management of Sustainable Energy Supplies
Sustainable Energy Supplies
Producing and using energy in such a way that it ‘meets the needs of the present without compromising the ability of future generations to meet their own needs’
Renewable/Non-Renewable
Renewable resources:
Offer unlimited use that contribute no atmospheric pollution when generating
Critical resources: require careful management (wood/dung for biomass) so they don’t become unsustainable
Solar: sunlight turned into electrical energy by striking photovoltaic cells (direct electricity conversion) or being focussed onto CSP tower, to heat steam to pass through a turbine
Advantages: cost reducing every year, needs little maintenance, saves 500,000 tons CO2 in Barcelona
Disadvantages: must be south-facing in a location with good sun exposure, expensive cells, needs large amount of land, harmful manufacture process
Plantar Solar 10: 35mcost,4yearstobuild,624mirrors,23.4GWhoutput,35mcost,4yearstobuild,624mirrors,23.4GWhoutput,6.3m revenue per year
Tidal: tidal movement drives turbines, or a barrage acts as a dam that channels water flow during tidal movements to drive turbines (GPE à KE à electrical). 50% of Europe’s tidal production is in the UK
Advantages: same benefits as HEP, no GHG emission, few wildlife impacts
Disadvantages: possibly increased salinity, disturbed wildlife and migration, expensive, silt build-up
Rance Barrage, France: 240MW facility on the coast of Brittany, 750m long with 24 turbines
HEP: fast flowing water (from a river, or released from a dam) is directed through turbines. The force of the water spins the turbine’s blades, generating electricity
Advantages: once operating they are very cheap and efficient to run, emitting no green house gasses
Disadvantages: building structures on rivers and dams may harm the wildlife, are expensive and may over flow or experience silt build up
See 12.2.2 – Located Example
Wind: wind hits angles blades, turning a turbine, which turns kinetic energy into electrical energy
Advantages: cost dropped 6x since 1980, no GHG emissions, will never run out, low operating costs
Disadvantages: intermittent, supply can’t rise with demand, harms wildlife, noise and visual pollution
Walney Island, UK: contributes 1GW to UK’s total 10GW, comprised of 87 turbines in Irish Sea to power nearly 500,000 homes
Geothermal: using either hot-dry rock (water injected into hot rocks, rises as steam) or high temperature geo-pressurised aquifer systems (steam rises from ground) to spin turbines. Low temperature aquifers heat water for home use. 4% growth per year
Advantages: no GHG emissions, small footprint power stations, free, no fuel required
Disadvantages: limited locations (needs geothermal activity and correct rocks), may run out of steam or heat, may release sulphur and hazardous minerals
Iceland: powers 95% of Reykjavik, 750MW power, heats 60m m3 of water to 86oC, saves 4m tons CO2
Wave: either a fixed structure at the coast, where waves rise on wall and compress air to turn a turbine, or oil moving through a structure at sea
Advantages: regular production, with less impact compared to a tidal barrage
Disadvantages: visual pollution, disrupts fishing and swimming, hard to get electricity back to the shore
Pelamis, Orkneys Islands: 750kW hinged device, where oil inside snake structure flows with wave oscillation spinning a turbine as it moves
Biomass: high carbon plants such as sugar cane or grains are turned into ethanol by putting plants in a gasifier, which is used as a fuel. Alternatively, solids such as sewage, wood and rubbish water are burnt
Fuel wood is the primary source of energy in many LICs. 2.5bn people rely on it for cooking and heat, but 1.5 million die per year due to smoke inhalation
Advantages: easy to store and scale to demand, absorbs CO2 while growing, allows the reuse of wastes
Disadvantages: produced CO2 during burning, farming is controversial (food dilemma, deforestation, soil erosion, habitat loss)
Brazil: around 27m cars (73%) run on an ethanol/ petrol mixture – reducing fossil fuel consumption
Non-renewable resources: Finite, so as they are used the total supply reduces. Eventually, they will become exhausted
Coal: 2nd most used after oil. Open cast, or deep shaft mines remove coal from coal beds in the ground. Coal is then burnt, and the heat turns water to steam, turning turbines
Advantages: easy and simple to build, high energy density, plentiful supplies, new technology allows for easy ground extraction, carbon capture = ↓ emission
Disadvantages: produces pollutants (SO2, CO2), bulky to transport, produces large volume of waste, high sulphur content (flue gas desulphurisation produces gypsum and needs a lot of limestone)
Drax, Yorkshire, UK: provides 6% of UK’s energy needs, produces 1.3GW from coal and 3.9GW from biomass. Imports coal from Poland/Australia
Oil: carbon dense crude oil from fossilised animals trapped in rock layers underground
Advantages: high energy density, easy to transport (pipes, ships), flexible use (petrol, heating oil, bitumen), cleaner and easier to burn than coal
Disadvantages: limited supply (30bn barrels used per year, only 4bn discovered per year), price fluctuates and vulnerability under control of OPEC and wars, issues with oil spills, produces atmospheric pollutants
North Sea Oil: between 1.7 to 3.3bn barrels are recoverable. Roughly 200,000 produced per day
Natural Gas: trapped in rocks deep underground – is blasted out with high pressure fluids (blasting and cracking shale rocks). Same steam/turbine process
Advantages: large deposits yet to be discovered, cleanest of the fossil fuels, 50% reduction in USA gas prices due to fracking, new technologies developed
Disadvantages: limited supply, produces GHGs, fracking induces seismic activity, associated health issues if gas/fluids leak into underground aquifers
Example: 1m fracking sites in the USA, across 30 states. 1000 drilling sites in Pennsylvania, $30-50m for 1 site with 8 lines. “More gas in USA than Oil in Saudi Arabia”
Nuclear: uranium ore is mined and turned into fuel rods that undergo radioactive decay. The splitting of atoms creates heat that warms water to steam, turning turbines
Advantages: very efficient (1 station = wind farm the size of Luxemburg), no atmospheric pollutant, reduced dependence on greenhouse gasses
Disadvantages: expensive to build/run, takes long time to plan and then decommission, hard to dispose of toxic water (U235 = 700m yr half life), disasters such as Chernobyl taint the image
Hinkley C, UK: plant in North Summerset will contribute 3.2GW to the UK’s total 16GW. It alone provides 7% of the UK’s power (6m homes) and 25,000 jobs