The physics of it is that your neighbors use that energy, and the power company can shut down some of their grid supply since they don’t need to generate as much power.
In theory, we can eventually generate enough power via rooftop solar and large-scale PV and wind to charge up batteries at large scale (where the term “battery” could include such energy-storage technologies as pumped hydropower storage, molten salt, air compression and, yes, good ol’ batteries).
We just added 20KWH of battery via an Anker Solix X1 system, so now we are pretty independent of the grid, although still tied. Coincidentally, we had multiple power outages the week after it went online. Felt great!
Yeah, I’m still trying to figure out the app to track it. The physics part is weird because today, we where generating a lot more power than we needed. So that extra power must get pumped into the grid. At night it will reverse.
I’m trying to figure out the app that tracks this. It will make more sense when we are up and running for a week or three. We produced 43kWh today. Looks like we used 47kwh.
But the app says we ‘exported’ 29.5 kWh. Huh? The numbers just don’t work.
Like I said, still trying to figure this out.
Coolio.
Our heat is natural gas. But depending on how this pans out we are going to use some electric space heaters more. We just turn them on when we are in the room, Say playing chess or darts or something. Then they always get turned off. Never on if we are not in the room. Never on while sleeping.
Based on how my app shows this I speculate your report reads thusly. But I’ll say the word ‘used’ here is vague. Is that your total site consumption (what I’m assuming here) or your amount used from the grid?
I’m still trying to figure it out @Pork_Rind . It’s only been operational for ~ a day and a half (I had to turn the thing on once I saw the email yesterday).
But it looks like we are banking kWh. So that’s great.
Well, as I figure it without seeing your app, you’re still pulling more from the grid in the evening that you’re sending in the day. But it’s close.
This is the physics part I don’t understand. What are the panels doing when they’re being hit by light, but the inverter is not connected to any load? I know if a generator is not connected to a load it is very easy to spin, but I’m having trouble translating that to a photovoltaic cell.
A photon hits the cell, if there is a load then an electron gets excited and either goes down the wire or jiggles in place, I forget which they do. Either way, some of the energy from that photon and all it’s friends is converted into electricity which powers a lightbulb that converts some of the electricity back into photons.
If the panel is not connected, what happens? Does the electron still get excited and just lose it’s energy as heat? Does it not get excited because there’s no place for it to go?
Are my black panels sitting in the sun, but not producing, hotter than my neighbors panels which are producing?
And I know it’s not how it works, but it would be great if I could run my panels backwards and turn them into spot lights.
What happens to the electrons in a 120v lamp circuit when the switch is off? Do they hit the air gap inside the switch, come shooting out the end of the wire, and fall to the floor? Nope.
The “pressure” of voltage pushes the electrons up against the air gap until there’s enough “back pressure” from that lack of ongoing conductivity that the electrons stop flowing. They’re simultaneously “pressurized” and trapped in a dead end.
Same result if you’re talking about a photovoltaic panel with its output wires dangling in space.
OK, so following that analogy, the electrons get excited, but have no place to go, so new incoming photons can’t excite them anymore, and it’s no different than if the photons had just hit my roof shingles.
I’m still curious about the heat thing. When a photon hits a non-connected solar panel, or just my roof, all of it’s energy (that isn’t reflected) is converted to heat. Does that mean a functioning panel is cooler, because some of that energy is instead converted to electricity?
IMO yes. Energy is being carried away down those wires if they’re connected to something. If not, not; it’s all just sitting there in the panels that are providing passive shade to your shingles.
It’s funny, there is an app I have on my phone that I can see the usage of import/export energy.
I look and OH, well I guess my wife just turned on the microwave, or clothes dryer or something.
That’s a fun part of the app. I can really isolate certain things and know exactly how much I’m increase my usage of electricity. If you’re interested, nothing uses as much as our radiant floor heat.
Noon in Colorado.Slight overcast. But we are producing 5.6kw. only using 0.6kw. So that is all getting banked for later.
I’ve got our floor heat on. (use it more when we’re home on gloomy winter days).
We’re using 9.2kw and only producing 3.3. But, it’s overcast, and this time of year in the Pacific North West, the sun doesn’t get too high over the horizon. Without the floor heat, but using regular heat and normal level of everything else, we’d probably be breaking even right now.
Producing 6.5kw now. But using 1.1. The furnace just kicked on so I suspect that is the furnace blower motor.
What a pain, I hope this doesn’t bite me in the ass too badly. I have a Tesla inverter, and the installer created a new Tesla account for me, and put the inverter in that.
I activated the account, then put the Tesla app on my ipad, and clicked the “transfer ownership” button, and put in my existing Tesla account as the new owner. My new Tesla account no longer owns the inverter. That sent a message to my existing Tesla account to adopt it.
I attempted to add it to my existing Tesla account. Instead of just adopting it as new, because it is un-owned, it requires uploading a deed. So I did, except the deed says I bought my house from the previous owner 15 years ago, not from myself this morning.
I’m sure it will get sorted eventually, and at the moment doesn’t actually matter because I’m not producing until my interconnect agreement is activated. It would have been nice if anywhere during this process the solar company had asked if I had an existing Tesla account.
So the inverter is still connected to my wifi, but is not owned by any Tesla account.
Yeah, and you can actually use that effect for some quick diagnostics… handheld or UAV-mounted infrared cams can detect anomalous hotspots on the modules: https://www.infraredtraining.com/en-US/home/resources/blog/identifying-issues-on-installed-photovoltaic-systems--using-thermal-imagery/
Interesting. I love learning about this. My system does have an app that you can look at to see the health of the panels. Also the power output. It’s very cool.
I’m a bit of a nerd about this and update my Wife a lot. She humors me, because she isn’t a tech nerd.
It’s cool, isn’t it? I’ve been fascinated by solar panels ever since I first saw one on a Casio calculator thirty years ago. It’s literally a quantum mechanical power plant that you can own.