Seb, the idea of a global power grid has a history extending well into the last century, and it has everything to do with attempting to provide a rational foundation for the religion of renewable energy.

"It would take a tiny piece of the Sahara Desert to power the world," or so the logic goes. Yet that any country would permit itself to become dependent for its supply of electricity on either the weather, or one country in Africa, is trivially absurd.

Allowing religion to guide rational decisionmaking has always had disastrous consequences, but none greater than now.

Nonsense, sorry for that. Sun and wind power have been created as distributed resources. The intermittency is a part of the beauty. Mankind has to utilize them in their locations. This is a kind of energy resources democracy.

So much is wrong with that idea!  The articles lists a few problems, the other commenters a few more.

Rather than add to the list, I'll point out something it gets right: 

The global super-grid idea is a proposed solution to a very serious problem with renewable energy, namely the local variability.  The US gov department of energy has funded many studies that show that using long distance transmission to aggregate renewable resources over a large area does tend to reduce the variability.  Unfortunately, the resulting variability is still too high, even over areas as large the existing US grids (i.e. CAISO, West, SPP, ERCOT, MISO, Southeast, PJM, JYISO, and ISO-NE).  Hence, adherents hope that ever more interconnection will solve the problem.

It is long past time for the environmental community to accept renewables for what they are: a way to prolong our addiction to fossil fuel while pretending to do the opposite.  Fossil fuel is by far, the best way to cope with variability on the grid, and renewables add more variability.

We must ultimately admit that deep decarbonization via renewables also requires a significant use of fossil fuel with CC&S (with all the problems that will entail), or simply adopt the only solution which has ever produced a deeply decarbonized grid in the real world: nuclear combined with hydro.