China may be tightening the tap on North Korea’s oil supplies. But Pyongyang may have found a “green” way to thumb its nose at Beijing and demonstrate its philosophy of “juche” or self-reliance.

38 North reports that North Korea is quickly expanding the acreage it’s devoted to algae ponds that can be utilized as a sustainable source of biomass energy. The respected Johns Hopkins University website dedicated to analysis of North Korea notes in an article that the nation has constructed more than 25 acres of ponds for algae production in less than two years.

The well-managed and cultivated facility only has the capacity to produce the equivalent of 350-600 barrels of oil per year. But 38 North notes the facility outside Wonsan, North Korea, “suggests growing interest in developing algae as a strategic resource to diversify sources of energy supplies and improve agricultural production, which could over time reduce the country’s vulnerability to sanctions.”

Algae fuel, also known as algal biofuel, or algal oil, is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Algae could also be used as a food source in the famine-prone country.

While the exact purpose of the North’s algae production isn’t known, the analysis said that it’s potentially “a multipurpose resource that can be used to produce food, fertilizer, feedstock and fuel all from the same biomass.”

“Such a resource could certainly have strategic value for North Korea and could, over time, mitigate the negative effects of sanctions both on the country’s energy supply and food security,” the article added.

38 North notes that Pyongyang’s stress on juche has historically encouraged it to invest large amounts of capital on projects that would otherwise seem futile in a free market economy with global access.