Chapter 9 - Energy resources Flashcards
what is geothermal power ?
Type of renewable energy taken from the Earth’s core or below the earths surface
what is the technical definition of geothermal power, in terms of below the earths surface ?
radioactive decay of isotopes (eg. uranium) in mantle releases heat which can be exploited for many things
what are 2 types of low temperature schemes for harnessing geothermal power ?
- geothermal springs
- geothermal aquifers
what are 2 types of high temperature schemes for harnessing geothermal power ?
- geothermal steam system
- hot dry rock system
what is a geothermal spring ?
groundwater is heated by hot rocks
what is a geothermal aquifer ?
Hot groundwater pumped from aquifer to surface
what is a geothermal steam system ?
Groundwater at high temps extracted using boreholes producing high temp steam that can generate electricity
what is hot dry rock system ?
Hot rocks near the surface but have no groundwater nearby to heat, to boreholes are used, water pumped down one borehole and hot steam is collected out of the other borehole
what is the local constraint of geothermal power ?
geothermal power stations use terbines that need a very high heat source and therefore need recent volcanic activity so the hot rocks are near the surface, if hot rocks are too deep in the ground drilling them in uneconomic
what are 3 environmental impacts of geothermal power ?
- infrastructure - steam and pipes can provide obstacles to movement of large mammals
- gaseous emissions - releasing this hot water can release small amounts of gas (eg. CO2 etc)
- waste water - contains salts and heavy metals
the new geothermal technology, low temperature fluids, what are different about these ?
they require lower temperature liquids to turn the turbines and create energy
3 examples of energy uses within agriculture and fisheries
- fuel for machinery like tractors / combine harvestors
- manufacture for chemicals like fertilisers
- food processing like sugar refining
3 examples of energy uses within ‘other industries’
- machinery operation like rock crushing
- heat for baking like pottery
- sewage treatment
3 examples of energy uses within domestic energy use
- space heating
- lighting
- running appliances like fridges
2 examples of energy uses within transport
- transport of goods - trains, trucks etc
- transport of people - cars, buses etc
what are the features of energy resources (15)
- renewable / non-renewable
- depletable / non-depletable
- abundance
- local constraints
- intermittency
- predictability
- energy density
- resource availability
- need for conversions to increase usefulness
- applicability to specific uses
- ease of storage
- ease of transportation
- environmental impacts
- technological development
- political / economic influences
what is meant by renewable and non-renewable energy sources ?
- renewable = naturally forms, reforms relatively quickly therefore infinite resource
- non-renewable = not being formed or reform so slow that current use > reform speed
what is meant by depletable and non-depletable energy resources ?
- Depleteable = use can reduce future availability
- non-depletable = the opposite
what is meant by an abundance in energy resources ?
- ensures there is enough of the resource that exsists
what are 3 things that affect the abundance of an energy resource that isnt it ‘just not exsisting’ ?
- fossil fuels deep upderground so cant extract
- winds too high above the ground and cant make aerogenerators that tall
- wave power to far from the coast therefore water too deep for anchor equipment
what are 3 things influencing energy resources in terms of local constraints ?
- energy resources are not evenly distributed - all have locational factors
- sources that can only be accessed via extraction may be located in favourable deposits
- sources that harness natural processes may depend on regional / local features (eg. climate / topography)
whats a local constraint of fossil fuels / what do power stations require access to
- fuel supplies
- suitable construction sites
- condenser cooling water (lake etc)
whats a local constraint of nuclear power / what do power stations require access to
- condensor cooling water (lake etc)
- suitable constructin site
whats 2 local constraint of solar power
- high light intensity
- low cloud cover
whats a local constraint of wind power ?
- area with strong, reliable winds (open plains etc)
- areas with low land conflicts
whats a local constraint of wave power ?
- strong reliable winds over water
- reliable prevailing wind direction
- long fetch (stretch of water over whcih the wind blows)
whats a local constraint of hydroelectric power (HEP)
- high reliable rainfall
- large catchment
- impermeable bedrock
- stable geology
whats a local constraint of biofuels ?
- nearby forest areas
- farmland for biofuels / crop or livestock waste
- nearby urban area
whats a local constraint of geothermal power ?
- hot rocks near the ground surface
- recent volcanic activity
whats a local constraint of tidal power ?
- tidal range is large
- coastal features that focus tidal flow to increase flow velocity or tidal range
what is meant by intermittency in energy resources ?
If energy resource is not available at times then its hard to rely on it
what is meant by predictability in energy resources ?
To know how much energy will be available and whether it will meet demand for energy
what is meant by energy density in energy resources ?
measure of the amount of energy in a given amss of energy resource
what energy density is most useful and why ?
High energy density becuase :
- smaller quantities needed ∴ storage + transport is easier
- easier to reach high temperatures
