Ethanol is used extensively as a solvent in the manufacture of varnishes and perfumes; as a preservative for biological specimens; in the preparation of essences and flavorings; in many medicines and drugs; as a disinfectant and in tinctures (e.g., tincture of iodine); and as a fuel and gasoline additive. The International Energy Agency predicts that together, conventional and advanced biofuels will represent 8%, or 400 billion liters, of transport energy consumption by 2025.