Techno-economic implications of flexible operation for super-critical power plants equipped with calcium looping cycle as a thermo-chemical energy storage system

Abstract

Calcium Looping (CaL) cycle is a promising energy-efficient and cost-reduction decarbonization technology as well as a thermo-chemical energy storage system. This process is based on multi-cycle carbonation – calcination of CaO – CaCO3 system. In this work, the CaL cycle is used both to decarbonize super-critical power plants and to improve the plant time flexibility using its energy storage capability. The coal and lignite super-critical power plants have 1000 MW net output with a 90% decarbonization rate. Corresponded non-decarbonized cases were also considered to calculate the energy and cost penalties for CO2 capture. In-depth evaluations covered the following elements: characterization of decarbonized super-critical power plants with CaL cycle with/without solid sorbent storage; defining a detailed integrated assessment methodology; performing detailed calculations of the main performance indexes and sensitivity studies using various key technical and economic elements. Base load operation without solid storage (as reference) and flexible part load operation with solid storage were assessed to see their influence on the overall performance indicators. The sorbent storage option improves the plant flexible operation (assessed for one-week period), reducing the capital cost by about 7–9% and the levelized cost of electricity (LCOE) by about 4%.