The purpose and focus of the Hydrogen Turbines project is to improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs.The final deliverable (D2) comprises eight separate components. This document is D2 WP3 Report – providing a series of supporting studies:Identification of potential salt cavern locationswithin UK and first 25 miles of UK Continental Shelf;Salt cavern cost structure;HSE challenges of cavern construction and operation;Managing loss of containment;Licensing and build timeline;Alternative cavern use; andLandscapingstudy of alternatives to salt caverns.