From the “Dirty 30” list to world’s cleanest — and 4 days of 100% renewable energy – in less than 10 years: Portugal

Last week, Portugal set a record for renewable energy use. Through a combination of hydroelectric, solar, and wind power, electricity use in the country was completely covered for four consecutive days.

The news was reported by the Portuguese Renewable Energy Association (APREN) in collaboration with ZERO System Sustainable Land Association. According to their measurements, from 6:45 a.m. on Saturday, May 7 to approximately 5:45 p.m. on Wednesday, May 11, Portugal was able to rely entirely on renewables for an impressive 107 hours, the longest the country has ever been able to go.

Renewable energy records like these are something Portugal has been striving for: The country is working to create a dramatic shift in how it is powered. Portugal was previously considered one of the European Union’s top producers of CO2 emissions, and in 2007 its coal-burning power plant Sines ranked 13th in the continent on the World Wildlife Fund’s “Dirty 30” list.

But recent years have seen a shift in Portugal, and while coal and natural gas have traditionally served to power the nation, there has been a concerted effort to move to renewable sources of power. This means the country has been investing significantly in alternatives to fossil fuel, creating opportunities for renewable energy streaks. In 2013, renewables powered 70 percent of Portugal’s electricity for three months, and in 2014 approximately 63 percent of its electricity for the year ultimately came from renewables. A drought in 2015 saw a decrease in Portugal’s ability to rely predominantly on clean energy, but last week’s success has sparked high hopes for 2016, in addition to furthering the country’s efforts in moving away from fossil fuels.

Portugal has favorable conditions at its disposal as it works to shift away from fossil fuels. Despite having a limited amount of offshore wind capacity, the country is one of the sunniest in Europe, and enjoys a significant amount of access to hydropower due to its coastal location. Hydropower is Portugal’s leading source of renewable energy and accounts for 30 percent of its electricity, with wind, biofuels and waste, solar, and geothermal energy accounting for the remainder. Natural resources aside, the Portuguese government has also played a crucial role in ensuring the nation’s transition towards sustainable energy. In working over the course of the past few years to replace oil and coal with renewable alternatives, the government has managed to change Portugal’s image as a fossil fuel-dependent nation into that of an energy leader.

Still, there are a few drawbacks to Portugal’s success. Hydropower is highly vulnerable to climate change. Droughts, like the one Portugal experienced in 2015, can severely impact hydropower, as can any shift in rainfall. Hydropower can also be destructive to the environment. Hydroelectric dams can disrupt wildlife and introduce low dissolved oxygen levels into water, and in some cases can even end up emitting significant amounts of planet-warming greenhouse gases. While the Portuguese government has invested millions in working to counteract climate change and create lasting and sustainable energy alternatives, the downsides to some of those alternatives can’t be ignored.

Potential pitfalls aside, Portugal’s recent achievement still speaks to the possibilities inherent in renewables. And it isn’t the only European country to have a recent renewable energy victory. Germany also set a record last week when, for a brief moment, 90 percent of its total electricity demand was met by renewable power. Germany is in the process of shifting entirely off of nuclear power by 2022 and doubling the percentage of renewables it uses by 2035 — something that its new milestone helped move along.

Portugal and Germany’s successes aren’t likely to be isolated. Austria and Scotland are also looking to boost their reliance on renewables, with respective emphases on hydro and wind power, further shifting Europe towards sustainable energy. Portugal’s achievement last week remains an impressive outlier at present, but in time it could be a regular occurrence.