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Environmental Science #1 > Renewables And Their Sustainability > Flashcards

Renewables And Their Sustainability Flashcards

(85 cards)

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1
Q

What lead to a reduction in the use of renewables?

A

Discovery of fossil fuels

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2
Q

Why did fossil fuels replace renewables?

A

As they were plentiful
Cheap to extract
Very energy dense

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3
Q

What has started a resurgence of renewables?

A

As the impacts of fossil fuels and realisation of how finite they are

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4
Q

Who invented the Diesel engine and when?

A

Karl diesel 1897

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5
Q

What was the car engine originally designed to run off?

A

Peanut oil a renewable

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6
Q

What are biofuels?

A

Liquids derived from plant and animal matter

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7
Q

What are the two main types of biofuel?

A

Bio-ethanol
Bio-diesel

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8
Q

What is bio-ethanol?

A

An alcohol which is made by fermenting the sugar ad starch components of plant materials

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9
Q

What is bio-diesel?

A

Form of diesel form plants or animals
Made by reacting lipids (animal fat, soybean oil) or some vegetable oil with an alcohol

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10
Q

Why is it an advantage of biofuels to have a range of sources/

A

Unlike fossil fuels which are from limited resources
Biofuels can be made from many materials

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11
Q

What are some animal materials that biofuels can be made from?

A

Crop waste
Manure
Other by-products

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12
Q

Why are biofuels renewable?

A

They can be grown again and again to match our needs

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13
Q

How will biofuels increase energy security?

A

Biofuels can be produced locally decreasing dependency on foreign energy (safe of influence)

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14
Q

How do biofuels cause economic stimulation?

A

Produced locally
Manufacturing plants hire local workers
Creating new jobs in rural areas

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15
Q

What are emissions like form biofuels?

A

Less carbon emissions
Produce less carbon and toxins when burned
Some are ‘carbon neutral’

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16
Q

What are the disadvantages of biofuels?

A

Energy output
Hefty carbon emissions (setup)
Affect food prices
Water use

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17
Q

What are he advantages of biofuels?

A

Range of source material
Renewability
Security
Economic stimulation
Lower carbon emissions

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18
Q

How is energy output a disadvantage of biofuels?

A

Lower energy output than fossil fuels so greater quantities needed for same amount of energy

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19
Q

Why is the process to produce the biofuels a disadvantage?

A

The machinery to cultivate the crops and the plants to produce fuel have hefty carbon emissions
Take some time to grow
Increase price of staple foods- tortilla riots

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20
Q

How do biofuels affect food prices? (Disadvantage)

A

As demand for food crop like corn grows for biofuel production it could cause the price of other staple food crop to increase(tortilla riots)

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21
Q

Why is the water use a disadvantage of biofuels?

A

Massive quantities needed for irrigation of crop and manufacturing the fuel which could affect local and regional water resources

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22
Q

What are some examples of biofuels being researched/ produced?

A

Sugar cane
Maize corn
Jatropha
Waste (poo bus)
Algae
Switch grass

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23
Q

What were the tortilla riots?

A

tens of thousands of people protested in Mexico City against the soaring prices of tortillas, from US$ 5.00 the year before to up to US$ 20.00 in some regions,
As it was an essential part of the Mexican diet and culture

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24
Q

What is the poo bus?

A

This was an initiative to power a bus by using bio methane form treated waste

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25
How can algae by used as a biofuel?
carbohydrates (sugars) from algae can be fermented to make additional biofuels, including ethanol, as well as other products such as plastics and biochemicals.
26
Why is switch grass being considered as a biofuel?
yields more than 540 percent more energy than the energy needed to produce and convert it to ethanol
27
Why does solar power technology need to be improved?
As their is enough solar energy at any one point for all human needs however the storage tech and solar panel tech is inefficient
28
What are the different ‘types’ of solar power?
Photothermal solar power Solar power heat pumps Photovoltaic solar power multi-junction photovoltaic cells Anti-reflective surfaces CSP- concentrating solar power
29
What is photo-thermal solar power?
Suns energy absorbed in order to produce heat Usually used to heat water (could be used for space heating, homes) Heated water stored in an insulated tank for some hours then used later
30
What are solar heat pumps?
Pumps that take heat from the earth and into a home (expensive) Uk government will fund half the cost Solar panels can be used to to produce energy needed for the pump
31
What is the problem with solar heat pumps?
The PV panels produce little electricity in winter when you need the heating the most
32
What is photovoltaic solar power?
PV- used to create electricity Photovoltaics is turning light into electricity (solar power calculators) Advantage- long lifespan of 40+ years Disadvantage- not very efficient at conversion
33
What are multi-junction photovoltaic cells?
Cell produces electric current in response to different wave lengths of light Use of multiple semiconducting materials allows more wavelengths of light to be absorbed improving efficiency Normal PV cells are 33% efficient and under normal conditions Multi-junction cells are 46% efficient
34
What are anti-reflective surfaces?
The shiny surface of solar panels causes it to reflect light (up to 30%) Using a grooved/ textured surface reduces reflectivity so more light can be absorbed
35
How can biomimetics be used for anti-reflective surfaces?
By mimicking the structure of the cornea of a moths eye as they are excellent at absorbing light
36
What is CSP? (Solar)
Concentrating solar power plants uses mirrors to concentrate the suns energy to drive steam turbines to produce energy Thermal energy from a CSP plant can be stored for when its needed (day or night) reducing intermittency
37
What is HEP, Hydro electric power?
Electricity from the kinetic (movement)energy produced when water drops or flows downhill
38
What must be present of HEP to be really viable?
A good volume of water (frequent rainfall) Good gradient drop (head) Low water turbidity Low seismic activity Impermeable bedrock
39
What are the two main types of HEP?
Low head turbines Helical turbines
40
What are low head turbines?
Used in rivers with a head of 20 metres or less to produce energy The head can either occur naturally (waterfall) or is produced by constructing a dam in a river creating a reservoir Controlled release of water from the reservoir drives a turbine very effective but has drawbacks
41
What are the benefits of low head HEP?
Medium efficiency No need for invasive infrastructure- no huge reservoir/ land flooding Low operational costs Long lifetime Low pressure differences and low rpm wont harm or kill migrating fish and machinery is partly or fully above water
42
Where can low head HEP be used?
Can be priced for rivers and estuaries Weirs, streams, locks, rivers and wastewater outfalls
43
Are there any problems with low head HEP?
A large volume of water is required to generate significant power using conventional technologies
44
How can the efficiency of HEP be improved?
Using helical turbines
45
What are the benefits of helical turbines?
Turbid water can be used (grey water) They don’t harm fish Water channels can be slower and smaller
46
What is wind?
Where air masses move from areas of high pressure to low pressure in order to try equalise pressure differences
47
What is the actual name for wind turbines?
Aero generators
48
What does HAWT stand for?
Horizontal axis wind turbines
49
Why is HAWT used?
Its been around for so long the technology is established and is more efficient
50
What are the issue with HAWT?
Need very tall towers to prevent blades reaching the ground Tower has to be bigger to support generator Blades are so long that they can be prone to cracking due the forces they are put under
51
What are the advantages of HAWT?
Very efficient High power output High operational wind speed
52
What are the disadvantage of HAWT?
Difficult to transport, setup and maintain Negative environmental impact Eyesore
53
What is VAWT?
Vertical axis wind turbine
54
What are the advantages of VAWT?
Produces energy at a very low wind speed Slower blade speed as blades are closer to axis of rotation
55
What are the disadvantage of VAWT?
Not as efficient as HAWT
56
What is wind assisted propulsion?
Practice of decreasing the fuel consumption of a merchant vessel through the use of sails or some other wind capture device
57
What vehicle is being used for wind assisted propulsion?
Ships by converting kinetic energy to thrust
58
What are the three ideas for wind assisted ships?
Wing sail concept Kite sail Flettner rotor
59
What is the idea of wind power ships?
Not to be the main source of power but support Diesel engines and reduce emissions and fuel 14% drop in fuel use
60
What makes an area viable as a wind farm?
Frequent and reasonably high velocity winds (not too high)
61
What locations are wind farms generally located?
Coastal locations Flat locations In the sea Upland
62
What are the common issues with wind farms?
May be in picturesque location so might affect beauty Ecological impacts could threaten birds and bats (male bats) Set up requires large machinery which could damage habitats
63
How is wave power produced?
The up and down motion of floating devices placed on the ocean surface
64
What are the positives of wave power?
Free Sustainable Renewable Produces zero waste
65
When was the first commercial wave energy system used?
Scotlands islay in 2000
66
What is the most common type of wave power technology?
Uses buoys or floats systems that rely on the rise and fall of swells to drive hydraulic pumps
67
What are the disadvantages of wave energy?
High production and installation costs Complicated maintenance and repair logistics Potential threats to marine life Noise pollution of onshore and off shore structures
68
What is geothermal energy?
Heat that comes from the sub-surface of the earth It is contained in the rocks and fluids beneath the earths crust
69
How is geothermal energy produced?
Well are dug a mile deep into underground reservoirs to access the steam and hot water which can be used to drive turbines connected to electricity generators
70
What is geothermal district heating? (GeoDH)
The use of geothermal energy to heat individual and commercial buildings
71
What are the positives of geothermal?
- environmentally friendly without significant amounts of pollution - geothermal reservoirs and naturally replenished thus renewable - massive potential, 2 Terawatts - excellent for meeting base load energy demand - no fuels needed for extraction less fluctuations of cost and electricity costs - small footprint on the land, partially underground - recent tech advancements, resources more exploitable and lowered costs
72
Negatives of geothermal?
Minor environmental issues- water wastes can contain salt and heavy metals and some gases (hydrogen sulphide) In extreme cases the plants can trigger earthquakes Heavy upfront costs Very location specific need to be at least 150*c so volcanically active or drill deep (expensive)
73
What is a new geothermal technology?
Low temperature fluids
74
What are low temperature fluids? (geothermal)
New turbine technologies that are being developed that use cooler liquids meaning water as cool as 60*c can be sued to boil butane or pentane
75
What does low temperature fluids mean for the uk? (Geothermal)
Cooler rocks could be sued like those in Cornwall
76
How are tides formed?
The gravitational attraction between the earth and the moon
77
How many ‘tides’ are there in a day?
2 high and 2 low tides every 25 hours
78
What are the three types of power/location that can be harnessed? (TIDAL)
Tidal barrage Tidal lagoon In stream turbines
79
What is a tidal barrage?
Where turbines are set across an estuary Tides are predictable Narrow area ensures all flow travels over turbines meaning good energy production
80
What are the negatives of tidal barrages?
Expensive and has environmental costs Considerable construction so impacts of material extraction and the barrage can affect hr heights of tides Can increase pollution build up around them due to settlement of sediments
81
What is a tidal lagoon?
Same as a tidal barrage but smaller A small area of coastline in enclosed Impacts are the same but smaller Migratory fish are able to pass causing less harm to the food chain
82
Who built the largest tidal lagoon in 2011?
South Korea
83
What is an example of a tidal lagoon in the uk?
Plan to build one in Swansea The walls will capture water when tide comes in and hold it when it goes out The walls will release the water back into the sea turning turbines making electricity Will power 155000 homes
84
What are in-stream turbines?
Function like underwater wind turbines Also called tidal turbines Cheapest and least ecologically damaging Potential power generation greater than wind turbine
85
Why are water turbines better than wind turbines?
Water is 800x denser than air so more power at low tidal flow velocities with similar wind speeds

Environmental Science #1 (90 decks)

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