In this paper, a proposed co-generation system (CGS) for a skyscraper complex building (JM Tower) in the centre of Shanghai has been evaluated. Two types of energy supply systems are considered: electricity-only and CGS. Compared with a conventional system, the CGS is capable of reducing the primary energy consumption by 29.94% per year. Sensitivity analysis about energy saving ratios is carried out in this paper to study influencing parameters, such as unit capacity, generator's scales and efficiency, partial load, increase-decrease rate of fuel charge. It is shown in result that different influencing parameters have different weight in energy saving ratio, and the power generation efficiency of CGS is the most important influencing parameter on energy saving ratio.
