Extreme ultraviolet (EUV) lithography tools will need a debris free source with a collectable radiation power of about 40 W to fulfill the prerequisites for an economical wafer throughput up to 80 wafer/hour with a wafer size of 300 mm in diameter. Laser produced plasmas and gas discharge based plasmas are under investigation by several working groups as EUV-sources for this purpose. In this paper the achieved results for the different sources are discussed regarding their emission characteristics in comparison to the demands of EUV lithography (EUVL).