Portugal managed to keep its lights on without burning fossils fuels, using only renewable energy for four consecutive days this month.  It's the second European country to report great success with its renewables in May, and people in the clean energy sector hope such announcements will become commonplace.

"We are seeing trends like this spread across Europe, last year with Denmark and now in Portugal," said Oliver Joy, Spokesman for the Wind Europe Trade Association.  "The Iberian peninsula is a great resource for renewables and wind energy, not just for the region but for the whole of Europe," he added.

From 6:45 AM on 7 May through 5:45 PM on 11 May, Portugal met all of its power grid needs with only wind, solar, and hydro sources.  That's 107 hours. 

According to the World Economic Forum, Portugal has been making major strides in beefing up its renewable energy sources.  Think a decade ago, when in 2007 the Sines coal-burning power plant ranked 13th in the continent on the World Wildlife Fund’s “Dirty 30” list.  But in 2013, the country reportedly generated 7.5 percent of its electricity with wind power.  And by 2015, that had increased to 22 percent.  The WEF also says Portugal got about half of its energy from renewable sources (including solar and hydro power) in 2015.

"The energy transition process is gathering momentum and records such as this will continue to be set and broken across Europe," said James Watson, CEO of Solar Power Europe.

Germany also hit a milestone on 15 May.  Clean power supplied almost all of Germany's energy needs, producing 45.5 gigawatts as demand was 45.8 gigawatts.