  The rapidly evolving communication landscape, with the advent of 6G
technology, brings new challenges to the design and operation of wireless
networks. One of the key concerns is the energy efficiency of the Radio Access
Network (RAN), as the exponential growth in wireless traffic demands
increasingly higher energy consumption. In this paper, we assess the potential
of integrating a High Altitude Platform Station (HAPS) to improve the energy
efficiency of a RAN, and quantify the potential energy conservation through
meticulously designed simulations. We propose a quantitative framework based on
real traffic patterns to estimate the energy consumption of the HAPS integrated
RAN and compare it with the conventional terrestrial RAN. Our simulation
results elucidate that HAPS can significantly reduce energy consumption by up
to almost 30\% by exploiting the unique advantages of HAPS, such as its
self-sustainability, high altitude, and wide coverage. We further analyze the
impact of different system parameters on performance, and provide insights for
the design and optimization of future 6G networks. Our work sheds light on the
potential of HAPS integrated RAN to mitigate the energy challenges in the 6G
era, and contributes to the sustainable development of wireless communications.
