Chile's forward-thinking investments in solar energy has generated so much power that spot prices on solar electricity dropped to zero for 113 days of the year through April.  The country is essentially giving away electricity.

That compares with 192 days in total in 2015; with more than half of the year yet to go, many more days of free solar power are expected to come.

"President Michelle Bachelet's government has set the energy sector as a priority,” said Carlos Finat, the president of Chile's renewable association Acera.  "But planning has been focused in the short term when it is necessary to have long term plans to solve these type of issues," he added.

The South American nation's central grid is now fed by 29 solar farms, and another 15 are planned for construction in the future.  The central grid is not connected to the northern power grid - Chile is responding to the need for better energy infrastructure.  Construction is underway on a 3,000 kilometer transmission line to link the two grids by 2017.  A separate 753 kilometer line is also in development, designed to alleviate congestion in the northern parts of the central grid, where excess electricity is driving prices down to zero.