Since silicon modules do not contain any toxic substances, there is no hazardous waste. From today’s standpoint, and given that the appropriate manufacturing technology was used, such photovoltaic installations are completely recyclable. Crystalline silicon cells take approx. two to six years to generate the same amount of energy that was used in their production; with amorphous silicon cells, this period is just one to three years. Only thin-film solar cells involve the use of small amounts of cadmium or arsenic.