Earlier this month, the country of Portugal set a new landmark achievement in power usage, with the entire country running on electricity generated solely from renewable sources; including solar, wind, and hydro-electric for a little over four days straight.

The 107-hour record was announced by Portugal’s ZERO System Sustainable Land Association, in collaboration with the Portuguese Renewable Energy Association (APREN), covering a period beginning in the morning on May 7, and concluding in the evening on May 11, a little shy of four-and-a-half days.

"These data show that Portugal can be more ambitious in a transition to a net consumption of electricity from 100 percent renewable, with huge reductions of emissions of greenhouse gases, which cause global warming and consequent climate change," according to ZERO’s website.

This achievement follows a similar event from Germany, where the country ran on 95 percent renewable energy over the course of May 8. During that period, the cost of energy production went so low as to run into negative numbers. "Power prices actually went negative for several hours," according to Quartz reports, "meaning commercial customers were being paid to consume electricity."

Clean energy runs like this won’t be quite the norm for a while yet, since many forms of renewable energy literally rely on the weather — in the case of the German event, the country had a fortuitous run of high winds and sunny weather. But as more regions convert over to renewable sources, we will see events like this more often.