The greenhouse gases subject to emission reduction commitments under the UN Climate Convention include the fluorinated compounds sulphur hexafluoride (SF6), perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs). The present study projects the emissions of these gases in Germany over the 1995-2010 period, with and without additional emission abatement efforts. In the business-as-usual scenario, total emissions of the three fluorinated gases rise over the 1995-2010 period from 11.1 to 27.4 million tonnes CO2 equivalent. This rise is 72% attributable to HFCs, used above all for refrigeration and stationary air-conditioning, for mobile air-conditioning, for blowing extruded polystyrene (XPS) foam and for one-component polyurethane (PU) foam. Soundproof glazing is the largest SF6 emissions sector. Most PFC emissions come from semiconductor manufacturing and aluminium smelting. The reduction scenario, too, does not achieve stabilization of fluorinated gas emissions. The rate of growth is only slowed, with 11.1 million tonnes CO2 equivalent in 1995 growing to 14.9 million in 2010. The measures proposed to attenuate emissions growth are: mandatory equipment maintenance in refrigeration and stationary air-conditioning, refrigerant substitution of HFCs by CO2 in mobile air-conditioning, partial HFC substitution by CO2 and ethanol in XPS foam blowing, 95% HFC substitution by flammable hydrocarbons in one-component PU foam. Complete SF6 phase-out is considered to be feasible in soundproof glazing. The PFC emissions of the semiconductor industry can be cut by 85% by new chamber cleaning technologies.
On the basis of the historical consumption and emission levels of the three fluorinated greenhouse gases - HFCs, PFCs and SF6 - in Germany from 1995 to 1997, emissions forecasts until 2010 are elaborated for each individual application sector, with and without additional abatement measures beyond business-as-usual.
A business-as-usual scenario assumes that present usage trends, including emission control measures already instituted today, continue, and extrapolates these to the year 2010. A reduction scenario assumes that existing technology potentials for abating or substituting emissions are exploited in each individual emission sector. In the reduction scenario, only emission reduction measures are included whose ecological effect is not neutralized by disadvantages elsewhere.
Neither business-as-usual nor the reduction scenario yield a stabilization of FC emissions. However, their rise by 150% over the 1995-2010 period in the business-as-usual scenario can be limited to a 34% rise in the reduction scenario.
1. 2010 Emissions of HFCs, PFCs and SF6 in the Business-as-Usual Scenario
In the business-as-usual scenario, total HFC, PFC and SF6 emissions grow over the 1995-2010 period from 11.1 to 27.4 million tonnes CO2equivalent, or by 146% (see Table I).
As to be expected, HFC emissions grow most, as these have only been produced specifically as substitutes for CFCs and HCFCs since 1990. HFC emissions grow over the 1995-2010 period from 3.1 million t CO2 equiv. to 19.8 million t, or by a factor of about 6. Overall FC emissions growth is mainly attributable to HFCs (cf. Table I and Diagram I).
SF6 emissions drop over the same period from 6.2 to 5.0 million t CO2 equivalent, or by 19%. PFC emissions, in contrast, rise by 43% from 1.8 to 2.5 million t CO2 equivalent.
Ranking emissions sources in the business-as-usual scenario
With business-as-usual, it is to be expected that in the year 2010 86% of FC emissions, amounting to 23.6 million t CO2 equivalent, will be attributable to the seven largest of the eighteen FC application sectors. These seven include four HFC applications, two PFC sources and one SF6 application. The following pie-charts show the shares of the various applications in the total CO2 equivalent emissions of the three FCs.
The most weighty sectors (cf. Table III), in terms of their contributions to total FC emissions, are, in the following order:
|1. Refrigeration and stationary air-conditioning (HFCs)||7,7 Mio. t CO2-equiv.|
|2. Mobile air-conditioning (HFCs)||4,7 Mio. t CO2-equiv|
|3. Blowing extruded polystyrene (HFCs)||3,0 Mio. t CO2-equiv.|
|4. Soundproof glazing (SF6)||3,0 Mio. t CO2-equiv|
|5. One-component polyurethane foam (HFCs)||2,7 Mio. t CO2-equiv.|
|6. Semiconductor manufacturing (PFCs)||1,4 Mio. t CO2-equiv.|
|7. Aluminium smelting (PFCs)||1,1 Mio. t CO2-equiv.|
2. 2010 Emissions of HFCs, PFCs and SF6 in the Reduction Scenario
In the reduction scenario, not only emissions of SF6 drop by 2010 from the 1995 baseline, but also those of PFCs. SF6emissions halve from 6.2 to less than 3.0 million t CO2 equivalent (Table II). PFC emissions drop from 1.8 to 1.1 million t CO2 equivalent, or by 35%, instead of rising - as in the business-as-usual scenario - by 43%.
The growth of HFC emissions is attenuated. These rise from 3.1 to 10.8 million t CO2 equivalent (Table II), i.e. by 244% instead of by 534% as in the business-as-usual scenario. However, this growth is still enough to make total FC emissions rise from 1995 to 2010 by 34%, from 11.1 to 14.9 million t CO2 equivalent (Table II). The reduction potential in the year 2010 of all measures proposed totals about 12.5 million t CO2 equivalent, or 46%.
Sector-by-sector reduction potentials
Beyond the absolute quantities of individual emission sectors, it is essential to environmental policy to know which sectors offer the greatest opportunities to abate radiative forcing emissions. In general, the largest emissions sources also offer the largest absolute reduction potential (cf. Table III).
Five of the eighteen emission sectors offer a reduction potential of more than 1 milliono. t CO2 equivalent in the 1995-2010 period: the three HFC applications refrigeration and stationary air-conditioning, one-component PU foam and XPS foam blowing, the SF6 application soundproof glazing and the PFC application semiconductor manufacturing (cf. Table III, right column).
- The largest reduction potential is in refrigeration and stationary air-conditioning, which is also the largest source of emissions in the business-as-usual scenario. In the reduction scenario, emissions in 2010 only figure 4.1 instead of 7.7 million t CO2 equivalent - 3.6 million t less than in the business-as-usual scenario. This reduction is the outcome of general mandatory maintenance for refrigeration and air-conditioning systems containing more than 1 kg refrigerant. This alone cuts total business-as-usual emissions of HFCs, PFCs and SF6 (27.4 million t CO2 equivalent) by 13%.
- Total emissions are further reduced by 9% by means of partial HFC substitution in propellants for one-component PU foamnamely 95% substitution by simple hydrocarbons. This measure has the potential to slash business-as-usual HFC emissions (2.7 million t CO2 equivalent) in 2010 in this sector to 0.2 million t.
- The third largest reduction effect compared to the business-as-usual scenario is also provided by HFC substitution. If in about 40% of of XPS foam panels HFCs are replaced as blowing agent by CO2 plus ethanol, then emissions from this application are cut from 3 million t CO2 equivalent to 1.7 million t. This measure alone would reduce total FC emissions in the year 2010 by 1.3 million t CO2 equivalent, or 5%.
- The fourth largest reduction potential is available in the semiconductor industry from 2000 onwards process chamber cleaning converts throughout to a new technology (upstream NF3) dissociation in microwave plasma). PFC emissions then drop from 1.4 million t CO2 equivalent in the business-as-usual scenario to less than 0.2 million t CO2 equivalent in the reduction scenario. This measure reduces total FC emissions by more than 4%.
- A reduction potential of 1 million t CO2 equivalent could be tapped if SF6 were no longer used in new soundproof glazing. Of the 3 million t CO2 equivalent emitted from this sector in the year 2010 in the business-as-usual scenario, 2 million t would remain in the reduction scenario due to decommissioning losses. The high filling losses would cease.
Diagram I: 1995-2010 emissions of the three gases in business-as-usual Scenario I [million t CO2 equivalent]. The steep rise in emissions until 2010 to more than 27 million t CO2 equivalent is almost exclusively attributable to HFCs (dark upper area). The sub-total of SF6 and PFC emissions (lower areas) drops until 2001, but then rises again until 2010.
Diagram II: 1995-2010 emissions of the three fluorinated greenhouse gases in reduction Scenario II [million t CO2 equivalent]. Both SF6 and PFC emissions (lower areas) drop over the 1995-2010 period. However, what is decisive for the reduction potential (white uppermost area) from the year 2000 onwards is the moderate rise in HFC emissions compared to Scenario I.
The sectors offering reduction potentials of more than 1 million t CO2 equivalent effectively also include the second largest emissions source of the business-as-usual scenario, mobile air-conditioning. The reduction potential only reaches 0.8 million t CO2 equivalent by the year 2010, but this is merely because the emission-abating factor, namely refrigerant conversion from HFCs to CO2, only develops its full effect a few years later.
The above six measures can tap 84% of the total reduction potential of 12.5 million t CO2 equivalent (Table I equivalent effectively also include the second largest emissions source of the business-as-usual scenario, II, right column).
Conclusions for Emissions Abatement Policies
Where emissions abatement policies need to set priorities, the finding that the bulk of the fluorinated greenhouse gas reduction potential in Germany is concentrated in six application sectors provides guidance. Nonetheless, it should be kept in mind that the other twelve sectors offer a substantial further reduction potential totalling 2 million t CO2 equivalents.
It is all the more important to keep this in mind in view of the further finding that even if all measures proposed are implemented, emissions will by no means be brought below the 1995 baseline by 2010. Germany has committed itself toreduce. by 21%, from the 1995 baseline, the total of all greenhouse gas emissions (fluorinated and non-fluorinated compounds). In contrast, exploiting the full reduction potential set out in this study for the three groups of fluorinated greenhouse gases leads not to a reduction, but to a rise of global warming emissions by 34%. This growth has to be compensated elsewhere (CO2, CH4, N2O) ). It is thus amply clear that no options to reduce global warming emissions should be neglected. On the contrary, efforts are necessary to tap further reduction potentials.
By the measure of the overall emissions of direct greenhouse gases in Germany, the emissions of HFCs, PFCs and SF6 may appear relatively unimportant. Together, their share in total emissions - expressed in CO2 equivalents (GWP with 100 year time horizon) - amounted to ca. 1% in 1995. Nonetheless, it would be ecologically inappropriate to neglect fluorinated greenhouse gases. For if no further abatement measures are implemented, their share in total direct greenhouse gas emissions will have risen to some 3% by 2010. A further aspect is that, over the medium term, no reversal of emission trends is in sight for the quantitatively most important group of fluorinated gases, the HFCs.
It must further be noted that the total of global warming emissions is made up of a great array of individual sources, each of which is generally small in itself, but all of which need to be scrutinized for abatement options as a part of the crucial effort to reduce greenhouse gas emissions.
Annex: Supplementary data
Tables IV to VII serve to complete the environmentally relevant emission data for fluorinated greenhouse gases in Germany.
Tables IV and V list gas emissions for the years 1995, 2000, 2005 and 2010 in tonnes per year. Table IV gives the figures for the business-as-usual scenario, Table V for the reduction scenario.
Tables VI and VII list the historical emissions of the years 1995 to 1997: Table VI in tonnes of gas and Table VII in million tonnes CO2 equivalent.