This article is part two of a short series for October’s National Energy Awareness Month by National Geographic Geography Intern Hannah Dempsey. Find part one on tidal power here.
What do natural gas, oil, sugar cane, corn, and algae have in common? They can all be used to create energy. Biomass energy can be generated from any organic material, but typically comes from crops (like corn, wheat, cotton, and soybeans), wood, and waste—and is often renewable, unlike natural gas and oil.
Creating energy from biomass
There are three ways energy is gleaned from biomass. Biomass can be: (1) burned for heat; (2) converted to electricity—there are several ways this can be done; and (3) processed into biofuel.
Humans have been burning biomass for heat for thousands of years, but only recently have taken advantage of biomass for power. As of May 2016, there were 227 biopower plants in the U.S., utilizing a range of materials such as municipal solid waste, wood chips, agricultural or food waste, or poultry litter to create electricity. The organic matter is dried (or allowed to decompose, in the case of solid waste or manure) and then burned.
Biofuel—ethanol or biodiesel—refers specifically to liquid created from organic material to power transportation. Frequently this comes from corn, soy, algae, or even a whale carcass, and is mixed with traditional fuel like gasoline.
Biofuel is created by pyrolysis or by gasification—processes that heat the organic material at extremely high temperatures in a low oxygen environment and result in a synthetic gas that we can ultimately use as fuel. (Or we can just add some bacteria that munch on plant sugars and produce ethanol themselves!)
Advantages and disadvantages of biopower
Biopower could be a highly renewable and efficient source of energy. We can use waste that would otherwise rot in landfills, plants that can be grown quickly, and materials that can act as a carbon sink during their lifetime.
However, biomass feedstocks can be depleted faster than we can replenish them, making biopower potentially unrenewable by definition. Crop cultivation is relatively quick, but contributes to the costs of industrial agriculture, namely monoculture, pesticides, and water usage—and is somewhat political as well.
There is also the complicated problem of how using food for fuel could affect food prices and availability, but there is little consensus among the economic experts about the impact biofuels could have.
Additionally, biofuel typically is not used by itself and merely assists fossil fuels to power cars.
Most unfortunately, biopower plants burn the organic material, resulting in carbon emissions and air pollution. Algal production is the most promising form of biopower (it doesn’t require arable land nor fresh water) but given technological constraints it is also the most expensive.
Despite these drawbacks, I am convinced that biopower will be a viable, clean, and prolific energy option in the future. If nothing else, we can decrease our municipal and agricultural waste while also creating energy–and hopefully savvy technology will one day provide us all cars that run on plants.
Check out Sanga Moses, a National Geographic Emerging Explorer who provides clean and inexpensive biomass fuel to his fellow Ugandans.
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