1 Why sustainable energy matters
Current use of fossil fuels not sustainable.
Finite supply(but not about to run out immediately)
Location of 2 thirds of oil in Middle East or N. Africa - has led to conflict.
Price rises led to protests. (Renewables need to enable the same level of affluence that fossil fuels have enabled, else acceptance will be low)
Accidents during extraction, distribution and use.
Pollutants from use. And CO2 leading to climate change affecting ecosystems, agriculture, sea levels
Nuclear is source of 7 percent of primary energy
No green house gases, but...Supply of uranium also limited (decades or possibly centuries at current rate of use), proliferation of weapons, problems of disposal and cleanup.
Efficiency of systems is an important factor in mitigating the effects of energy use.
Renewables - Replenished by natural processes.
Solar energy, bioenergy, hydroelectricity, wind and wave power
Current costs can be higher than conventional sources, slows take up.
Need:-
- To reduce impact of fossil and nuclear
- To develop and deploy renewables
- To improve efficiency of conversion, distribution and use
Energy is the capacity to do work.
Power is the rate of doing work.
Energy = power x time
Sustainable development is ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs ’ (United Nations, 1987).
3 Present Energy Sources and Sustainability
80% of energy comes from fossil fuel at present
At current rate-200 years of coal, 60 years gas, 40 years oil
Hydrocarbons release co2 on combustion, a greenhouse gas.
Nuclear:Energy released by splitting uranium atoms (fission)
Major concerns are safety and disposal of waste
Biofuel:Combustion of straw and forestry waste. Incomplete combustion can release pollutants. Only sustainable if trees replanted ( also only sustainable if biodiversity of resource is maintained.)
Hydroelectricity 17% of electricity produced in 2000 came from hydroelectric.
- indirectly solar power from evaporation of water to rain
