Energy Resource Flashcards
Individuals hold different viewpoints on the purpose and challenge of creating a
sustainable energy supply system. Identify three such viewpoints.
Fossil Fuel Prolongation. Challenge: Replacing/Subsidising fossil fuel energy
production systems with equivalently priced systems.
Climate Change Mitigation. Challenge: Providing carbon and greenhouse gas
neutral energy which are capable of matching the instantaneous and fluctuating energy
demand.
Security of Energy Supply. Challenge: Using power not based upon intermittent or
politically volatile fuel resources would require large scale investment in new
technologies.
Individuals hold different viewpoints on the purpose and challenge of creating a
sustainable energy supply system. Identify the conflicts between view points.
While fossil fuel prolongation wishes to retain the use of fossil fuels, this somewhat conflicts with
climate change mitigation as it does not specify upon whether alternatives would be carbon neutral.
Climate Change Mitigation and Security of Energy Supply conflict since Climate Change Mitigation would likely increase the use of nuclear
power while Security of Energy Supply would oppose its political implications.
Elaborate approaches to demand reduction and barriers for each approach to create a sustainable energy system
District heating. BARRIER significant investment for maintenance
Smart Grids. BARRIER requires high levels of comms. between demand and supply. Costing a lot to maintain and run.
Mircogeneration. BARRIER. to be considered sustainable input fuels must be renewable
Elaborate approaches to energy supply barriers for each approach to create a sustainable energy system
Combined Renewable/storage solution. BARRIER requires investment for infrastructure
Coal replaced by biofuels. BARRIER B.F does not have the same power as coal.
Why is renewable enery resource not capable of matching the demand in the UK?
Resources such as wind cannot be utilised in urban areas.
The UK is not blessed with abundant renewable sources.
Max consumption is much greater than the achievable renewable power.
Intermittent and unreliable, and storage is required
Carnot Efficiency
1-(t2/t1)
t2 is min temp
t1 is max temp
Endoreversible Efficiency
1 - sqrt(t2/t1)
t2 is min temp
t1 is max temp
How can a solar power plant, making use of a intermittant resource, become a steady supply
Change water system to use silica or salt as thermal storage and heat transfer medium.
Furnace will heat salt solution to be circulated and stored
Energy can be gather during the day and stored at night, making the source steady
State whether a solar power plant is viable in a climate the same as Glasgows, explain.
Radiation from the sun reaches earth in the form of beam and diffuse radiation.
Only beam energy can be focused and is vital to solar energy generation.
Glasgow rarely has clear skies meaning less beam energy can get through.
Therefore Concentrate Solar power is not viable.
Also large scale derelict land is required
A Large Coal Power plant operates with an efficiency of below 40%. Why is this efficiency so low?
Efficiency is limited due to governing laws of thermodynamics.
Not all heat is utilised in power production and heat is rejected through the exhaust and condenser.
A Large Coal Power plant operates with an efficiency of below 40%. How can this efficiency be improved?
Combined Cycle Gas Turbine can use rejected heat from exhaust for useful energy.
Use rejected heat as a heating supply to nearby buildings.
Heat exchangers with exhaust fumes will decrease hear input required in the boiler
Explain the functions of a moderator in a nuclear power station.
To slow down the neutrons within the reaction chamber, slower neutrons are more likely to be absorbed by uranium nuclei.
Slows down free neutrons making them less likely to be captured by U238.
Materials used as moderators
Graphite, heavy water and water
How can a moderators performance be improved?
If the fuel is enriched to increase the amount of U235.
Explain the function of control rods in a nuclear power plant.
to actively adjust the reactivity in the reaction chamber by absorbing the neutrons.
Control rods are lowered or retracted to slow or increase the rate of the reaction
What are control rods typically made from?
Boron, Silver, etc
a material that can absorb neutrons without fission occurring.
What kind of turbine would be used with a pump storage scheme and why?
REACTION TURBINE.
This turbine can create static pressure difference similar to a centrifugal pump
Benefits of a new hydro scheme in the scottish highlands.
Increase the reliable base load capacity of the grid.
Can reduce supply when demand is not required (?)
Designed to last.
100% green.
high efficiency
relatively safe compared to other methods.
Arguments against the building of a new hydro scheme in the scottish highlands.
oversized dams can have seismic effects.
high capital investment.
Ruins aesthetics of the area.
Connection to the grid may be hard if it is remote.
Main features of UK renewable obligation?
started 2002
increase a proportion of the energy supply to 10% renewable.
Suppliers gain RO certificates if they meet these standards.
Suppliers who fail to meet obligation must pay an equivalent amount into a buy out fund.
ended 2015
Why are energy systems hard to model?
Energy systems are:
Dynamic, different flow paths vary at different time rates.
non-linear
systemic, they usually influence each other
stochastic, are influenced by random effects.
three underlining principles that are needed to b observed in energy systems modelling
Discretisation levels: how many domaines are to be included in the simulation and what resolution will be the domains
Establishment of equations: Required to detail how domains influence one another and behave within their own boundaries.
Boundary conditions: Important to input reliable boundary conditions to the system. i.e external temperature.
Three possible approaches to turbine sizing for power extraction from the phased operation of multiple sites over the lunar cycle
Lunar cycle has a period of 12hr 25mins
Land mass influences tidal range and create very large ranges in some parts of the world.
When the earth, moon and sun are aligned spring tides are created. base flow 1/3 peak.
when moon and earth and sun dont align, neap tides are created and the output is 1/4 peak.
SIZING
turbine size is restricted to maximum output experience during neap tides.
during non spring tides introduce other sources of energy to meet shortfall
introduce long term energy storage.
Three principle categories of wave power device.
Passive Device
Relative Motion
Oscillatory Water Column
P.R.O
How does a passive wave power device works
designed to guide the waves to spill over elevated
reservoir, which then drains through conventional low-head hydraulic
turbines into the sea
How relative motion wave power device works
between structural parts with the motion
employed to transfer a working fluid around a circuit to drive a rotary
machine
How Oscillatory Water Column wave power device works
Seawater is fed into a chamber
which is vented to the atmosphere.
Fundamental efficiency limitation affecting single junction PV cells
Shockley-queisser limit
(this question is four marks so i dont know what else to add…this is a problem for future fionn and future gang, much love past fionn haha)
Explain the operation of a single effect tidal barrage power system
Basin is filled through the sluices until high tide; sluice gates are closed
There may be pumping using grid electricity to raise the level further.
Turbine gates closed until the sea level falls to creat sufficient head across the barrage.
Gates opened and turbines generate until the head is again low (LOL)
Sluices are opened, turbines disconnected and the basin is filled again
Is kWh/yr a unit of energy
no
is kg/ms^2 the fundamental units of energy
no, energy is kgm^2/s^2
if the average rise in world energy consumption is sustained at 2%. How long will it take for energy consumption to double?
2%=1.02^n
ln(2) = n ln(1.02)
n=ln2/ln1.02
Individuals hold different viewpoints on the purpose and challenge of creating a
sustainable energy supply system. Identify three such viewpoints.
Fossil Fuel Prolongation. Challenge: Replacing/Subsidising fossil fuel energy
production systems with equivalently priced systems.
Climate Change Mitigation. Challenge: Providing carbon and greenhouse gas
neutral energy which are capable of matching the instantaneous and fluctuating energy
demand.
Security of Energy Supply. Challenge: Using power not based upon intermittent or
politically volatile fuel resources would require large scale investment in new
technologies.
Individuals hold different viewpoints on the purpose and challenge of creating a
sustainable energy supply system. Identify the conflicts between view points.
While fossil fuel prolongation wishes to retain the use of fossil fuels, this somewhat conflicts with
climate change mitigation as it does not specify upon whether alternatives would be carbon neutral.
Climate Change Mitigation and Security of Energy Supply conflict since Climate Change Mitigation would likely increase the use of nuclear
power while Security of Energy Supply would oppose its political implications.
Elaborate approaches to demand reduction and barriers for each approach to create a sustainable energy system
District heating. BARRIER significant investment for maintenance
Smart Grids. BARRIER requires high levels of comms. between demand and supply. Costing a lot to maintain and run.
Mircogeneration. BARRIER. to be considered sustainable input fuels must be renewable
Elaborate approaches to energy supply barriers for each approach to create a sustainable energy system
Combined Renewable/storage solution. BARRIER requires investment for infrastructure
Coal replaced by biofuels. BARRIER B.F does not have the same power as coal.
Give 3 substantial reasons why the renewable energy resource in the UK is likely to be
substantially less than the total energy consumption
- Due to safety concerns, resources such as wind power cannot be fully utilised in urban areas.
- While other countries have significant natural resource, e.g. hydropower in Norway,
Geothermal in Iceland, the UK is not blessed with such an abundance. - Densely populated country, with high energy use per capita due to first world comforts.
- Political, would require a substantial investment into the sector across all boards.
Why is a combined cycle gas fired power plant more efficient than a nuclear power plant.
A nuclear power plant relies on a standard steam cycle where the boiler produces steam through heat provided by the reaction. This is limited to 35% efficiency by laws of thermodynamics.
CCGT the heat rejected in the exhaust is utilised to become useful power.
How can thermal efficiency be improved?
heat rejected could be used as low grade heating in nearby buildinsg
3 emissions associated with the burning of fossil fuels, and the environmental problems that come with them
CO2 - climate change
Nitrous Oxide - is toxic to most organic life
Soot: decrease air quality.
Process of nuclear fission
Neutrons collide with U235 particles which causes fission to happen. This results in fission products, neutrons and ENERGY.
The role of water in PWR
Coolant and Moderator.
Moderator slows fast neutrons down allowing more chance of them to interact with fission materials.
what is the carnot efficiency equation and what does it imply
1-(t2/t1)
maximum theoretical efficiency
what is the endoreversible efficiency and what does it imply
1- sqrt(t2/t1)
a more realistic efficiency
An example of Impulse turbine
pelton wheel/turgo
An example of reaction turbine
propellor/francis/kaplan
Differences between Impulse and reaction turbines
Reaction turbines can be used as a pump
reaction turbines are fully submerged to create a pressure drop.
Reaction uses pressure and kinetic energy, while impulse only uses kinetic.
An impulse turbine is struck by water to drive its blades. meaning that velocity is important
Arguments for building a large gorge hydro scheme
100% carbon neutral
provides means for energy storage.
built to last a long time.
Contribute to the supply base load.
Arguments against building a large gorge hydro scheme
High cost
spoil aesthetics
seismic effects
decommissioning is very difficult
damage to reservoir can cause severe flooding
Primary emissions from fossil fuel combustion, and how he impact might be mitigated
Emissions - CO2 NOx unburnt hydrocarbons.
In a car NOx and carbon monoxide can be less harmful with a catalytic converter.
CO2 can be mitigated through carbon capture and storage - where CO2 is either compressed or converted to a carbonate solution and stored in a geological formation
Three categories of biofuel and give an example of each
Solid - Wood chips
Liquids - Methanol
Gaseous - Methane
3 categories of wave power devices and give an example
Passive - elevated reservoir with low head (lol) turbine drainage
Relative Motion - Raft Wave Energy Converter
Oscillating Water Column - Wells Turbine and generator.
Explain the operation of a single effect tidal barrage power system
Basin is filled through open sluice gates until tide is high, at peak tide, the gates are closes.
Additional water may be pumped when supply>demand to raise water further.
Gates are closed until tide is low enough to create significant head across the barrage
Once tide is sufficiently low the gates are opened and the pressure difference allows the turbines to generate until the head is low again
Sluice gats are opened again, the turbine is disconnected from the generator and the process repeats.
