A smart energy system is a system that integrates multiple energy vectors to support various energy demands such as electricity, heat and fuel. It can be a solution to decarbonize hard-to-abate industries by providing flexibility to distribute energy vectors efficiently and ensuring that energy demand is met without wastage. In this chapter, a mathematical model of a smart energy system is developed to determine the optimal configuration for decarbonizing a hard-to-abate emissions process, using the cement industry as a case study. The model focuses on minimizing the total annualized cost of a smart energy system. Two different scenarios were investigated, one focusing on different carbon pricing and the other on different carbon pricing and a 45% carbon reduction mandate. Different sub-scenarios with varying carbon pricing are analyzed to assess their impact on carbon reduction strategies, choice of low carbon fuels, and the optimal configuration of the smart energy system. The findings reveal that carbon pricing is effective to an extent, but it is not sufficient on its own to achieve extensive carbon emissions reduction. For more substantial and impactful reductions, carbon pricing should be complemented by mandate that enforce specific emissions reduction targets. This combined approach can drive the cement industry to adopt more aggressive and sustained decarbonization strategies, ensuring progress beyond what carbon pricing alone can accomplish.