Energy Production (Energy Sources) Flashcards
Define Primary Energy Sources
Source of energy which has not been transformed or converted before consumption
ex:
- Fossil Fuels
- Coal
- Old corn wind-mills
Define Secondary Energy Sources
The result of the transformation of a primary source of energy
ex:
*Electricity
What are Renewable Energy Sources?
A PRIMARY energy source that is replenished in a relatively short time, matching or continually growing at the rate it’s consumed. ex:
- Biomass
- Wind
- Water
What are Non-Renewable Energy Sources?
A PRIMARY energy source that is replenished over a VERY LONG TIME, can’t match the rate of consumption, thus is depleting. ex:
- Coal
- Oil
When consumed, Biomass releases CO2, why is this not as bad as when fossil fuels do it?
Biomass releases the CO2 that the plant RECENTLY took from the atmosphere.
Fossil fuels release carbon that was stored for MILLIONS of years, increasing the overall CO2 content of the present time
Define “Specific Energy”
number of Joules that can be released by 1kg of a fuel
mass
Define “Energy Density”
number of Joules that can be released by 1m^3 of a fuel
volume
What is a Sankey Diagram? What rules does it have?
a visual representation of the flow of energy in a process
Rules:
- energy sources & losses are represented by an arrow
- Width of the arrow is proportional to the amount of energy it represents
- Energy flow is from LEFT to RIGHT (source left; output right)
- Energy lost from the system is expressed with arrows pointing UP or DOWN
- Power transfers can also be shown with energy flow
What is a Thermal Power Station?
A station where a primary source of energy is converted to internal energy (heat) then to electrical energy
Primary sources = Biomass, Fossil fuels, Nuclear energy
(internal) (electrical) Primary source -----> water -----> turbine -----> generator
(kinetic)
- Energy from primary fuel source heats up water in a pressurized vessel (Boiler) to create steam
- steam is superheated (waay above 100 Celcius) because of the massive pressure
- steam is directed to the turbines and spins them, creating kinetic energy
- turbine’s axel is connected to an electric generator, converting Ek to Electricity
- the steam ends up at a “Condenser” where it is cooled back to water and goes back to the Boiler
Be able to draw this diagram
What are the Pros and Cons of using Fossil Fuels?
Produced by decomposition of buried and pressurized plant/animal material over millions of years
Pros:
- High energy density
- used directly and easily by many vehicles/devices
- Cheap
Cons:
- Non-renewable
- releases CO2, leading to Greenhouse Effect
- Power stations lose useful output in mass transportation
Define Degraded Energy
energy that is “lost” because of energy transfer, unable to be used for its intended purpose
What is a Thermal Fission Reactor?
a Pressurized Water Reactor (PWR) - which uses Uranium-235.
- When mined, 99% of Uranium is U-238.
- PWR’s needs around 3% of U-235 b/c U-238 absorbs neutrons too well (non-fissionable) and stops the cycle. So the fuel is “Enriched”
- Enriched Uranium is kept in tubes called “FUEL RODS”
- As uranium undergoes Fission, it emits neutrons with high Kinetic Energy (at very high speeds)
- the (Graphite) MODERATOR near the fuel rods slows down the speed of the free neutrons when they collide with it and slow to an optimal Kinetic Energy for electric production
- There are CONTROL RODS made of neutron-absorbing materials (like Boron) which, when lowered to the reactor, regulate the power output and can shut down production by reducing the no. of free neutrons, preventing subsequent fissions, decreasing the rate of reactions
- this all happens in the REACTOR VESSEL, which has pressurized water absorbing the Ek from the neutrons and is heated up to steam.
- The steam goes to a HEAT EXCHANGER, which is a closed water system of another water pipe which absorbs the thermal energy of the reactor steam and becomes steam itself. This is needed b/c the reactor steam may transfer radioactive material if it was used directly.
What are the Pros and Cons of Nuclear Energy?
Pros
- High Energy Density
- Is renewable b/c some nuclear waste can be used as a fuel source
- there are large reserves of Nuclear fuel
- No greenhouse gas emissions
Cons
- Risk of nuclear explosion (but the low occurance actually means fossil fuels causes more deaths than nuclear power plants)
- Can be used to create nuclear weapons
- nuclear waste is RADIOACTIVE with LONG half-lives. (safe disposal is still a big issue)
- Uranium decays into Radon gas (carcinogen). big issue for miners who inhale this
What is a Solar Panel
system on roofs which heats up water using the sun’s thermal energy
Solar energy —> thermal —> electric
What is a Solar Cell
Converts Solar energy (light) directly to electricity using photovoltaic cells
