Renewable fuels are energy sources which are produced from renewable resources. These include biofuels, hydrogen fuel, and other energy sources that can be replenished. They are in contrast to non-renewable fuels, which are petroleum, natural gas, LPG, and other fossil fuels. This can include nuclear energy. There are numerous efforts underway to develop the technologies and fuels that renewable energy requires.
Cellulosic biomass biofuels
Cellulosic fuels are renewable and clean energy resources derived from biomass. This source of energy is a great resource that can help the US reach energy independence. Since 1995, the National Renewable Energy Laboratory (NREL) has been researching cellulosic ethanol. It manages the National Bioenergy Center which has been developing cellulosicethanol as an alternative to gasoline.
Biodiesel
Biodiesel can be made from renewable resources. It is a cleaner-burning alternative to petroleum diesel. It produces lower levels of emissions than petroleum diesel and can be biodegraded (as fast or faster as sugar). It has many advantages for the environment, and the economy. Biodiesel can also be made from locally grown crops. Some projects even make biodiesel from kitchen waste.
Bioethanol
Bioethanol can be made by fermenting sugars with oxygen. The yeasts are facultative anaerobes living in sugar-rich environments. Yeasts used in bioethanol production can be either obtained from culture collections or isolated from their natural environments. The best yeasts for bioethanol production are those that are naturally grown. They are more efficient at converting sugars and alcohol.
Biomethane
Although the biomethane-renewable fuel industry is quite small, there are significant opportunities for growth. It can also be used on existing infrastructure. Policy changes that reduce the carbon footprint of gas supply will determine the future growth of the biomethane market.
Bio-diesel
Bio-diesel is an alternative fuel that is produced from renewable resources. It is the preferred fuel of the U.S. government. It is also used in manufacturing and construction. As the demand for diesel-powered cars decreases, this renewable fuel is expected grow in popularity. Diesel-powered passenger vehicles account for just 1% of all U.S. vehicle sales.
Bio-ethanol
Ethanol is a biofuel that is produced from fermentation of carbon-based fuels. These feedstocks, which use sunlight to generate energy, are renewable in that they return all the nutrients used for their growth back to the soil. These feedstocks include sugar cane, sugar beets and bagasse as well as cellulose wastages.