Lecture 15/16: hydropower Flashcards
where does the energy for hydro come from?
- ultimately comes from the sun via the hydrological cycle (evaporation, condensation , gravity as water flows back)
Which renewable energy provides the most energy?
- Hydropower supplies more electricity than any other renewable source
- Canada’s #1 source of renewable energy
Describe the order of renewables in order of EROEI
- hydropower > wind > nuclear > coal > PV> geothermal > Natural Gas
Describe the variations of dams
- earthen dams
- concrete dams (the 3 gorge dam, the hoover dam)
- Muskrat falls/churchill falls
What is the largest dam in the world in terms of energy output?
- the 3 gorges dam
What are some actions associated with building a dam?
- changing flow of the river, storing water, flooding/clearing ecosystems
are dams totally carbon neutral once built? Why or why not?
- no, they release methane and Co2
- bubbling releases methane, flooded soil and vegetation releases Co2 and methane, and then degassing releases methane after the dam
Describe the accumulation of mercury as a result of dams
- flooding of vegetation/soil causes mercury to be released into the water
- bacteria in the water converted organic mercury into methyl mercury which is more bioavailable, and accumulates in organisms
What impacts the amount of GHGs released by hydro projects?
- location, climate, age of impoundment, etc
What is problematic about Churchill falls and muskrat falls?
- built on Innu territory: important land for fishing (physical/mental wellbeing)
- seafood consumption higher in these communities so MeHg contamination is a threat
In canada, how many hydroelectric dams are located on indigenous land?
- 131 hydroelectric facilities (~50% of installed capacities) are located within indigenous treaty/land claim areas
Why are food consumption advisories inadequate to address mercury poisoning?
- the reduced intake of traditional foods (fish) can exacerbate food insecurity and contribute to malnutrition
What is run-of-river hydroelectric generation?
- diverting flow of the river to powerhouse
- does not require a dam and reservoir/ less disruptive
Review the construction impact of a dam:
- note: creates employment but also has emissions, threatens ecosystems/habitats, and at the end of life there is steel and concrete waste management
Describe china’s role in hydropower
- 2020: china consumed and produced the most energy
- lead the world in renewable energy capacity
- creates the most hydropower energy in the world (28%)
- hydropower is the second largest source of electricity after coal
Do dams built in tropical or temperate regions emit more emissions?
- shallow tropical reservoirs have greater emissions than those in temperate/boreal forests
why might dams still a reasonable option despite emissions?
- some say that the savings outweigh the emissions
