«Summary Report Life Cycle Assessment of Float Glass Title of the Study: Life Cycle Assessment of Float Glass Client: Glass for Europe November 2010 / ...»
5.3 Eutrophication potential Eutrophication potential (EP) is a measure of emissions that cause eutrophying effects (over nourishment) in the environment. Though the impact category employed is an indication of the impact for both terrestrial and aquatic systems, the eutrophication of an aquatic system, caused by excessive inputs of nitrogen and phosphorus, is of particular concern as this stimulates the growth of certain aquatic species to the detriment of the ecosystem, in particular through dissolved oxygen depletion. Eutrophication Potential is expressed as kilogram of Phosphate Equivalent; see Annex II: Description of Selected Inventories and Impact Categories for details.
The total EP value is 8.81E-04 kg Phosphate equivalent per kg of float glass. As shown in Figure 9, the on-site float glass production contributes with 67%. The remainder of the impact comes from the production of batch materials (28%) and energy sources (6%).
Figure 9: Total EP per 1 kg float glass, cradle-to-gate Figure 10 gives an overview of the contribution of different emissions to EP, among these nitrogen oxides dominates with 76%, followed by ammonia with 12% and ammonium with 6%, while the sum of other emissions account for 6%.
Life Cycle Assessment of Float Glass Figure 10: Total EP main contributing emissions per 1 kg float glass, cradle-to-gate Figure 11 shows the contribution from the different batch materials to EP. The main contributor is sodium carbonate with 94%, followed by sand (4%), and sum of other materials (2%).
Figure 11: EP from batch materials production per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass Figure 12 shows the contribution of the different energy sources to EP. This mainly comes from electricity generation (58%), followed by natural gas (28%), and heavy fuel oil (14%).
Figure 12: EP from energy sources per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass
5.4 Acidification potential Acidification potential (AP) as defined by the Dutch CML is a measure of emissions that cause acidifying effects to the environment, see Annex II: Description of Selected Inventories and Impact Categories for details.
Figure 13 shows the total AP value of 8.61E-03 kg of SO2 equivalent per 1 kg of float glass. The on-site float production contributes with 69%, followed by the production of batch materials (materials upstream) with 18% and the energy sources (energy upstream) with 13%.
Figure 13: Total AP per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass Figure 14 gives an overview of the contribution to AP of different emissions, among these sulphur dioxide has a biggest contribution with 47%, followed by nitrogen oxides (42%), ammonia (7%) and sum of other (5%).
Figure 14: Total AP main contributing emissions per 1 kg float glass, cradle-to-gate Figure 15 shows the AP related to batch materials production. As with the other inventory and impact categories, most of the acidification potential from batch materials production comes from the sodium carbonate with 92%. Sand contributes with 5% of the acidification potential and all the other materials contribute with 3%.
Life Cycle Assessment of Float Glass Figure 15: AP from batch materials production per 1 kg float glass, cradle-to-gate Figure 16 shows the AP from the production of energy carriers. Where, electricity production contributes with 68%, followed by natural gas (22%), and heavy fuel oil (10%).
Figure 16: AP from energy sources per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass
5.5 Photochemical ozone creation potential Photochemical ozone creation potential (POCP) is a measure of emissions of precursors that contribute to ground level smog, produced by the reaction of nitrogen dioxide and volatile organic compounds (VOC) under the influence of ultra violet light. The photochemical ozone creation potential is expressed as kilogram Ethene equivalents, see Annex II: Description of Selected Inventories and Impact Categories for details.
Figure 17 shows the total POCP value, which is 4.65E-04 kg Ethene equivalent. From Figure 17 we can also see that float glass on-site production has the biggest contribution to POCP with a share of 56% and followed by energy sources (energy upstream) with 23% and batch materials production (material upstream) with a share of 21%.
Figure 17: Total POCP per 1 kg float glass, cradle-to-gate Most of the POCP is coming from the SO2 and NOx emissions with the share of 42% and 31% respectively, carbon monoxide (11%) and group NMVOC to air (11%). The sum of other contributes only 4% (see Figure 18).
Life Cycle Assessment of Float Glass Figure 18: Total POCP main contributing emissions per 1 kg float glass, cradle-to-gate Figure 19 shows the main contributors from the production of batch materials; as in other impact categories, sodium carbonate contributes the most with 89%, followed by sand (6%) and sum of other materials (5%).
Figure 19: POCP from batch materials production per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass Figure 20 shows the detail of the contributions from energy sources; the contribution from electricity generation (power) is the highest with 44% of the total followed by the production of natural gas with 41% and production of heavy fuel oil with 15%.
Figure 20: POCP from energy sources per 1 kg float glass, cradle-to-gate Life Cycle Assessment of Float Glass ANNEX I: Primary data of float glass provided by GfE Life Cycle Assessment of Float Glass ANNEX II: Description of Selected Inventories and Impact Categories Acidification Potential
Eutrophication Potential Eutrophication is the enrichment of nutrients in a certain place. Eutrophication can be aquatic or terrestrial. Air pollutants, wastewater and fertilization in agriculture all contribute to eutrophication.
The result in water is an accelerated algae growth, which in turn, prevents sunlight from reaching the lower depths. This leads to a decrease in photosynthesis and less oxygen production. In addition, oxygen is needed for the decomposition of dead algae. Both effects cause a decreased oxygen concentration in the water, which can eventually lead to fish dying and to anaerobic decomposition (decomposition without the presence of oxygen). Hydrogen sulphide and methane are thereby produced. This can lead, among Life Cycle Assessment of Float Glass
Global Warming Potential The mechanism of the greenhouse effect can be observed on a small scale, as the name suggests, in a greenhouse. These effects are also occurring on a global scale. The occurring short-wave radiation from the sun comes into contact with the earth’s surface and is partly absorbed (leading to direct warming) and partly reflected as infrared radiation.
The reflected part is absorbed by so-called greenhouse gases in the troposphere and is re-radiated in all directions, including back to earth. This results in a warming effect at the earth’s surface.
In addition to the natural mechanism, the greenhouse effect is enhanced by human activities. Greenhouse gases that are considered to be caused, or increased, anthropogenically are, for example, carbon dioxide, methane and CFCs. Figure A 23 shows the main processes of the anthropogenic greenhouse effect. An analysis of the greenhouse effect should consider the possible long term global effects.
Life Cycle Assessment of Float Glass
Despite playing a protective role in the stratosphere, at ground-level ozone is classified as a damaging trace gas. Photochemical ozone production in the troposphere, also known as summer smog, is suspected to damage vegetation and material. High concentrations of ozone are toxic to humans.
Radiation from the sun and the presence of nitrogen oxides and hydrocarbons incur complex chemical reactions, producing aggressive reaction products, one of which is ozone. Nitrogen oxides alone do not cause high ozone concentration levels.
Hydrocarbon emissions occur from incomplete combustion, in conjunction with petrol (storage, turnover, refuelling etc.) or from solvents. High concentrations of ozone arise when the temperature is high, humidity is low, when air is relatively static and when there are high concentrations of hydrocarbons. Because CO (mostly emitted from vehicles) reduces the accumulated ozone to CO2 and O2, high concentrations of ozone do not often occur near hydrocarbon emission sources. Higher ozone concentrations more commonly arise in areas of clean air, such as forests, where there is less CO (Figure A 24).
Primary energy demand Primary energy demand is often difficult to determine due to the various types of energy source. Primary energy demand is the quantity of energy directly withdrawn from the hydrosphere, atmosphere or geosphere or energy source without any anthropogenic Life Cycle Assessment of Float Glass change. For fossil fuels and uranium, this would be the amount of resource withdrawn expressed in its energy equivalent (i.e. the energy content of the raw material). For renewable resources, the energy-characterised amount of biomass consumed would be described. For hydropower, it would be based on the amount of energy that is gained from the change in the potential energy of the water (i.e. from the height difference). As
aggregated values, the following primary energies are designated:
The total “Primary energy from non renewable resources”, given in MJ, essentially characterises the gain from the energy sources natural gas, crude oil, lignite, coal and uranium. Natural gas and crude oil will be used both for energy production and as material constituents e.g. in plastics. Coal will primarily be used for energy production. Uranium will only be used for electricity production in nuclear power stations.
The total “Primary energy from renewable resources”, given in MJ, is generally accounted separately and comprises hydropower, wind power, solar energy and biomass.
It is important that the end energy (e.g. 1 kWh of electricity) and the primary energy used are not miscalculated with each other; otherwise the efficiency for production or supply of the end energy will not be accounted for.
The energy content of the manufactured products will be considered as feedstock energy content. It will be characterized by the net calorific value of the product. It represents the