The invention relates to a method for improving energy efficiency in a lighting system having at least one light source (3), wherein the light source (3) can be connected to an external electrical energy source, for example the grid, for power supply purposes via an operating device (2). In order to avoid standby losses which arise when the operating device (2) needs to be connected to the grid even in the inactive state in order to generate the necessary runup energy for a semiconductor IC (8) when a switch-on command arrives via the bus, it is proposed that additional electrical energy is recovered from the light from the light source (3) which is not used for lighting purposes or from the direct or indirect light from neighbouring luminaires (2); or from the ambient light by means of photovoltaic energy conversion and is supplied to the operating device as runup energy for the semiconductor IC (8). In this way, the operating device (2) can be isolated from the grid at least during the inactive state.