Hydrogen usage and storage may contribute to reducing greenhouse gas emissions by decarbonising heating and transport and by offering significant energy storage to balance variable renewable energy supply. Underground storage of hydrogen is established in underground salt caverns, but these have restricted geographical locations within the UK and cannot deliver the required capacity. Hydrogen storage in porous geological formations has significant potential to deliver both the capacity and local positioning. This study investigates the potential for storage of hydrogen in porous subsurface media in Scotland. We introduce for the first time the concept of the hydrogen storage play. A geological combination including reservoir, seal and trap that provides the optimum hydrogen storage reservoir conditions that will be potential targets for future pilot, and commercial, hydrogen storage projects. We investigate three conceptual hydrogen storage plays in the Midland Valley of Scotland, an area chosen primarily because it contains the most extensive onshore sedimentary deposits in Scotland, with the added benefit of being close to potential consumers in the cities of Glasgow and Edinburgh. The formations assessed are of Devonian and Carboniferous age. The Devonian storage play offers vast storage capacity but its validity is uncertain due to due to a lack of geological data. The two Carboniferous plays have less capacity but the abundant data produced by the hydrocarbon industry makes our suitability assessment of these plays relatively certain. We conclude that the Carboniferous age sedimentary deposits of the D'Arcy-Cousland Anticline and the Balgonie Anticline close to Edinburgh will make suitable hydrogen storage sites and are ideal for an early hydrogen storage research project. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.