The so-called "net metering" is a service which allows to put in the web the electricity produced by a photovoltaic system (or supplied by renewable sources) but not immediately auto consumed and then use it in another moment in order to satisfy clients'consumption.
The net metering is the most convenient contractual arrangement of course for who auto consumes most of electricity produced in his own photovoltaic plant or by renewable source.
In this case there is an indirect profit. It is given by the saving from the bill, which generally goes from 0,20€/kWh upwards (you can calculate the saving/profit in your specific case simply dividing the total expenditure of the bills in one year for the number of the same period of time).
In addition to the incentive tariffs foreseen by the "Fourth Energy Bill", electricity produced by normal power photovoltaic plants which does not exceed 200 kW will benefit of the service "Net metering", which can be applied after 20 years of duration of the incentive tariffs. In the net metering the energy put in the net -which serves as a huge accumulator- is counted and withdrawn when it is needed, and at the end of the years there is an adjustment balancing the en energy produced and the used one: in the case in which the first exceeds the second, it will be used afterwards. The electricity produced by the photovoltaic plants which do not benefit of the net metering, if it is included in the power supply (by using the regime called "network disposal", it can be: (a)withdrawn with conditions and methods set by the Italian Electricity and Gas Authority - this option is called "Dedicated Withdrawn" - or (b) placed on the free market.
For people who present a little or null percentage of self-consumption, they can use the service called "network disposal" (or "dedicated withdrawn"), i.e. the sale of electricity produced to the operator, which is about 0.1 €/kWh.