Increase Your Boiler Pressure to Decrease Your Electric Bill: The True Cost of CHP

Abstract

The majority of small scale steam turbine generator projects are installed as an afterthought to overall plant design. As a plant manager or process engineer, the primary concern is providing the process with the thermal load it needs at the lowest $ per Btu. The viability of installing a steam turbine generator set comes after the plant is in operation and pressure reducing valves (PRV's) have been installed, providing the opportunity has been proven to be sufficient for onsite power generation. This methodology produces reliable systems that operate with whatever steam conditions were present. What if users could take a step back to the initial design of the steam boiler? Plant engineers can proactively analyze the impact of folding a steam turbine generator set into the overall plant design at the pre-construction phase, significantly decreasing total energy costs and reducing the net $ per Btu. This paper analyzes the costs and benefits of integrating a steam turbine generator set into the initial boiler plant design, with marginal fuel increase and equipment cost yet providing the added benefit of clean, low cost and reliable onsite power production.