High-efficiency fiber-based extreme ultraviolet driver in the alignment-free configuration has been experimentally achieved with a maximum intensity of 6.4×1010 W/cm2 on target at a repetition rate of 20 kHz. The output EUV signal within 10∼20 nm in wavelength was confirmed with a Si/Zr-coated x-ray photodiode by varying numbers of Be and Al foil filters. The measured spectral range is consistent with that obtained by the weighted oscillator strengths of Sn8+ to Sn+13 ions using an one-dimensional hydrodynamic code coupled with the ionization model of collisional-radiative equilibrium. The driver is based on a 1064-nm nanosecond coiled ytterbium all-fiber laser system in diode-seeded master oscillator power amplification. With an overall optical efficiency up to 56%, it can deliver a 1.16-mJ, 117-kW, 6.1-ns laser pulses with a FWHM linewidth of 10 nm and beam propagation factor of M2∼1.55. The full advantages of using fiber laser for a movable LPP EUV metrology source are revealed.