Integration of renewable energy sources into combined cycle power plants through electrolysis generated hydrogen in a new designed energy hub

Abstract

Integration of intermittent renewable energy sources (REs) such as wind and solar into larger scale fossil fueled combined cycle power plant (CCPP) utilizing hydrogen as the energy vector is presented in this study in order to provide the needed load following energy profile and lower emissions. Such ‘Energy Hubs’ have the potential to provide a unique future integrated system to meet consumer's energy demands utilizing conversion and storage technologies for multiple energy carriers such as electricity and hydrogen. Storing hydrogen in the natural gas pipeline network is an effective factor in reducing the cost of clean power produced. Wind turbines, solar farms, and CCPPs act as energy generation and transformation components within an energy hub. Maximizing revenues from selling power and from emissions credits represent the objective function; whereas hydrogen percentage in CCPP fuel represents the decision variable. Meeting power demand and hydrogen limits in CCPP fuel are the most effective constraints. GAMS is used to model energy hub costs to approach the problem using mathematical programming while power cost and emission credits represent the model outputs. Such a model will aid in sizing of the key components within the hub and optimizing its operation. Hydrogen production cost is found to be an average of $4.10 per kg representing an extra cost while reducing CO2 and NOx emissions by about 2%.