Restaurant fryer oil is a common source of biodiesel A different type of fuel is being made in Atlanta Georgia A white tanker truck pulls up to a restaurant The driver is not looking for a meal She is collecting used fryer oil Restaurants use this oil to make fried foods Used oil usually goes to waste Today scientists can turn it into a fuel called biodiesel Ethanol and biodiesel are biofuels A biofuel is a fuel produced by a biological process such as plant growth Biofuels may someday replace fossil fuels Fossil fuels are today’s most popular energy source They include gasoline and diesel 6
Fossil Fuels Gas and diesel have been used for more than 100 years They are efficient and powerful Crews drill deep into the ground to find petroleum They pump it to the surface This substance is also called oil It is made into gas and diesel Almost all cars run on these fossil fuels Fossil fuels have downsides Using them releases carbon dioxide This gas traps heat in the atmosphere These emissions lead to climate change Another problem is that fossil fuels are 7 Carbon Footprint A carbon footprint is the amount of carbon dioxide each person is responsible for releasing into the atmosphere About 40 percent of a person’s carbon footprint comes from direct energy use Examples of this are riding the school bus or using air conditioning The other 60 percent comes from indirect energy use Examples include eating food that was transported to the grocery store People can reduce their carbon footprints They can buy local foods They can walk instead of drive And they can unplug electronics when not in use
nonrenewable Once they are gone they cannot be replaced Because of these downsides researchers are seeking new energy sources Biofuels Biofuels are sources of energy that come from biomass Biomass is living matter This includes plants Chemical processes change biomass into ethanol or biodiesel Ethanol is a clear colorless alcohol It makes up 70 percent of today’s biofuels Most cars cannot run on pure ethanol It would damage the engine For this reason ethanol is mixed with gasoline Most fuel is sold as E10 It is 90 percent gasoline and 10 percent ethanol 8 Flex-Fuel Vehicles Some new cars can use higher levels of ethanol They are called flex-fuel vehicles FFVs FFVs can run on gasoline or a mix of ethanol and gasoline A sensor in the car determines which fuels are in the tank The car adjusts how the engine runs to match the fuel
Not all engines run on gasoline or ethanol Buses and other large vehicles often use diesel Diesel engines are loud and dirty For this reason many drivers are switching to biodiesel It burns cleaner and quieter Biodiesel makes up 30 percent of today’s biofuels Biofuel Benefits Biofuels have many benefits The first is the price Ethanol often costs less than gasoline When ethanol is blended with gasoline drivers pay less The environment also benefits from biofuels Like fossil fuels they release carbon dioxide when burned However the plants also absorbed carbon dioxide as they grew The total amount of carbon dioxide in the air does not increase much Biofuels are also safer to transport Ethanol that spills will break down safely If an oil tanker spills the oil harms nearby plants and animals Biofuels are renewable Crops can be replanted every year This ensures a steady supply of energy 9
