Brazil generates practically all its 240 GW as hydroelectric power, leaving fossil fuels (mainly petroleum) for use in transport; its biofuel programme for motor vehicles is by far the largest in the world. Sugarcane juice is fermented and distilled to give ethanol (containing 5-7% water as the only major impurity), which is used directly in 4 M vehicles and as lead-free gasohol (10-22% ethanol) in 7 M vehicles; in ~10 years, lead pollution in São Paulo and other cities fell by 75%. From 1978 to 1986, the ethanol yield per hectare of sugarcane increased from 2700 to 3700 litres. Since most sugarcane in Brazil is harvested manually and the factories use bagasse as fuel, the major consumption of fossil fuel by the industry is in preparing land for planting (necessary every 7-10 years) and in transporting cut cane to factories. The amount of N fertilizer needed is low (60-80 kg/ha) thanks to N-fixing bacteria; with further research, it might be eliminated, improving the effective energy balance. Smoke and soot from cane burning causes pollution, and soil fertility improves if unburned cane trash is left on the fields, but the higher labour cost of harvesting unburned cane dissuades most producers from abandoning cane burning. Replacing gasoline by bioethanol has caused problems for the state-owned oil refineries of Petrobras, which produce more gasoline than needed because throughput is governed by the demand for diesel fuel, and the ratio between the outputs of these fuels cannot be altered much. It has been estimated that the whole diesel consumption could eventually be substituted by renewable oil if African oil palm could be planted over 5-6 Mha of Amazonia (i.e. 15-18% of the area already deforested); the investment required is unlikely to be committed.