I am going to be a wet blanket and explain, briefly, why Dr. Jacobson’s ideas, while visionary and incredibly appealing, are also simply not possible.Before I go much further I want to give a hat tip to physicist Dr. Jani-Petri Martikainen at the blog PassiiviIdentiteetti [I copy and pasted that name as I had no chance of spelling it correctly otherwise]. As readers of my blogs know I have already looked at Dr. Jacobson’s work in three previous blog postings:Deconstructing the 100% Fossil Fuel Free Wind, Water and Sunlight USA paper – Part I Why no nuclear power?,Deconstructing the 100% Fossil Fuel Free Wind, Water and Sunlight USA paper – Part II What about those pesky rare earth metals?, andDeconstructing the 100% Wind, Water and Sunlight scenarios – Part III Issues with energy storageIn those blog posts I looked at big picture features of the Jacobson model but I never dug down into the country-specific numbers. This week I was directed to a brilliant blog post by Dr. Martikainen Part 1: Why does Mark Jacobson hate Finland? that humorously skewered the work by looking at the assumptions for a single country (Finland) to show how many of the conclusions aren’t based on reasonable assumptions. This encouraged me to go to the supplementary information that came with the paper, in particular the spreadsheet used to do the calculations. Dr. Martikainen’s blog thus served as the inspiration for this blog post.