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Tesla Energy

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Re: Tesla Energy

#451

Post by webXL »

jarvist wrote: post #343
Angostura wrote: post #314

Earlier quoted context omitted.

I think I'd want to see an environment impact assessment of manufacturing the batteries.

OK; here's a well cited study from 2010 on electric cars: http://pubs.acs.org/doi/abs/10.1021/es903729a "The share of the total environmental impact of E-mobility caused by the battery (measured in Ecoindicator 99 points) is 15%. The impact caused by the extraction of lithium for the components of the Li-ion battery is less than 2.3% (Ecoindicator 99 points). The major contributor to the environmental burden caused b…

15% and 2.3% didn't really mean much to me without seeing the total composition (chart on page 3). Turns out operation is dominant source of electric vehicles' environmental impact. I guess the operational impact is primarily from electricity generation, which is always going to be cleaner than refining crude oil unless every power plant switches to coal. Compared to internal combustion engine vehicles, the battery impact is much less than the total improvement in operational impact in all 4 impact assessments.

But if the ease of installing these batteries makes home solar panels more attractive, that may offset their impact outside of EV use.

Re: Tesla Energy

#452

Post by [deleted] »

at-fates-hands wrote: post #365
ams6110 wrote: post #345

Earlier quoted context omitted.

I would guess for most people it would show an ROI number that is not conducive to sales. Also, what is the environmental impact of the manufacture of LI batteries at this scale? Lithium mining, processing, assembly, delivery... we can't just ignore that.

I agree. Strangely, all of these issues were conveniently left out of the article. Not sure everybody knows this, but its not economically feasible to recycle these batteries: "Recycled lithium is as much as five times the cost of lithium produced from the least costly brine based process. It is not competitive for recycling companies to extract lithium from slag, or competitive for the OEMs to buy at higher price po…

[deleted]

Re: Tesla Energy

#453

Post by bloaf »

chrisamiller wrote: post #431

A quick analysis of our local (St Louis) rates for an average (1700 sq ft) suburban house indicate that time shifting to get peak rate savings isn't worth it: Payback time on the 10kWh battery would be around 26 years, and on the 7kWh battery would be 33 years. So, at least in the midwest, I think you'd have to be either using a ton of peak energy or coupling the battery pack with solar to make the investment worth i…

Isn't that the idea though? Solar + battery + electric car = no gasoline, electricity, or natural gas bill.

If the average car gasoline bill is $3000/year, electricity is $1000/year, and we demand a 5-year payback, we can spend at most $20,000 on a solar+battery+car system over what we would spend on a conventional gasoline-car and grid-house.

Re: Tesla Energy

#454

Post by rhino369 »

ZoFreX wrote: post #261

This is a three-pronged stroke of genius: 1) Immediate benefits to just about anyone. If you have your own solar panels, you need this (or something like it). Even if you don't, you can benefit by drawing more power during cheaper off-peak times. 2) If lots of people get in on this, we'll have the storage capacity we need on the grid to be more dependent on renewable energy. Lack of storage capacity is one of the big…

1) You don't need this if you have solar. Most states and utilities have pretty favorable subsidies for "selling back" energy to the grid. The utility is credit the feeding back to the grid at 100%. This device will introduce efficiency losses and it is expensive.

Unless you have extreme peak v. non-peak fees, I doubt this will save you money. Even at 20 cent difference, 7kW hours is a 1.40 a day. But that assumes that you could use all 7kW hours at peak times (you probably aren't). Also, you'll lose 10% going form AC-DC, you'll lose 8% on the battery, and you lose 10% going from DC-AC. That is about 25% loss.

2) If lots of people get them, the peak v. non-peak difference will collapse.

Re: Tesla Energy

#455

Post by robot »

I think this is a move that will break the focus rule for a startup. Batteries _and_ cars. There is room for only one.

Re: Tesla Energy

#456

Post by watty »

je_bailey wrote: post #298
watty wrote: post #276

Earlier quoted context omitted.

I don't see how it's immediately beneficial for just about everyone. I currently have a flat rate for kWh and no solar panel... and moving soon. It's not worth the $. In 6 months I'll be renting for a year, still not beneficial. Perhaps in a couple years I can purchase solar, a battery, and an energy system that can automate some demand shedding but we're talking about 1%ers here. In fact, I'd say it's only immediate…

You missed an additional subset of users. I live in an old neighborhood that experiences power outages and fluctuations once or twice a year. This is fantastic and something I will be installing as soon as I can. So older neighborhoods, rural areas with inconsistent power supply. All of these potentially benefit from this.

I actually didn't miss it, I was simply pointing out types of users who don't benefit from it to counter the "beneficial to almost everyone" argument. I realize there are many types of people who will use this product and benefit immensely.

Re: Tesla Energy

#457

Post by geoffharcourt »

danielweber wrote: post #390
geoffharcourt wrote: post #295

Earlier quoted context omitted.

NYC has it now, but I think as generation/fuel prices rise (in the long-term) and utilities get slightly more sophisticated, we're going to see more on-demand pricing as utilities seek to apply the same price changes they pay generators for peak-demand supply to consumers. In a situation where many people were doing load shifting, I think this could even benefit those who aren't doing load shifting themselves (by red…

For each person that load-shifts, it slightly reduces the payoff for the next person to load-shift. In the UK, the peak demand is already in the evening[1], because solar has eaten the cheap lunch during the day (which it was supposed to do, but it means that each additional solar panel is going to have a harder job paying for itself). And the demand difference between low and high is about 30GW to 40GW. [1] http://w…

Great point about marginal benefits of load shifting. I do think we're so far from that reduction being significant at this point that it's worth attempting.

I believe peak demand in most non-industrial areas is already evening, because residential areas tend to have less efficient energy use than commercial spaces due to density, and everyone is home at the same time, often doing energy intensive tasks such as cooking, using the A/C, opening the fridge. I heard from someone at a power company that advertisements during the Super Bowl are a major issue, because everyone opens their fridge and flushes the toilet at the same time, and power supply has to spike for 3 minutes and then return to normal.

Re: Tesla Energy

#458

Post by dpark »

billiam wrote: post #425
ZeroGravitas wrote: post #412

Earlier quoted context omitted.

Your comments on his reasons are clearly counter-factual: Load shifting on a consumer scale has been happening for decades in various places around the world (e.g. cheap nuclear energy at night powering storage heaters) Self-consumption: in a grid increasingly fed by solar power all those peaks hit at the same time and there's been multiple recent news stories about power prices going negative at those peaks. Backup…

Not at all trying to pick a fight. But: >Load shifting on a consumer scale has been happening for decades in various places around the world (e.g. cheap nuclear energy at night powering storage heaters) Sorry, but as a consumer I pay the same rate day and night, and I think most in the US are like me. I personally have no incentive for load-shifting. Why do I need PowerWall? >Self-consumption: in a grid increasingly…

> Sorry, but as a consumer I pay the same rate day and night, and I think most in the US are like me.

Where do you live? I pay the same rate 24 hours/day as well, but I could switch to a plan with different rates if it provided value to me. I suspect most power companies provide the option at this point.

> Okay, but it seems like a pretty expensive way to ride out a few hours of blackout.

Is there actually a cheaper option, aside from sitting in the dark with flashlights and making sure that no one opens the fridge or freezer? If you want to ride out a blackout without basically sitting in the dark, you need either a big battery backup or a generator. My in-laws put in a whole-house generator and I think the total cost was nearer to 30K than 3K. (Edit: Actually, just looked at generators and they seem closer to 3K, so I have no idea why their setup would have cost nearly 30K. Edit2: They probably installed something closer to a 25kW generator, which would explain much of the cost.)

> The economics/policy of electric cars seem much better than home electricity storage, and all the benefits of PowerWall

A battery in my car will spend a large chunk of its time somewhere else. It's in intriguing idea to use the car battery this way, but it means when I take my car out, my backup power is gone. If I have solar panels, it also means my daylight charging is also gone (assuming I'm gone, with my car, during the day). So I think this would be great, but would not obviate most of the value of a home battery.

Re: Tesla Energy

#459

Post by Florin_Andrei »

msandford wrote: post #287
roel_v wrote: post #200

Earlier quoted context omitted.

"and can only provide 2kW output." only 2kW? 2kW is enough to power any residential, single-family house for 95-98% of the time; you only need (a little bit) more than that at very short (few minutes) peak intervals - when heating up an oven, or some cycles of doing laundry. A second unit would provide that headroom, and otherwise (when the extra $5k for a second unit is prohibitive) you could still draw from the gri…

> only 2kW? 2kW is enough to power any residential, single-family house for 95-98% of the time You obviously don't live where it's hot. I live in Houston, TX and while I rarely run the A/C right now, in another month it's going to run on average 15 minutes per hour, every hour, for 3-4 months straight. Highs in the low 90s to high 100s and lows in the 80s (F). I have 2.5 tons of A/C which is pretty moderate. The cond…

> You obviously don't live where it's hot.

It's a really strange paradox that, in places where it gets very hot during the day, we're drawing tons and tons of energy from the grid to cool the house precisely at the time of the day when even more energy is pouring down on us freely from the skies.

Seriously, A/C is basically Universe's most heavy-handed hint that we should use more solar.

Re: Tesla Energy

#460

Post by Florin_Andrei »

Animats wrote: post #195

The wall mount surprised me, but 10KWh at the same density as the Model S battery should be only 155lb. That's not too bad, although you need a solid connection to the building structure. Having it above floor level is a good thing, since it won't be shorted out by minor flooding. If you get a new solar installation, installing one of these seems an obvious win. The solar installation already includes the inverters a…

I wish the thing was built in such a way as to allow it to sit on a raised pedestal of sorts, with only lightweight bolts into the wall. That would address the flooding concern just fine.
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