Happy to announce that a few days ago I received my “Permission to operate” from my electrical provider (Eversource in Connecticut).
I was up and running and due to the sunny weather I was able to have a great first day experience – between solar and the powerwall the system covered 42% of my energy usage with less than 8 hours of winter sunshine – this was encouraging!
To be honest though, the next day was miserable weather and production was really low – it is winter after all.
Tesla designed the to be a set-it-and-forget-it install, so it does not require allot of testing and fiddling to run. The only real decision I had to make is the amount of reserve energy I set the powerwall to (see picture below). Some of my testing has shown that with my average winter/Christmas power consumption I can expect the powerwall to be able to run the house for about an hour while using 10% of it’s capacity.
Currently, I have the system set to [Self powered] with a reserve of 40% and [Storm Watch] enabled. With the self powered setting the system will first use solar power to charge the powerwall to it’s reserve capacity and the house is served by grid power. Once the battery is charged to it’s reserve capacity, the system switches to powering the house from solar and only excess electricity over what the house requires is then used to charge the battery to full. If the house needs more than solar can provide the battery will kick in and supply the necessary energy until either solar production can cover the house’s energy needs or it hits it’s reserve capacity setting. The reserve capacity is only used to power the house if there is no grid power.
If the combination of solar and battery cannot cover all the energy that the house is using then the system adds grid power as needed. This is all seamless and unless you look at the app you would not notice it.
What is next?
Now I stop fiddling, let the system run every day and just ignore it. Winter production will be low, I am mainly interested in seeing some electric assistance and having the security of being able to run the house for at least ~4 hours without having to do anything – and longer if I start turning off all kinds of energy using appliances!
[Storm Watch] will make sure that in the event of an upcoming storm the battery will be charged to 100% (using grid power if necessary) and run in back-up only mode for the duration of the storm event. I really like this feature and once I see it kick in (we always have winter storms, it will kick in sooner or later) I will post about it.
Once spring and summer comes around and we have more sun I can start looking at what the system really covers and also see what the actual impact to our electricity bill looks like. With that data we can then make some more decisions regarding our ideas of possibly switching some of our appliances and services to electric. More on that when there is more data to look at.
I have not had the opportunity to write and update lately – the holidays have been busy. however – I am happy to report that Tesla scheduled my install in the beginning of December and over the course of two days installed the solar array and my powerwall battery.
It took two days because we had a snow storm a few days before Tesla came and the roof was not 100% safe and needed some clearing which delayed the team and the cold weather and snow and ice also made the overall install much slower.
I won’t go into a play-by-play, but I have to really say that the Tesla team were all very, very , V E R Y professional and really good at their job. From the guys climbing on my roof to the master electrician it was quite an experience to see such a well oiled crew work together.
The electric work – the cabling, the powerwall, the tying into the grid and all the bits and pieces of the controlling components were all done on day one and – it is all much smaller than I thought it would be.
After the installation and some follow-up visits by Tesla to install extra grounding rods and meet with my town’s building inspector to the main inspection the system is now ready … all I am waiting for is the electric provider (Eversource in my case) to finish their review and inspection and for them to install a new meter that supports net metering (=selling of extra electric production back to the grid) and I can turn on the system for full production. I was able to run it for some testing and to charge up the battery which is running in back-up mode now and I can’t wait until I get my final go ahead.
I will write another follow-up and write on the topic of the economics and how I calculated if this project is worth it – and what kind of results I am hoping to achieve during the coming year.
As I mentioned in my previous post, I have been thinking of solar for a few years now and with Tesla changing the market I finally have the opportunity to actually get that technology on my house.
Ideally I would actually prefer the Tesla solar tiles as I can’t say I really think that solar panels themselves are particularly pretty. However, the tiles are still very expensive, take forever to get in line for an install and are likely just not really mature enough yet. I also have been reading of some new panel technology that is slowly making it’s way towards real world implementation and is likely a few more years out from being available in the market at prices I woudl want to pay.
Also, my roof has probably another 10 years or so of life in it and that is also the period that powerwalls are warranted for … so my thought is to get Solar now, not have to do any capital investment, get some reduction in our electric bill (even with the monthly rental fee) and have security from outages with the powerwall and then in 10 years or so re-asses and either upgrade,change or do whatever makes sense then. Tesla Solar Tiles Version 3 maybe? This simply works for me and has few potential downsides.
If you want to know more of what went into the decision (electric rates, net meetering in Connecticut, etc.) ask away and I will answer the questions.
In the meantime, here is what Tesla said my roof installation will look like: