what are the main new clean technologies which can be introduced to mitigate environmental consequences of nuclear and fossil fuel energy.
what is carbon sequestration
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Sustainability and stewardship should be our priority.
What is Renewable energy?
Cleaning-up fossil and nuclear technologies means mitigating some of the adverse ‘environmental’ consequences of fossil and nuclear fuel use through the introduction of new, ‘clean’ technologies that should substantially reduce pollution emissions and health hazards.
• ‘supply-side’ measures to improve the efficiency with which fossil fuels are converted into electricity in power stations;
• cleaner and more efficient combustion methods;
• the increasing use of ‘waste’ heat in combined heat-and-power schemes; and
• ‘end of pipe’ technologies to intercept and store pollutants before they enter the environment.
This approach also includes ‘carbon sequestration’ and ‘fuel switching’ - shifting our energy use towards less-polluting fuels, for example from coal to natural gas.
It may also be possible to ‘clean up’ nuclear power by adopting more advanced technologies that are safer and entail the emission of fewer radioactive substances over the entire nuclear fuel cycle.
One way of mitigating climate change that could be important is called ‘carbon sequestration’. To sequester means to ‘put away’, and sequestration of carbon essentially involves finding ways of removing the carbon generated by fossil fuel burning and storing it so that it cannot find its way back into the atmosphere.
One way of sequestering carbon is to plant additional trees which ‘soak up’ CO2 from the atmosphere while they are growing. However, whilst this could provide a partial response to the problem of rising CO2 levels, the sheer magnitude of world emissions is now so great that sequestration in forests alone is probably impractical.
Another approach to sequestering CO2 is to extract it after combustion in, for example, a power station and store it in some suitable location. It appears to be technically possible to transport by pipeline large quantities of post-combustion CO2 and store it indefinitely in disused oil or gas wells or in saline aquifers beneath the sea bed.
Further research is required to confirm the feasibility, security, safety and economic viability of such techniques. They would only be a realistic option in the case of power stations or similar large installations. It would hardly be practicable to apply this approach to emissions from vehicles or homes.
It seems inevitable that relatively clean renewable energy sources will see extensive development during the 21st century. Only hydropower has been exploited close to capacity so far. Investment and environmental disruption remain barriers for further hydro schemes, both on a large scale in developing countries and on a small scale anywhere.
This is true for many of the renewable energy sources, though some countries have fostered major renewables industries (e.g. wind power, offshore in Denmark and onshore in Germany).
Ironically, the geographic distribution of renewable energy potential is just as uneven as that of fossil and nuclear fuels, so that some countries have a far greater endowment than others.
The UK, for example, is well-placed for wind, wave and tidal power, but much less so for hydro, solar and geothermal resources. In future such global inequalities in energy resources will have to be smoothed out by international trade, probably of generated electricity.
Another widespread difficulty with many renewable sources is intermittency of supply combined with unpredictability; the fact that the amount of electricity generated often varies on short timescales. Some sources are unpredictable (wind and wave energy), others are cyclical (tidal, solar), and others are more constant (geothermal). In designing an electricity supply system that can guarantee to meet demand, a delicate balancing act would be required.
It is unlikely that renewable sources alone could provide a stable electricity supply, especially as most countries will not have the full range of renewable options. Thus, one of the most important features of future energy supply systems will be integration, that is, the ability to manage a complex mix of different energy sources to produce a stable power supply that can track the demand curve.