Tesco, the world's third-largest retailer, opened a new store (december 2009) in Ramsey, Cambridgeshire, United Kingdom, that is the first zero-carbon store of this company. It uses a biofuel combined heat and power (CHP) plant producing more than the building needs and selling the excess back to the grid. The store also incorporates a number of environmentally friendly design features and technologies, including sustainably sourced timber frame, roof lights and sun pipes that allow natural daylight into the sales floor and staff areas, energy-efficient heating and air conditioning systems, natural ventilation, rainwater collection to flush the toilets and run the carwash, low global warming potential refrigerants in the refrigerators, heating, ventilation and air conditioning systems, the first LED-lit car park in the UK, solar-powered streetlights, energy-efficient equipment, such as low-energy bakery ovens.