The development of ways to increase the intensity of extreme ultraviolet (EUV) light sources for future EUV lithography is important to realize high throughput fine patterning. The energy-recovery linac (ERL) free-electron laser (FEL), which is an accelerator based light source, is a candidate for this. We clarify the design concept of the ERL-FEL for EUV light sources for future lithography, delivery systems of the FEL light to multiscanners, and future development items of the accelerator technologies and a possibility of the beyond EUV.