Finnish homes could soon be powered by a new type of green energy: horse poop. Fortum, a Finnish energy company, is experimenting with a new biofuel harvested straight from the stables. 

Fortum estimates that the manure of three horses could heat a single-family home for a year, based on a spring pilot with four stables and one power plant. That means Finland’s 70,000 horses could power 23,000 homes. 

The system uses the wooden shavings that already line the stalls of many horse stables. After the horses poop in their stalls, Fortum gathers the wood and manure mix and spreads it on a field to make sure the moisture levels are even. Next, the mixture goes to a biomass power plant, where it’s mixed with other wood shavings (recycled from the country’s large timber industry) and burned. 

Pre-fuel mix. Image Credit: Fortum

So far the pilot tested a combination of wood and waste with only 10 percent manure, but they plan to up the proportion to 20 percent soon, with an expanded pilot of the biofuel system planned for the fall. 

Horse manure doesn’t pose quite the environmental problem it did back in the days of horse-drawn carriages, but it still can pose a water pollution risk. A mixture of horse manure and stable bedding isn’t ideal as compost for plants, and in the European Union, manure can’t be spread on sloped land, lest it run down the hill and into the water supply during a storm. Finnish horse lovers can't dispose of the animals' waste in landfills, either, per a law that takes effect in 2016. Thus, turning what would be stable refuse into energy addresses Finland's poop problem and puts the country back on the road toward replacing a portion of its fossil fuel usage with biofuels. If it proves successful, other horse-loving countries (like the 9.5-million-horse-strong U.S.) might follow suit. 

[h/t: CityLab]