env100 note 53.docx

38 views5 pages
28 Mar 2012
School
Department
Course
Professor

For unlimited access to Class Notes, a Class+ subscription is required.

ENV100 Lecture Notes Mar 12, 2012
Conventional Energy continued
Readings: Chapter 16
Most serious proposed solutions for permanent disposal of radioactive waste involve
storage by geological isolation
Fusion remains a dream
Nuclear fusion = forcing together the nuclei of lightweight elements under extremely
high temperature and pressure
o Scientists have not yet achieved “cold” fusion useable for commercial power
generation
o If we could control fusion, we could produce vast amounts of energy from water
Biomass energy comes from organic matter
People have long harvested biomass energy from many types of organic matter
o Wood from trees
o Charcoal from burned wood
o Matter from agricultural crops
o Combustible animal waste products
Fuelwood and other biomass sources constitute 80% of all renewable energy used
worldwide
Traditional biomass sources are widely used in the developing world
In some areas, almost total dependence on fuelwood for energy
About i billion people depend on fuelwood as a primary energy source
Can lead to deforestation biomass is only renewable if it grows faster than we harvest
it
o (main causes of deforestation are still land clearing, logging, disease,
environmental change)
Electricity generation from biomass is called biopower
Many sources of biomass:
o Waste products of existing industries or processes
o Woody debris from logging operations and sawsmills
o Crops can be specifically grown, such as fast-growing willow trees or bamboo
o Co-firing combines biomass with coal
o Bacterial breakdown of waste to produce methane
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
Biofuels can power automobiles
Biofuels = biomass sources converted into fuels to power vehicles
Ethanol = produced as a biofuel by fermenting carbohydrate-rich crops
o Any vehicle will run well on gasoline blended with up to 10% ethanol
o Flexible fuel vehicles = run on 85% ethanol
Biodiesel = biofuel for diesel engines produced from vegetable oils
Biomass energy has environmental and economic benefits
It is essentially carbon-neutral, releasing no net carbon into the atmosphere
o Only if biomass sources are not overharvested
Other benefits include ...
o Supports rural communities
o Reduces dependence on fossil fuel imports
o Reduces air pollutants such as sulphur dioxide
Biomass energy also has drawbacks
Health hazards from indoor air pollution
Rapid harvesting can lead to deforestation
Growing crops exerts tremendous impacts on ecosystems
o Fertilizers and pesticides
o Land converted to agriculture
Biofuel competes with food production
Substantial inputs of energy are required
o Current EROI for corn ethanol may be 1.5:1
Corn ethanol: food or fuel?
Do you think producing and using ethanol from corn or other crops is a good idea?
Do the benefits outweigh the drawbacks?
Do you think it is ethical to put a material that people might have eaten as food into the
gas tank of an automobile?
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class