6.7 biomass

Objective/Eks/Skill

●Utilized primarily in developing world for heating homes & cooking food
●Easy to harvest, available, cheap/free (subsistence fuel)

Biomass vs. Biofuels 🌽⛽

Biomass organic matter (wood/charcoal, dried animal waste, dead
leaves/brush) burned to release heat - primarily for heating homes/cooking

●Can also be burned in PPs to generate electricity (less common than FFs)

Biofuels 🌽⛽

liquid fuels (ethanol, biodiesel)

created from biomass (corn, sugar cane, palm oil)

●Used as replacement fuel sources for
gasoline, primarily in vehicles

Human health & Env. Consequences of Biomass Burning

⛰

Biomass burning releases CO, NOx, PM, and VOCs - all respiratory irritants 👁

●3 billion people globally cook on open, biomass fires, mostly in developing world

●Lack of environmental protection laws & financial resources for other fuels
lead to more biomass deforestation in developing nations

●Hab. loss, soil erosion, loss of CO2 sequestration, air & H2O filtration

●Biomass burn. indoors for heat/cooking worsens effects (pollutants trapped & conc.)

○Worsened asthma, bronchitis, COPD, emphysema, eye irritation

⛰

Environmental consequences = deforestation & air pollutants 🪓

🌳

🔥🌫

●NOx, VOCs, and PM
all contribute to smog
formation

Modern vs. Fossil Carbon

⛰

Biomass burning releases CO2, but doesn’t increase atmospheric CO2

levels like FF burning does

●Burning biomass releases modern carbon (CO2 that was recently
sequestered, or taken out of the atmosphere) whereas FF burning releases
fossil carbon that had been stored for millions of years

●Biomass burning is considered “carbon neutral”

●Think of spending a dollar someone just gave you vs. withdrawing
from your long-term savings account to spend

Biofuels: Ethanol 🌽⛽

& Algae 🧫

⛰

Corn & sugar cane are fermented into ethanol which is mixed w/ gasoline

●Corn grain/sugar cane broken down & yeast ferment sugars → ethanol

●Soil erosion, hab. loss, GHG release (ag. soils, tractors, fertilizers) H2O use

●Lots of corn needed, relative to petroleum; can compete w/human cons. of corn

●E85 or flex fuel = 51-83% ethanol + gasoline mix; used in flex-fuel vehicles

○Decreases oil consumption for transport, but is less efficient than pure gasoline

⛰

Environmental consequences = all the neg. consequences of monocrop ag.

●“renewable” only to the extent that the production of corn is sustainable (sugar cane is
a perennial, and is more sustainable)

●Algae produce oils that can be used as biofuels more sustainably than corn

Biodiesel🌴⛽

⛰

Liquid fuels produced specifically from plant oils (soy, canola, palm)

●Palm oil biodiesel has been found to produce 98% MORE GHGs than FFs, due to
clearing of forest for palm plantations

●Can be more sustainable if already cleared land is used, or if plantations are
continually replanted (however, also causes all the env. impacts of ag.)

CO2 release

Loss of hab.

Soil erosion

Loss of air/H2O filtration

Practice FRQ 6.7

Explain why biodiesel fuels have a different effect
on atmospheric carbon levels than fossil fuels do.

Describe TWO environmental benefits of using
algae for biofuel production, rather than corn, palm
oil, or sugarcane.