While MacKay's work is excellent for a general lay audience to understand general scales of the issue, there are now far more advanced models for this that do things like replay historical weather and demand, down to 15 minute scales, to more least cost systems for zero carbon grids.

They are also so advanced as to take into current grid structure and generation resources, and the cheapest way to transition to zero carbon from our current resources.

Christopher Clack's models are probably the most advanced. The latest iteration has the very surprising finding that deploying lots of grid-edge solar and storage right now will save us a ton of money because it will use current transmission and distribution assets more effectively and reduce the need for future investment in these assets (T&D is the majority of our electricity bills, not generation!)