There is a growing focus on safeguarding the planet to limit the worsening of climatic conditions, global warming, and pollution in general. Every sector has been striving to move towards reducing energy and resource waste, thereby optimizing energy efficiency while performing the same operations. In recent years, this trend has also included the heavy-duty vehicle sector, which, due to limited alternative options and the difficulty of achieving the same performance with a minimal increase in costs, had remained more on the margins of the ongoing shift in approach. This study focuses on hydraulic excavators, analyzing one of the most promising proposals in the current landscape: the Common Pressure Rail (CPR) architecture in its hybrid hydraulic version, with a specific case study of a 9-ton excavator.