Renewable Energy in a Nutshell: Liquid Biofuels

The Science

Liquid biofuels are fuels that are produced from biomass feedstock. They can complement and/or replace fossil fuels and reduce carbon emissions in the transport sector with only modest changes to the vehicle’s engine and to existing infrastructure for fuel distribution. They include bioethanol from sugar and starch crops, and biodiesel from oil crops and waste oil.
 
Liquid biofuels are usually referred to as conventional or advanced biofuels.
 
Conventional Biofuel Technologies

The production of 1st generation biofuels is based on well-known technologies that are still evolving to improve energy efficiency and reduce GHG emissions and costs.

• Bioethanol: Commercial bioethanol can be produced from many types of feedstock, including sugarcane, sugar beets, corn, wheat, and potatoes. The biochemical process for production is based on enzymatic or acidic hydrolysis to convert cellulose and hemicellulose into sugars, followed by fermentation and distillation to ethanol.

• Biodiesel: Commercial production of biodiesel is based on trans-esterification of vegetable oils (chemically or mechanically extracted from rapeseed, palm seeds, sunflowers, etc.), animal fats and waste oil through the addition of methanol and catalysts.

 
Advanced Biofuel Technologies

Advanced biofuels promise to be more sustainable, with higher emissions reductions. They are based on biomass resources and land not used for other primary needs, such as food production and farming. A graphic overview of feedstock, processes and output for advanced biofuels is given in the figure below.

The Economics

Conventional Biofuel

The cost of conventional biofuels is very sensitive to the feedstock price, which accounts for 50-60% of the final cost of Brazilian sugarcane and for between 80-90% of the cost of palm biodiesel, corn ethanol and rapeseed diesel (assuming a biomass cost of USD 2-3/GJ and an energy content of 20 GJ/t).
 
The cost of conventional biofuels is unlikely to decrease significantly over time as the cost of conventional feedstock tends to increase in both energy and non-energy markets.
 
Advanced Biofuel

At present, advanced biofuels are significantly more expensive than conventional biofuels, but their cost is expected to become more attractive over time. To become economically competitive with sugarcane ethanol and conventional gasoline, the typical price of advanced biofuels should be as low as USD 0.6 per liter of gasoline equivalent, almost 50% below the current level.
 
Advanced biofuels are more capital-intensive than conventional biofuels. The investment costs for a commercial-scale plant with a capacity between 50 and 150 Mega liters/year range from USD 125-250 million – that is, up to ten times more than a conventional biodiesel plant with the same capacity.
 
Policy Making Implication

Mandates and incentives for blending biofuels with fossil fuels are in place in many countries and contribute significantly to the ongoing growth in biofuel use. However, policy measures should only promote advanced technologies with best performance in terms of land use, GHG reductions and socio-economic impact. Particular support should be granted to biofuel production from residues and to lingo- cellulosic crops grown on non- arable land.
 
At present, the European Union, the United States and other countries provide financial support for advanced biofuels through grants, loan guarantees and feed-in tariff mechanisms. Blending targets or tax credits are also in place in Brazil, China, India, South Africa and Thailand, among others. In the EU, market penetration of biodiesel has been significantly boosted by the establishment of quality standards while sustainability certifications would help regulate the production in developing countries.
 
Canadian Insight