The country's energy supplies were delivered entirely by wind, solar and hydro power between May 7th and 11th
Portugal has successfully run on only renewable energy sources for more than four consecutive days.
An analysis by Zero shows that the milestone was achieved between 6.45am on Saturday May 7th and 5.45pm on Wednesday May 11th - a total of 107 hours.
During that time, consumption of electricity in the country is said to have been fully covered by renewable energy sources such as wind, solar and hydropower without having to resort to natural gas or coal.
The CEO of SolarPower Europe, James Watson, told The Guardian that the 'significant achievement' of Portugal "will be commonplace in Europe in just a few years".
A report last month found that Ireland needs to treble efforts to upgrade homes and businesses for energy efficiency if we are to avoid fines of up €130 million.
The report suggested that while 40,000 homes and 550 businesses are using some form of renewable heat technologies, that level needs to increase sevenfold.