  Can pulsar-like compact objects release further huge free energy besides the
kinematic energy of rotation? This is actually relevant to the equation of
state of cold supra-nuclear matter, which is still under hot debate. Enormous
energy is surely needed to understand various observations, such as
$\gamma-$ray bursts, fast radio bursts and soft $\gamma-$ray repeaters. In this
paper, the elastic/gravitational free energy of solid strangeon star is
revisited for strangeon stars, with two anisotropic models to calculate in
general relativity. It is found that huge free energy (> $10^{46}$ erg) could
be released via starquakes, given an extremely small anisotropy ($(p_{\rm
t}-p_{\rm r})/p_{\rm r} \sim 10^{-4}$, with $p_{\rm t}$/$p_{\rm r}$ the
tangential/radial pressure), implying pulsar-like stars could have great
potential of free energy release without extremely strong magnetic fields in
solid strangeon star model.
