Tesla Wants to Build a Battery for Your House

[Living Large]

I am ashamed to admit that there have been a few months (June, July & August) in the past years where my 30 day consumption has exceeded 2000 kWh or about 67 kWh a day.

67kWh would indeed be something to be ashamed about. I believe you mean 67Wh - which is still eye popping to me, but I live by myself and I don't have a pool!

[SunEagle]

But then again that is my opinion. My wife has her own opinion which is why my home's average electric usage (June through September) is around 2000 kWh. [COLOR="#0000FF"]
SUNEAGLE is that 2000 kwh for the whole period? or a month??. If for the month if its ok can you tell me how you use that much electricity,..??

I am ashamed to admit that there have been a few months (June, July & August) in the past years where my 30 day consumption has exceeded 2000 kWh or about 67 kWh a day.

The reason for this high usage is multi-layered. My wife is very sensitive to warm temperatures so she would like to have the house (~2200 Sq ft) kept at 75 F. My AC system was 12 years old (just replaced it last week) and inefficient.

I also have a 3/4 hp pool pump which runs 8 hours a day in the summer.

With 3 to 4 people in the home there are a number of TV's running at the same time along with room lighting and other electrical devices.

I am not sure what my neighbors are using but from what they tell me about their electric bills, they must be using more.

Before Oct 2010 I also had an electric water heater. Replaced it with a solar drain back system along with more attic insulation, thermal barrier, LED lighting and saw my bills drop from an average of 2200 kWh per month to 1500 kWh. So performing a little conservation went a long way to reducing my yearly electric usage but still had some higher monthly usage in the summer. I expect to see another drop with the newer and higher efficient AC unit that just went in.

[russ]

Amend to that. I always tell my wife a Hooker is cheaper and not near as much trouble.

Tell Donald Sterling that - think he might not agree.

[Sunny Solar]

But then again that is my opinion. My wife has her own opinion which is why my home's average electric usage (June through September) is around 2000 kWh. [COLOR="#0000FF"]
SUNEAGLE is that 2000 kwh for the whole period? or a month??. If for the month if its ok can you tell me how you use that much electricity,..??

[RedDenver]

I've wondered if perhaps Tesla might try to reuse their car batteries in stationary applications after they reach 80% of original capacity. For their 85 kWh batteries, that's still 68 kWh of capacity remaining. I'm not sure if this possible, since I don't know how the chemistry behaves at end of life.

[SunEagle]

Amend to that. I always tell my wife a Hooker is cheaper and not near as much trouble.

That might work for you but my wife knows how to accurately shoot and answer questions with a straight face.

[Sunking]

The GC who did our major house remodel told us of one customer who calculated that it would actually have been cheaper to send his wife to Europe for three months than the eventual cost of all the change orders she added to their remodeling project.

Amend to that. I always tell my wife a Hooker is cheaper and not near as much trouble.

[inetdog]

I am thinking of sending her on a cruise to Antarctica during those months but the cost for that is much more than what I would save on my electric bill.

The GC who did our major house remodel told us of one customer who calculated that it would actually have been cheaper to send his wife to Europe for three months than the eventual cost of all the change orders she added to their remodeling project.

[Ian S]

Yet being comfortable by owning a very expensive energy storage system that may save me $150 annually and take decades to pay for itself would not be my first motivation. I would look for other ways to stay comfortable that is less costly.

But that's my point: you don't need a large battery system to save $150/yr. In reality, I think you'd want perhaps a 5-10 kWh battery system and perhaps save $300-500/yr. Even in that case it's going to have to last much more than 5 years to make it pay at current prices.

But then again that is my opinion. My wife has her own opinion which is why my home's average electric usage (June through September) is around 2000 kWh.

I am thinking of sending her on a cruise to Antarctica during those months but the cost for that is much more than what I would save on my electric bill.

Nah, you just have to occasionally let her out of that hot kitchen!

[SunEagle]

@ $300/kWh, that would give you a 3 kWh battery. Theoretically, with a triangular shaped peak, that would give you a maximum reduction of 1 kW over 6 hours. I think 3 hours would be sufficient and would provide a safety margin. So I think we're really close. Note however, that you'd only save the $15/month during the 6 month summer rate period. The rest of the year you might only save $10/month. Plus, you'd need some smart controlling so that the peak shaving occurs at the right time of day summer and winter.

I agree that in certain climates shedding high loads (like AC) may make living uncomfortably. So it would come down to what each person (or household) believes is a the higher priority. Comfort or Cost reduction.

Yet being comfortable by owning a very expensive energy storage system that may save me $150 annually and take decades to pay for itself would not be my first motivation. I would look for other ways to stay comfortable that is less costly.

But then again that is my opinion. My wife has her own opinion which is why my home's average electric usage (June through September) is around 2000 kWh.

I am thinking of sending her on a cruise to Antarctica during those months but the cost for that is much more than what I would save on my electric bill.

[Ian S]

Yeah - demand management is probably the sweet spot for the moment.
Demand charges will drive development and widespread use of both demand management systems and storage systems at some point.

Is it already economical to do peak shaving with batteries that survive 5 years of daily charge/discharge cycles in Arizona?
If you save $15/month for 5 years, that's $900. Can you buy a replacement battery for that little yet?

As battery lifespans increase, the economics will make peak shaving storage systems widely economical. It's just a question of when.

@ $300/kWh, that would give you a 3 kWh battery. Theoretically, with a triangular shaped peak, that would give you a maximum reduction of 1 kW over 6 hours. I think 3 hours would be sufficient and would provide a safety margin. So I think we're really close. Note however, that you'd only save the $15/month during the 6 month summer rate period. The rest of the year you might only save $10/month. Plus, you'd need some smart controlling so that the peak shaving occurs at the right time of day summer and winter.

[DanKegel]

The load shedder could turn everything else off at 5pm.

It could also just turn up the thermostat 1 degree at 5pm. Come to think of it, so could a programmable thermostat.

Yes, a battery would let you avoid that. Is there one up to the task yet? How much does it cost per year to buy one and replace it when it wears out?

[Ian S]

I think APS asking for $3/kw solar connection charge is a little too much. And the option of going to a TOU plus Demand charge may not be much better.

But I could build a simple "load shed" system for a home for a lot less than what that battery will cost you to reduce your peak load.

When it's 110F at 5PM, is your load shed system going to turn off my AC? Because, if it doesn't, I don't see how it could cut my power enough to make a difference. And if it does, I'm going to be extremely uncomfortable. The battery however could get recharged cheaply and shave the peak every single day as it must do to avoid the demand charge. And it's not going to affect my comfort.

[DanKegel]

Yeah - demand management is probably the sweet spot for the moment.
Demand charges will drive development and widespread use of both demand management systems and storage systems at some point.

Is it already economical to do peak shaving with batteries that survive 5 years of daily charge/discharge cycles in Arizona?
If you save $15/month for 5 years, that's $900. Can you buy a replacement battery for that little yet?

As battery lifespans increase, the economics will make peak shaving storage systems widely economical. It's just a question of when.

[SunEagle]

That storage can work in the near future when you use it to smooth your peak power requirements under a demand rate plan. Here in Arizona, based on APS' existing Demand rate structure, reducing your peak by 1 kW over a couple of hours every day during the summer will reduce your monthly bill by about $15. That's a big payback!

I think APS asking for $3/kw solar connection charge is a little too much. And the option of going to a TOU plus Demand charge may not be much better.

But I could build a simple "load shed" system for a home for a lot less than what that battery will cost you to reduce your peak load.