Flexible lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O-3-0.2 mol%Y nanofibers (BCTZY NFs) were synthesized by electrospinning and their corresponding nanogenerators (NGs) with vertical alignments were fabricated. The low-temperature sintering properties of BCTZY NFs were investigated, to optimize their synthesis path and minimize the thermal energy consumption during the sintering process. The continuity, flexibility, and stability of the BCTZ-based NFs were improved by adding Y3+. Moreover, the temperature-evolved Raman spectra displayed a high Curie temperature of 280 degrees C for BCTZY NFs, which was far higher than that of about 90 degrees C for BCTZ-based ceramic bulks, owing to the discontinuous physical property of NFs. The dielectric, ferroelectric, and piezoelectric properties of the vertically aligned BCTZY NFs/PDMS were estimated and compared with those of BCTZ NFs/PDMS composites, to verify the advantages of vertical alignments and the donor doping effect of Y3+. Vertically aligned BCTZY NF-based NGs showed an average V-OC of 3.0 V and I-SC of 85 nA by finger tapping, suggesting their potential applications in tiny energy harvesting.