Unlike oil and coal, which are compressed forms of energy, renewable energy requires unusually large land areas. This article calculates the consequences of a switch to hydrogen-cell vehicles powered by electricity from wind turbines. It then re-does the calculation for three other green energy...

Countries often spend billions on university research. There is growing interest in how to assess whether that money is well spent. Is there an objective way to assess the quality of a nation's world-leading science? I attempt to suggest a method, and illustrate it with modern data on economics....