  We report the experimental results on certifying 1% global optimality of
solutions of AC-OPF instances from PGLiB via the CS-TSSOS hierarchy -- a
moment-SOS based hierarchy that exploits both correlative and term sparsity,
which can provide tighter SDP relaxations than Shor's relaxation. Our numerical
experiments demonstrate that the CS-TSSOS hierarchy scales well with the
problem size and is indeed useful in certifying global optimality of solutions
for large-scale real world problems, e.g., the AC-OPF problem. In particular,
we are able to certify 1% global optimality for a challenging AC-OPF instance
with 6515 buses involving 14398 real variables and 63577 constraints.
