12 - Alternative forms of energy Flashcards
Clean vs green vs renewable energy
Clean: energy gained from sources that do not release air pollutants
Green: energy derived from natural sources; often from renewable E sources
Renewable: energy is power generated from sources that are constantly being replenished
Clean vs green vs renewable energy in simplest terms
Renewable = recyclable/replenishing sources
Green = natural (mostly renewable) sources
Clean = clean air
Example of energy source being renewable but not clean?
Biofuels/bioenergy from burning biomass
We can regrow plants to burn for fuel, but burning plants releases CO2
Example of a carbon-free (clean) but not renewable source of energy?
Nuclear energy: nuclear power plants do not emit GHG’s, but reactors use uranium that we can’t get back
Types of renewable energy (5)
- wind
- solar
- water
- geothermal
- biomass
How does wind power work? Wind speeds need to be… Lifespan of turbines
Using the power of the wind to turn a set of blades and generate electricity
Wind speed has to be between 13 km/h and 90 km/h
Life of a turbine is 20-25 years, operating continuously for up to 120,000 hours
Types of wind turbines
Land-based
Shallow water
Deep water (floating platform)
Time it takes a wind turbine to generate a months worth of electricity for the average US home? Tokyo would need how many turbines? One wind turbine requires how much space?
46 minutes
Tokyo would require 10,310 turbines
One wind turbine requires 3/4 of a football field
Problems with wind power
- ideal wind sites are often in remote locations
- installation is expensive
- wind does not always blow
- turbines produce noise and alter landscapes
- wind plants can impact local wildlife
How is electricity generated via solar power?
Use solar radiation to generate electricity via photovoltaic cells; also used for heating
Slide 21
How solar works
What is the Brooks Project?
Western Canada’s first utility-scale solar project
17 Mw solar project near TransCanada Highway in Brooks, AB
Currently 48,582 panels and powering ~3,000 homes
Largest utility scale solar plant in AB
Problems with solar power
- initial cost of installation still high
- weather dependent (sunlight)
- storage batteries are expensive
- requires space
- transportation and installation of solar systems = GHGs
- some toxic materials used in manufacturing
How is power generated in hydropower? Water is captured from…
Using fast moving water in rivers or from waterfalls to generate electricity
Water can be captured from:
- movement of a river
- wave power
- tidal power
Two main types of hydroelectric plants and their characteristics
Run of river
- less environmental disturbances but highly dependent on flow of water (droughts)
- flow of river turns turbine generator produces electricity
Dam
- control over the amount of energy produced
Slides 28, 29, 30, 32
Pics
Problems with water power
- strong environmental impacts (habitat alteration/destruction)
- can affect water quality and supply
- can displace people and wildlife
- there can be droughts or floods
- constructions of dams can be challenging and dangerous
- safety concerns and maintenance over time
How does water power produce GHGs? Decrease quality of water?
Floods kill vegetation, decomposing plants create GHGs
Water upstream moves slower bc of dam = cannot hold as much oxygen (running water holds more)
Decreases quality of water = some organisms who need more O2 cannot survive
What is geothermal power? How is it captured?
Using the heat trapped inside the Earth to bring highly heated water to the surface and generate electricity
Captured through:
- geothermal power plants, using heat from inside the Earth to generate steam= electricity
- Geothermal heat pumps, using heat close to the Earth’s surface to heat water or provide heat to buildings
Slides 36-38
Geothermal power
Direct uses of geothermal heat
- hot water used for bathing and swimming
- space and district heating
- greenhouse heating
- aquaculture
- hot springs
- de-icing roads
Problems with geothermal power
- production limited to areas near tectonic plate boundaries
- some locations may cool down over time
- drilling and exploration for new sites is expensive and high temps make env quite aggressive
- releasing of potentially harmful gases or other low-level toxic compounds
- potential earthquakes due to water injections
What is biomass power?
Use of organic material from plants and animals including crops, trees, and waste wood
Generated from biological or thermal conversion of biomass resource
Other functions of biomass
- can be converted into liquid biofuels such as ethanol and biodiesel, used to power vehicles
- rich in hydrogen, which can be extracted and used to generate power and fuel vehicles
Slide 45
Look
Problems with biomass power
- not pollution free: there are GHG emissions
- uncontrolled biomass production can lead to deforestation and destruction of habitats
- less efficient than fossil fuels or other renewables
- requires a lot of space and is expensive
- unpleasant odors, possible pathogens
- large amount of water
What is hydrogen power? Where do we find hydrogen?
Using fossil fuels, renewable energy or nuclear power, we can produce H gas (H2), store it, transport it, and burn it to generate power
H2 rarely exists in isolation but is amassed in water, hydrocarbons and biomass
Three ways of producing hydrogen
- thermochemical processes: natural gas or coal reforming
- biological processes: bacteria fermentation
- H2O splitting processes (electrolytic, photolytic)
Uses for hydrogen
- fuel for transport, power production
- heat for industry, buildings
- feedstock for products and chemicals
Problems with hydrogen
- expensive and still inefficient
- lack of H infrastructures (pipelines, production facilities)
- H production can have environmental impacts
- dependent on fossil fuels
- H highly flammable
What is nuclear fission? Fusion?
Fission = splitting apart of atomic nuclei (releases energy)
Fusion = forcing together of atomic nuclei (requires E)
Major nuclear fuel
Uranium
Slides 56-58
nuclear fuels
Major problem with nuclear fuels? Example of disaster
Uranium tailings
- often stored in water to prevent oxidation and contain radiation
- excess water is treated as nuclear waste
E.g. drinking water contamination in Navajo Nation, USA
Categories of waste? Based on…
Based on radioactivity
Low-level
Intermediate-level
High-level
Proposed solution for nuclear wastes
Bury it in deep geological repositories
Find rocks that can contain radioactivity
How common are nuclear power accidents in Canada and the US?
Rare, only 10 in Canadian history; no fatalities
56 in the USA, 12 fatalities (mostly non-radiation related injuries)
Two nuclear power accidents with widespread, measurable environmental damages
- Fukushima Daiichi, 2011
- Chernobyl, 1986
How to ensure nuclear power is safe
Operate and maintain it properly
- never shut off safety systems
- don’t build them in questionable locations
- find better way to reduce, reuse or store nuclear wastes
