ZEN Renewables Photovoltaïc systems are installed grid connected. A private installation will convert the DC power to AC power, which can be used directly. The power grid is a backup supplier when the solar energy contribution is reduced.(at night, shorter winter days, clouded weather). furthermore, the power can generated be "feedin" to the grid at times of surplus. typically the annual production is to be related to the yearly need of the private household or electricity requirements of a company, utility or industry. In most European countries the principle of 'grid connection' is established by law. Also in most countries there are financial incentibes through a feed-in system and sometimes investment subsidies.