Future carbon footprint reduction for power generation – Ways to mitigate emission:
The greatest potential for carbon footprint reduction is in conventional fossil fuelled electricity generation, using improved combustion technologies, carbon capture and storage and co-firing with biomass. We tried to examine most the technologies available to know the potential to reduce their carbon footprint.
a. Fossil fuel generation – future carbon footprint - Technology improvements could increase the energy efficiency of existing coal fired plants from current levels of ~35% (where only 35% of the fuel energy is converted into electricity) to over 50% (by using super-critical thermal power plant). Improvements in energy efficiency can halve life cycle carbon emissions in both coal and gas fired plants. Carbon capture and storage (CCS) could potentially avoid 90% of CO2 emissions to the atmosphere in the future.
b. Co-firing fossil fuels and biomass - Co-firing biomass along side fossil fuels in existing power plants can also significantly lower their carbon emissions, because the fossil fuels are replaced by ‘carbon neutral’ biomass.
c. Future carbon footprint reductions in all technologies - Carbon footprints could be further reduced in all electricity generation technologies if the manufacturing phase and other phases of their life cycles were fuelled by low carbon energy sources. For example, if steel for wind turbines were made using electricity generated by wind, solar or nuclear plants. Using fewer raw materials would also lower life cycle CO2 emissions, especially in emerging technologies such as marine and PV. New semi-conducting materials (organic cells and nano-rods), are being researched for PV, as alternatives to energy and resource intensive silicon.
d. Future nuclear footprint & global uranium resources - Some analysts are concerned that the future carbon footprint of nuclear power could increase if lower grade uranium ore is used, as it would require more energy to extract and refine to a level usable in a nuclear reactor. Point is to be noted: if lower grades of uranium are used in the future the footprint of nuclear will increase, but only to a level comparable with other ‘low carbon’ technologies and will not be as large as the footprints of fossil fuelled systems.
Overview of future carbon footprint reduction –
(1) All electricity generation technologies emit CO2 at some point during their life cycle. None of these technologies are entirely ‘carbon free’.
(2) Life cycle inventory analysis is used to measure the amount of CO2 emitted by each technology.
(3) Fossil fuelled electricity generation has the largest carbon footprint (up to 1,000gCO2eq/kWh). Most emissions arise during plant operation.
(4) ‘Low carbon’ technologies have low life cycle carbon emissions (<100gco2eq/kwh).>
(5) Future carbon footprints can be reduced for all electricity generation plants if high CO2 emission phases are fuelled by low carbon energy sources.