Film lovers in the UK have already experienced screenings projected the environmentally friendly way with the pedal-powered Cycle-in Cinema. In Brazil, the Santa Rita do Sapucaí prison has taken a similar approach in its attempts to produce green energy – harnessing the pedal work of its inmates. According to reports, two exercise bikes have been placed in the courtyard of the penitentiary and are hooked up to batteries. Cyclists’ kinetic energy is converted into electricity which charges the battery and a device on the handlebars alerts the rider when it’s time stop. The fully charged batteries are then taken into the city and used to power street lamps – one day’s cycling can provide enough energy to run six light bulbs. On a mass scale, the country’s prisoners could be a source of alternative energy for illuminating a city’s worth of street lights. In order to incentivize use of the bikes, city judge José Henrique Mallmann is waiving a day off the sentence of prisoners for every 16 hours pedalling they complete. The facility aims to install a further eight bikes following the success of the scheme. The idea enables prisoners to keep fit, wardens to benefit from occupied detainees and offers a source of sustainable energy. One for expansion and adaption near you? Spotted by: Judy McRae