Tesla to sell battery packs for home use - Page 1
Forum section: electronics / general

author: Rory
author_rank: Frequent Contributor
timestamp: February 16, 2015, 03:45:58 am
content: 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

author: miguelvp
author_rank: Super Contributor
timestamp: February 16, 2015, 03:57:20 am
content: Wall mounted, I hope people don't put nails on it to hang picturesOf course they wouldn't do that right?I think it's a great idea, we will have to see what the price is first

author: dannyf
author_rank: Super Contributor
timestamp: February 16, 2015, 12:21:15 pm
content: 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.

author: tom66
author_rank: Super Contributor
timestamp: February 16, 2015, 12:59:13 pm
content: 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 theduck 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?Quote from: dannyf on February 16, 2015, 12:21:15 pmI have a problem with this statement.http://www.transportation.anl.gov/pdfs/B/855.PDF(page 5, paragraph 2)QuoteThe 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#post908698From 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.

author: johansen
author_rank: Super Contributor
timestamp: February 16, 2015, 09:59:43 pm
content: 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.

author: rx8pilot
author_rank: Super Contributor
timestamp: February 16, 2015, 10:14:44 pm
content: 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.

author: tom66
author_rank: Super Contributor
timestamp: February 16, 2015, 10:24:11 pm
content: Quote from: rx8pilot on February 16, 2015, 10:14:44 pmEr, 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.Quote from: johansen on February 16, 2015, 09:59:43 pmIt'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.svgIf 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.

author: dannyf
author_rank: Super Contributor
timestamp: February 16, 2015, 11:00:00 pm
content: QuoteShort-term is exactly what those guys are all about. They aren't capable of looking more than a couple steps ahead.

author: cosmicray
author_rank: Frequent Contributor
timestamp: February 16, 2015, 11:28:22 pm
content: Quote from: tom66 on February 16, 2015, 10:24:11 pmOther 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.

author: tom66
author_rank: Super Contributor
timestamp: February 16, 2015, 11:39:06 pm
content: 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.)

author: mtdoc
author_rank: Super Contributor
timestamp: February 16, 2015, 11:51:42 pm
content: 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.

author: free_electron
author_rank: Super Contributor
timestamp: February 17, 2015, 12:18:15 am
content: 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.

author: EEVblog
author_rank: Unknown
timestamp: February 17, 2015, 12:39:50 am
content: Quote from: dannyf on February 16, 2015, 12:21:15 pmI'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.

author: nctnico
author_rank: Super Contributor
timestamp: February 17, 2015, 02:17:28 am
content: Quote from: EEVblog on February 17, 2015, 12:39:50 amStill 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.

author: ludzinc
author_rank: Unknown
timestamp: February 17, 2015, 02:25:45 am
content: Quote from: EEVblog on February 17, 2015, 12:39:50 amAn interesting exercise - What would be cheaper in the long run:Solar charging the battery, using the power at nightorOff-peak charging the battery, using the power in peak times...

author: free_electron
author_rank: Super Contributor
timestamp: February 17, 2015, 03:51:46 am
content: Quote from: nctnico on February 17, 2015, 02:17:28 amWhat 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.

author: eas
author_rank: Frequent Contributor
timestamp: February 17, 2015, 08:42:13 am
content: 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.Quote from: nctnico on February 17, 2015, 02:17:28 amKeep 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.

author: tom66
author_rank: Super Contributor
timestamp: February 17, 2015, 11:45:54 am
content: Quote from: ludzinc on February 17, 2015, 02:25:45 amAlmost certainly solar, unless your payback time for a typical system is more than the expected cycle life of the battery pack.

author: dannyf
author_rank: Super Contributor
timestamp: February 17, 2015, 12:10:45 pm
content: QuoteNot 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.

author: tom66
author_rank: Super Contributor
timestamp: February 17, 2015, 01:25:34 pm
content: 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.

author: MacAttak
author_rank: Unknown
timestamp: February 17, 2015, 08:49:24 pm
content: Houses in the US (and I presume many other 1st-world countries) are generally made fromwoodand 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.

author: AG6QR
author_rank: Frequent Contributor
timestamp: February 17, 2015, 09:32:31 pm
content: 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.

author: ttt
author_rank: Regular Contributor
timestamp: February 17, 2015, 10:12:59 pm
content: Quote from: nctnico on February 17, 2015, 02:17:28 amThe 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.

author: tom66
author_rank: Super Contributor
timestamp: February 17, 2015, 11:15:18 pm
content: Quote from: AG6QR on February 17, 2015, 09:32:31 pmBy 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.

author: cosmicray
author_rank: Frequent Contributor
timestamp: February 18, 2015, 03:38:01 am
content: Quote from: AG6QR on February 17, 2015, 09:32:31 pmLead-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.

author: mtdoc
author_rank: Super Contributor
timestamp: February 18, 2015, 06:56:00 am
content: Quote from: AG6QR on February 17, 2015, 09:32:31 pmShorter lifespan, lower charge efficiency and higher maintenance.

author: dannyf
author_rank: Super Contributor
timestamp: February 18, 2015, 11:56:29 am
content: QuoteOr metal-air (Fe-air or Zinc-air for example).

author: nctnico
author_rank: Super Contributor
timestamp: February 18, 2015, 12:09:48 pm
content: Quote from: free_electron on February 17, 2015, 03:51:46 amThe lesson to be learned here is that critical parts of the infrastructure of a country should not be 100% privatised. That is an entirely different problem and does not get solved by people having their own batteries. Besides that in most cases the DC-to-AC inverters won't even start without mains applied.Oh, and having AC is getting popular in the EU as well.

author: nctnico
author_rank: Super Contributor
timestamp: February 18, 2015, 12:28:59 pm
content: Quote from: MacAttak on February 17, 2015, 08:49:24 pmIn the EU most houses are made from brick/concrete (including the inner walls). Wooden houses are 'for the poor' so to say. But they do contain lots of stuff like furniture, carpets, etc which will burn. Also the electrical feed isn't that big; usually a few tens of amps 3 phase or single phase (which each circuit protected by a 16A fuse).

author: tom66
author_rank: Super Contributor
timestamp: February 18, 2015, 12:49:39 pm
content: Quote from: nctnico on February 18, 2015, 12:28:59 pmIn the UK most houses have a 100A feed, single phase. Even my father's tiny bungalow has a 63A single phase supply. Three phase is comparatively rare in the UK, I'm not sure why, as it would make a lot of sense for cookers and showers (our shower pulls 30A on one phase.)

author: nctnico
author_rank: Super Contributor
timestamp: February 18, 2015, 06:09:34 pm
content: I guess in the UK using electricity for hot water and heating is more common than in the NL.

author: Monkeh
author_rank: Super Contributor
timestamp: February 18, 2015, 06:11:17 pm
content: Quote from: nctnico on February 18, 2015, 06:09:34 pmNot that common. Only in areas without gas or for cheapskates who don't realise electric showers cost them more in the long run.

author: SeanB
author_rank: Super Contributor
timestamp: February 18, 2015, 06:27:23 pm
content: I changed to gas for cooking and water heating, mostly due to having Eskom power, mostly intermittently. Gas is at least quicker for cooking, and more importantly I can cook when load shedding is on, along with being able to make a cuppa as well.

author: tom66
author_rank: Super Contributor
timestamp: February 18, 2015, 06:45:15 pm
content: Quote from: nctnico on February 18, 2015, 06:09:34 pmMany houses have electric showers here. Luckily we have a gas powered shower in the basement. (Well, boiler uses gas and it runs on hot water.) It's quite good. The second floor has an electric one because the water pressure isn't high enough to make one usable that high.A lot of houses also have emergency electric heating ("immersion heater") for the water, which is used in cases where there the gas meter has run out.

author: ttt
author_rank: Regular Contributor
timestamp: February 18, 2015, 08:48:17 pm
content: Quote from: nctnico on February 18, 2015, 12:28:59 pm"So to say" :-) Rich people don't have the choice to build using bricks either. New houses made from (unreinforced) brick have been illegal in California since 1933 as survivability in these structures during earthquakes is much lower, also see what happened in Haiti and Italy in recent years. Cost is of course also a factor. Reinforced brick based structures (I include 'modern' grey concrete bricks here) turn out to be more expensive than just building the whole thing using reinforced concrete which is now much more common in California, at least with multistory buildings. Areas with tornado risk in the US have similar rules, though getting impaled by flying 2x4s is no fun either.That said the biggest risk for fires in California is as always blatant code violation and lack of enforcement. When I bought my house a couple of years ago I had to deal with fabric insulated electrical lines from 1925. The copper wires close to the outlets snapped by just looking at it funny it was so brittle. No grounding anywhere. And literally a 50/50 chance of line vs neutral being correctly wired :-(

author: free_electron
author_rank: Super Contributor
timestamp: February 18, 2015, 09:20:21 pm
content: last week i had to deal with a family of tree squirrels that made a love nest in my attic. they had been feasting on my ROMEX wires... causing a massive short circuit. Anyone for grilled squirrel ?I had the electrician replace it all with corrugated aluminum cable (copper wires inside) . Let them bite through that. Bloody vermin.Any squirrel i encounter crossing the street from now on, and i have the chance, will go from being a three dimensional lifeform to something resembling a two dimensional object. My car weigh 4700 pounds without me in it. we'll see who will win.

author: eas
author_rank: Frequent Contributor
timestamp: February 18, 2015, 09:23:45 pm
content: Quote from: mojo-chan on February 18, 2015, 10:35:14 amNo argument that EVs can be both practical and financially viable. My point is simply that a huge part of the market for Tesla cars are buying based on something other than a basic cost-benefit analysis. I'm pretty sure that most of the Teslas I see in Seattle aren't doing enough miles to justify their cost based on energy savings, unless you compare them against a "mid-range" Mercedes or BMW. Even in cases where buying Tesla pencils out on lifecycle costs alone, the Leaf may still be more attractive (though the Tesla's resale value probably complicates the picture).Similarly, I expect that there will be a significant market for the Tesla home packs among "conspicuous conservers" who are buying for reasons other than basic economics.

author: eas
author_rank: Frequent Contributor
timestamp: February 18, 2015, 09:30:21 pm
content: Quote from: ttt on February 18, 2015, 08:48:17 pmWell, that, and the fact that the ecosystem of the southern part of the state isborn to burn(link to a great chapter from a great book by John McPhee on major ongoing battles in the battle between humans and the rest of nature, it also features the epic struggle against the Mississippi river, and an Icelandic volcano).

author: zapta
author_rank: Super Contributor
timestamp: February 18, 2015, 11:21:06 pm
content: Quote from: mojo-chan on February 18, 2015, 05:05:50 pmThis calls for a smart multi car charger that assigns charge based on availability and driving patterns and state of each car. Or at least a planner/scheduler that coordinates between chargers and other loads. It's a workaround but may still be useful.

author: tom66
author_rank: Super Contributor
timestamp: February 19, 2015, 12:20:13 am
content: Quote from: eas on February 18, 2015, 09:23:45 pmLike the first gen Prius, having a Tesla is as much a status symbol as it is being green. I don't have a problem with it - whatever floats their boat - if it's beneficial for everyone in the end.In some ways a Tesla is a downgrade on BMW/Mercedes: interior is a little spartan, and apparently the ride performance isn't as good. Reliability is also so-so, on the earlier models at least, although Tesla has been very proactive to fix issues. But, what's interesting is how successful Tesla has been despite the fact that they weren't able to get it near competitor quality on the luxury side of things. It shows how big the EV market -could- be, if manufacturers were just prepared to take (an admittedly big) risk and develop the technology properly, not make some half-arsed compliance car.I honestly could see this doing a lot of damage to Toyota/Honda, if they don't react quick enough to the market shift that may occur in 2017/2018 when GM's Bolt & Tesla's Model 3 get released. They're pushing fuel cell EVs but pretty much anyone involved in the auto biz knows they're ridiculously impractical. Lots more needs to be sorted out before they'll work properly. They're using them only as good PR, sold in limited units, on restricted leases... "The Power of Dreams"... you really do have to dream hard to get a FCEV to work in the real world!

author: mtdoc
author_rank: Super Contributor
timestamp: February 19, 2015, 12:35:08 am
content: As far as lack of wood frame construction in Europe, I think it has a lot to do with the historical deforestation. Wood is a great building material but it does not last as long as stone (as long as earthquakes are not an issue as is true in Europe).Over the centuries as wood structures rotted or burned down they were replaced by stone structures since wood was less available due to deforestation. Stone structure stay around unless destroyed by earthquake or humans (bombs!).It was a real revelation from my time in Europe to see many people living in centuries old stone buildings. In the US the few old stone buildings are generally public works (cathedrals, courthouses, etc) and not homes.It is much more expensive to build with stone (which may have something to do with the smaller average home size in Europe).I spent some time working with a stonemason in England - you just don't find those kind of stone craftsmen commonly in the U.S.

author: miguelvp
author_rank: Super Contributor
timestamp: February 19, 2015, 01:50:43 am
content: Quote from: mtdoc on February 19, 2015, 12:35:08 amA lot of old houses and even those stone ones have wood frame support, but the difference is that they used old beech and oak trees for the support columns and roof. Those trees where cut at a given time in the year at a certain moon phase when the tree was getting ready for winter or something like that, that had natural defenses against rot. Not sure if they were treated as well, this was done after centuries of observation and now it's probably a lost knowledge.Those old big support beans are as strong now as they were centuries ago. Same deal with old fishermen boats. But those old traditions and ways to do things are a thing of the past since no one now is going to wait a whole year to harvest trees at the right time since now we can treat them against weather, but still the old forgotten method seems to yield better results.

author: nctnico
author_rank: Super Contributor
timestamp: February 19, 2015, 07:15:34 pm
content: Quote from: mtdoc on February 19, 2015, 12:35:08 amIt depends a bit on where you are. In the UK for example it is easy to find stones to build houses from; stones where/are the cheapest building material. In the NL and surrounding low lands stone is very hard to find (try to find stones in a swamp!) so stones house became a status symbol. In some cases people had the front of the house made of brick while the rest was wood. It surfaces in the language as well: in the UK they say 'stone broke' to a poor person in the NL we say 'stone rich' for a wealthy person.

author: Luap2
author_rank: Contributor
timestamp: February 19, 2015, 07:27:24 pm
content: http://www.aquionenergy.com/Is this the new /next gen storage battery for stationary usage ?

author: free_electron
author_rank: Super Contributor
timestamp: February 19, 2015, 07:53:51 pm
content: Quote from: tom66 on February 19, 2015, 12:20:13 amPlus, it's so much fun to take the piss out of the testosterone pumped petrolheads at the traffic light with their posh TT's , A8's ,M series and AMG's. 'Look at the guy with the foodblender' they scoff...And then their jaw hits their steering wheel when the 'foodblender' rockets forward and hits the 60mph point after a mere 3 seconds. It kinda hurts their ego when the 'soupmixers' leaves them behind in an electromagnetic field .Then they go : Shit, we paid more for our hi-end 'explosion motor' relics than that cuisinart costs and we just got handed our driveshaft, gearbox and tailpipe.It never gets old. I do it at least once a day. Gives me a warm fuzzy feeling.

author: eas
author_rank: Frequent Contributor
timestamp: February 19, 2015, 08:22:32 pm
content: Just in case anyone else was misled by that blog post at the start of the thread, the pictured battery pack is from a Nissan Leaf. Indeed, if you look to the far left, you can see the Nissan logo. Also, the file name.I thought it was odd that Tesla would be packing their home batteries like the batteries in a Leaf, but didn't have a chance to dig further until now.

author: zapta
author_rank: Super Contributor
timestamp: February 20, 2015, 01:45:54 pm
content: Quote from: mojo-chan on February 19, 2015, 04:26:05 pmThat's very basic, like recording TV shows using the VCR's timer. Compare this with a modern DVR that has knowledge of the TV guide and your preferences and can make smart scheduling.

author: tom66
author_rank: Super Contributor
timestamp: February 20, 2015, 01:57:55 pm
content: Quote from: zapta on February 20, 2015, 01:45:54 pmTesla's got something like this called "smart preconditioning" where the car will notice you usually use a specific temperature/ac setting/fan setting/etc for your morning commute and automatically do that every morning. I expect they'll do the same for charging soon, maybe if suppliers start offering more fine-grained demand pricing (on say ~15min intervals) Tesla could use a network of cars as arbitrage, transferring energy between the grid and car as and where it is required.

author: eneuro
author_rank: Super Contributor
timestamp: February 22, 2015, 06:26:57 pm
content: Future energy storage might look different and winner might be not TeslaIsn't it simple?And something for home grid without bloody chemistry and flamable Lithium at house

author: EK701
author_rank: Contributor
timestamp: February 22, 2015, 07:47:11 pm
content: Quote from: eneuro on February 22, 2015, 06:26:57 pmYou probably won't want to be around that during an earthquake...

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 09:35:12 pm
content: I do live offgrid and I do use Lithium for energy storage.I'm also the developer of the Solar BMS a solar charge controller for Lithium (any type but I recommend LiFePO4)That Tesla battery seems to be large enough is 10x the capacity of my main battery (but I'm more in to high energy efficiency than most people)Form what I see in the photo they use the same or similar battery used in Nissan Leaf there are 4 cells in each of those metal box connected 2s2p 30Ah each cell for a total of 8.4V (fully charged) 60Ah that is around 0.5kWh and I see about 50pcs in that also see a 24 something on the other side so most probably 24kWh capacity.My OffGrid battery is 10x less at just 2.5kWh and together with 3x 240W PV panels allow me 60 to 90kWh/month power consumption (good enough for me) but most people use up to 10x that so the Testla battery seems adequate capacity.Here is a photo with my OffGrid Setup and a 7 day energy production / consumption graph.

author: dannyf
author_rank: Super Contributor
timestamp: February 22, 2015, 11:06:22 pm
content: You guys are so not green.Here are my energy storage devices: I chop two or three of them down each year and no need for all of your fancy stuff.It is renewable, clean and most of all, greenest of the green energy your green dollars can possibly buy.

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 11:29:42 pm
content: Quote from: dannyf on February 22, 2015, 11:06:22 pmCan you prove that ? Also how did you post this message based on that energy source ?

author: johansen
author_rank: Super Contributor
timestamp: February 23, 2015, 12:59:21 am
content: Quote from: electrodacus on February 22, 2015, 11:29:42 pmits amazing, even harvard scientists don't know that trees are not carbon sinks.

author: miguelvp
author_rank: Super Contributor
timestamp: February 23, 2015, 01:10:14 am
content: Energy from trees are considered zero emission because it's not trapped carbon.And Harvard scientists know that.

author: RJFreeman
author_rank: Regular Contributor
timestamp: February 23, 2015, 02:05:31 am
content: The graph below (hopefully) shows NSW power consumption 1st to 9th February 2011 (data from AEMO -http://www.aemo.com.au/)these dates are interesting because we had a cool change on the 6th and it clearly shows the difference in power consumption between hot days and much cooler days.The interesting thing is that power demand (on hotter days) peaks around 3:00pm whereas I understand Solar power generation peaks a couple of hours earlier (this does seem to be supported by the graph from Electrodacus) so a couple of hours storage would help smooth that out.now while as consumers we pay a fixed price for power AEMO determine pricing throughout the day and this price (per MWh) can vary between around $20 (at night when demand is lowest) and $2000 (when demand is around 14GW) so even if you just added a battery in theory you could buy power at 2C/kWh then store it to sell back at peak times on hot days at $2 per KWH and if you are a data geek you can find current and projected pricing at:http://www.aemo.com.au/Electricity/Data/Price-and-Demand/Price-and-Demand-Graphs/Current-Trading-Interval-Price-and-Demand-Graph-NSW

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 02:49:22 am
content: Quote from: RJFreeman on February 23, 2015, 02:05:31 amNot sure I get where you fount that $20/MWh to $2000/MWh ?I can only see there a 3:1 fluctuation on price not 100:1.

author: RJFreeman
author_rank: Regular Contributor
timestamp: February 23, 2015, 03:07:31 am
content: Quote from: electrodacus on February 23, 2015, 02:49:22 amthe price starts climbing significantly once power consumption goes over 11-12GW, and over 13.5 GW it climbs even more steeply, while recent power consumption has been a leisurely 9GW or so peak (it has been humid, but not really hot in NSW).So you do need to look further back to see where it peaks for example if you pull the CSV for NSW from Feb 2011 from say:http://www.aemo.com.au/Electricity/Data/Price-and-Demand/Aggregated-Price-and-Demand-Data-Files/Aggregated-Price-and-Demand-2011-to-2015#2011you can see where power prices really hit their peak on 1/02/2011 the price hits $5039.89 at 13:30, and by the time power consumption hits 14.525GW at 16:00 the price is at $12,136.so you need a good hot summer to earn the serious money (and of course by then keeping your batteries cool may be an issue)

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 03:29:12 am
content: Quote from: RJFreeman on February 23, 2015, 03:07:31 amI see what you mean but it seems extreme not sure what was the problem there. You can actually produce energy with about 3 cent/kWh from PV panels and the LiFePO4 storage cost around 20cent/kWh all this do not include cables controller inverters support is just the cost of amortisation for 1$/Watt PV over 25 years considering you can actually use all that energy and LiFePO4 battery storage varies from manufacturer to manufacturer it can be as low as 8cent/kWh stored over the life of the battery up to 25cent/kWh so it depends on how optimist is the manufacturer with the spec. I think 20cent/kWh is reasonable in my experience and knowledge about LiFePO4.Here in Saskatchewan Canada electricity to consumer is sold at a fix rate It was about 11 cent/kWh about two years ago before moving offgrid but total bill is higher with some fixed costs so if you divided the monthly bill to kWh was about 20cent/kWh Canadian dollar but at the moment about the same value as Australian.There are provinces with even lower cost of electricity in fact significantly lower.I will expect price for electricity to drop and not rise in the future. Price of grid power was not my reason for moving OffGrid.For me the amortisation cost will probably be the same as I paid when I had grid power but is not as convenient since you need to manage power consumption in a more active way.Here is a link with electricity cost in Canada is quite small especially in some locationshttps://www.hydro.mb.ca/regulatory_affairs/energy_rates/electricity/utility_rate_comp.shtml

author: RJFreeman
author_rank: Regular Contributor
timestamp: February 23, 2015, 04:23:08 am
content: In NSW as a consumer we buy at a fixed rate, but not as cheap as that. either around 26c per KWH (without time of day metering) or if we move to time of day metering there are 3 different rates:Peak - (2pm to 8pm, Monday to Friday) = 51.8C /KWHShoulder - (7am to 2pm and 8pm to 10pm Monday to Friday, 7am & 10pm Saturday/Sunday and Public Holidays) = 20.4c/KWHoff peak - ( 10pm to 7am, Monday to Sunday) = 11.2c/KWH(https://secure.energyaustralia.com.au/EnergyPriceFactSheets/Docs/EPFS/E_R_N_RSOT-E_EA_01-01-2015.pdf)Solar power we currently get paid 9c per KWH for excess power fed back into the grid (so if you use it you can save 20.4 to 51.8C but if you aren't at home during the day and feed pretty well all that power back into the grid you only get 9c)The other prices are what the power generating companies get paid by the distributors and I am being overly generous in presuming that a small scale generator would be able to get those sort of rates.....The power grid in NSW is mostly coal fired power stations, with about 4GWof Hydro available from the snowy mountains scheme, but I am not sure what transmission losses from there are (I would be guessing fairly high) - some of the dams in the snowy mountains scheme are used for energy storage in that they pump water back up hill during the night. The snowy mountains scheme is also shared with (and closer to) Victoria so I am also not sure how much of that 4GW we would be getting on hot days anyway.Power is also shared to some extent with other states and I am guessing that hotter days they just start firing up the brown coal stations and bugger the expense but as my earlier graph showed, on cooler days power demand plateaus around 9-10GW while peak on hotter days exceeds 14GW and it seems that last extra GW or so, is the really really expensive bit....

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 05:04:35 am
content: Quote from: RJFreeman on February 23, 2015, 04:23:08 amThanks for the overview. As expected those peaks are so occasional that is worth paying much more for them. Not sure there is any advantage to the 3 rates for most people over the fix rate but is an advantage for the energy suppliers since it encourages the use of less energy in the peak periods.I think people should integrate more thermal mass in buildings and use solar PV directly to cool the house. But I'm relay getting off topic here.That Tesla battery has the right capacity for heavy users ( 800 to 1000kWh/month) but not sure if that battery is economical based on cost. If is the same battery in Leaf then that will degrade fast in high temperatures.Maybe they will only charge each cell to only 4V so that it will last much longer at reduced capacity since energy density is not important in stationary applications and thus having a better amortisation cost.But since people are not educated they will prefer a battery rated at 20% higher capacity and wont know to care about the fact that it last 4x less.

author: RJFreeman
author_rank: Regular Contributor
timestamp: February 23, 2015, 05:28:44 am
content: Quote from: electrodacus on February 23, 2015, 05:04:35 amoddly the fixed rate seems to have come down relative to peak time of day pricing, 4 years ago (2010) it was:18.8 cents per KWH for the first 2,500 KWH (per quarter) then 26.62 cents per KWH.while the time of day pricing was:Shoulder 18.48 cents per KWHPeak 31.68 cents per KWHoff peak 9.46 cents per KWHso it was between 60 and 84% of peak pricing, but is now about 50% of peak time of day pricing?probably the biggest power consumer in NSW is cooling in summer, heating in winter is mostly only a concern at night (below 20C is a cold day here), when other power consumption is dropping off anyway. and cooling is mostly required when solar energy is available.....

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 06:22:40 am
content: Quote from: RJFreeman on February 23, 2015, 05:28:44 amIt was -33C last night in here luckily is easier to heat than to cool. I will to the heating with PV electric in the near future.

author: miguelvp
author_rank: Super Contributor
timestamp: February 23, 2015, 06:42:40 am
content: Hasn't been to bad here in Chicago this year, I think the lowest has been is -8F (-22C) in a 100 year old house, but nothing like last year that we had Highs below 0F (-18C)natural gas heat our water radiators just fineRight now it's a toasty 4F (-16C) and it seems we are going to break the 32F (0C) by next week, time to wear t-shirts again

author: eneuro
author_rank: Super Contributor
timestamp: February 23, 2015, 08:27:59 am
content: Quote from: EK701 on February 22, 2015, 07:47:11 pmDo you mean a few kWh flywheel in the garden a few meters under ground or Tesla flamable Lithium inside your bed room wall inside the house ?

author: tom66
author_rank: Super Contributor
timestamp: February 23, 2015, 10:45:38 am
content: Quote from: dannyf on February 22, 2015, 11:06:22 pmChopping down trees to burn is carbon neutral. Is it sustainable? Maybe, if carefully managed. Still produces pollution but not so much of a problem if kept away from large population areas. In the UK we have a few tree-/bio- fired power stations converted from old coal plants (it's less than 500MW total though)Deforestation has led to increases in net carbon (as well as human emissions), as there are less trees to absorb the carbon. Also don't forget about %CUTE_ANIMAL% that lives in the same area otherwise greenpeace will be after you.

author: eneuro
author_rank: Super Contributor
timestamp: February 23, 2015, 01:34:41 pm
content: Quote from: mojo-chan on February 23, 2015, 10:21:35 amFor PV it might work, but for CSP thermal system more accurate positioning is needed.Anyway decent scientific work prooves this what I've got from Bird Sky Model simulation with my sun tracking software and conclusion from this paperresearchgate.net: Performance comparison of a double-axis sun tracking versus fixed PV systemis:It is calculated that30.79%more PV electricity is obtained in thedouble axis sun-tracking systemwhen compared to the latitude tilt fixed system.Some CSP thermal systems could be useless without sun tracking and while I'm talking abput 3m dish and area of 7m2, so if we get from the sun 500W/m2, we have 3.5kW thermal energy, so 30% less energy means 1kW of lost power.Maybe for very small and unefficient PVs (in comparision to thermal solar systems efficiency), this 30% loss and additional costs for sun tracking mechanical system means that our ROI will not be significant and we can forget about sun tracking unless we haven't got compact mechanical design of solar system

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 05:34:07 pm
content: Quote from: eneuro on February 23, 2015, 01:34:41 pmNot sure you read my answer to this there are many other problems fist is the cost effectiveness of the tracking in any form vs just adding 30% more PV, second for OffGrid you have wasted energy since battery size is limited you do not have the grid to push any excess and third those 30% are an annual average most of that is done in the summer when there is even more excess as you seen from my date 4 to 10% is only done in winter when I will actually need the most and that percentage is just a few $ of additional panels 72$ I think for my 3x 240W PV array.I will be happy to see any method of tracking that cost 72$ for 3x 240W panels and last for 25 years since that is what additional 72$ of PV will do for winter and about 200$ for the entire year but like I mentioned in Offgrid you have excess so producing more with tracking, PV or any other method is normally useless especially in summer.

author: eas
author_rank: Frequent Contributor
timestamp: February 26, 2015, 05:41:05 pm
content: Quote from: electrodacus on February 22, 2015, 09:35:12 pmThanks for your perspective and the details of your system.FYI, the reason it appears to use the same or similar battery as the Nissan Leaf is that some blog used a photo of a Nissan Leaf battery pack (and many others copied them). The photo puzzled me at first, because I assumed that Tesla would be leveraging their 18650 pack technology, and probably be repurposing modules from retired Tesla automotive packs. Once I did some digging, I found that it was a picture of a Leaf pack. Only then did I notice the nissan logo on the left of the photo, and the fact that the filename for the image is something like "nissan leaf battery pack."Tesla has actually been deploying packs to some SolarCity customers for a while now. I don't know what they look like on the inside, but my understanding is that they are ~10kWh, so, smaller than that Leaf pack, but still 4x the size of yours.On the subject of LifePO4, my understanding (from alecture by Dr Jeff Dahn on Why Lithium Batteries Fail) is that aging accelerates rapidly with temp (at least for commercial varieties available a coupel years ago), with obvious differences even at 40C. Do you have temperature control for your packs?

author: eas
author_rank: Frequent Contributor
timestamp: February 26, 2015, 05:42:05 pm
content: Quote from: eas on February 26, 2015, 05:41:05 pm

author: eas
author_rank: Frequent Contributor
timestamp: February 26, 2015, 05:54:39 pm
content: Quote from: tom66 on February 23, 2015, 10:45:38 amBurning biomass is interesting, because depending on how you manage the combustion, you can end up with a significant amount of the original carbon content trapped as charcoal. If you then grind that charcoal up and put it in the ground, rather than burning it for fuel, it will take a very long time before it is returned to the atmosphere, and it provides an excellent soil amendment.There is a big push to provide better cooking stoves for the 1B or so people who still cook over wood or charcoal. The potential benefits are huge, because the existing approach creates a lot of indoor and outdoor air pollution, causes extensive deforestation, and requires families spend more and more time finding fuel. More efficient cleaner burning stoves can bring health improvements, reduce deforestation, and allow kids time to go to school. I'm particularly impressed with the approach Nate Mulchay of Worldstove is taking. His stove designs have a pleasing elegance, and that elegance is matched by the elegance of the manufacturing supply chains and economic networks he's creating to produce stoves and fuel.

author: electrodacus
author_rank: Super Contributor
timestamp: February 26, 2015, 05:55:15 pm
content: Quote from: eas on February 26, 2015, 05:41:05 pmThanks. I did not realised it was a Leaf pack it make sense since is the size (capacity) of an EV pack. I knew Tesla used smaller 18650 cells so I was surprised to see those cells but did no future investigation.I seen that video and normal operation without any significant degradation for LiFePO4 is 0C to 45C for charging and for discharging lower temperatures are no problem.Based on Sony LiFePO4 there is more degradation even in storage at 45C vs 23C for 20 years it was 3% at 23C and about 10% at 45CLiFePO4 is quite different from LiCoO2 variants but Solar BMS supports both even if I recommend LiFePO4 for stationary energy storage.Yes the Solar BMS has an external temperature sensor but I do not use it in my pack. It makes no sense since my Battery is inside the house with ambient range of 15C to 27C and at the charge discharge rates it is used in this sort of applications usually under 0.5C the battery temp raise above ambient is less than 2 or 3C so is well within the normal operating range.

author: electrodacus
author_rank: Super Contributor
timestamp: February 26, 2015, 06:00:24 pm
content: Quote from: eas on February 26, 2015, 05:54:39 pmI was thinking at biomass for my house heating but that was when I designed the house few years ago now the least expensive option is to use solar PV panels for heating so that is what I will be using. Already most of the energy I use is for electric cooking.I do not think biomass is a good idea and can not be used at large scale that will be a disaster with 7B people.