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NapierC ENVS 3100 Fall2021
Sustainability topic lecture
Energy and energy alternatives
Energy
Defined as the capacity to do work
Types
o Kinetic: energy possessed by something in motion
o Potential: energy contained by something but not yet released
o Chemical: released after chemicals undergo a chemical reaction (eg batteries)
o Mechanical: potential and kinetic energy combined
Solar power
Photovoltaic solar panel: Electric charge produced when exposed to sunlight via its
semiconductors (typically made of silicon)
Concentrated solar thermal plants (CST): large mirrors focus sunlight towards liquid-
filled pipes, which then heat water and creates the steam needed to power turbines
and generate electricity
Advantages
o No usage costs
o Non-depletable
o No air or water pollution contributions
o No extraction/transport of the fuel needed
Challenges
o Variable generation (fluctuating solar radiation)
o Construction of cells uses hazardous materials (negative environmental
impact)
o CST requires an input of water
Wind power
Less than 2% of global energy consumption (but over 40% of Denmark’s)
Wind turbines: air flow propels turbine blades, which then powers a generator and
creates electricity
Advantages
o No usage costs
o Non-depletable
o No air or water pollution contributions
o No extraction/transport of the fuel needed
Challenges
o Variable generation (fluctuating wind conditions)
o Large amount of land required (loss of biodiversity)
o Favourable wind sources often in remote locations
NapierC ENVS 3100 Fall2021
Sustainability topic lecture
Energy and energy alternatives
Energy
Defined as the capacity to do work
Types
o Kinetic: energy possessed by something in motion
o Potential: energy contained by something but not yet released
o Chemical: released after chemicals undergo a chemical reaction (eg batteries)
o Mechanical: potential and kinetic energy combined
Solar power
Photovoltaic solar panel: Electric charge produced when exposed to sunlight via its
semiconductors (typically made of silicon)
Concentrated solar thermal plants (CST): large mirrors focus sunlight towards liquid-
filled pipes, which then heat water and creates the steam needed to power turbines
and generate electricity
Advantages
o No usage costs
o Non-depletable
o No air or water pollution contributions
o No extraction/transport of the fuel needed
Challenges
o Variable generation (fluctuating solar radiation)
o Construction of cells uses hazardous materials (negative environmental
impact)
o CST requires an input of water
Wind power
Less than 2% of global energy consumption (but over 40% of Denmark’s)
Wind turbines: air flow propels turbine blades, which then powers a generator and
creates electricity
Advantages
o No usage costs
o Non-depletable
o No air or water pollution contributions
o No extraction/transport of the fuel needed
Challenges
o Variable generation (fluctuating wind conditions)
o Large amount of land required (loss of biodiversity)
o Favourable wind sources often in remote locations
