Biofuels
Biodiesel can be used for heating (in place of #2 or #6 fuel oils) or in vehicles (in place of diesel fuel).
Biodiesel is non-toxic and biodegradable. B20 (20% biodiesel, 80% petrodiesel- one of the most common types that is used) reduces total hydrocarbon emissions by up to 30%. Sulfur, carbon monoxide, smoke, and particulate matter emissions are also reduced. Net CO2 emissions are reduced by 15.66% (B100 reduces net CO2 by 78%) due to carbon recycling by the soy plants (based on a life cycle analysis). Environmental benefits increase as greater percentages of biodiesel are used (such as B50 or B80).
Biodiesel for Heating
Bioheat, (also called biodiesel or biofuel), is a blend of heating oil and biodiesel. Biodiesel is most often made from soy, palm, or processed used vegetable oil. Biodiesel can be blended with any type of heating oil, including #2 for residential boilers, #6 for industrial boilers, and ultra low sulfur heating oil. The ratio of heating oil to biodiesel can vary, but it is most often combined as B5 (5% biodiesel), B10 (10% biodiesel), or B20 (20% biodiesel). As the percentage of biodiesel increases, the viscosity increases.
In tests conducted by Brookhaven National Laboratory, bioheat at low blend levels showed little or no negative impact on a burner’s performance while simultaneously improving the emissions, lubricity, efficiency, and cleanliness of combustion. Bioheat has been used in Europe for over 20 years but is just beginning to gain in popularity in the United States. The oil heat industry is trying to get B5 to be certified as the same as standard heating oil, as they are virtually interchangeable in terms of performance.
Boilers do not need to be converted to use bioheat of B20 or less. Biodiesel mixes of greater than 20% can be used, but retrofits might be needed because the control system often shuts down and pumps and seals may break down due to biodiesel’s solvent properties. The use of bioheat in boilers does not have any of the cold weather problems associated with vehicular biodiesel.
Biodiesel’s high solvency properties may cause clogging due to the dissolution of sludge in the boiler, so filters may need to be changed soon after the switch.
Bioheat is regulated by two national standards. The industry standard for biodiesel is ASTM D6751, which ensures that biodiesel is good quality, will perform 
consistently, and meets certain criteria (such as flash point and viscosity). The BQ-9000 is a voluntary quality control program for vendors and manufacturers. It requires that all batches are tested for compliance with ASTM D6751 and includes storage, sampling, testing, blending, shipping, distribution, and fuel management best practices.
Many institutions have tested bioheat including: The Vermont Biodiesel Project, the states of Maine and Massachusetts, Middlebury College, Bates College, Colby College, University of Southern Maine, Eastern Connecticut State University, and Rhode Island Public Schools.
Fact Sheet
Interested in using bioheat at Harvard? Our fact sheet goes through the basics of what you need to know.
Biodiesel for Transportation
For diesel vehicles that want to run on biodiesel, there are two options- converting an engine to run on straight vegetable oil (SVO) or using a biodiesel blend, such as B20.
Straight vegetable oil:
This is a great option for a university, as the dining halls produce a lot of waste vegetable oil that they usually have to pay for to get hauled away. SVO cannot be put directly into an engine, the engine must be converted first. SVO cannot be run the first and last 10-15 minutes of a trip (petroleum diesel is used then) since the oil needs to be heated first. SVO is a great option since it completes the recycling loop and gets around the feedstock issues of biodiesel (ie palm and soybeans). Harvard uses SVO in its recycling truck.
Biodiesel blends:
Biodiesel blends (like B20) can be used in any diesel engine without any retrofits or problems. Harvard has an on-site B20 filling station, which is used by 60+ diesel vehicles.
Biodiesel Feedstocks
Biodiesel is most often made from tallow or soybean, palm, canola, or used vegetable oil. Many of the feedstocks have environmentally harmful practices associated with their production. All biodiesel in Massachusetts (as of August 2007) comes from World Energy, which uses mostly soybean oil processed in Florida as a feedstock (and also some animal tallow and soy from other parts of the United States).
Soybeans
Soybean oil from the Midwest contributes to environmental pollution in the Gulf of Mexico and Midwest, due to the use of pesticides and fertilizers. Additionally, the soy is often genetically modified and raised as a monoculture, which reduces biodiversity.
Fertilizer use increases the amount of N20 (nitrous oxide), a potent greenhouse gas, released into the atmosphere. Nitrous oxide has a global warming potential of 296, meaning that it is 296 times more destructive than an equal amount of carbon dioxide. Two recent life cycle analyses of soybean oil derived biodiesel take this into account. They come to different conclusions about how this impacts the greenhouse gas reductions associated with using soy based biodiesel.
Study 1: Environmental, Economic, and Energetic Costs and Benefits of Biodiesel and Ethanol Biofuels finds that relative to the fossil fuels they replace, ghg emissions are reduced only 41% by using 100% biodiesel (this is a lower ghg emission reduction than non-life cycle studies).
Study 2: N20 Release from Agro-biofuel Production Negates Global Warming Reduction by Replacing Fossil Fuels finds that N2O emissions from fertilizer used in biofuel production can actually increase global warming for certain feedstocks (corn, rapeseed, and sugar cane).
The impact of fertilizer use on biodiesel’s ghg emissions is important, but hard to account for due to the scope of Harvard’s greenhouse gas emissions inventories. There are two main reasons that we cannot take into account the soybean life cycle analysis at this time:
- Standard greenhouse gas emissions inventories do not take into account life cycle analyses for any fuels, including petrodiesel, which biodiesel is replacing.
- Harvard’s greenhouse gas inventory has a limited scope and does not take into account farming (ie. it does not include the fertilizers used to produce the food the dining halls serve), so it does not make sense at this time to include fertilizer impacts for only one product in the inventory.
Palm
Palm oil, which is cheaper to produce and being increasingly used, comes from overseas (countries like Indonesia, Thailand, and Malaysia. The problems associated with growing palm oil include the destruction of the rainforest (a major carbon sink) for farming land and the energy needed to ship the oil overseas to the U.S. It is unlikely that it will be a major feedstock for U.S. biodiesel due to a 4.6% import tariff levied on it.
Waste Vegetable Oil
Waste vegetable oil is the ideal feedstock, since it is a recycled material that Harvard already produces in its dining halls and other facilities. Harvard does not currently have its own processing plant, but an MIT group, Biodiesel@MIT, won $25,000 from MTV and GE to build a processing plant that may have extra capacity to process some of Harvard's waste oil into biodiesel.
More Information:
Massachusetts Oil Heat Council
MA Biofuels Initiative: Moving the Commonwealth to Biofuels
Environmental, Economic, and Energetic Costs and Benefits of Biodiesel and Ethanol Biofuels
N20 Release from Agro-biofuel Production Negates Global Warming Reduction by Replacing Fossil Fuels
The Ethanol Illusion (Harvard Magazine, Professor McElroy)
Water Implications from Biofuels Production in the U.S. (ethanol)