Coming up with alternative energy sources is essential due to the energy demands of a growing population and dwindling supplies of fossil fuels. This list is an overview of available alternative sources of energy:
Biofuels: Biofuels are made of biomass products and can be used to generate electric power as well as fuel transport. Crops and crop residues (particularly corn) are used to produce ethanol, a liquid commonly added to gasoline. Other grains such as wheat, rye, and rice are used to produce biofuels. Soybeans, peanuts, and sunflowers are used to make biodiesel fuel.
Biomass: Biomass is sawgrass, mulch, corn, and so on, that can be burned in raw form or processed into liquid fuels or solid fuels. Wood and grasses are directly combusted to provide heat for boilers which can drive turbines and produce electricity. Corn, animal waste (yes, poop!), and wood pellets are burned in residential stoves to provide heat.
Electric vehicles: Electric vehicles use only electricity to power the drive train. The electricity comes from batteries or fuel cells.
Fuel cell–powered vehicles: Hydrogen fuel cells combine oxygen and hydrogen to produce water and electrical energy. The fuel cells are used to propel either an electric vehicle or a hybrid.
Fuel cells: Fuel cells produce electrical power from nothing more than hydrogen and oxygen, are completely free of carbon, and exhaust only water and heat.
Geothermal power: Heat from the earth is redistributed into a building or is used to generate electrical power.
Hybrid vehicles: Hybrid vehicles are a combination of electric and internal combustion power trains. When power requirements are low, the vehicle operates in electrical mode. When more power is needed, or when the electrical batteries are near depletion, an internal combustion engine provides power.
Hydropower: Dams provide high-pressure water flows that spin turbines, thereby creating electricity. Hydropower can be used on both a macro and micro (individual) level.
Nuclear fission: Splitting atoms creates heat energy, which is used to generate electrical power by spinning large turbines.
Solar power: Solar power uses sunshine to create both heat and electricity, as well as passive heating and cooling effects in buildings.
Wind power: Windmills produce electrical power via spinning turbines.