|
|
 |
 |
 |
| Thursday, 29 August 2002 |
 |
|
 |
Features | |
| News Business Features Editorial Security Politics World Letters Sports Obituaries
|
by Professor Priyantha , D C Wijayatunga , Centre for Energy Studies (CEnS), University of Moratuwa Global warming which is caused by increased greenhouse gas (GHG) concentration in the atmosphere, has been the subject of discussion for some time in the recent past mainly due to its impact in various areas of the global environment such as the global temperature and the sea level. It is very relevant to discuss this topic at the time when the 2nd Earth Summit is being held in Johannesburg. This article attempts to highlight the connection between global warming and the emissions in the power sector and how the emissions contributing to this phenomenon can be mitigated to a certain extent by choosing alternative electricity generation options and energy efficient technologies at the consumer level. Effect When solar radiation reaches the earth it interacts the earth surface in several different ways. Part of the radiation is reflected back by the earth's atmosphere while a large portion penetrates onto the earth surface. This radiation reaching the earth surface is largely absorbed resulting in surface warming. Most of this absorbed energy is radiated back from the surface in infrared wavelengths, which will in turn interact with the atmosphere. Though some of this energy escapes back to the space, most of it is reflected again back to the earth surface further warming the surface. This process finally leads to an equilibrium temperature on the surface of the earth. This is called the greenhouse effect. Not all the constituent gases of the atmosphere are responsible for this process leading to greenhouse effect. The main gases contributing to greenhouse effect which are called greenhouse gases, are carbon dioxide (CO2), methane, nitrous oxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). Three of these gases are of primary concern due to their close association with human activities. They are nitrous oxide, methane and carbon dioxide. Without these gases in the atmosphere contributing to the greenhouse effect, the temperature on the earth's surface would have been about 600F colder. In other words, these gases act as an insulator maintaining the surface temperature. When the concentration of these gases grows in the atmosphere it tends to block more infrared radiation escaping the atmosphere resulting in increased surface temperature which will in turn have a serious effect on the ecological systems on the earth surface. Therefore climates suitable for human existence can be maintained on the earth only within a limited range of concentration of these gases in the atmosphere. When the concentration of these gases gradually increases as a result of anthropogenic emissions the average earth surface temperature increases and this phenomenon is known as global warming. This phenomenon causes drastic adverse impacts on various forms of ecological systems in the world, which will in turn threaten the very existence of humanity in the longer term. Thermal-power Sri Lanka electricity generation sector is transforming itself into a thermal-power based system from a predominantly hydropower based system as a result of growing demand and unavailability of large economical hydro resources in the country. While all the existing thermal plants are based on petroleum fuels, a considerable capacity of coal-fired stations is to be added in the future to satisfy the base-load generation requirements. All these plants based on fossil fuels will result in substantial increase CO2 emissions in the power sector. For instance, CO2 emissions in the power sector is expected increase by 10 fold within the next 10 years becoming one of the major sectors contributing the GHG emissions in Sri Lanka. Therefore it is important to examine the opportunities available for GHG emission reduction in the power sector. Options GHG emission mitigation options can be either in the power generation sector or in the form of using energy efficient technologies at the consumer-end. Both these types of options have their own costs. In a limited number of cases not only these options reduce the GHG emissions but also result in financial savings. But in most other cases GHG mitigation can be achieved only at a certain cost. Recently a major study to examine various GHG mitigation options involving the Sri Lanka power sector was completed jointly by the Sri Lanka Energy Managers Association and the Centre for Energy Studies at the University of Moratuwa under the Asian Regional Research Project on Energy, Environment and Climate Change (ARRPEEC) coordinated by the Asian Institute of Technology, Bangkok with the financial assistance from the Swedish International Development Cooperation Agency (Sida). This research project investigated the use of clean coal and renewable technologies as well as energy efficient end-use components as means of GHG mitigation in the Sri Lanka power sector under three emission reduction scenarios. In this process the costs and benefits of using clean coal technologies such as Integrated gasification Combined Cycle plants and Pressurised Fluidised Bed Combustion were considered. Further, the use of wind power, micro-hydro and wood fuel based plants to replace conventional fossil fuel based thermal generation was also included in the study. The energy efficient technologies such as compact fluorescent lamps (CFL), energy efficient air-conditioners and refrigerators were used as the options for GHG mitigation at the consumer-end. The costs of these options were later analysed to see the practicality of implementation of these options. Cost of GHG When only the generation options are considered, under three-emission control scenarios where approximately 10 percent, 20 percent and 30 percent reductions in CO2 are achieved the cost of these reductions amounts US$ 46, US$ 57 and US$ 67 respectively for a tonne of carbon. The tighter the emission control regime the higher cost of achieving it particularly due to the selection of more expensive renewable energy based technologies such as wind, hydro and dendro plants and replacement of coal plants with diesel-fired combined cycle plants. It is interesting to note that under none of these CO2 emission control regimes the clean coal technologies were selected. As a result of the inclusion of the energy efficient end-use equipment such as energy efficient air-conditioners and refrigerators and CFLs as options for selection the total generation capacity requirement has reduced by approximately 35 percent over the next 15 years due to reduced demand for electricity and some of these options being economically beneficial. This has resulted in an automatic reduction in total generation costs, inclusive of the cost of these options, by about 20 percent just by switching to these economically feasible energy efficient technologies. Also it has introduced a reduction in CO2 emissions by 22 percent along with reductions in the SO2 and NOx emissions in the range of 15 percent to 17 percent. Even further reductions of CO2 up to about 45 percent can be achieved without any overall increase in costs. The study clearly indicates that there are technically feasible options for reduction of GHG emissions in the power sector. When generation options are used for this purpose percentage increase in costs is less than half of the percentage reduction in CO2. Further, penetration of some end-use energy efficient technologies such as CFLs can reduce GHG emissions to as much as 45 percent even without any increase in costs creating a win-win situation. However as expected, some of these reductions cannot be effected within the first few years as some clean coal technologies and renewable options have their own lead times. Further, these results should not be taken in isolation, especially because of the underlying assumptions of the availability of commercially proven Clean Coal and some renewable energy Technologies at economically competitive prices. In conclusion it can be stated that the study shows promising results, which definitely need very fine examination and re-assessment of the new technologies introduced. Therefore further work is now desirable on the level of technologies
that were identified for their technical and commercial viability. More
importantly the environmental and social acceptance need to be carefully
assessed before embarking on their large-scale use for GHG mitigation. Korean artist tries to save the world South Korean artist Byung-Soo Choi just never gives up. Choi, who has been staging large installations at all global conferences since the first Earth Summit in Rio de Janeiro 10 years ago, was Tuesday trying to save the world by carving penguins out of iceblocks and leaving them to melt. The fortyish, self-taught artist, who comes from a deprived background, has been following summits with a vengeance. He started with a massive work called "Garbage" in Rio - a giant mound made up exclusively of rubbish generated by what he calls mindless consumerism. His other oeuvres include a burger stuffed with endangered species and paintings of humanity's wanton disregard for the environment. Choi on Tuesday mounted an installation at Nasrec, Johannesburg's expo centre, with cardboard cutouts of the continents topped by little replicas of well-known landmarks such as the Statue of Liberty and the Eiffel Tower. Surrounding the world are melting ice penguins carved out of 50-centimetre (one-and-a-half-foot) -high ice blocks. He works incessantly and hopes to make "at least 40 penguins" by the end of the day. He leaves them to dissolve but turns down requests from some passersby who ask him if they can take one as a souvenir. "This is a work thing," he says. "Please don't ask me." The backdrop of the installation is a beautiful giant oil painting of a dying whale, speared by a harpoon. The mammal carries threatened animal species on its back. "I do not have much hope in this summit but my message to Bush and the rest of the world is that we have to stop carbon dioxide emissions and global melting ... otherwise the world will become like this," he said, pointing to giant puddles surrounding his artwork. "Tomorrow I will carve pandas and other animals." Choi was in Kyoto when the so-called Kyoto Protocol was formulated to trim greenhouse-gas emissions - the byproduct of burning oil, gas and coal - by 5.2 percent of 1990 levels by 2008-12. REUTER |
|
News | Business | Features
| Editorial | Security
Produced by Lake House |
