1 - Currently (I believe) only grid operators can make profit on grid arbitrage, since in all cases I know you are either paid a lower tariff (i.e. the maximum

1 - Currently (I believe) only grid operators can make profit on grid arbitrage, since in all cases I know you are either paid a lower tariff (i.e. the maximum you pay is lower than the minimum you're sold for), or nothing at all. The only arbitrage you can make is as described here, by storing to avoid buying from the grid, that is, "self-arbitrage", for the back of a better term. Perhaps you could even sell your neighbor some energy, I don't know if regulations anywhere would allow that. That said, this is obviously the way to go in the future, but it needs a good system-wide regulatory design first (from both an economic and technical perspective) to avoid things like grid instability (from the technical side) and compromising utilities and grid maintenance financially (from the economical side).