  We discuss thermal transport of two-dimensional topological superconductors
(TSCs) with broken time reversal symmetry, which are described by Bogoliubov-de
Gennes (BdG) Hamiltonians. From the calculations of bulk quantities only,
without refereeing to Majorana edge states, we show that the thermal Hall
conductivity of two-dimensional TSCs in the low-temperature limit is quantized
in multiples of $1/2\frac{\pi T}{6}$, which is exactly one half of the value of
quantization in the case of the integer quantum Hall effect, and that this
exact half-quantization is caused by the structure of the Nambu spinor and the
particle-hole symmetry, which BdG Hamiltonians generally have. In the case of
spinless chiral p-wave superconductors, this result is in perfect agreement
with the argument based on the Ising conformal field theory with the central
charge $c=1/2$, which is an effective low-energy theory of the Majorana edge
states.
