I used to pay 26ct/kWh and get 26ct/kWh for what I supply to the grid. So 4000kWh/year would make me 1040 euro/year (either by using directly or supplying to the grid). With the new tarif system, I pay (approx) 22ct per kWh and also get 22ct per kWh, so I would still make 880 euro/year. However, due to supplying around 2500kWh/year back to the grid, I need to pay a fee around 240 euro. So the 'profit' from the solar panels went from 1040 euro / year to 640 / year.
So did I understand correctly - for you, value of sell-to-grid is 640 / 4000 = 16 cents/kWh, and value of self-use is, as always, equivalent to buying price, that is 22 cents/kWh.
So "having to sell" would lose 27% of the value compared to self-use.This doesn't sound bad to me at all, just understandable and fair. Say you are a nuclear plant or a coal power operator. It's not like you get paid for the final customer price either; there is value added in the chain, producer always gets less.
Here we don't have such weird "first someone gives you too much credit for something then you have to return part of it" system, but the difference between buy/sell results in from having electricity bill consist of two different parts, paid to two different companies: energy itself which you can buy from multitude of providers, and transmission/grid fee which you have to pay to your local grid company. When you sell excess production to grid, you sell the
energy to the energy company of your choice, hence get paid for energy, but you do not get the transmission fee; which is understandable, because transmission fee is meant to cover for the costs of maintaining the grid and distribution.
Here energy companies only accept to buy your excess production with spot price terms, which means that often the price you get from the excess is near zero. But many/most people find it somehow still feels like a fair system because it's all based on free market operating, on understandable terms. After all, if you need to sell for zero energy cost, you are also allowed to buy for zero! So this motivates people to (1) time the use of their energy, (2) increase self-use of PV, both very good things. At least much better than complaining about conspiracies as some others do.
But I understand that your NL case where you are first subsidized and then penalized feels stupid and wrong. Similar to our system where EVs are free from one type of car taxation, but then have another EV-specific extra tax so that the end result is close to normal ICE taxation. It feels stupid as hell.