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FLEXO Magazine : August 2011
www.flexography.org AUGUST 2011 FLEXO 29 sustainability program were also calculating their carbon footprint to some level. In general, companies often cite the following business goals as reasons for compiling a GHG inventory1: • Managing GHG risks and identifying reduction opportu- nities. • Public reporting and participation in voluntary GHG programs. • Participating in mandatory reporting programs. • Participating in GHG markets. • Recognition for early voluntary action. • Customer request. Once the size of a carbon footprint is known, strategies can be devised to reduce it by technological developments and/ or better process and facility management. Calculating a carbon footprint will highlight the greatest areas of concern, where improvements might be achieved and to determine long-term trends. Progressive businesses are using carbon footprint figures in their decision-making process as they choose future products and services. For companies calculat- ing their footprint for the first time, a baseline carbon footprint is established to analyze future trends and make compari- sons to other, similar facilities. Gases that contribute to global warming include four gases and two groups of gases: • Carbon dioxide (CO2) - Created by burning of fossil fuels and deforestation. Generated in flexo as a result of the use of air pollution control devices, such as catalytic oxidizers or regenerative thermal oxidizers. • Methane (CH4) - Created by livestock enteric fermenta- tion, paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions. Also may be calculated in a flexo plant as a result of electricity purchased. • Nitrous oxide (N2O)- Typically, used for its anesthetic and analgesic effects, as well as being used as an oxidizer in rocketry and in motor racing to increase the power output of engines. In flexo, also generated as a result of the use of air pollution control devices, such as catalytic oxidizers or regenerative thermal oxidizers. • Sulfur hexafluoride (SF6) - Used in the electrical industry as a gaseous dielectric medium for high-voltage (35 kV and above) circuit breakers, switchgear, and other elec- trical equipment. Also employed as a contrast agent for ultrasound imaging. • Perfluorocarbons (PFCs) - Used in refrigeration units. • Hydrofluorocarbons (HFCs) - Used in refrigeration units. Within a printing facility, some of the major sources of emis- sions which may be included in a carbon footprint calculation are: • Purchased energy (upstream and transmission losses). • On-site combustion of fuels. • Company owned or leased vehicles. • Transport of finished product. • Production of packaging materials. • Production of plates. • Employees commuting. • Production of cleaning agents. • Production of fuels (upstream). • Production of inks and varnishes. • Transport of raw materials. • Production of substrate. GHG emissions are typically expressed as metric tons of CO2. Those GHGs that are not CO2 are expressed as a CO2-equivalent or CO2e. To make this conversion, the global warming potential (GWP) of the gases must be considered. The CO2e describes, for a given mixture and amount of GHG, the amount of CO2 that would have the same GWP, when measured over a specified timescale (a 100-year standard). GWP values are applied to units of mass (e.g., kilograms, pounds, metric tons, etc.), not to units of volume (e.g., cubic meters, cubic feet, liters). The CO2e emissions are calculated by multiplying the mass of the gas by its GWP value (See Table 1). The resulting emis- sions are not labeled as CO2, but as CO2e. According to the Intergovernmental Panel on Climate Change (IPCC), GWPs typically have an uncertainty of roughly ±35 percent, though some GWPs have greater uncertainty than others. Currently, there is no government mandatory standard for measuring GHG emissions produced in the United States; however, there is an international, voluntary standard the Greenhouse Gas Protocol (GHG Protocol), which is used by many worldwide. The GHG Protocol divides the types of emis- sion sources of GHGs into three "scopes": Scope 1 - Direct emissions: Onsite combustion and mobile sources Scope 2 - Indirect emissions: Purchased electricity Scope 3 - Optional Emissions: Product transport, employ- ee business travel and employee commuting TABLE 1. Global Warming Potential of Gases Gas GWP Carbon dioxide (CO2) 1 Methane (CH4) 21 Nitrous oxide (N2O) 310 Sulfur hexafluoride (SF6) 23,900 Perfluorocarbons (PFCs) 6,500 Hydrofluorocarbons (HFCs) HFC-23 11,700 HFC-32 650 HFC-125 2,800 HFC-134a 1,300 HFC-143a 3,800 HFC-152a 140 HFC-236fa 6,300 Although the GHG Protocol has defined the various scopes as listed below, there is often confusion as to what is included in each set of calculations. It is important for the facility to keep