Study of Carbon Management through Abatements of Carbon Dioxide Emissions in the Nothern Kyungki Province

Transcription

1 Study of Carbon Management through Abatements of Carbon Dioxide Emissions in the Nothern Kyungki Province Young Gyu Park 1, Jung-in Kim 2, GapCheol Kim 3 Department of Chemical Engineering, Daejin University 11-1 Sundandong Pocheonsi Kyungkido Korea, ypark@daejin.ac.kr Department of Industrial Economics, Joongang University, Ansung Kyungkido Korea, jeongin@cau.ac.kr Neoecos, Mapodong Mapoku Seoul Korea, ecocap@neocos.com ABSTRACT In order to make the best choice for CO 2 abatement using renewable energy technologies, it is important to be able to adapt these technologies on the basis of their sustainability, which may include a variety of environmental indicators. This study examined the comparative sustainability of renewable technologies in terms of their life cycle CO 2 emissions and embodied energy, using life cycle analysis. The models developed were based on case studies of bioenergy pilot plant in Pocheonsi of nothern Kyungki province. The comparative results showed that power generation of biogas was associated with.96 kwh/m 3 biogas and the reduction of CO 2 emission was 2.1kg of CO 2 /kgbiomass, other environmental indicator using wood pellet was -.717kg of CO 2 /kgbiomass. These indicators applied to gain a complete picture of the technologies studied in the regional area. Final results were total emission of CO 2 in Pocheonsi is 448,21 tco 2, around 399,877 tco 2 for electricity and for heat generation, and 47,45 tco 2 for transportation. When used 1,984 m 3 /day of waste (pig manure etc.) and operated CHP with wood pellet of 22, m 3 /year, the CO 2 emission in Pocheonsi was left as is an emission of 23,7 tco 2 and an abatement of CO 2 in this region was increased by 49.9%. KEY WORDS: Renewable technology, Bioenergy, Biogas, CO 2 emissions, Kyungki Province, LCA 1. INTRODUCTION Due to increasing concerns over greenhouse gas emissions and declining fossil fuel stocks, interest in renewable energy technologies is growing rapidly. Many countries are now looking to invest heavily in renewable energy sources in order to meet the electricity requirements of their populations and reduce their contribution to global greenhouse gas emissions. While this trend has been progressing in Korea for some years now, for example with a prominent recent example has been United States President Obama s announcement to reduce greenhouse gas emissions to 199 levels by 22, through a cap-and-trade system. While electricity generation technologies that rely on renewable resources are perceived to be clean, a more appropriate definition would be to say that they are cleaner than fossil fuel-based technologies, by life-cycle methodology which renewable generation systems still consume energy and produce emissions during the construction, maintenance, and deconstruction/disposal (i.e., the whole life cycle) of the required infrastructure. Because the number of sites for new large-scale biogas plant in Korea is limited, it is likely that new electricity developments will look to alternative technologies. This study was to compare the differences in the life cycle sustainability of greenhouse gas by renewable bioenergy technologies in a Korea with the abatement of CO 2 emissions in the regional town, using the indicators of associated CO 2 emissions. Therefore, the objective was to demonstrate the self-sustainability of the town regarding no-co 2 emissions and energy. This includes the construction, maintenance, and decommissioning phases, and the transport associated with each phase. It is recognized that other factors influence the sustainability of a product, but an evaluation of both life cycle CO 2 and energy will provide an initial comparison. CO 2 emissions and embodied energy can reveal the importance of hidden processes and materials pertaining to an individual product or component. This in turn gives an indication of the environmental impact of bioenergy technology in terms of their contribution to environmental effects such as climate change and resource depletion. However, because sustainability is an extremely broad field, although these indicators provide a salient overview of each system, relying on just environmental indicator such as GWP limits the possible measure of sustainability. Many other environmental sustainability indicators (such as ecotoxicity) were not quantified, and social and economic indicators were also ignored Embodied Energy Although embodied energy (sometimes referred to as energy ) is not yet widely used as an indicator of sustainability, it provides a good indication of the level of resource consumption required to create or extract an energy consumption and to transport it to its final destination. Embodied energy includes all primary energy used by a system, including fuel and electricity. These energy inputs come from various sources, such as the boilers used in the combustion of fuels, transport of the cars to the business trip, manufacturing industry, and transport associated with the final end use. In this study, the initial energy (intrinsic energy stored in raw materials) of the raw materials has been excluded, mainly due to the difficulty associated with quantifying this energy. This, however,

2 maintains consistency with the main source of town and process data used for this study (Bare, 26). 1.2 Life Cycle Analysis Methodology ISO Standard 1444 is the standardized method for life cycle analysis (LCA). It consists of four steps: goal and scope definition, inventory analysis, impact assessment, and interpretation. This methodology was followed as closely as possible for this study. A LCA was chosen for this study, the inventories were entered into LCA software, and the results were compared on a normalized basis (per kg of mass or kilowatt-hour). As suggested by SETAC, a level one approach was taken for this study, in which the third step of impact assessment was not applied due to the comparative structure of the study. SimaPro 7 software was chosen for this study to quantify the embodied energy and CO 2 emissions for life cycle bioenergy type of generation technology (Goedkoop, 26). 1.3 System Boundaries. As this study was of a comparative nature, the LCA system boundaries were drawn around the unique aspects in the Pocheonsi of northern Kyungki province, and boilers common to all types of energy consumption were not separately classified, including combustion types such as gas and liquid, as well as house and building infrastructure such as apartment. CO 2 emissions and embodied energy related to the combustion of materials were included but assembly or fabrication of whole components of combustion apparatus was not. Electricity Consumption (kwh x 1 6 ) Month (a) Electricity Consumption (kwh x 1 6 ) Number of House Number of House passenger cars using by habitants themselves, as it was assumed that building emissions and energy would be proportional to the emissions and embodied energy of the materials and, in this context, the omission of building requirements would have a negligible effect on the relative performance of the compared technologies. Fugitive emissions from transportation fields were noted, though not added to the result for transportation fields were noted, though not added to the result for transportation of habitants of Pocheonsi, but all other CO 2 emissions pertaining to this study arose from construction, maintenance, and cultivating of bioenergy, since renewable technology emits CO 2 during normal operation. 2. EXPERIMENTALS Biochips for a bioenergy were obtained in the area of northern Kyungki province by hammer milled through 1/2 screen and used as a biomaterials. The material moisture was determined to be 5.9 wt%. These chips were used to generate a heat energy and an electricity, the concentration of CO 2 emissions was detected in the pilot scale (1 m 3 /hr) of combustion with 3M gas detector (Minneapolis, USA). Also a concentrated pig manure produced in Pocheonsi often release excess amounts of nutrients that accelerate eutrophication and result in the degradation of water quality. The pilot plant of scale of.1 m 3 /day is operating in the Pocheonsi, the acidogenic digestion step produces carboxylic acids, which take the form of organic salts as a result of base addition for ph control. Methanogenesis is a relatively sensitive process, and sour digesters are a common occurrence, often triggered by process upsets such as changes in hydraulic flow rate, temperature, or organic loadings. 3. RESULTS AND DISCUSSION 3.1 Total CO 2 emissions generated in the Pocheonsi (Pocheon city) Table 1 shows main compositions of energy-production sources inside a city and data of CO 2 emissions produced in the city to analyze the CO 2 emissions depending on petroleum energy in the Kyungki provincial area. The estimated total CO 2 emissions, embodied energy, and energy generation for the renewable energy technologies will be studied. The life-cycle methodology for CO 2 emissions and embodied energy were normalized to obtain the CO 2 emissions and embodied energy per kilowatt-hour of output. Table 1: The annual estimation of CO 2 emissions in the Pocheonsi of northern Kyungki province Item Number Electric Consump tion (1 6 KW h) Heat Consumpti on (1 6 Mcal) CO 2 Production (tco2) (b) Figure 1: Number of house in the pocheonsi and their electricity consumption(a) and a map of pocheonsi area (circle) in the northern Kyungki province (b) Additionally, energy consumed and CO 2 produced in each home and industrial facilities were quantified but not the life cycles of the facilities carrying out these processes, as the combustion apparatus has a separate life cycle. For example, transportation of cars and truck used to commute were included, as well as House 44, , ,843 Building 14, ,8 93,684 School ,555 Factory 6,15 1,214 1, ,853 Agricultu ral sector 9, ,4 Total 75,672 1,897 4,77 399,877

3 As shown in Table 1, total CO 2 emission produced in the Pocheonsi was about 4, ton CO 2 eq.. CO 2 emission produced in the houses of Pocheonsi was 36.1% of total emissions and that in the factory was 34.6%, those in the commercial buildings, educational school and agriculture fields were 23.5%, 17.5% and 5.5%. If CO 2 emissions in the house and building are converted to technologies by renewable energy, the emissions can be decreased significantly. CO 2 emissions by transportation in the city were also estimated as following equation (Park et al., 28). EF KM,i = [SEC x,i ⅹ(EF CO2,x + EF CH4,x + EF N2O,x )ⅹ(N x,i / N i )](1) EF KM,i : Transport Emission Factor per Transport Method i (gco 2eq / km ) SEC x,i : Fuel Consumption per transporter i (l/ km ) EF CO2,x : CO 2 emission factor of fuel (gco 2eq /l, GWP) EF CH4,x : CH 4 emission factor of fuel (gco 2eq /l, GWP) EF N2O,x : N 2O emission factor of fuel (gco 2eq /l, GWP) N i : Total number of transport N x,i : Number of transport by fuel type x The transport emission factor can be referred as shown in Table 2. The CO 2 emissions in the transportation of the city can be estimated as shown in Table 2. Table 2: Transporation emission factors depending on the type of car and fuel used (unit: gco 2eq /l) Method CO 2 Emission factor(ef) CH 4 emission factor(ef) N 2O emission factor(ef) Gasoline Diesel Gasoline Diesel Gasoline Diesel Bus 2,313 2, Passenger car 2,313 2, CO 2 Emission amount (tco 2 per year) Passenger car Van Truck Special car Total Type of car Figure 2: CO 2 emissions depending on type of transporter Figure 2 indicates that the CO 2 emissions by transportation in the city were dominated by medium & large passenger cars and truck. CO 2 emissions by transportation during one year was estimated by 47,45.3 tco 2. Also CO 2 emissions by heat and electricity during one year was estimated by 399,877 tco 2. Total CO 2 emissions in the Pocheonsi were 448,21 tco Adaption of renewable energy in a city A perspective as an alternative energy is relevant since biomass is to some extent regionally oriented, and a regional perspective has relevance since the market for biogas and for some solid biofuels (wood pellets, wood chips, tree trunks, and straw pellets) is expected to become oriented in the future. The bioenergy by a renewable technology can be applied to reduce the CO 2 emissions, a Life Cycle Assessment (LCA) of bioenergy was analyzed in this light of the constraints on biomass availability using LCA software of Simapro as follows.. The CO 2 emissions by transportation traveled in the Pocheonsi (traveled distance: 35km) were estimated as measuring the data in the city, they can be written as shown in Table 3. Table 3: Daily estimated CO 2 emissions by transportation methods traveled in the Pocheonsi Type Fuel Efficiency (km/l) Travel distance (km) Number of CO 2 Production Transport (g CO 2) (a) Very small ,25,385.6 Small ,738,218.4 Medium ,29,699.6 Large ,978,964 Bus ,286,8 Truck ,29,1 (b)

4 CH4 (%) (c) Figure 3: LCA results to analyze environmental aspects of wood-use and manure fermentation, (a),(b) LCA result of wood (GWP: kgco 2 /1kg-biomass) and pigmanure(gwp: 2.36 kgco 2 /1kg-biomass) by Simapro 7.1, (c) Comparisons of CO 2 emission effects during wood cultivation, maintenance and manufacturing The assessment is based on comparing studies of technical biomass potentials with the biomass required to meet conflicting uses of biomass. The technical biomass potential is defined as the amount of biomass that, based on the available technology, can become available for energy purposes while still securing the demand for woodpellet, animal manure, and other biomaterials. The technical biomass potential is based on inventories of potential bioenergy sources, including organic residues and waste and use of land for biomass production, with an evaluation of possibilities to utilize the sources for energy purposes. The potential utilizations of biomass for energy include electricity, heat, and agriculture fuel production, substituting fossil fuels in the Pochensi. The amount of biomass required for fossil fuel substitution therefore represents the maximum potential demand for biomass for energy. We estimate the biomass required for fossil fuel substitution based on energy demand scenarios set up, concerning future use of fossil and renewable energy sources. Figure 3 shows the LCA result of percent contribution to total CO 2 emissions and embodied energy by component for bioenergy technology, with each component further subdivided into percent contribution of each life cycle phase. Where the absorption of CO 2 accounts for negative contribution, such as in the case of photosynthesis, this is shown as a negative bar on the left-hand side of the chart as shown in Figure 3(c). Concentration(%) wood pellet 1kg (9612) CO(%) CO 2 (%) 2nd Regression flow(m/sec) 9th Regression Time(min) (a) Flow rate (m/sec) Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Acidogenic Methanogenic Gas collector Time (day) Figure 4: Experimental results through measurements of production of green house gases: (a) the CO 2 emission (64.55g/1kg-woodpellet) by combustion process of biomass (wood pellet) and (b) the CH 4 emission (.22 m 3 /kg-manure) by anaerobic fermentation process of pig manure Figure 4 shows that An experimental study for combustion undertaken suggests CO 2 emissions of anywhere.63 kg of CO 2 /kg-biomass for pine tree and.19kg of CO 2 /kg for coal. (b) Another study calculated the CO 2 emissions coefficient at.225kg of CO 2 /1.24MJ for electricity and.767kg of CO 2 /.266kg for growing pig farms (Raven, 27). While these results vary quite widely, it was felt the results obtained from this study generally confirmed, considering the comparative nature of the study (Murphy, 24). However, total CO 2 emission releases around 2.21kg of CO 2 /.935kg pig-manure, during normal operation. None of the other technologies studied release CO 2 during operation (apart from maintenance, which is included in life cycle CO 2 ). On the other hand, the biogas production using pig manure in the anaerobic bioreactor was 1,984 2 m 3 /day (total generation amount of pig manure in Pocheonsi plus waste from outside city), of which has 68.9% of CH 4 contents as shown in Figure 4(b). Final technical results has production 1.115m 3 CH 4 per VS 1kg, which used for the production of electricity using generator of consumption of 36.9 liter/day light oil. 626 kwh/day of electricity and 689 Mcal/kg VS were produced based on LCA simulation in locations (Raven, 27). As we has shown in Table 1, the electricity generation and heat generation by fuel energy, with total life cycle CO 2 emissions and total embodied energy, had the global warming potential in the total life cycle energy generation. The life cycle CO 2 emissions and embodied energy for electricity generation hope to be only slightly lower, compared to the very high values of all calculated for coal-based and oil-based electricities. Let s estimate the CO 2 emissions of coal-based and oil-based energies and electricities based upon life cycle methodology. While coalbased and oil-based electricities both showed significantly higher life cycle CO 2 emissions (CO 2 emissions at a scale of 1 ton building were 29.9tCO 2 eq. and 26.2tCO 2 eq.) and embodied energy than bioenergy-based electricity generation (biogas:12.1tco 2 eq., biopellet: 6.96tCO 2 eq.), the total energy generation for bioenergy-based electricity was 5% lower than that calculated for coal-based electricity as shown in Figure 5. Coal-based and oil-based electricities generation benefit from their higher load factors, which allow a much greater output in the plant lifespan compared to bioenergy-based electricity generation. So, although there is a much higher materials investment in coal-based and oil-based electricities, the load

5 factor brings the values for both CO 2 emissions and embodied energy into close proximity with the values for bioenergy-based electricity generation. Figure 5 shows that when the heat energy converted coalbased fuel to wood pellet based fuel, CO 2 emissions in the coalbased electricity generation were 8% smaller that those in the biopellet-based electricity generation, and 67% of CO 2 emission were decreased obtained in the oil-based electricity and heat generation. Figure 5: Conversion effects of CO 2 emissions by changes of heat energy sources and electricity energy sources Overall, use of bioenergy electricity and heat generation had the lowest of both CO 2 emissions and embodied energy per kilowatthour compared to the other technologies studied as shown in Figure 5. Conversely, coal-based electricity generation had the highest values of CO 2 emissions and embodied energy per unit output. As this was a comparative study and components common to all power stations (such as combustion systems) were not considered, the results may be used for comparison but not as definitive value additionally, manufacture of bioenergies for each plant was quantified but fabrication of components from those materials was not. This means that the results calculated are probably slightly lower than the reality. CO 2 Emission amount (tco 2 ) 3e+5 2e+5 1e+5-1e+5-2e+5-3e+5 CO 2 Production (ton CO 2 eq) BioGas BioPellet H:Bio, E:Coal E: Oil E: Biogas E:BioPellet E:Solar E: LNG H: Heat Source, E: Electriccity Electric Power Heat Energy TransportationBioenergy(wood) Biogas Photosysthesis Figure 6: CO 2 estimation by the renewable technologies in the Pocheonsi, black colored bar: Emission of CO 2 before renewable technologies, gray colored bar: Emissions of CO 2 after renewable technologies Pochensi plan to establish centralized biogas plants and to convert the heat boilers of bioenergy into CHP(combined heat and power) plant of 22,m 3 /year, which implemented the Green Village Energy Project. The plant process 1,98 tons of manure and additional amounts of industrial, commercial organic waste per day. In locations where there was no natural gas available, biomass should be used instead. Energy from biogas was now at least more competitive than in many other countries after the decease in global oil prices. The CO 2 emissions in the Pocheonsi were described as shown in Figure 6. Another study calculated a CO 2 emissions can be decreased by CO 2 absorption of forest and this is also important role to abate the CO 2 emision in the town. Taken altogether, Figure 3 suggests that the greenhouse gas emissions for biogas generation originate primarily from fugitive CH 4 emissions. Although biogas facilites allow CH 4 to become concentrated at the outlet of the biogas reactor, these emissions can be counteracted by natural forest rather than by the presence of a energy plant, and as such, they have been also added to this study s result for the absorption of CO 2 by forest of Pocheonsi. The trees per 1 ha planting in mountains and forests of Pocheonsi consisted of 17,943 no. of needle leaf tree, 17,422 no. of broad leaf tree, 16,464 no. of mixed tree, and total area of forest in Pocheonsi is 25,816 ha (Pocheonsi, 27). The absorption rate (tco 2 /ha) of tree has been estimated based on 2 years tree, it has an average value of 7.6 in cases of needle leaf tree. And there has average values of 11.3 of broad leaf tree, 9.1 of mixed tree. Based on this statistical data, the total absorption amount of CO 2 by photosynthesis was 229,761 tco 2. The fugitive emissions in the biogas energy refer to operational CH 4, rather than life cycle CH 4 ; the latter comprises the CO 2 emissions resulting from the lifespan of energy generation system and its maintenance. However, these additional emissions should be taken into account when considering the sustainability in terms of CO 2 emissions from energy are highly site-specific, and so CO 2 release will vary widely between the types of energy generation. In Pochensi, biogas plant fugitive CO 2 emissions are estimated annually as ranging around 189,7 tco 2 for electricity, 21,177 tco 2 for heat generation and 47,45 tco 2 for transportation, the average heat being 689g Mcal /day; Biogas production is 45,2 Nm 3 /day and annual amount of CO 2 abatement substituted by biogas is 66,7 tco 2. Likewise, in electric power systems, CO 2 emission released from the combusting of wood pellet increases the technology s associated greenhouse gas release. In the combustion of wood pellet, released amount is 6,3 t CO 2, and CO 2 emission of wood pellet by LCA results can be decreased, -157,74 tco 2, reducing the associated CO 2 production as shown in Figure 3; while CO 2 emission in Pocheonsi is left as is an emission of 23,7 tco 2, and depending on the scale of the bioenergy plant and area of forest, there may be more or less planted per unit area, as well as more or less decreased depending on the amount of biomass. 4. CONCLUSIONS. This study was to compare the differences in the life cycle sustainability of greenhouse gas by renewable energy technologies and the abatement of CO 2 emissions generated in the Pocheonsi, using the indicators of associated CO 2 emissions. When the use of energies converted to renewable energies, the total CO 2 emission in the Pocheonsi was decreased 454,51 tco 2 to 23,7 tco 2, 5% amount of CO 2 emissions was abated. The abatement amounts by biogas and bioenergy by wood pellet combustion were respectively -66,7 tco 2 and -157,74 tco 2.

6 CO 2 absorption of Pochensi (25,816 ha of forest area) was estimated -229,761 tco 2. This estimation will be demonstrated the self-sustainability of the town regarding no-co 2 emissions and energy-independency by the enlargement of bioenergy (two times bigger in bioenergy plant capacity than now). If the area of forest will be increased two times bigger than now, it will be also the same result of the self-sustainability of town. This study proved that the bioenergies of renewable energies play an important role to abate the CO 2 emission in Pocheonsi. ACKNOWLEDGMENTS Authors appreciate technical supports of Sunyoung Lim of Daejin University and Hyungsuk Kim of DSK engineering, and financial support of 21 Daejin University. And authors should be also thankful to Korean Environmental Industrial research Institute. REFERENCES Bare, J. C. and Gloria, T. (26), "Vritical Analysis of the mathematical Relationships and Comprehensiveness of Life Cycle Impact Assessment Approaches, Environmental Science & Technology, Vol. 4, pp Murphy, J. D., McKeogh, E. and Kiely, G. (24), "Technical/economical/environmental Analysis of Biogas Utilization, Applied Energy, Vol. 77, pp Goedkoop, M., (26), Simapro 7, chapter 4, Pre Consultants, Nedehland. Park, J., Kim, D. and Cho, J., (28), Implementation Strategy of CDM in Trnasport Sector, Report of The Korea Transport Institute, pp Pocheonsi, (27), Information of Internet Site, Raven, R. P., Gregersen, K. H., (27), "Biogas Plants in Denmark: Successees and Setbacks, Renewable & Sustainable Energy Review, Vol. 11, pp