Abstract: Growing energy demands and climatic changes, exacerbated through rapid increases in CO₂ emissions, are two major global issues facing nations. Therefore ongoing research is being conducted on projecting supply / demand scenarios that look to match future energy demands against energy supply mixes. This requires energy providers to foresee the impact of various electricity generation scenarios on CO₂ emissions and to assess the sustainability of, and risks involved with each so that an attitude of energy provision ‘whatever the cost’ does not prevail decision-making in the face of a plethora of electricity supply mixes and/or energy demand predictions is a complicated procedure which requires in depth consideration of the various scenarios that are being developed. This requires a high level of knowledge that is available only within a team of experts. Furthermore forecasting the possible impacts of various electricity scenarios on climate change as well as considering the associated cost just adds more complexity. This paper explores the features and choices available to decision-makers through the development of an Excel-based tool. The tool acts as a database for existing energy supply/demand scenarios and allows the user to look up existing scenarios or mix and match existing scenarios for the UK leading to a range of new possibilities. The benefits of creating and using the developed tool are explored within the paper and it is concluded that the tool begins to address the complex issues of projecting the most appropriate electricity supply mix and electricity demand by using a range of existing energy studies. In so doing it facilitates greatly decision-makers in beginning the process of further assessing the risks that might be involved. An example of using tool for developing three very different supply mix scenarios for the UK (including one with high share of interconnections) is provided.