Comment by scarecrowbob
2 hours ago
Horses for courses. My system is off grid, so any extra power is just not used, and its designed in a way that a 2-5% change doesn't do anything. That might be a more meaningful change if I were selling power to other folks.
Kind of off topic, but I see a lot of folks proximate to me have built systems to turn panels so they face the sun more closely. I can see the use in that if you don't have much space or if you have a large commercial operation, but this area is very rural.
My array (4kw) which I built myself has 10 400W panels. The panels cost me $1200 because the minimum order is 12 and the supplier suggested buying extras; shipping large panels one at a time isn't cheap. In fact, the shipping for the entire system (about $5000 worth of equipment) was almost $1000.
But my feeling is that for the cost of a moving array that tracks the sun / time of year would have cost quite a lot more and have involved construction that I personally wasn't comfortable with. The conclusion I came to is that it would cost about the same to build a second array, angle it for "summer" (mine is angled to be most efficient in winter), and hook it to the other MPPT on my controller.
That would take up a lot of space, but a) I am 40 acres and b) then I could run a mig welder with impunity during the day...
A lot of these designs are an artifact of a time when the panels themselves would have been far and away the most expensive component in the system. The place I'm in originally had 10 125W panels that probably cost north of $8k when installed, and they were mounted on a rotating, tilt-adjustable post. Also the entire house was wired to run off DC as much as possible, with three different wiring schemes throughout and rare & expensive appliances. It reminded me strongly of RV power schemes, and maintenance was probably a huge headache.
I replaced it all with 9kW worth of panels (about $3k, shipped) on 4 simple 60° ground mounts, normal wiring and appliances. Angle is optimized for early spring / late fall - there's effectively no sun in winter, and the rest of the year I have excess power even with fixed, sub-optimal angles.
The diminished cost of panels alone over the past 20 years has transformed "off-grid" from a pastime for wealthy hippies into a reasonable solution for remote living.
It does no longer pay to be clever with solar panels; they're too cheap. Angle not quite right? Add a couple extra. Summer vs. Winter? Add a couple extra.
Except in germany where if you install too many you get classed as an energy company and have to pay extra tax. yay.
Your post sounds like there is some strange rule regarding taxation of solar installations, but it is (or rather was) just treated as any other income from commercial operation.
- If you have any income from commercial operation (selling stuff) you are required to declare that, when doing your taxes.
- When selling electricity you're not so much classified as an energy company, but fall under similar taxation rules as a company. This also means you can get the VAT back, you paid when buying panels, inverters etc.
- Since 2023 solar installations smaller than 30 kWp are completely exempt from this taxation scheme. This means you're not paying any VAT, when buying equipment for your solar installations and don't have to declare the revenue.
- You can get around the 30 kWp limit under some circumstances by having multiple separate installations.
- Parent post is talking about an off-grid installation, which would be exempt anyway, because there is no revenue from selling electricity.
The tax exemption from 2023 was a very welcome move by SPD and the Green party to reduce bureaucracy regarding solar installations and I think the 30 kWp is pretty reasonable
Would be interesting to see, how other countries are handling this.
You don't get "classed as an energy company", you just have to pay taxes on the money you make from selling the energy. This starts at 30 kWp (up to that size, the income is tax free), which is very likely more than what you could put on a private home.
even for the off grid system not connected to the grid?