Convert grid system to off-grid during powerouts?

[AustroTom]

Hello All,
New to this forum and glad to have found you!

In 2012 we installed our 13.8KW solar system with (60) 230w Phono solar panels and Enphase M215 micro inverters.
We are located in Murrieta California, and in our neighborhood powerouts are a common occurrence.
Is there a system available on the market that would allow me to switch to off-grid everytime Edison turns off the power?
Any help greatly appreciated.
Thank you,
Thomas

[SunEagle]

Hello Austro Tom and welcome to Solar Panel Talk

At this time you would need to install a hybrid inverter along with some type of battery system to use your solar panels when the grid is down.

That may be costly and depending on the number of outages and length of time you might find a propane generator be more helpful to give you some power when the grid is down.

[solarix]

$8,000 to 10,000 and up is what I tell my customers who ask this question. Can't do off-grid solar without some serious batteries and the equipment to go with.

[Ampster]

$8,000 to 10,000 and up is what I tell my customers who ask this question. Can't do off-grid solar without some serious batteries and the equipment to go with.

That is a reasonable estimate. I added a hybrid inverter and some used Nissan Leaf battery modules as DIY system to a 5.7 kW existing grid tie system for $8,000. The alternative was a Tesla PowerWall for $10,000 for a turnkey solution. My system doesn't have the capabilities of the Tesla PowerWall.

[Buck Rogers 2000]

You could make a couple of lists: 1. Document the power outages and their duration. 2. Create a list of indispensable equipment and the expected duration (based on list 1) add up the power/duration expectations. I suggest you ONLY include the absolutely necessary stuff, you might get away with only a small turnkey system.

[AustroTom]

Thank you for your replies.
I was definitely thinking long-term which includes natural disasters as well, (and we are also charging EVs), so I understand that it could get expensive.
Are Tesla PowerWalls worth the money or are there other battery packs out there that are more affordable and equally efficient?
Would a system like that be an auto switch-over or would it have to be manually turned on and off?
Ideally I would like to be 100% independent of any utility if "dirt hits the radiator" . (A well is the next task).

[AustroTom]

Hello Buck,
Good points. However, I'm trying to "run" our entire property to full capacity "all the time". We have 5 acres and I operate our Artistic Metal business out of our studio. So all our power,
(home and business), comes from our solar system + Edison, (since our system still needs about 12-15% more production in order to eliminate Edison's help).

[J.P.M.]

Hello Buck,
Good points. However, I'm trying to "run" our entire property to full capacity "all the time". We have 5 acres and I operate our Artistic Metal business out of our studio. So all our power,
(home and business), comes from our solar system + Edison, (since our system still needs about 12-15% more production in order to eliminate Edison's help).

That may become a rather expensive proposition.

1.) Given where you are and what you've described so far, your annual usage looks like ~ 25,000 to 30,000 kWh/yr., or ~ 27,500/365 = 75 kWh/day. Add ~ 30% to that daily load if you want to meet summer A/C loads, and then search for off grid stuff that will handle that and also handle surge/starting loads for any metal working equipment you have and don't want to shut down.

2.) Residential battery option sizing tends to be in the 10-20 kWh range at this time. If you want to go beyond meeting emergency loads for more than a day or so as you seem to be describing, you'll probably need something a fair amount larger than that.

Residential battery storage will happen and is making progress, but it's probably not at a point where you can get what it seems you may want in terms of turnkey convenience, size and price.

I'd first do as Buck Rogers 2000 suggests. It's the first step in terms of a sensible approach to the situation. Get an emergency load scenario in terms of loads and how long you what to supply that emergency power.

Then, get some quotes on what it will take in terms of equipment and cost to do that minimum in a safe and fit for purpose way. Be sitting down when you get the costs.

Then, scale up as your needs/budget/compromises/realities make themselves known.

Do some homework with respect to what's really available in residential battery storage before you contact vendors. Doing so will help you spot the sales hype and B.S. from vendors.

Add: Back of the envelope stuff: If the Tesla Powerwall 2 can be had for, say $10K installed per unit, and each unit has 13.5 kWh storage size w/a max. 5 kW draw, you might need 5 or 6 of them to get close to what you write of as wanting to do.

[Ampster]

....
Are Tesla PowerWalls worth the money or are there other battery packs out there that are more affordable and equally efficient?
Would a system like that be an auto switch-over or would it have to be manually turned on and off?
Ideally I would like to be 100% independent of any utility if "dirt hits the radiator" . (A well is the next task).

Tesla PowerWalls have become very popular and are a good value depending on who you purchase them from. 3rd party installers are charging as much as $13,000 whereas from Tesla you can get them for less, but might have to wait for an install. They have automatic switchover. They are not good for off grid but work well to keep existing grid tie solar functioning during an outage.

[AustroTom]

Thank you so much fro your responses. That's exactly the jump start I need.

[SunEagle]

Hello Buck,
Good points. However, I'm trying to "run" our entire property to full capacity "all the time". We have 5 acres and I operate our Artistic Metal business out of our studio. So all our power,
(home and business), comes from our solar system + Edison, (since our system still needs about 12-15% more production in order to eliminate Edison's help).

Well first off if the "dirt hits the radiator" I would think a metal business not necessarily be important to survive. So in that case of the grid disappearing I would not worry that you have too much load.

As for being independent of the grid then going with a generator is still the cheapest and easiest way to power your loads. Think about all of the hospitals in the county. I believe they use generators for emergency power source and not solar/batteries. But if you have the funds and get the correct engineering I am sure you can add a hybrid system to your existing grid tie system.

[Ampster]

Generators are less expensive but do have operating costs. They also cannot leverage your existing solar during a power outage like a Powewall can. You will have to do the math to decide what is the most cost effective solution for you. Some of that will depend on your usage patterns and how much capacity you need to get through the night and whether your power outages occur during cloudy weather.

[AustroTom]

We do have a 20KW Generac backup generator for the house that runs on propane but it kills me that every time Edison decides to turn off power because of high winds I can't generate my own power. Good point on not worrying about the business during extreme situations .

[Ampster]

We do have a 20KW Generac backup generator for the house that runs on propane but it kills me that every time Edison decides to turn off power.....

Generac recently purchased Pika and they may have a cost effective battery solution that could allow you to run your solar and have the generator for the nighttime.

One issue that I discovered on a other forum is that those older M215 microinverters require a larger battery as a buffer to keep the GT solar running during a power outage.

[SunEagle]

We do have a 20KW Generac backup generator for the house that runs on propane but it kills me that every time Edison decides to turn off power because of high winds I can't generate my own power. Good point on not worrying about the business during extreme situations .

You are not alone concerning the feeling bad about not being able to generate when the grid is down. The problem is cost. If you can afford it then go with a hybrid system and batteries. They have proven to be cost effective for people that live in areas that the POCO charges higher rates in their TOU structure. But for most of us a battery will not pay for itself even if we had a lot of outages. What a Powerwall can produce in kWh is minimal and the cost is astronomical but each person has to decide what they can afford and if there is worth in it.