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(6.7) What is biomass?
Organic matter (wood/charcoal, dried animal waste, leaves) burned to release heat - primarily for heating homes/cooking
What is biofuel(s)?
Liquid fuels (ethanol, biodiesel) created from biomass (corn, sugar, sugar cane, palm oil). Used as replacement for uel sources for gasoline, primarily in vehicles
Modern VS. fossil carbon
Biomass burning releases CO2, but doesn’t increase atmospheric CO2 levels like FF burning does
Human health consequences of biomass burning
Biomass burning releases CO, NOx, PM, and VOCs - all respiratory irritants
Environmental consequences of biomass burning
Deforestation and air pollutants
Biofuels: ethanol
Corn and sugarcane are fermented into ethanol which mixed with gasoline
Biofuels: Algae
Environmental consequences = all negative consequences of monocrop agriculture
Biodiesel
Liquid fuel produced specifically from plant oils (soy, canola, palm)
Explain why biodiesel fuels have a different effect on atmospheric carbon levels than fossil fuels do.
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
Describe TWO environmental benefits of using algae for biofuel production, rather than corn, palm oil, or sugarcane.
The oils that algae produces are more sustainable than corn when being used for biofuel. - - Does Not require soil, takes less space to produce more
non-competitive land use and carbon dioxide absorption (
(6.8) Active solar energy
use of mechanical/electrical equipment to capture the sun’s heat , or convert light rays directly into electricity
Passive solar
Absorbing or blocking heat from the sun, without use of mechanical/electrical equipment
Solar energy cons
Semiconductor metals (silicon) still need to be mined - to produce PV cells (solar panels)
Explain the relationship between the tracking ability of a solar PV system and its energy production.
The relationship between tracking and energy production is that, with one axis tracking PV the energy production is the most successful, a fixed tilt PV tracking is the least successful and 2 axis is in between.
Solar energy pros and cons
No air pollutants, no CO2 releases when generating electricity, renewable
Silicon is a limited resource, solar panel farms can displace habitats
(6.9) Hydroelectricity basics
Kinetic energy of moving water → spins a turbine (mechanical energy) → turbine powers generator
Water impoundment
Dam built in a river creates a large artificial lake behind the dam
-Damming the river enables operators to allow more or less water through the channel in the dam, increasing or decreasing electricity production
Run of river system and tidal energy
A dam diverts the natural currents of a river through a man-made channel beside the river
natural currents of the river turns the turbine → powers the generator
Drawbacks of hydroelectric dams
Reservoir flood habitats behind the dam, FF combustion during dam construction, homes and businesses have to be moved to somewhere else, sedimentation goes downstream
Benefits of hydroelectric dams
No GHG emissions when producing electricity, and allows for control of downstream seasonal flooding
Explain TWO benefits other than agriculture and recreation that people gain from constructing dams on rivers.
Allows for jobs to be created to maintain the dam
Allows for control of downstream flooding
Fish ladder
Cement “steps” or series of pools that migratory fish like salmon can use to continue migration upstream, around or over dams