(M2) 15 - Alternative Energy Forms Flashcards
Definitions: clean vs. green vs. renewable enrgy
Clean Energy: energy gained from sources that do not release air pollutants.
- clean air
Green Energy: energy derived from natural sources; it OFTEN comes from renewable energy sources.
- natural (mostly renewable) sources
Renewable Energy: power generated from sources that are CONSTANTLY being replenished over short time or be recyled.
- recyclable/replenishing sources
- MOST (but not all is C-free)
Example of how “not all renewable energy is C-free and not all C-free energy is renewable”
Bioenergy = renewable
- We can regrow plants that we burn for fuel, but growing plants absorbs CO2 while burning plants releases it.
Nuclear energy = C-free
- Nuclear power plants don’t emit any GHG but nuclear reactors use uranium that we can’t get back.
5 sources of renewable energy
- wind power
- solar power
- water power
- geothermal power
- biomass power
Wind Energy
- what is the source
- how energy is produced with the source
- pros
- main problems
Source: Wind
How: Using the power of the wind to turn a set of blades (of a wind turbine) and generate electricity.
1. Rotating generator converts wind energy to electricity.
- Wind Power —> Mechanical Power —> Electric Power
2. Transformer increases voltage for transmission to substation.
3. Substation increases voltage for transmission over long distances.
4. Transmission to the grid.
Pros:
- Renewable
Main problems:
- Ideal wind sites are often in remote locations
- Installation is expensive
- The wind doesn’t always blwo
- Turbines produce noise and alter landscape aesthetics
- Wind plants can impact local wildlife
Solar Energy
- what is the source
- how energy is produced with the source
- pros
- main problems
Source: Solar radiation
How: Using solar radiation to generate electricity via photovoltaic cells; also used for heating (solar thermal)
1. Solar panel converts sunlight to direct current (DC; e.g., batteries, solar cells) aka electricity
2. Inverter converts electricity DC to alternating current (AC; e.g., generators, outlets) enable it to power electrical items.
3.Take electricity your home requires
4. Extra electricity credited on grid
Pros:
- Enough energy to meet the planet’s power needs for an entire yr reaches the Earth from the Sun in just 1 hr.
- An average home has more than enough roof area for the necessary number of solar panels to supply its power needs.
Main problems:
- Initial costs for installation are high
- Weather-dependent; solar panels are dependent on sunlight to effectively gather energy
- Storage batteries are expensive
- Space
- Transportation and installation of solar systems have been associated with the emission of GHGs
- Some toxic materials and hazardous products used during the manufacturing process of solar panels
- Need to improve waster management from solar
Are Solar Panels Toxic?
- Modern solar panels are silicon-based (aka don’t contain cadmium or telluride) = not toxic unless we dispose of them improperly!
- They contain several polymers (plastics), some still have lead in the solder but nothing that can leach during use
- We need to recycle the panels properly at the end of their life
The ‘Brooks Project’ in Alberta
Wester Canada’s first utility-scale solar project; the largest utility-scale solar plant in AB
Water Energy (hydropower)
- what is the source
- how energy is produced with the source
- pros
- main problems
Source: Fast moving water
How: Using fast moving water in rivers or from waterfalls to generate electricity. Waters can be captured from: movement of a river, wave power, tidal power. Dam example:
- Water captured and forced into a tunnel where turbines are connected and once activated they activate a generator
Pros:
- The World’s lowest carbon electricity generation
Main problems:
- Strong environmental impacts
- Can affect water quality and supply
- Can displace ppl as much as wildlife
- Can be droughts or floods
- Constructions of dams can be challenging and dangerous
- Safety concerns and maintenance over time
What are the 2 main types of hydroelectric plants?
- Dam
- Run of river
Geothermal Energy
- what is the source
- how energy is produced with the source
- pros
- main problems
Source: Heat trapped into the Earth
How: Using the heat trapped inside the Earth to bring highly heated water to the surface and generate electricity. It’s captured through: geothermal power plants, using heat from inside the Earth to generate steam and produce electricity OR geothermal heat pumps, using heat close to the Earth’s surface to heat water or provide heat to buildings
1. Inject water to source of heat via injection wells; in some cases there is already water underground and it doesn’t need to be injected.
2. Hot water or steam is pumped under pressure to the surface
3. Change in pressure = lots of steam = activates turbines = activates generator that transforms mechanical energy to electrical energy.
4. Steam from turbine condenses to water and is pumped back down to geothermal reservoir
Pros:
- How water used for bathing and swimming
- Space and district heating
- Greenhouse heating
- Aquaculture
Main problems:
- Production is limited to areas near tectonic plate boundaries
- Some locations may cooldown over time
- Drilling and exploration for new sites is expensive and high temperatures make the enviro quite aggressive
- Releasing of potentially harmful gases, such as hydrogen sulphide, or other low-level toxic compounds from geothermal fluids
- Potential earthquakes due to digging and high-pressure water injections
Where does the heat come from for geothermal energy?
- Earth’s core is made up of very hot molten iron surrounding a solid iron inner center
- Around the Earth’s core is the mantle, which is partly made of rock and partly of hot magma
- The outermost layer of the Earth is the crust
- Sometimes the crust can crack or thin, allowing plums of hot magma from the mantle to rise
Biomass Energy
- what is the source
- how energy is produced with the source
- pros
- main problems
Source: Organic material from plants and animals, including crops, trees, and waste wood (also sewage, municipal solid wastes, and food processing wastes).
How: Power is generated from biological (ex. anaerobic digestion) or thermal conversion (ex. combustion) of biomass resources. Biomass can be converted into liquid biofuels such as ethanol and biodiesel, which is used to power vehicles. Biomass is rich in hydrogen, which can be chemically extracted and used to generate power and fuel vehicles.
CYCLIC:
- Forest absorbs CO2 through photosynthesis
- Forests can be harvested sustainably to produce biomass
- Biomass can be converted into heat and power
- CO2 is released back into the atmosphere…
Pros:
- Versatility; biomass can be used to produce renewable fuels, power, and everyday products like plastic
- Value for wastes
- Abundant
- Economic impact
Main problems:
- GHG emissions
- Uncontrolled biomass production can lead to deforestation and destruction of habitats
- Less efficient than fossil fuels and other renewable energies
- Requires a lot of space to set up and it’s very expensive
- unpleasant odors and concerns about pathogens
- Requires large amounts of water
Hydrogen as source of energy:
- Clean vs. non-clean forms
Global Hydrogen Production by Energy Source
- 48% Natural Gas
- 33% By-product
- 18% Coal
- 0.48% Oil
- 0.48% Electricity and others
Hydrogen as source of energy:
- Methods of H production and how to generate energy with H
Using fossil fuels, renewable energy, or nuclear power, we can produce H gas, store it, transport it, and burn it to generate power.
Hydrogen Production Pathways
1. Fossil resources
- low cost, large scale H production
- thermochemical processes
- Biomass/waste
- biological processes (biogas reforming or bacteria fermentation)
- byproduct benefits include clean water, electricity, and chemicals - H2O splitting
- processes: electrolytic, photolytic, photoelectrochemical
Hydrogen as source of energy:
- What we use H energy for and main problems
What we use H energy for:
1. Fuel for transport and power production
2. Heat for industry and buildings
3. Feedstock for products and chemicals
Main problems
- Rarely exists in isolation but is amassed in enormous quantities in water, hydrocarbons, and biomass
- Expensive and still inefficient
- Lack of H infrastructures: pipeline networks, production facilities, fuels stations; and it’s not easy to convert existing infrastructures
- Large enviro impact depending on how it’s produced
- Too dependent on fossil fuels
- Highly flammable
