 A number of states have set up schemes to encourage the uptake of solar PV power generation involving households installing solar panels and selling excess electricity to electricity retailers to put into the electricity grid, widely called "feed-in".Each scheme involves the setting of feed in tariffs, which can be classified by a number of factors including the price paid, whether it is on a net or gross export basis, the length of time payments are guaranteed, the maximum size of installation allowed and the type of customer allowed to participate.Many Australian state feed-in tariffs were net export tariffs, whereas conservation groups argued for gross feed-in tariffs.