An apparatus made from discarded plastic containers provides hot water, making use of the abundant solar energy of the southern Brazilian state of Paraná. Constructed with bottles made from polyethylene terephthalate (PET) and milk containers, the system varies in size, depending on the need, and heats water up to 50 degrees Celsius in the summer and 38 degrees in the winter.

In addition to recycling containers, the project of the state’s Environment Secretariat saves electricity. “The idea is to stimulate the use of solar energy in a country with a lot of sunshine, while lowering the amount of garbage,” José Alano, inventor of the device, told Tierramérica.

Already 6,000 of these “ecological water heaters” have been produced. The largest, made from 1,800 PET bottles and 1,500 containers, was inaugurated in late July in the town of Palmas.