The UK’s Department of Energy and Climate Change has a very nice interactive web application that can be used to investigate the impact of various choices regarding energy production and use (for example, an emphasis on solar power, or the electrification of all transport, or better insulation for all homes) upon greenhouse gas emissions and the amount of land required to be devoted to different modes of energy production in the UK of 2050.
The app is necessarily sophisticated, and therefore somewhat difficult to use, but I recommend persevering–the results are fascinating. It’s both surprising and disturbing to discover how much land needs to be devoted to energy production and/or carbon capture to meet greenhouse gas emission targets. (The number of turbines required for the most ambitious level of onshore wind generation works out to be the equivalent of a turbine every 600 metres alongside every motorway, dual carriageway, and trunk road in Britain.)
To get a feel for how the app works, I suggest starting with the “Example pathways” dropdown menu in the top right. From here you can choose from a list of presets–more nuclear, more offshore wind, etc.–as well as the strategies of a few prominent individuals and groups. (The image at the top of this post shows the land required to be devoted to different energy-production modes under the Friends of the Earth’s scheme.)
It would’ve been nice if the costs of different schemes were considered, but I suppose this is fairly hard to estimate. Still, cost does make a difference. (Also not considered: whether nuclear energy and geosequestration are safe.)