- Created on Sunday, 16 September 2012 19:39
World demand for energy is expected to more than double by 2050 and more than triple by the end of the century. At the same time, oil prices are rising and fossil fuel reserves are diminishing. The alleviation of dependence on imported oil is a major concern for many countries. Biofuels have been identified as one component in reducing countries dependence on foreign oil and its contribution to climate change.
Biofuels – broadly defined as any fuel derived from biomass which is living or recently living plant material – offer some of the most promising alternatives to decrease dependence on traditional fossil fuel sources (oil, gas, petrol, coal, etc). Biofuels offer the only immediate alternative to fossil fuels, help limit impact on the environment from fuel emissions and are the only direct substitute for oil in transport that is available on a significant scale in most countries. All new biofuels production under the recently-passed Renewable Fuels Standard (RFS) must meet stringent greenhouse gas reduction targets.
Types of biofuels
Ethanol - is liquid alcohol and is obtained from the fermentation of sugar or converted starch contained in grains and other agricultural or agri-forest feedstocks.
Feedstocks - Starches (maize, grains, potatoes), sugars (sugar cane, sugar beet), biomass. It is used primarily as a blended with petrol to use as transport fuel.
Biodiesel - is a non-toxic, biodegradable fuel. Most biodiesel is made from oily feedstocks in a process called transesterification, where the oil reacts with an alcohol (usually methanol) in the presence of a catalyst (such as sodium hydroxide).
Feedstocks - Vegetable oils (canola, maize, cottonseed, palm, soy, sunflower) animal tallow, recycled greases. Biodiesel is used as a replacement for diesel or in a blend with traditional diesel fuel. It is used primarily as a transport fuel, but can replace diesel in any engine.
Biogas - consists mostly of a gas called methane. Bacteria produce methane as they break down cellulosic material, whether in a swamp, or bog, or in an industrial biogas generator, which is an airtight container that allows collection of the biogas for power generation. Another type of biogas is carbon monoxide rich gas made via thermal gasification.
Feedstocks - Landfill gas, sewage sludge gas, corn silage, liquid manure, cereals. Biogas can be used in motors that can use natural gas. Currently only a very small proportion of the biogas production is used in transport. Most of the biogas is used in the production of electricity and heating.
Agricultural products specifically grown for use as biofuels include maize, soybeans, flaxseed, rapeseed/canola, sugar cane, palm oil, cassava and Jatropha. Since the fuel can be made out of nearly any organic matter that ferments, many other forms of biomass can also be used. It can be easily blended with existing fossil fuels and it can be used directly by adapting existing equipment or engines to burn different biofuel products without the need for blending.
How biofuels work
Biofuels work on the principle that plants capture and store the sun’s energy through the process of photosynthesis. By biocatalysis, the energy stored in the plant can be converted into any number of biofuel products. The process of making each type of biofuel is different.
Productivity enhancing technologies, such as biotechnology, have the potential to make biofuels a sustainable energy choice. Simply put, plant biotechnology allows more to be done with the same land. Developments in the plant biotech industry that can help biofuel production are plants that provide greater yields for biofuel crops, plants that provide more oil per unit mass, plants that grow in marginal or degraded soil, and plants that are more suitable for fuel production.
With increased yields, farmers are able to meet the increased demand for material to produce fuel while still providing crops for food. With greater oil content in oil seeds, fewer kilograms of seed are needed to produce a litre of fuel. With more robust plants that grow in marginal or degraded soil, farmers can use previously unproductive land to grow crops that can be used for fuel. The possibilities are many.
Other than plant biotechnology, a number of other factors can prevent fuel from being produced at the expense of food. In many cases, a plant can produce both commodities – first the food can be processed, and the remaining plant material be used to produce fuel. For instance, bagasse is the biomass remaining after sugarcane is crushed to extract the sugar. Bagasse is a feedstock for sugarcane-based ethanol.
Furthermore, many of the most suitable biofuel crops are not usually used as food. Sweet sorghum, Jatropha, switch grass, types of wood and other non-edible plants are all ideally suited for the production of fuel.
Finally, it is likely that second-generation biofuels feedstocks will be available within 5 to 10 years. These second-generation feedstocks are typically non-food plants, such as switchgrass, and will not affect the food supply.
An important measure of fuel efficiency is the energy returned on the energy invested in producing that fuel.
The production of any fuel requires the investment of energy. For instance, making petrol requires pumping crude oil, transporting the crude oil and refining it into petrol. Similarly, producing biofuels requires cultivating a feedstock, usually an agricultural crop, harvesting the crop, transporting it to a site and converting the feedstock into biofuel.
Most research shows that the energy balance for biofuels is positive; more energy is returned than invested in the production of a biofuel.
The energy required to produce biofuels is declining every year as more research is conducted into how to best produce biofuels. In fact, most studies show that biofuels return more energy than is invested in producing them. At the United States Department of Energy's Argonne National Labs, Dr. Michael Wang conducted an extensive review of all the studies on biofuels, which showed that the majority of studies find a positive energy balance for corn ethanol at somewhere between 1.3 and 1.8. As a comparison, petrol has an energy balance of only 0.08, according to Dr. Wang’s study.
Economic impact of biofuels
Of the world’s 47 poorest countries, 38 are net oil importers, and 25 of these import all of their oil. Yet many of these countries have substantial agricultural bases and are well-positioned to grow highly productive energy crops. Over the last 10 years, biotech corn has produced an additional 1.9 billion gallons of ethanol, enough to power more than 2.5 million cars for an entire year.
The World Bank reports that biofuel industries employ about 100 times more workers per unit of energy produced than the fossil fuel industry. The ethanol industry is credited with providing more than 200,000 direct jobs in the United States and 500,000 direct jobs in Brazil.
Biofuels can also help limit demand for petroleum and hence contribute to limit the upward pressure on petroleum prices. According to a study published in 2008, 485 million barrels of ethanol were produced in 2007/2008, which is equivalent to 320 million barrels of gasoline. If these 485 million barrels were not available for use, the world’s oil refiners would need to produce an additional 1.9 million barrels of crude oil per day, or 2.2% of current world production. Given that oil supply does not expand easily, meeting such an increase in demand would likely result in a short-term price increase of 27.5%.