This working paper summarises the results of a scenario development exercise by team members of the Tyndall Centre research project: The Hydrogen Energy Economy: Its Long Term Role in Greenhouse Gas Reduction. The project's aim is to develop and assess alternative transition paths to the widespread use of hydrogen in the UK in 2050. It develops four alternative energy scenarios for the UK in 2050, with a particular focus on the role for hydrogen within each. The working paper begins with a short methodology section that puts the scenario exercise into context. This shows how the scenarios link with the other elements of the project, particularly the analysis of alternative pathways for hydrogen to 2050. Following this, the paper sets out the basic scenarios framework that has been employed, including examples of its previous use within the UK government. The paper builds on these previous uses, and elaborates each scenario with a specific focus on the consequences for hydrogen production, transmission and use. It also quantifies UK energy demand growth and estimates hydrogen's contribution to demand for 2050. This quantification process also draws on previous work, particularly that by the Performance and Innovation Unit (PIU) within the Cabinet Office. The results summarised in this working paper include a wide range of possibilities for the future of hydrogen within the UK: from a World Markets scenario in which there are no explicit drivers for hydrogen to a Global Sustainability scenario in which hydrogen becomes a central component of the UK energy system. These results are being used within the project to model a set of transition pathways from the present energy system to alternative possibilities for 2050. A stakeholder workshop is planned to critically examine these pathways. The outcomes will help the project team to identify the technology breakthroughs and policy decisions that are necessary features of each pathway.