Renewable Energy - Wind Energy Flashcards
How much has wind capacity grown from 2008 to now?
100gW in 2008 and 830 in 2019
How much wind capacity is onshore compared to offshore?
933% and 7%
Capacity Additions
This is the adding-up of futher power generation through small-power projects like new generators.
How much wind energy is in Asia?
41%
How much global electricity does wind energy produce and how much by 2050?
Currently 6% by 2050 be 35%
Why is offshore currently behind?
Developed much later, first farmi in Denmark in 1991.
What do the International Renewable Energy Agency project tthe distribution of wind energy globally for onshore.
By 2050, 50% in Asia, 23% in NA and 10% in Europe
What does a wind turbine do?
Converts kinetic energy into electricity, through turning of a turbine, rotational energy moving a shaft connected to a generator, producing electrical energy.
What is the general mechanism of spin of a turbine?
Low pressure air on one side of the blade, pulling blade towards it generating lift.
How do wind farms regulate under high winds?
Anemometer measures wind speed.
Nacelle
Includes rotor hub, generator and gearbox, housing the components that transfer wind kinetic energy into mechanical energy to run the generator.
What connects to the gearbox?
Wind turbines via a shaft.
How do wind turbines optimise outputs under varying wind speeds?
Electrical components that alter balde angle.
What is energy output determined by?
Third power of wind speed and to the square of swept area
Swept area
The area of the circle created by the blades as they sweep through the air.
Why is hub height important?
Wind increases the higher up
What is an example of the importance of location for wind farms?
Coasts have higher amounts of winds, as do the poles compared to the equator.
Why are floating offshore wind farms benefical?
They can be deployed in deep ocean
What are the current proportions of a wind turbine?
50-200 meteres high and rotor diamets being about 110m(doubling from 50 in 2020)
What is a trade off with increasing height?
With increasing height the turbine is subject to more turbulence, requiring stronger building materials.
How much did doubling of rotor diamter increase capacity?
250%
What is a downside of building wind farms in windy area?
You take up space in windy areas, thus must be in less windy areas.
How can we adapt to building wind farms in less windy areas?
Increasing tower height, decreasing generator size proprotional to blade size for higher capacity utilization.
What is a downside of decreasing generator size?
It means at higher wind speeds not all electricity is converted.
What are some alternative ways to improve wind farm efficiency?
AI generation algorithmis to optimise placement of turbines
How does installation cost differ from China and UK?
1170 per kW in China whilst 2030 kW in the UK
Why do regional differences affect wind turbine costs?
Size of blades and towers require costly transports, as well as electrical production
How much has wind turbine cost dropped since 2010?
22%
What has caused decreased costs in wind utrbines?
Increasing learning rates and technological advancement, like larger generators and longer blades.
Why is offshore wind three times more expensive?
Specialised ships for transport and grounding them, maintenance more difficult
Levelised Cost of Electricity
This is the discounted lifetime cost of building/operating generation assets expressed as cost per unit of electricity genertaed
How much is LCOE of offshore expected to decrease?
From $60 per MWH(2018) to $40 per MWh by 2030.
What does offshore exceed in compared to onshore?
Higher capacity factors and steadier generation profiles.
Why is LCOE a poor measurment of cost improvements?
It does not measure time value.
Time value
The concept that a sum of something is worth more now than the same sum will be at a future date.
Where are high potential zones for wind farms?
South America and New Zealand, as well as north and baltic seas
Capacity Factor
The ratio of actual electrical energy output over a given period of time to the theoretical electrical energy.
What is wind farm capacity in response to wind variation measured by?
Capacity factor.
How does capacity factor compare in offshhore vs onshore?
35-65% in offshore whilst 30-40% onshore
Why is energy variability an issue?
Off-peak energy demands must be met another way.
Capacity Value
The amount of energy capacity something can replace without reducing energy securirty.
What is an issue with offshore wind farms?
Grid integration.
Water Electrolysis
Decompostion of chemicals by passing electrical currents through a liquid or solution containing ions.
How can poor grid integration be overcome?
By powering of water electrolysis.
