Alternatives and substitutes for HFCs, perfluorocarbons (PFCs), and ozone depleting substances (ODSs) have recently been extensively evaluated. The Montreal Protocol Technology and Economic Assessment Panel (TEAP) and its technical committees published a comprehensive assessment (UNEP, 1999b). Furthermore, reports were published within the framework of the joint IPCC/TEAP workshop (IPCC/TEAP, 1999) and the second non-CO₂ greenhouse gases conference (van Ham et al., 2000).

The HFCs that are projected for large volume use have global warming potentials (GWPs) which are generally lower than those of the ODSs they replace. The GWP of HFCs replacing ODSs range from 140 to 11,700. HFC-23 with a GWP of 11,700 is used as a replacement for ODSs to only a very minor extent. However, there are relatively large emissions of HFC-23 from the HCFC-22 manufacturing process. The majority of HFCs have GWPs much lower than that of HFC-23. PFCs have GWPs that are generally higher than those of the ODSs they replace, ranging from 7,000 to 9,200 (IPCC, 1996). Table A3.1 lists the atmospheric properties of the HFCs and HFC blends considered in this Appendix.

Table A3.1: Atmospheric properties (lifetime, global warming potential (GWP)) for the HFC chemicals described in the Appendix (IPCC, 1996; WMO, 1999)
Sub-sector	Chemical formula	Lifetime (yr) (IPCC, 1996)	GWP (100 yr) (IPCC, 1996)	Lifetime (yr) (IPCC, 2000)	GWP (100 yr) (IPCC, 2000)
HFC-23 HFC-32 HFC-125 HFC-134a HFC-143a HFC-152a HFC-227ea HFC-245faa HFC-365mfca HFC-43-10mee	CHF3 CH2F2 CHF2CF3 CH2FCF3 CH3CF3 CF3CHFCF3 CF3CH2CHF2 CF3CH2CF2CH3 CF3CHFCHFCF2CF3	264 5.6 32.6 14.6 48.3 1.5 36.5 - - 17.1	11,700 650 2,800 1,300 3,800 140 2,900 - - 1,300	260 5.0 29 13.8 52 1.4 33 7.2 9.9 15	12,000 550 3,400 1,300 4,300 120 3,500 950 890 1,500
R-404A    (44% HFC-125,    4% HFC-134a,    52% HFC-143a) R-407C    (23% HFC-32,    25% HFC-125,    52% HFC-134a) R-410A    (50% HFC-32,    50% HFC-125) R-507    (50% HFC-125,    50% HFC-143a)			3,260 1,525 1,725 3,300
a No lifetime or GWP listed in IPCC (1996) Note: GWP values to be used by Parties for reporting any emissions and for any other commitments under the Kyoto Protocol are the 100 year GWP values from IPCC (1996) (decision taken at CoP 3, 1997)

Most HFCs are used for energy-consuming applications such as refrigeration, air conditioning and heat pumps, and building and appliance insulation. Life cycle climate performance (LCCP) analysis is being used to estimate the net contribution to climate change. It includes all direct greenhouse gas emissions and indirect emissions related to energy consumption associated with the design and the operational modes of systems (UNEP, 1999b; Papasavva and Moomaw, 1998). The LCCP is a very system specific parameter that can be used to make relative rankings. However, LCCP analysis involves regional differences – including different fuel sources – and the related equipment operating conditions; the results can therefore not be generalized in order to make globally valid comparisons.

The energy efficiency of equipment and products can be expressed in at least three ways: theoretical maximum efficiency, maximum efficiency achievable with current technology, and actual efficiency for commercial scale production (often expressed as a range of values). Systems optimized for a new refrigerant have been compared to sub-optimum systems with other refrigerants. Furthermore, appliance sizes and features that influence energy performance vary between studies and test conditions, and methodologies are often significantly different. These factors have led to a wide range of energy efficiency claims in technical reports and commercial publications. Ultimately, the performance and cost effectiveness of specific products from commercial scale production must be directly compared. Furthermore, costs reported in this appendix might not always be comparable because of differing estimation methods, including estimates based on both consumer and producer costs.

Unlike anthropogenic greenhouse gases emitted as an immediate consequence of the burning of fossil fuels to generate energy, most HFCs and PFCs are contained within equipment or products for periods ranging from a few months (e.g., in aerosol propellants) to years (e.g., in refrigeration equipment) to decades (e.g., in insulating foams). Thus, emissions significantly lag consumption and, because HFC systems are relatively new, emissions will continue to grow after 2010.

Both the quantities used and patterns of use of ODSs, HFCs, and PFCs are changing (see Figure A3.1) as ODSs are phased out under the Montreal Protocol (IPCC/TEAP, 1999; McFarland, 1999). In 1986, less than half of total ODS use was in insulating foams, fire protection, refrigeration, air conditioning, and heat pumps, with more than half as aerosol product propellants, non-insulating foam, solvent, and specialized applications. However, by 1997, the global consumption of fluorocarbons (CFCs, HCFCs and HFCs) had decreased by about 50% as solvent, aerosol product, and non-insulating foam applications switched to alternatives other than fluorocarbons. Refrigeration, air conditioning, and insulating foam accounted for about 85% of the remaining total fluorocarbon use. 80% of projected chlorofluorocarbon demand was avoided by reducing emissions, redesign, and use of non-fluorocarbon technologies. As CFCs, halons, and HCFCs are phased out globally, the quantities of fluorocarbons are expected to continue to decline in the short term, but are expected to grow in the longer term.

Future global HFC and PFC consumption and/or emissions as substitutes for ODSs have been separately estimated by IPCC (1995), Midgley and McCulloch (1999), and UNEP (1998a). Midgley and McCulloch (1999) projected carbon-equivalent emissions of HFCs and PFCs (excluding unintended chemical by-product emissions) at 60MtC_eq in 2000, 150MtC_eq in 2010 and 280MtC_eq in 2020. Projected consumption data for 2000 and 2010 are primarily based on UNEP reports (UNEP, 1998f, 1999b) and are shown in Table A3.2. Considering that emissions lag consumption by many years, the Midgley and McCulloch figures are much larger than the UNEP figures. This discrepancy is consistent with the Midgley and McCulloch scenario which was constructed to represent plausible upper limits to future emissions (McFarland, 1999). HFC emissions in the SRES scenarios (IPCC, 2000) are 54MtC_eq in 2000 and 130-136MtC_eq in 2010. These values are higher than those presented in Table A3.2 because of the top-down approach used in SRES that does not adequately account for delay between use and emissions in the 2000 to 2010 timeframe. Considering this fact and given the options for substitution, containment, etc., it is estimated that emissions in 2010 could well be about 100MtC_eq below the SRES forecast at a marginal cost lower than US$200/tC_eq. None of the scenarios have considered the implications of new uses of HFCs or PFCs other than as substitutes for ODSs.

Projected consumption and emission estimates for HFCs by sub-sector for 2000 and 2010 are summarized in Table A3.2.

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