuel oils; about 4% is from propane,
and the remainder mostly from coal

The energy density of a typical Tesla Model S battery module? Someone's done the math:
http://www.teslamotorsclub.com/showthread.php/34531-Plan-Off-grid-solar-with-a-Model-S-battery-pack-at-the-heart/page19?p=908698&viewfull=1#post908698

From this we can see 205Wh/kg (from 10.55lbs/kg), and using the 44.7MJ/kg (12.41kWh/kg) figure to be offset, it would take... about 62 cycles to break even.

These batteries easily last 500 cycles when abused, and 1,000+ cycles are easily possible if capacity is kept between 20 and 80%.

Here, we're assuming that we can store all the energy from the solar panels, and that the solar energy is zero-CO2. This means that producing 1kWh of solar energy and selling it into the grid effectively offsets 1kWh of carbon-powered generation. This assumption is only correct when proper grid storage is implemented. Solar without grid storage can increase net CO2 emissions because the only generators that can cope with such a sudden increase in demand are CCGT.

[johansen]

natural gas turbines are generally used for peaking plants, and those are low CO2 anyways.

the problem is, the battery life cycle cost per kilowatt hour is far too high.
dollars spent on batteries generates just as much CO2 as does dollars spent on natural gas, at the end of the cycle.
unless you can hire children to do the labor.. their energy expenditure in the form of purchasing power is much less than yours.

if all the coal power plants were replaced with solar, and natural gas was burned at night.. you'd have much less co2 at the end of the day.
the problem is ensuring that the co2 associated with all the economic activity that built the solar cells is less than coal.
now with coal power plants costing 4$ a watt in america, as opposed to perhaps 25 cents in china, it should be self evident that solar at 2$ a watt will easily produce more electricity per pound of co2 at the end of 15 years than the coal plant will.

[rx8pilot]

Massive quantities of non-recyclable  lithium-ion batteries are really being considered a good idea for stationary power? 

The long-term must be considered and these batteries are a poor solution even in the short term.

[tom66]

Massive quantities of non-recyclable  lithium-ion batteries are really being considered a good idea for stationary power? 

The long-term must be considered and these batteries are a poor solution even in the short term.

Er, Li-Ion is recyclable. There are concerns over cell safety, but they certainly aren't non recyclable. And even if they were not recyclable, you can see the energy pay off occurs within ~60 cycles, if your energy input is solar.

One good example is that if EV batteries reach end of life (say less than 80% of design capacity and 2xESR) they have a second life as a household backup system.

Tesla are building the gigafactory to produce and recycle cells, building new cells from worn out ones.

natural gas turbines are generally used for peaking plants, and those are low CO2 anyways.

the problem is, the battery life cycle cost per kilowatt hour is far too high.
dollars spent on batteries generates just as much CO2 as does dollars spent on natural gas, at the end of the cycle.
unless you can hire children to do the labor.. their energy expenditure in the form of purchasing power is much less than yours.

It's unclear what you mean here. Germany is a good example. Before the solar switch they had a good amount of nuclear with mostly coal and CCGT. Because of the great amount of solar power being added to the grid, suppliers needed to use fast-reacting coal and CCGT plants, and they shut down many existing nuclear plants in the process. Nuclear is near zero emission, certainly much lower than other sources. This short-sightedness increases power emissions! http://en.wikipedia.org/wiki/Electricity_sector_in_Germany#mediaviewer/File:Electricity_Production_in_Germany.svg

If you read the study I linked above, you'll see that whilst you do expend energy producing a battery kWh, it is no where near the same amount of energy you can charge/discharge a cell. You can get about 20x as much energy in/out of it as you put in. And combined with a smart solar grid, this can enable nuclear to come back and replace CCGT/coal (as the grid would not need to respond as fast - nuclear is horrible for response time.)

On a life-cycle CO2 basis, lead acid is probably better, and lead acid batteries are more recyclable. But it's not exactly practical to have a Pb installation in every household, with limited space. Lithium ion is probably best for the average household. For areas where space is of little or no concern (such as large grid storage), Pb works better (or, even better are pumped storage systems.)

-

So currently solar systems primarily sell between 12pm and 3pm. Prices are low during this period. A better system would have houses on a sort of rota, with appropriate prices matching demand, so that during the periods of 3pm-8pm, or 9am-12pm they sell into the grid. The way this would work is the solar system charges the battery, and when the grid is in need of power, the system discharges. Can also work with EVs - lets say they need 100 miles range to get to work and the car has 200 miles charge. When the owner gets home, it can (if selected of course) discharge to 50 miles during the high-demand period, and then charge up at night using cheap energy, acting as a grid buffer.

[dannyf]

these batteries are a poor solution even in the short term.

Short-term is exactly what those guys are all about. They aren't capable of looking more than a couple steps ahead.

[cosmicray]

So currently solar systems primarily sell between 12pm and 3pm. Prices are low during this period. A better system would have houses on a sort of rota, with appropriate prices matching demand, so that during the periods of 3pm-8pm, or 9am-12pm they sell into the grid. The way this would work is the solar system charges the battery, and when the grid is in need of power, the system discharges. Can also work with EVs - lets say they need 100 miles range to get to work and the car has 200 miles charge. When the owner gets home, it can (if selected of course) discharge to 50 miles during the high-demand period, and then charge up at night using cheap energy, acting as a grid buffer.

Other than the obvious consideration of when the home RE system has excess to sell to the grid. If you think about a normal solar home-owner, the home's batteries are at their lowest ebb near sun-rise. There has been no solar charging since the previous evening, and now it is time to replenish. If the day has a good and clear amount of sun-light, it may be noon when the batteries are up to a level that there is power to share. All of this has to do with the home owners level of consumption, now well they charged the prior day, etc. Some people, who are truly off-grid, have to resort to generator recharging on days with poor insolation.

[tom66]

That is exactly why the batteries should be used only as a grid buffer. Unless the whole house goes off grid, it creates disruption to the grid to sell energy at peak times. So, the battery must be charged by yesterday's sun and discharge in the morning (or, it can discharge in the evening - depends on the grid prices and requirements at each particular moment.)

[mtdoc]

The off grid and "grid tied with battery back-up" market is fairly large - (in the millions worldwide depending on how you count it) - though still puny in relation to the strict grid tied PV market.

Many of those like myself with battery back up systems live places where the grid may be unreliable.

I assume it's those systems (off grid and grid tied with battery back-up) which this will be marketed to first. For a strict grid tied system to implement this, a charge controller and new inverter would be needed as well.

Though I think in the long term decentralized electricity production and energy storage will be the norm (decades from now), I do not see there being large conversion of strict grid tie systems (or new systems) to battery back up or off grid anytime soon.

In the off-grid and battery back up system world - LiFePO4 are just now beginning to be used instead of traditional Lead-acid batteries.  At this point it's still a DYI kind of market where only those with the technical knowledge are making the switch.  It makes sense that Tesla, with their new battery factory in the works, would take advantage of another market in which to sell their batteries.

[free_electron]

A problem is that Lithium-Ion is a name for a collection of different technologies. The Tesla battery is one of these technologies and heavily tuned and conditioned.  The current battery pack for the car has 8 years warranty UNLIMITED miles. There are known cases where people cycle the entire pack every single day. All 85 Kilowatt/hours of it. They have been doing that for 2 years without degradation.

So careful when doing calculations based on cycles and or lifespan... Apples <> oranges. They are both round , but that is where similarities end.

[EEVblog]

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.
Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

[nctnico]

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.
Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

Still it would require a massive change in how electricity is generated because the power plants which are operating now aren't designed for widely varying loads. Guess who is going to pay for that. Not using the grid is going to make other people pay through the nose for their electricity.

[ludzinc]

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.
Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

An interesting exercise - What would be cheaper in the long run:

Solar charging the battery, using the power at night

or

Off-peak charging the battery, using the power in peak times...

[free_electron]

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.
Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

Still it would require a massive change in how electricity is generated because the power plants which are operating now aren't designed for widely varying loads. Guess who is going to pay for that. Not using the grid is going to make other people pay through the nose for their electricity.

What about the opposite scenario : the times the grid can't cope and slams shut. Having a bunch of people that have their own 'mini plant' and be able to feed power into the localized grid would take the strain of the big grid.

Want examples ? Every year, during summer in the US, we have rolling outages in multiple states. Because all the people's AC are running and the power use is so high the grid cannot cope.
I want my cool air in the summer ! People from Europe may not perceive that as a problem as very few people there have AC. Go live in Texas or the Aussie outback and this changes very quickly.

Want another case ? Have you been following the Belgium news lately ? They have a massive problem with 'the grid'. They got two of the nuclear plants shut down because of cracks in the reactor vessel. Both reactors are condemned. Of the three remaining ones, one was deliberately sabotaged by draining the oil out of the turbine and the other two are 40+ years old and have cracks in them as well, although not as bad as the other two that are permanently down. They will never power up again.

The private owner of the grid has been lacking in maintenance to the point they installed a complete new mains feed (400 kilovolt) all the way to the dutch border so they can tap into the grid there. Small detail: the last 1000 meters of the cable is missing because of territorial dispute. Stupidity and short shortsightedness like that sets a whole country in the dark...

Go read up on the news. The parliament and ministers had to come up with 'the big shutoff plan'. In case of power problems during the upcoming summer they will shut off certain cities and towns in a rolling wave. Each town will see its power cut for up to 2 hours a day. They are faced with this massive problem and the best they can come up with is: we'll plunge people back into the stone age.. Be happy o plebeians. You can huddle up under a blanket next to the fire, like in good old times. It will be cozy. 

What is this  ? The 21st century ?
Capital of Europe. In the dark ages, yes.

[eas]

A lot of chasing red herrings in this thread. The technical arguments are kind of beside the point.

People don't buy a Tesla over a Camry today because of the break-even on charging with electricity instead of gas. People buy it because they can afford it, and after that, some combination of other factors, including amenities, outward expressions of identity, curiosity, appreciation of the engineering, a huge crush on Elon Musk, etc.

The purchase of one of these home batteries at the present day and time is going to be similar.

Now, back to more of the economic/engineering point of view.

I recently talked to someone with decades of experience in electrical utilities, much of it focused on addressing peak load scenarios as part of research into my own project to try and bootstrap a business in Lithium Ion battery reuse. Long story short, there is a market for this.

The paradox here couldn't have been bigger. The grid works on the network effect: the more people using it, the more attractive it is for more people to use it.
Unfortunately, the inverse is also true - as more and more people live off the grid, the less and less attractive it is for those to remain on the grid. If living off the grid becomes wide spread (I don't think it will be for a large portion of the society), grid will fail to exist.

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

Still it would require a massive change in how electricity is generated because the power plants which are operating now aren't designed for widely varying loads. Guess who is going to pay for that. Not using the grid is going to make other people pay through the nose for their electricity.

Keep in mind that residential use is less than half of total electricity consumption in the US, and probably other developed countries. And while some people think they want to be "off-grid" the person you are replying to (Dave) has no such plans.

You are also oversimplifying. A portion of power generation is designed for base load service. Such plants aren't designed for widely varying loads, but they tend to be designed for fuel efficiency, because they are operating at or near full load constantly. Utilities have to turn to other methods for that. Gas turbines powered with natural gas are popular for peak demand, because they can be spun up quickly. However, because their duty cycle is probably at best 20% or so, they need to be relatively cheap, and efficiency is traded for cost.

Against this reality, grid-tied solar with battery banks that someone else is paying for are going to get the attention of the power industry, if they don't have it already. Utilities would be happy to tap battery capacity during peak demand, and, in the net-metering regimes in the US, at least, they can pay it back with off-peak power. They have already dabbled in signing up institutional entities (hospitals, manufacturers, datacenters) who maintain backup generators for high-availability to provide power back to the grid in peak-load situations.

Oh, and for what it is worth, Elon Musk is chairman of the board at Solar City, which has built a nice business financing and installing residential solar. I'm sure they'll be an important sales channel for the Tesla home packs, and will be able to aggregate a lot of residential customers when negotiating with the local electric utility to provide peak demand service.

[tom66]

An interesting exercise - What would be cheaper in the long run:

Solar charging the battery, using the power at night

or

Off-peak charging the battery, using the power in peak times...

Almost certainly solar, unless your payback time for a typical system is more than the expected cycle life of the battery pack.

[dannyf]

grid-tied solar with battery banks that someone else is paying for are going to get the attention of the power industry, if they don't have it already.

Not sure about utilities but I am sure sometime down the road, if this becomes popular, your fire chief would want to know if you have such a contraption at home before sending their guys in.

I don't see this as a viable large scale solution to peak demand - if it is, it will be a raw deal for consumers with such capabilities.

I do, however, see this as a viable backup system, to replace (small) power generators used at homes for backup. Rather than using a 5kw gas generator, you can get this one that's always fully charged and ready to roll.

However, you just have to limp.

[tom66]

People already have hybrids (including Li-Ion PHEV) and pure EVs parked in their garages and I don't see any significant additional concerns arising from a separate battery pack. Lithium ion batteries do like to burn, but they're comparably safe compared to something like a petrol tank which could easily cause an explosion if there's a nearby fire.

[MacAttak]

Houses in the US (and I presume many other 1st-world countries) are generally made from wood and contain many ultra-flammable materials such as bedding, carpeting, draperies, furniture, etc. They also typically have natural gas piped in and a few hundred amps of electrical service ready to contribute to a blaze.

Those are going to be more of an urgent consideration to the fire chief than the intumescent-filled box of Li-Ion cells on the garage wall.

[AG6QR]

If you need batteries at home, why not lead-acid?

I know that Li-ion has much better energy density, both as measured in Joules per unit weight, and Joules per unit volume.  And those are both important factors for transportation applications and other portable uses.  But for something that is stationary, energy density isn't quite so critical.  Life cycle cost, safety, simplicity, and maintainability become much more important.

Lead acid is a very mature technology, with lots of competitive suppliers producing 6V or 12V batteries in fairly standard sizes, so you can be confident it'll be very easy to recycle and replace batteries when the time comes.  Charging algorithms are simple.  There is a potential problem with hydrogen outgassing, but it's well understood and easy enough to avoid and/or mitigate.

I look at the issues Boeing has had with the Lithium batteries in the 787, and while I understand the premium they placed on compact size and light weight for that application, I really don't think I want to make the same tradeoff for my own stationary home.

[ttt]

I'd love one of these and wouldn't want to live off the grid.
It could be used to store excess energy during the day and then power stuff at night, with the grid as the backup.
At present we can't use all the power we generate during the day.

Still it would require a massive change in how electricity is generated because the power plants which are operating now aren't designed for widely varying loads. Guess who is going to pay for that. Not using the grid is going to make other people pay through the nose for their electricity.

The writing on the wall, at least here in California, is that everyone will have to be connected to the grid no matter what and pay a base fee for maintenance and upgrading of the grid. The city can enforce this through their inspection process and fines. Another option would be to include the costs of the grid into the property tax. I already pay extra local fees for some school stuff.

Personally I don't think this a problem as long as I am allowed to run off my solar panels and batteries when the grid is down. Which my city currently does not allow, apparently for safety reasons. I am not allowed to install batteries either.

[tom66]

If you need batteries at home, why not lead-acid?

By far and away lead acid is extremely cost effective and, at least for the time being makes sense for most home backup solutions that are used infrequently.

However, lead acid is particularly bad when cycled, and under high discharge loads. Most cells are only rated around 1/10 to 1/20C for the rated capacity. It's reasonable to expect a home system to draw ~5kW from a backup bank, but to do that you'll need at least 5-10kWh to get reasonable runtimes (due to the Peukert effect.)

The cost difference will likely shrink rapidly when we see old EV batteries being scrapped in 10-15 years time when they are no longer useful for 100kW discharges, but can still support ~10kW for much longer.

[cosmicray]

If you need batteries at home, why not lead-acid?

Lead-acid is somewhere between fully mature and hobbyist. Unless you use a qualified installer, FLA is somewhat less than plug-n-play. All the pieces are there, but  finding the correct combination, for your specific needs and solar insolation can be daunting. What advice is perfectly valid in one location, may be less so somewhere else. Grid power, OTOH, is so fully mature, that it is a no-brainer. I's like to see RE advance to the plug-n-play status.