Generating electricity is one of the issues for very remote mine sites which are 'off the grid'. Usually diesel fuel is transported to the site to power conventional generators. Rio Tinto has recently switched on stage one of Australia's first hybrid photovoltaic solar - diesel generating system at it bauxite mine at Weipa in far north Queensland. While it is estimated that the hybrid system will reduce the use of diesel fuel by 600,000 litres per year and reduce greenhouse gas emission by 1,600 tonnes per year, the diesel back-up will be used to manage the variability of the solar generation in order to maintain reliability. The plant was built with financial backing from the Australian Renewable Energy Agency (ARENA).