ᐅ Using Photovoltaic Systems for Household Electricity without Grid Feed-In Control

Hello,
what technical requirements are we missing to use the electricity generated by our photovoltaic system in the house without a battery storage and without the grid frequency signal (kHz) from the utility company? We would like to be self-sufficient.
To explain: We use our self-generated electricity when it is bright, but we always rely on an active connection to the existing house grid from the utility for the frequency reference. (I hope I understood our photovoltaic technician correctly, but unfortunately, he is no longer available.)
Thanks for your feedback
Carlanickel

I don’t quite understand the issue here. If you generate and use electricity during the day, you are not drawing power from the grid. And apparently, you need a (permanent) connection anyway since you have no storage capacity and might want to use electricity at night as well.

What is the purpose of the question?

Carlanickel schrieb:

Hello,
what technical requirements do we still need to meet to use the electricity produced by our photovoltaic system inside the house without a battery storage and without the grid frequency signal (kHz) from the utility? We would like to be self-sufficient.

This is only possible with the right inverter and a battery storage system. Additionally, you have to hope that enough electricity is generated in winter. However, it can work with a sufficiently large system and adequately sized storage.

What capacity do you have installed on your roof? 50 kW peak? What kind of storage are you considering to cover, for example, about three weeks of winter without sunlight? Do you have a backup diesel generator available if needed?

Finally, a question for you: What are you really trying to achieve?

Hm, I’m not sure how to reply to each responder individually. So, thanks to everyone who answered here:

We have a 50 kW peak system on the roof. The installer told us that when electricity is flowing from the system, we can use it directly without any battery storage; we only need the grid’s frequency signal. The inverter handles this automatically. Therefore, all devices in our home are only operated during the day.

But what happens if this frequency signal is not available, for example during a power outage? Then we have electricity on the roof but no way to use it. So the question is: how can we simulate this frequency signal so that electricity can still be used directly? Of course, we would only draw a small amount of power—no washing machine or dishwasher.

Our goal is that during a grid outage, 1. the aquarium continues running (power consumption 150 W/h), 2. the heating cartridge of the buffer tank produces hot water at the lowest level (1 kW/h) for 3 hours per day. We don’t expect to be without the main power grid for several days, but want to avoid being without electricity for about 30 hours.

Maybe this is too much worry, but if you already have electricity from the roof…

Carlanickel schrieb:

We have a 50 kW peak system on the roof. The installer told us that when electricity is fed in, we can use it directly without a battery! We just need a timing signal from the grid.

"Timing signal" is a polite way to put it. Let’s just say your system is connected to the grid.

Carlanickel schrieb:

But what if there is no timing signal due to a power outage? Then we have electricity on the roof without any way to use it.

That depends on the inverter. There are devices that will disconnect you from the grid (otherwise you could damage the grid if you keep feeding power into lines that might be under repair—put simply). You just need to adjust some electrical settings, and that’s it.
So just buy a suitable inverter. Your solar installer can help with that.

Carlanickel schrieb:

Our goal is that during a power outage 1. the aquarium keeps running (power demand 150 W/h), 2. the heating element of the buffer tank runs on its lowest setting (1 kW/h) to produce hot water for 3 hours a day. We don’t expect to be without the grid for several days but want to have power for about 30 hours. Maybe that’s too much worry, but if you already have electricity from the roof…

With such a large system, you will always have enough power. But there are few consumers for such a huge house (or farm where the whole barn is covered with solar panels).
And what do you do at night? When you shower in the evening, the hot water is gone. The aquarium has no power at night, either. And so on.

As an example inverter, something like a Fronius Symo Gen24 works. But I have no idea how your system is currently set up—the type and number of inverters.

If cost is not an issue for you, then retrofit. It should still be under five figures. What do I personally think of it? Complete nonsense.

Carlanickel schrieb:

Hm, I’m not sure how to reply to each individual commenter. So thanks to everyone who responded here:
We have a 50 kW peak system on the roof, and the installer told us that when power is flowing from the panels, we can use it directly without a battery storage system. We just need a control signal from the grid. The inverter would handle this automatically...

A 50 kW peak system on the roof and no information about off-grid operation or similar? I don’t think so, sorry.

Carlanickel schrieb:

That’s why we only run appliances during the day.
…

Seriously?
The solution for you would be "picea." But don’t just install a system over 100 kW without informing yourself first – you know 😉