3. Greenhouse Gas Emissions from the Plastics Processing Industry
3.1 Introduction
Climate change is an important global topic, and the connection between atmospheric concentrations of greenhouse gases, air pollution, atmospheric warming and specific weather events is very complex. The potential risks associated with climate change are significant enough that reducing greenhouse gas emissions is necessary.
This chapter provides background information on the relationship between energy consumption, plastics production and greenhouse gas emissions, and what is being done to deal with this important issue.
3.1.1 Greenhouse Gases
There are six principal greenhouse gases. The list of gases and their global warming potential are indicated in Table 3-1.
| Greenhouse Gas | Abbreviation | Global Warming Multiplier |
|---|---|---|
| Carbon dioxide | CO2 | 1 |
| Methane | CH4 | 21 |
| Nitrous oxide | N2O | 310 |
| Hydrofluorocarbons | HFCs | 140–11,700 |
| Perfluorocarbons | PFCs | 6,500–9,200 |
| Sulphur hexafluoride | SF6 | 23,900 |
Greenhouse gas emissions are generated primarily as a result of energy consumption in the plastics processing industry. There are minor quantities of HFCs emitted from the extruded polystyrene and polyurethane foam-production process that will be discussed in a later section.
3.1.2 Energy and Greenhouse Gas Emissions
As mentioned above, greenhouse gas emissions are generated primarily as a result of energy consumption in the plastics processing industry. The significant growth that the plastics processing sector has experienced over the past decade has been accompanied by a growth in energy consumption and associated greenhouse gas emissions. The Canadian Plastics Industry Association, in cooperation with the Canadian Industry Program for Energy Conservation (CIPEC), commissioned a Review of Energy Consumption and Related Data (CIEEDAC, 2005), which highlights some of the difficulties in obtaining an accurate representation of energy efficiency and emissions intensity of the Canadian plastics industry. The major limitations to the data for the plastics industry are related to the differences in sector population definition and the fact that production data are not readily available for the sector to estimate energy performance trends. In spite of these limitations, the following section provides a brief summary of the energy consumption trends for the sector and an estimate of the energy efficiency performance of the sector for the period from 1999 to 2004.
The two primary forms of energy used by the plastics processing industry are electricity and natural gas. As indicated in Chapter 2, electricity is the main source of energy with electrical costs accounting for 3 to 4 percent of the cost of production. Electricity is used to provide heat to extruder barrels and to energize extruder drives. Electricity is also used as a power source for hydraulics, chilling, heating and compressed air, and for providing ventilation, air conditioning and lighting for the building. Natural gas costs can account for approximately 1 to 2 percent of the cost of production. Natural gas is primarily used for heating water and facilities, but can be used in many other applications within the plastics-manufacturing process.
The total energy consumed by the Canadian plastics processing sector (as defined by NAICS 3261) for the period from 1999 to 2004 is presented in Figure 3-1. The sector gross domestic product (GDP) is also shown in Figure 3-1, which gives an indication of the growth of the sector for the same period.
For the six-year period 1999–2004, the total energy consumed in the plastics products industry increased 36 percent from 19,950 terajoules to 27,050 terajoules. For that same period, GDP increased by 46 percent from $5.7 billion to $8.4 billion.
3.1.2.1 Greenhouse Gas Emissions Performance
Greenhouse gas emissions are considered as either direct emissions, as a result of combustion of fuel at the plastics processing facility, or indirect emissions, as a result of fossil-fuel combustion required to generate the electricity used by the plastics processing facility. The factors used to estimate the emissions of CO2, CH4 and N2O resulting from the combustion of natural gas (which represents approximately 85 percent of the plastics product sector direct emissions) are shown in Table 3-2.
| Gas | Emission Factor (g/m3 fuel) |
|---|---|
| CO2 | 1880 |
| CH4 | 0.0048 |
| N2O | 0.02 |
The CH4 and N2O emissions are minor compared to the CO2 emissions. The convention of reporting greenhouse gas emissions on a CO2-equivalent basis will be used throughout this report.
Canadian plastics products processors should be concerned with the greenhouse gas emissions performance of their operations, or the emissions per unit of production. On a Canadian aggregate basis, there are no data available to measure the production levels annually, but, as shown in Figure 3-1, the GDP can be used as an approximation. This is useful to get a sense of the performance trend, but could be skewed by disproportionate increases in price of products and other monetary factors.
By improving energy efficiency, plastics processors can reduce both direct emissions (from consuming fossil fuels on site) and indirect emissions (associated with electricity generation off-site). Indirect-emissions intensity will be influenced by the form of electrical generation (i.e. thermal versus hydropower), which will vary significantly between provinces/territories, and will not be within the control of the plastics processors. The direct emissions are most relevant and controllable by the plastics processing facilities. The trend in direct emission performance, as a function of GDP, is presented in Figure 3-2 based on data from the Canadian Industrial Energy End-Use Data Analysis Centre (CIEEDAC) for Canada, for the 1999–2004 period.
As shown in Figure 3-2, direct greenhouse gas emissions as a percentage of GDP have been stable for the past three years but, overall, have decreased by 15 percent since 1999.
3.1.3 Hydrofluorocarbon Emissions from Plastics Processing
Hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC) are used as blowing agents in the production of extruded-polystyrene and polyurethane foams. The use of HFCs in plastics processing globally is currently on the rise as the greenhouse gas HFC is used as a replacement for the ozone-depleting HCFCs. The use of HCFCs or HFCs in the Ontario plastics processing sector is minor, with only three companies reporting HCFC emissions in the National Pollutant Release Inventory (NPRI) database (companies are not required to report HFCs to the NPRI program).
Specific data on HFC emissions are not available and much of the work in evaluating alternatives to the use of these compounds is proprietary. Canada's Greenhouse Gas Inventory estimates that 10,000 kilotonnes of CO2-equivalent HFCs were emitted from foam blowing in Canada in 1997. There are no data available to estimate the HFC emissions from Canadian plastics processing, and therefore it is not possible to determine if HFC emissions in Canada are increasing or decreasing. In discussions with one Canadian plastics processor, it was reported that it had successfully eliminated the use of HCFCs and HFCs from its production. Further references for more information on HFC use in plastics processing are provided in Chapter 9.
3.2 Opportunities for Reducing Greenhouse Gas Emissions
Direct emissions from plastics processing in Canada are small (less than 1 percent) in relation to discharges from other manufacturing activities in Canada. Direct emissions have increased by 8 percent since 1999, but emission intensity has decreased by 15 percent as shown in Figure 3-2.
Both direct and indirect greenhouse gas emissions can be reduced through ongoing improvements in energy efficiency at any given plastic processing facility. Investments in energy-efficient technologies and capital upgrades must make financial sense if plastics processors are expected to make such investments.
The rate of investment in energy efficiency is determined to a large degree by the following two factors:
- Age, capability and depreciated value of the existing capital stock – the average service life of machinery and equipment for the plastics product industry is 13 years. It is not uncommon for small operations to be using equipment in the 20- to 30-year age range.
- Rate of return expected on investment in new technology and equipment – currently, the amount of investment generated from energy savings alone falls short of covering the capital costs of replacing existing equipment with highly energy-efficient equipment.
Information on energy efficiency programs and resource material is provided in Chapter 9.
Plastics Help Reduce Greenhouse Gas Emissions from Automobiles
As automakers continue to look for ways to reduce vehicle weight, to reduce costs and to improve fuel economy, a related benefit is a reduction in greenhouse gas emissions per kilometre driven. Here are just a few examples:
- The 2001 Chevrolet Silverado used reinforced-reaction injection-moulded (RRIM) plastic fenders and a structural-reaction injection-moulded (SRIM) composite cargo box to make the truck's total weight 25 kilograms lighter than with conventional steel components.
- The 2001 Chevrolet full-size and heavy-duty pickups have RRIM rear fenders saving 30 kilograms of weight.
- DaimlerChrysler and Ford Motor Co. introduced plastic rear bumpers on selected models. This was the first non-metallic rear bumper in its class, and the bumper system is 41 percent lighter than its steel counterpart.
Greenhouse gas emissions from passenger automobiles and light trucks continue to grow, as more vehicles are driven more kilometres. With more than 31,000 kilotonnes of CO2 emissions from this sector, representing approximately 16 percent of Ontario's total greenhouse gas emissions, every incremental reduction will have an impact.
Reference:
http://findarticles.com/p/articles/mi_m3012/is_10_180/0/p1/article.jhtml
3.2.1 Canadian Industry Program for Energy Conservation
The Canadian Industry Program for Energy Conservation (CIPEC) is a national program that "promotes effective voluntary action that reduces industrial energy use per unit of production, thereby improving economic performance while participating in meeting Canada's climate change objectives." CIPEC is composed of sectoral task forces, each of which represents companies engaged in similar industrial activities.
CIPEC works through its Task Force Council to establish sectoral energy-intensity improvement targets and publishes an annual progress report.
Plastics Energy and Greenhouse Gas Savings Using House Wrap
A case study prepared in 2000 for the American Plastics Council and the Environment and Plastics Industry Council (EPIC) of the CPIA demonstrated the greenhouse gas reduction benefits associated with applying a plastic house wrap to the exterior of single-family residential housing in the U.S. and Canada. The life cycle analysis methodology demonstrated that a CO2-equivalent reduction of between 360 and 1,800 kilograms could be achieved by reducing energy use for a typical Canadian house on an annual basis. The study also reported that if all of the houses built in Canada during the period 1991–1995 had been built with house wrap, the estimated reduction in energy-related greenhouse gas emissions for Canada would be 1.8 to 8.2 million metric tonnes of CO2 equivalent over the same period.
Reference: www.plasticsresource.com
3.3 Summary
Energy use by the plastics processing industry in Canada has increased by 36 percent over the 1999–2004 period. Plastics production increased by 46 percent over the same period. The resulting energy intensity (energy per unit production) has improved by 15 percent over the six-year period. These numbers indicate that energy efficiency improvements have been made by the plastics processing sector and that greenhouse gas emissions per unit of production have decreased.
Discussions with Canadian plastics processors have indicated that there are many opportunities for increasing energy efficiency and decreasing greenhouse gas emissions, which will be implemented when the economic factors (payback, rate of return) are favourable. Programs or specific tools that would assist plastics processors in assessing energy efficiency opportunities would be of value to the sector and would help the greenhouse gas reduction efforts.
Further study is required to determine what tools would be most effective in facilitating energy efficiency improvements.
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