A Proposed Study of Liquid Air Energy Storage (LAES) with Fossil Energy Generation

Coal plants are designed as ‘baseload plants’ and are not able to profitably operate in market environments with negative pricing.This project will define a process model that shows how deep electricity storage of several hundred megawatthours can allow a coal plant to absorb negative or low pricing and benefit from high demand curves. We will show how electricity storage using cryogenically cooled air will be able to use heat generated by the coal plant to recover stored electricity with great efficiency and flexibility. Phase I will seek to develop a liquid air energy storage (LAES) process model using IDEAS modelling framework. Phase II will optimize this model to show how LAES can achieve well over 80% round trip efficiency. In Phase I we will implement a thermally couple LAES system for use with a 400MW sub-critical PC coal plant. This will include modelling a large molten salt thermal storage system that will be connected to a re-gasifying turboexpander. Further, regasification cold can also be used to further cool condenser water which can improve current steam generator performance by another 5% to 10%. The model will reflect 1,000 – 2,000 Megawatthours of energy storage that is supplied with liquid air by a 25 – 40 MW liquefier. The commercial applications include deploying LAES for any high temperature energy generation system, in particular the advanced Coal FIRST plant designs, as well as solar thermal, natural gas-fired cogeneration, and any industrial process that produces high-grade waste heat. These will benefit from improve steam turbine efficiency and a certain inurement to market pricing volatility.