Biofuels are solid, liquid or gas fuels made from recently-harvested biological material (biomass). Most biofuel is derived from plants, either crops grown specifically for fuel use or material left over from plants harvested for other uses.
Burning biofuel releases carbon dioxide to the atmosphere, just as burning any other fuel does. However, unlike fossil fuel, biofuel can be renewable and low in carbon intensity -- if it is derived from plants that are grown sustainably (with new growth continuously replacing harvested material).
In New York State there is some unproductive and marginal farmland with the potential for growing dedicated energy crops for cellulosic biofuels production. In addition, more than 18.5 million acres of New York timberland are being renewed at a rate greater than 3 to 1, meaning that low-grade timber can be harvested in a sustainable manner for producing energy.
Emissions, health effects and land use impacts associated with biofuels are not well understood. The State Task Force on Renewable Energy points out the need to examine environmental impacts of biofuel production, particularly on local water and air quality, as well as the land use impact from diversion of crops and the larger impact on the agricultural industry.
- Biofuels can be low in carbon intensity (the net amount of carbon released to the atmosphere) - as long as uptake by other growing plants balances the carbon that is released in biofuel production and use.
- Locally-grown biofuel can enhance energy security by increasing independence from petroleum.
- Some biofuels may burn more cleanly than fossil fuels, though considerable study is still needed to identify all biofuel combustion products and pollutants.
- Marketing of biofuel feedstocks can boost the profitability of farming and logging, and improve the economies of rural communities.
- Some biofuel formulations remove materials, such as used cooking oil or logging waste, from the waste stream. In addition to recovering energy that would otherwise be wasted, use of biological wastes for fuel saves the cost, pollution and carbon release associated with traditional disposal.
How Biofuels are Made
The energy that we get from biofuels originally came from the sun. This solar energy was captured through photosynthesis by the plants used as feedstocks (raw materials) for biofuel production, and stored in the plants' cells.
Many different plant materials can be used for biofuel:
- Sugar crops (such as sugar cane or sugar beet), or starch (like corn or maize) can be fermented to produce ethanol, a liquid fuel commonly used for transportation.
- Natural oils from plants like oil palm, soybean, or algae can be burned directly in a diesel engine or a furnace, or blended with petroleum, to produce fuels such as biodiesel.
- Wood and its byproducts can be converted into liquid biofuels, such as methanol or ethanol, or into woodgas.
- Wood can also be burned as solid fuel, like the familiar firewood. Chipped waste biomass, such as the tops of trees discarded by logging operations, can be burned in specially designed furnaces.
Researchers are working to improve biofuel production processes. Before bioenergy can make a larger contribution to the energy economy, feedstocks, agricultural practices, and technologies that are efficient in their use of land, water and fossil fuel must be developed.
The federal Energy Independence and Security Act of 2007 called for advanced biofuels, including cellulosic ethanol and biomass-based diesel. Federal law mandates production of 9 billion gallons of renewable fuel by 2008, with production to rise to 36 billion gallons by 2022.
Biofuel is usually used as liquid fuel for transportation, mixed with fossil fuel. The United States produces mainly ethanol (most of it currently from corn) and biodiesel.
Ethanol. The US currently produces some 7.2 billion gallons of ethanol per year. Fourteen per cent of the US corn crop is now dedicated to ethanol production, and the USDA says that is expected to rise to 30 per cent in 2009-2010. Most US cars can run on blends of up to 10 percent ethanol, while "flexible-fuel" vehicles can use gasoline and ethanol blends as high as 85 percent ethanol (E85).
Cellulosic biofuels. Cellulosic biofuels, made from non-food crops, are under development but not yet in production at industrial scale. Research on cellulosic ethanol is currently underway at several major research institutions in New York, focusing on regionally available feedstocks.
Biodiesel. Commercial production of biodiesel in the United States began in the 1990s. The US Energy Information Administration says that the country produces around 500 million gallons of biodiesel per year.
Biodiesel is a diesel fuel derived from biological sources such as soybean oil, animal fats, waste vegetable oils, or even some strains of algae. In the United States most biodiesel currently is made from soy oil, but this fuel can also be made from other vegetable oils, including rapeseed (canola), palm tree, olive, peanut, safflower, sunflower, and castor. The most common feedstocks for biodiesel production in the United States are soybean oil and yellow grease (primarily recycled cooking oil from restaurants).
Biodiesel can be used in place of, or mixed with, petroleum diesel in commercial and personal vehicles, in oil burners (including home furnaces) and in other diesel engines. A fuel blend that includes up to 20 percent biodiesel can be used in most diesel engines with little or no modification.
In times of high oil prices, some people become interested in producing small quantities of biodiesel for use in their personal vehicles or home heaters. However, biodiesel production can be hazardous, as well as smelly and messy, and requires that producers take care not to contaminate the environment or violate tax laws.
Benefits of Biodiesel
- Biodiesel can be a renewable fuel, if the plants used to produce it are grown sustainably.
- Plant-based biodiesel is a low carbon intensity fuel, if the carbon dioxide (CO2) emissions from burning it are balanced by CO2 uptake into a new crop.
- Domestically-produced biofuel can help reduce dependence on foreign petroleum.
- Biodiesel production is a beneficial re-use of restaurant waste grease and animal fat that otherwise might end up in landfills.
Issues Associated with Biodiesel
- When biodiesel is made from food oils, a potential conflict arises between food and fuel uses of the plants and the land where they are grown.
- Air pollutants produced from biodiesel combustion need additional study and, possibly, control measures.
- Like any other biofuel, biodiesel requires energy to transport the feedstock material, to produce the fuel, and to transport the fuel to where it is used. Calculations of the cost-benefit of biodiesel must include energy consumed in the complete life cycle of the material, from field to delivered fuel.
Biofuels in New York State
Currently, New York's renewable fuels infrastructure is based largely on corn-to-ethanol and soybean-to-biodiesel production. Nearly 400 million gallons of corn-based ethanol and agriculture-based biodiesel capacity are currently either in the planning or construction phase, although energy planners see these fuels as a transition to more beneficial biofuels now under development and biofuel producers are already looking beyond grain-based feedstocks.
Life-cycle environmental consequences
Evaluations of the energy balance of biofuels, and of biofuels' contribution to energy independence are currently incomplete. Most such evaluations do not take into account fossil fuel use and emissions from harvesting and transporting biofuel feedstocks, and for most processing of plant material into biofuel, nor do they include land use impacts of expanding the development and deployment of renewable fuels. Crops grown for biofuels are the most land- and water-intensive of the renewable energy sources. In 2005, for instance, about 12 percent of the nation's corn crop (11 million acres of farmland) was used to produce four billion gallons of ethanol-which equates to about 2 percent of annual US gasoline consumption.
Obtaining sustainable feedstocks
Balance between the carbon released by biofuels and carbon uptake by growing plants can be achieved by producing biofuels from feedstocks (raw materials) that come from managed forests or sustainably cultivated crops. However, the metrics of sustainable management, as well as models and measurement tools to assess management, remain to be developed.
Like any fuel, biofuel can be a source of air pollution. Biofuel air pollution is not yet fully understood. Widespread use of these fuels would necessitate further research and, possibly, emission controls. Any use of waste biological materials for fuel requires special care in evaluating air pollution implications.
Biofuel infrastructure and distribution
Existing oil pipelines are impractical for transporting ethanol, because ethanol is very easy to contaminate with water (commonly present in pipelines), and also because most ethanol is produced far from existing pipeline access points. So ethanol will continue to require fuel-intensive (and expensive) truck transport.
More about Biofuels:
- Biodiesel Fact Sheet - Before you consider making biodiesel at home ... Read this fact sheet.