Sweden’s successful waste-to-energy program converts household waste into energy for heating and electricity. But they’ve run into an unusual problem: they simply aren’t generating enough trash to power the incinerators, so they’ve begun importing waste from European neighbors.

When it comes to recycling, Sweden is incredibly successful. Just four percent of household waste in Sweden goes into landfills. The rest winds up either recycled or used as fuel in waste-to-energy power plants.

Burning the garbage in the incinerators generates 20 percent of Sweden’s district heating, a system of distributing heat by pumping heated water into pipes through residential and commercial buildings. It also provides electricity for a quarter of a million homes.

According to Swedish Waste Management, Sweden recovers the most energy from each ton of waste in the waste to energy plants, and energy recovery from waste incineration has increased dramatically just over the last few years.

The problem is, Sweden’s waste recycling program is too successful.

Catarina Ostlund, Senior Advisor for the Swedish Environmental Protection Agency said the country is producing much less burnable waste than it needs.

‘We have more capacity than the production of waste in Sweden and that is usable for incineration,