Australia emits grams of CO 2 per kWh of electricity and heat production from coal, and grams per kWh from gas. There are small scale projects in operation and under development that capture CO 2 for commercial applications.
An example is the Victor Smorgon Group project in Victoria where CO 2 is stripped from flue gases and used in an algal bioreactor; the algal mass is dewatered then processed to produce biofuel. Much effort is being focused on geosequestration, that is the injection of liquefied CO 2 into geological traps such as exhausted gas and oil wells after capture and transport from the emission source.
Figure 2: Greenhouse gas emissions from various energy sources. Figure 2. Land use-related net changes in carbon stocks mainly applicable to bio-power and hydropower from reservoirs and land management impacts are excluded; negative estimates for bio-power are based on assumptions about avoided emissions from residues and wastes in landfill disposals and co-products.
Summary for policy makers, May Figure SPM8. The practical application of geosequestration to achieve meaningful CO 2 reductions appears to be several decades away. The development, infrastructure and operational costs of CCS are expected to increase the overall cost of electricity by 25 — 50 per cent, to between 4.
Figure 3: CO2 emissions from a coal-fired power plant with and without carbon capture and storage. Shown here are business-as-usual annual carbon dioxide emissions from coal-fired plant in Australia, with and without geosequestration, between and — 4 year moving average. Saddler, C. Riedy and R. Presently, nuclear reactors operating in 30 countries have an installed capacity of about GWe.
In , they generated 2, TWh, which is around 17 per cent of world electricity production. The majority of this growth reflects strong economic development e. China alone accounts for more than one third of the planned and proposed reactors , but the desire to reduce greenhouse gas emissions is another reason — for example, there are new nuclear reactors slated for developed countries such as Japan and the USA.
Current disadvantages of nuclear power include investment and financing risks, long construction times compared with most other electricity-generating technologies, persistently negative perceptions, especially regarding the safety of nuclear waste disposal, and a possibility of accidents releasing harmful radiation.
There is also a need to provide specialist regulatory agencies and detailed safety regimes. Opponents of nuclear energy consider that the full environmental costs, and the cost of disposal of high-level radioactive waste, are not factored into the claimed low cost of nuclear-sourced electricity. They also cite concerns over the danger of transporting either radioactive waste or nuclear fuel, the potential for long-term human health effects and ecosystem damage following accidental release of radioactive material from the power plant, and deliberate targeting of nuclear facilities by rogue elements.
A wide range of technologies offer potential for energy generation from renewable resources. These include hydro power, biomass, wind power, solar power photovoltaics and solar thermal , ocean energy, tidal power, and geothermal. Background information was recently gathered on these renewable resources by the House of Representatives Standing Committee on Industry and Resources. Key characteristics of the renewable energy sources reviewed in this paper are described here and summarised in Table 3.
Hydro power is a long-standing source of electricity generation using renewable energy, but its role in meeting demand for clean energy is severely limited by lack of suitable new sites for dam construction; community resistance to land flooding; and concerns that climate change may reduce flows and thus reduce the certainty of future energy supply.
Worldwide, in response to these limiting factors, there is a move toward development of mini-hydro power systems that are applicable in smaller rivers and more distributed locations. In a recent innovation, a mini-hydro project has been developed in Victoria to utilise the energy in an existing water pressure reduction station between the mains and distribution water pipe systems. In Australia, hydro power is being used increasingly to meet peak load requirements owing to its inherent flexibility.
Australia has about hydroelectric power stations with 7, MW capacity providing about 16, GWh annually. A further MW are either under construction or planned. Biomass as an energy source involves two different methods: burning vegetative material, and burning biogas methane produced by the breakdown of organic matter. Australia has about MW of electricity generation capacity in total from biomass sources. Small amounts of energy are also produced by burning wood waste at some timber mills.
Vegetative matter can be grown specifically to be burned directly to produce energy, or to make biofuels, but this is considered environmentally and economically inefficient as it would supplant other, more high-value forms of agriculture such as plantation timber or food cropping. Biomass as biogas entails harvesting methane from the breakdown of organic material — principally human or animal sewerage, municipal rubbish, and waste from food processing. Installed capacity for biogas electricity production in Australia was MW in , having grown at around 78 per cent per year since Most of the capacity is at sewage treatment plants, which are considered highly cost-effective.
Parallel development of biomass production for electricity generation, and biofuel production for petroleum substitution, would offer greater certainty to the agricultural sector. The gas is fed into small generators on-site, which produce about 27, MWh annually at the Canberra rubbish tips— enough to power around 4, homes. When fully operational, the Woodlawn operation will produce 20 MW, enough for around 20, homes.
Veollia Environmental Services brochure, Woodlawn Eco-precinct,. Wind power Total installed wind capacity in Australia is currently MW, and has grown strongly in recent years by MW in About 2, GWh is generated annually.
Costs and efficiencies are improving, particularly as the size of rotors and turbines increases. The IEA anticipates that wind power technology will continue to improve and capital costs will decline with larger volumes of turbines produced.
The trend towards larger rotors and taller towers is expected to continue, improving performance and reducing the unit cost of electricity. At the best sites, wind may become competitive with the cheapest fossil fuel resources by While the generating costs in good sites are quite close to the cost of conventional technologies, additional costs to cope with intermittency and grid integration tend to increase the generating cost of wind substantially.
Australia is not particularly well-endowed with sites for wind farms, and development tends to be restricted to southern regions, which is where the windiest locations are. The risk of bird deaths has affected the final siting of some projects, and required special monitoring and mitigation procedures which appear to have reduced the general level of concern.
Wind can contribute to small community off-grid systems, as well as supporting remote end-of-grid consumers by improving stability and reducing transmission loss. Options for managing intermittency of power supply include reserve power plants; interconnection with other grid inputs; distributed generation; matching demand to the intermittent supply; and electricity storage.
As the market penetration by wind power increases, the impacts of intermittency on the NEM will become more apparent and will require technical compensation. Therefore, growth beyond about 20 per cent of the market share may require major advances in management of distributed and intermittent power sources, such as developing reliable wind forecasting ability to pre-empt the effects of intermittency of supply; and by making the grid more flexible in its receipt of intermittent power.
Photovoltaic PV technology transforms the energy of sunlight solar photons into direct electric current using semiconductor materials. The basic unit of this technology is a PV or solar cell. When photons enter the PV cell, electrons in the semiconductor material are freed, generating direct electric current. Solar cells are made from a variety of materials and come in different designs. The most important PV cells are crystalline silicon and thin films, including amorphous silicon.
The amount of energy that can be produced is directly dependent on the intensity of available sunshine and the angle at which solar PV cells are oriented. PV cells are still capable of producing electricity even in temperate winter conditions and during cloudy weather, albeit at a reduced rate. Obviously, however, the cells will not work at night. Most current photovoltaic power is decentralised, being generated on rooftops to power individual buildings.
PV is an attractive option in areas of abundant sunshine such as in Australia, and may play a useful role in meeting peak consumption associated with the use of air conditioning systems. In remote areas it can also be a cost-effective option. Most non-rooftop Australian installations are in remote areas such as Kings Canyon and Hermannsburg in the NT , where peak output tends to match peak demand owing to the use of air conditioning in the hotter parts of the day.
Installed capacity grew by 24 per cent in to PV rebates and feed-in tariff developments are likely to sustain and possibly strengthen this trend.
PV is reliable and low maintenance, albeit predictably non-constant over a hour cycle. It is readily adaptable and scaleable, from stand-alone off-grid systems where back-up is generally required commonly in the form of a diesel generator; to grid-connected systems where excess electricity production can be sold into the grid, and there is no requirement for storage or back-up systems; and utility-scale systems. PV installations are almost all roof-mounted systems at the domestic scale.
However, the longer term commercial potential is considerable provided capital cost can be brought down. Technologies are also under development to better integrate PV into building architecture, including modular rooftop PV systems, the development of a solar PV rooftop tile, and solar PV wall panels.
Whilst it is unlikely that PV technology for off-roof utility-scale generation will become price-competitive for another twenty years, [39] significant technological advances are being made: A grid-connected MW CPV Concentrated Photo Voltaics plant is being developed in Victoria.
Pre-commercial development work has been completed. A 2MW demonstration plant is to be constructed by mid ; construction of the full scale MW plant near Mildura is expected to begin in and take around 2 years. The project is being funded by The Victorian and Federal governments. Future policy frameworks including subsidies, and variations in the level of feed-in tariffs, could significantly influence the uptake of PV and the size of its contribution to the NEM.
If technology delivers a substantial reduction in capital cost, then PV may develop into a significant contender for generation into the grid, particularly from building-integrated installations.
The output is times the power output of the same area of a conventional PV cell. Solar Systems, Factsheet :. Solar thermal technologies STT concentrate solar radiation on to a receiver, where it is converted into heat, which can then boil a liquid to produce steam to drive turbines. STT is suitable for large-scale electricity generation and there are a number of technology options available, although they are at different stages of deployment and development.
STT can be split into two groups:. Solar thermal energy is emerging as a cost-competitive source of electrical power, especially because it can combine beneficially with current energy sources such as coal power generation. In , costs were predicted to become equal to coal-fired generation once global capacity reached 5, MW, by around Table 1: Brief description of some zero to low concentration, low temperature solar thermal technologies. A body of saline water several metres deep with increasing salinity with depth.
Solar radiation entering the pond is stored as heat in the lower layer. Possible applications include agriculture, aquaculture, water desalination and salt production. It is not suited to electricity generation, but can reduce electricity demand. Heat-absorbing flat panels or tubes capture solar radiation and transfer the heat by circulating water to a storage tank. Mostly used for domestic and small-scale industrial use, with fixed collectors mounted on the roof, sometimes on frames to place the collector perpendicular to the incidence angle of winter midday sunlight for maximum efficiency.
Not applicable to electricity generation, but reduces electricity demand. Table 2: Brief description of some high concentration, high temperature solar thermal technologies. Constructed as a long parabolic mirrors which concentrate and reflect sunlight onto a horizontal tube.
Fluid running through the tube picks up heat and is used to heat steam in a standard turbine generator. The mirrors can be rotated to track the sun on a daily or seasonal basis. Thermal efficiency for heating the fluid ranges from per cent.
Overall efficiency from collector to grid is about 15 per cent, similar to Photovoltaic Cells. An array of flat, movable mirrors heliostats focuses sunlight upon a collector tower, in which a substance is heated. Water was originally used for immediate power generation via a steam turbine, which did not allow for power generation when the sun was not shining.
Other media can be used to store heat from which steam can be generated to run turbines at any time of day: purified graphite is being used in the 10 MW power plant in Cloncurry; liquid sodium sodium is a metal with a high heat capacity has also been successfully demonstrated as a heat storage medium. A curved mirror which concentrates sunlight on to a focal point where the temperature may reach up to 3, 0 C.
This heat can be used to generate electricity or make hydrogen fuel. A series of long, narrow, shallow-curvature or flat mirrors focus light onto one or more linear receivers positioned above the mirrors. On top of the receiver a small parabolic mirror can be attached for further focusing the light.
Cost is lower than trough and dish concepts because a receiver is shared between several mirrors; there is just one axis for tracking; and as the receiver is stationary, fluid couplings are not required.
The mirrors also do not need to support the receiver, so they are structurally simpler. Several tower-mounted receivers stand close together so that the surrounding heliostat fields partly overlap. In some parts of the total heliostat field the mirrors are alternately directed to different aiming points on different towers, so that radiation is collected which would usually remain unused by a conventional solar tower system due to mutual blocking of the heliostats. Barriers to uptake include the high up-front cost of equipment to collect and store solar energy, the need for large collecting areas, and intermittence.
The capacity to generate high temperatures provides the potential for hydrogen production as a method for storing energy for use in producing continuous energy supply; hydrogen also provides the possibility for energy use beyond the stationary electricity sector see discussion on energy storage below. Whilst the intermittency of solar energy i. PV and solar thermal is sometimes used as a basis to argue against its potential for supplanting energy from hydrocarbons, it is worth noting that in summer the diurnal fluctuation in solar power output approximately parallels demand associated with airconditioning.
Demand tends to occur later in the day due to temperature peaking in mid to late afternoon as well as the concurrent demand of office and home airconditioning systems in the late afternoon and early evening as workers return home. Current costs of solar thermal systems are the lowest of any solar technology, but more expensive than hydro, wind and biomass.
Ocean energy can be tapped from a range of sources including tides, waves, marine currents, thermal layering, and salt gradients. France, Canada, China, Russia and Norway operate tidal power stations, and there is a commercial wave power plant in the United Kingdom.
Only two of these sources are being investigated for development in Australia — tides and waves. Tidal power incurs relatively high capital costs, and construction times can be several years for larger projects.
In addition, operation is intermittent with a relatively low load factor 22—35 per cent. Thus, although plant life can be very long, the high capital costs and long construction time have deterred the construction of large tidal schemes. The environmental impacts from the large scale excavations required during construction are a further impediment, as is the potential for significant and possibly permanent alteration of estuarine tidal dynamics.
Tidal energy was considered for the Derby region of WA. However, economic and environmental considerations made a gas-fired power station a more cost effective option in that case. A tidal range of at least 5 m is considered necessary for large-scale installations. However, given the high costs of transmitting the power to far-away metropolitan regions, the resource may only be suitable for local demand.
A low probability role could be to generate hydrogen, if a hydrogen-based economy were to develop in the future. Wave energy depends on wind speed, the distance over which the wind interacts with the water, and the duration of time for which the wind blows.
Wave energy systems do not make use of waves as such, but rather the swell that occurs in deeper water or which can be captured by coastal installations. Currently in the world, only two wave power installations are operating as commercial-testing installations. The fact that there are many different concepts under investigation in various countries e. Scotland, Portugal suggests that the best technology has not yet been identified.
The technology is relatively straightforward compared to most other renewable energy technologies, and is easily scaled up to match supply opportunities. An added bonus is the capability to co-generate desalinated water. Projected costs into the long term are the lowest amongst the renewables. Reliability is relatively high, although predictable periods of lower output would be associated with calm ocean conditions. It appears to have a fairly low priority for commercialisation or for research.
Nevertheless, wave power holds promise for offshore installations with minimal environmental impact, and is able to be sited close to coastal settlements with little effect on access to or utilisation of the adjacent coast or sea. If the technology were to develop faster than anticipated, Australia has suitable coastline conditions in its southern regions, and local technological expertise.
Two systems currently under trial in Australia are described in the boxes. The motion of underwater balloons is used to pump seawater ashore under pressure to produce electricity via a turbine, or for desalination. The system is modular, with each balloon capable of generating kW. A grid-connected commercial plant is in the detailed design phase and construction is planned for OceanLinx is a moored system in which wave energy is focussed in a confined chamber; the resulting airflow passes through a turbine to create electricity.
Recent work has focussed on improved turbine design. Geothermal energy sources originate from thermal energy trapped beneath and within the solid crust of the Earth. Theoretically, the total accessible resource base of geothermal energy to a depth of 5 km is over one million terawatt-years TWa , but only an extremely small fraction of this total could ever be captured, even with advanced technology.
Geothermal energy for electricity generation is cheap where it is easily accessible, but that tends to be in places that are volcanically active. In the longer term, tapping geothermal energy by pumping water into subterranean hot fractured rocks may become a useful source of renewable energy with wider availability.
The IEA suggests that it is possible, with the full exploitation of opportunities, that geothermal energy could supply 5 per cent of global electricity by Geothermal aquifer: Australia has very limited geothermal aquifer resources — unlike the volcanically active regions of New Zealand which have been tapped as a source of geothermal energy for electricity generation since the late s and currently provide an installed capacity of MWe or 7 per cent of New Zealand's total installed capacity for electricity generation of about 5, MWe.
Two small-scale power plants utilise low temperature hot water to generate electricity for remote settlements, and a small geothermal power station is operating as a demonstration in Birdsville. As the resource is available only in central Australia it can supply only the very few towns located near the resource, where the total demand for power is about 20 MW.
Present capacity is 18 MW and annual production about 43 MWh. This represents an enormous energy resource which can be tapped by pumping water into the HFR and extracting it as high pressure steam to run conventional steam turbine power equipment. The technology holds the promise of providing continuous power output. To develop this resource, boreholes need to be drilled into the HFR to facilitate the injection of water, which passes through fractures in the rock to extraction boreholes and returns to the surface as steam.
Future development of drilling and extraction technologies is expected to expand the available geothermal resource. Hot Fractured Rock technology is at the experimental stage with no commercial schemes anywhere in the world. Successful development of the main areas in remote Qld and SA will require large-scale engineering and major infrastructure development to link it to the grid.
There is also some potential in the Hunter Valley which is well located to tap into the existing electricity grid. Twenty-seven companies are exploring for geothermal energy resources over about sq km in Australia. The Energy Supply Association of Australia suggests that 6. Without the pricing of CO 2 emissions, this is considerably more expensive that many forms of conventional energy generation from coal and natural gas. Current drilling limitations may need to be overcome to allow widely distributed implementation.
Remoteness of currently viable geothermal resources will require substantial investment in infrastructure to extend the grid, and will incur significant transmission losses using conventional 3-phase AC high tension lines.
High voltage direct current transmission lines result in less energy loss, and are calculated to limit energy losses between remote NE South Australia and Port Augusta or Brisbane to around 5 per cent to 8 per cent respectively. These additional costs may affect the market competitiveness of this technology.
Table 3: Summary of key features for alternative renewable resources for electricity generation. Renewable type. CO 2 emissions. Financial performance measures include the farm sector's receipts and expenses; gross and net value added; and both net cash farm income and net farm income. Measures also include changes in the sector's assets, debt, and overall wealth, as well as financial ratios that depict solvency, liquidity, and efficiency.
Taken together, the measures summarize the financial condition of the farm sector. Skip to navigation Skip to main content. You could order topic wise PDF or the whole subject. Mail to info civilserviceindia. Our advice is not to read everything. Instead focus on selected study material and for specific topics refer to other materials as and when needed. We have researched and listed books that are the best in an orderly manner into subjects and topics. Read More. Notice Board.
Will the fortification of rice help eradicate malnutrition in India? Articles Brus of Mizoram Views :
0コメント