Since 1972 I have been advocating construction of a worldwide electrical grid, permitting complete replacement of fossil fuels by solar energy.
This grid would solve solar energy's chief problem — its extreme variation from day to night, summer to winter, and good weather to bad weather. It could eliminate the need to store electricity for when the sun isn't shining, since the sun is always shining somewhere in the world.
The grid would just transmit solar energy from where it can be generated to where it is needed.
It recently occurred to me that the worldwide grid — originally proposed by Buckminster Fuller in the 1930s — is no longer just a good idea. It is already being built!
The people currently constructing the grid may not be aware that they are doing this. They are just building larger (but still not universal) grids in order to increase efficiency and decrease the cost of delivering dependable power to consumers.
They are taking advantage of opportunities created by improved electrical technology.
A number of long-distance high-voltage direct current (HVDC) lines have been built, and more are under construction. Connections between various European countries are already operating, as are long-distance lines in North America, China, Africa and South America.
Plans are afoot for a connection bringing solar energy from sunny Morocco to the United Kingdom. A 2,600 mile subsea cable will carry solar energy from Australia to Singapore. And a 9,300-mile line between the Chilean desert and China is being seriously discussed.
All of these existing and projected grids will be elements of the universal grid when the logic of the situation has taken its full course and they get connected together.
The "logic"of the situation rests on the fact that in any network the value of each part of it becomes greater the larger the network is. The internet, for example, has made each individual computer connected to it far more useful and valuable than it would be if it could not communicate with so many other computers.
When locally available solar and wind energy exceed local demand, their production has to be "curtailed" — turned off — wasting the energy they could have provided. With a better connection to a larger grid this surplus could be transmitted to another location, allowing less coal or natural gas to be burned there.
The supergrid will minimize curtailment, allowing local surplus to go anywhere in the world where current conditions are not favorable for solar energy.
Solar PV panels are better investments the bigger the grid they are connected to. But they are already valuable enough to motivate the investments needed to produce the smaller grids.
Larger grids will also allow local utilities to buy the cheapest possible electricity from a wider area, fostering healthy competition between producers and benefiting consumers.
For awhile the world may be divided into two supergrids — one for the Americas (north, central, and south) and possibly Antarctica, and one connecting Europe, Asia, the Middle East, Africa, Australia and Asia. These two grids, basically north-south connections, will cancel out the large seasonal variations in energy since winter solar lows in the northern hemisphere will be balanced by highs in the southern hemisphere, and vice versa.
Ultimately the eastern and western grids will probably be connected, to take full advantage of time zone differences. Local demand for electricity rises and falls each day, but peak demand does not occur simultaneously in all time zones. East-west transmission will allow daily differences in peak demand to come out in the wash.
The world's grossly inadequate political institutions appear unable to accelerate the move to solar energy and in some respects are even impeding it, but this energy is now so cheap that market forces are driving it forward.
But will this happen fast enough? We must hope it will enable discontinuance of fossil fuels before they wreck the world climate.