No, it is not at all reserved for big players. You just need to get a dynamic price electricity contract, and a smart-meter in your home and you can do this right now.
In Sweden you can also register your battery to an aggregation service that makes money (and gives you a share) from balancing the grid.
So there is not only a market for buy/sell, you can also be stand-by for charging your battery when grid frequency increases and consumption needs to increase.
So there is not only a market for buy/sell, you can also be stand-by for charging your battery when grid frequency increases and consumption needs to increase.