Solar Power and Battery Backup: Tesla and SolarCity's Dream Home

[gjunky]

I am in the process of getting a SC installation at my house as well and asked them about the battery backup. I was told that there are 300 test installation in CA only but that they might offer them in the future. No date or other information was given / available.

 

[ecarfan]

I was told yesterday they had 400 beta test sites of the a Tesla battery backup.

 

[myl55]

I had a Solar City system installed last June and it's been great for my electric bill. Initially, I was just going to put a few panels in to offset my monthly usage from going into the higher tiers, but after talking to neighbors in my area they convinced me to offset my entire electric bill. Solar City recently installed a backup battery system which will power 1 inverter and 4 circuits when our power goes out. (I have a 12.72kW system with 53 panels. As of today, it has generated 18,257kW this year. It would have generated more but SC took it offline while installing the backup). It's not active yet--I'm waiting for the final inspection by Edison before I can turn it on. I can charge my MS and it's still generating enough power to offset my electric bill. I guess I lucked out in getting the backup. Here's a picture of the system:

 

[djplong]

Any idea how much storage is in that battery in KWhs?

 

[myl55]

It's 10kWhs. The system is designed to turn on when the power fails. The inverters Solar City installed (SMA sunny boys) will not work without the grid supplying power. There is a newer inverter made by SMA (Sunny Boy SMA 3000TL-US) which will work without external power but you need to manually flip a switch after the power fails to energize it. It also appears to supply power to 1 dedicated outlet that doesn't appear to receive any power normally. The SC system has been wired through our main panel and I was given the option to chose 4 circuits we wanted to power during the outage. These are circuits that are normally in use. We also do not need to manually flip a switch. I was worried about the battery being depleted during night time usage during a failure, but I was told it has management software to prevent it from bricking; so when the sun comes up the next day, it will have enough power to turn on the inverters and charge itself up again. Of course, I was told it will not power our home to the same degree as when there is no outage, but it will ensure our refrigerator and freezer will keep our food supply safe as well as keep us from living in the stone age until the power is restored.

Our previous home in Palos Verdes Estates had underground electrical utility lines and during the 14 years we lived there, we had a few random (from a few hours to up to a week long) power outages. So Cal Edison even brought in a semi-truck size generator to power our neighborhood during one event. We live in a newer house nearby but I did not want this happening again. I inquired about the battery backup before choosing the company to install our panels. At the time, SC was the only one with this option.

 

[ecarfan]

I had a Solar City system installed last June and it's been great for my electric bill. Initially, I was just going to put a few panels in to offset my monthly usage from going into the higher tiers, but after talking to neighbors in my area they convinced me to offset my entire electric bill. Solar City recently installed a backup battery system which will power 1 inverter and 4 circuits when our power goes out. (I have a 12.72kW system with 53 panels. As of today, it has generated 18,257kW this year. It would have generated more but SC took it offline while installing the backup). It's not active yet--I'm waiting for the final inspection by Edison before I can turn it on. I can charge my MS and it's still generating enough power to offset my electric bill. I guess I lucked out in getting the backup.

Wow you sure did luck out! I was told by SC last week that the battery backup would not be for sale until next year.

Where do you live? I am on the San Francisco peninsula. Am talking to SC now about installing a 5.75kW solar system soon (will offset 85% of my electric use) and really want the battery backup.

 

[Dave EV]

It's not active yet--I'm waiting for the final inspection by Edison before I can turn it on. I can charge my MS and it's still generating enough power to offset my electric bill. I guess I lucked out in getting the backup.

Good luck - apparently SCE has started denying installs of PV systems installed with battery backup...

A couple articles:
Solar Energy Battery Backup Under Attack in California?
Fight Over Battery-Backed Solar in Southern California : Greentech Media
Solar Battery Backup Faces Opposition from SCE | Ameco Solar

 

[myl55]

I live in LA in the South Bay on the Palos Verdes Peninsula. I inquired about the system and backup in December 2011 when I signed the contract. I was told after the panels were installed and the system was active that I would be placed on a waiting list for the backup. This was about a year ago. I kept asking when the backup would be available and was told it was dependent on the availability of either state or federal funding to help offset the costs. Solar City finally contacted me earlier this year and they installed it this past August-September (it took less than a week). I could be wrong but I think the funding becomes available in the beginning of the year. That's possibly why they told you it wouldn't be available until next year. Ask you SC salesperson to put you on the list. And ask if there is another contact person who handles the backup contract so you can stay in contact with that person.

- - - Updated - - -

Just saw your answer drees. I'll call my SC contact who is managing the backup installation and ask him about this. I believe these are the same teams that install the garage chargers for Tesla.

 

[evme]

When this was originally reported the date they said was 2015:

http://www.bloomberg.com/news/2013-...atteries-reduce-risk-of-utility-backlash.html

 

[ecarfan]

Thanks for posting links to those articles. It appears that so far only SCE is trying to obstruct PV systems with battery storage, but of course PG&E could decide to follow suit. The utility position is of course nonsensical, but that won't stop them from trying to block battery storage since it threatens their business model, and they wield tremendous influence over the CPUC. I will discuss this further with SolarCity next week and let you know what they say.

 

[Cassie'sflight]

I also have a new Tesla 10 kWh battery back-up that Solar City recently installed in my garage to back up my solar panels in case of an outage ... and it will work independently from the grid, should there be a black-out, and will power everything in my home (including charging my Model S) indefinitely because my solar panels will continuously recharge it. However, I missed the original $10/month lease program, so I opted to buy it for $15,800 ... with SDGE giving a whopping $10,800 rebate! That makes the out of pocket $5,000, with a ten year warrantee. Still not a bad deal. There is not problem with SDGE here near San Diego, as far as installing these units, as they are cooperating fully. And also, you might like to know that I was told by the Tesla technician that the batteries in my unit were absolutely brand new and NOT used in any way. I received the early model in September, but he said that a smaller, upgraded model will be on the way for 2014, when Tesla expects to be selling about 10,000 of these battery back-up units. My system is now temporarily off-line pending SDGE installing the meter, hopefully within the month ... then it will be on full time. And, since there is a warranty for 10 years, I am not worried about any degradation. Oh, by the way, these batteries have no heating and cooling as do the cars - at least that is what the Tesla tech told me - so he said that because of this (no heating or cooling draw) there is no drain from the system when they are not being used, as with the cars.

 

[liuping]

with SDGE giving a whopping $10,800 rebate! That makes the out of pocket $5,000, with a ten year warrantee. Still not a bad deal.

I have not heard of SDG&E give rebates for Battery backup systems. do you have any more info on that program?

For $15k it's hard to justify. For $5k I'd do it tomorrow...

 

[myl55]

My Solar City rep replied to my email and informed me that: "We are expecting interconnection will take place in 30-60 days. The utilities are finalizing a few things, but we have sent in all the paperwork necessary for your project to be interconnected as soon as they begin doing so."

 

[jcstp]

So this system does not supplement the house with electricity in the evening, it stored during the day?

 

[myl55]

It is primarily designed to function during power outages

 

[beths11]

I was reading a similar conversation on this site. The person who installed the battery unit indicated that although it was a back up for power outages it could also be used to reduce electric cost. He was talking about using the unit when electric company rates where high and charging the unit at night when rates were low. Does this makes sense?

 

[Zzzz...]

I was reading a similar conversation on this site. The person who installed the battery unit indicated that although it was a back up for power outages it could also be used to reduce electric cost. He was talking about using the unit when electric company rates where high and charging the unit at night when rates were low. Does this makes sense?

This is exactly how Green Charge Networks operate. They sell battery packs to commercial customers, packs charge at night and shave off peak demand, reducing peak charges. Plus battery discharges during highest rate hours. GCN claims that they see payback time as low as one year. Sure enouph Tesla/SolarCity are very interested in the market. And Tesla already got whole line up of products, Tesla talking not only about residential, but also up to MWh commercial installations AND muti-MWh batteries in container format for grid storage application.

 

[myl55]

After asking for further information regarding the battery backup, this article confirms what I was told how the system works. It seems it can offset power usage during peak periods as well as supply power to critical circuits that solar city has wired into our main panel to function during a power failure. Tesla's Solar Power Storage Unit - Businessweek

 

[Raffy.Roma]

Problem is that SolarCity works only in the USA. Does somebody know if in the future SolarCity will work also in Europe?

 

[ecarfan]

This article confirms what I was recently told how the backup system works. It seems it can offset power usage during peak periods as well as supply power to critical circuits that solar city has wired into our main panel to function during a power failure. Tesla's Solar Power Storage Unit - Businessweek

That article contains a rather elementary error. Quote:

-----
“If you go to the end of the manufacturing line at the Tesla factory where they put the battery pack on, you will see these storage systems being assembled,” says Pete Rive, the co-founder and chief technology officer at Tesla.
-----

Rive is the CTO, COO, and co-founder of Solar City (and Elon's cousin).