The last detailed official inventory of the UK's fluorinated gas emissions was produced in 1999 by consultants March (ENDS Report 288, p 11 ). The new report, by AEA Technology, offers an updated assessment.
In 1995, the base year for reporting the gases under the Kyoto Protocol, emissions stood at about 17.2mtCO2e (million tonnes of CO2 equivalent) - about 2.5% of the UK's total greenhouse gas releases (see table).
Emissions fell by some 30% by 2000, mainly because of abatement of HFCs from refrigerant manufacture. The growing use of HFCs in refrigeration, mobile air conditioning and foam blowing is expected to increase emissions by 20% by 2005, followed by a steady fall to 13.1mtCO2e by 2010 - roughly 1mtCO2e higher than earlier estimates.
However, AEA reports significant differences in emissions from individual sectors. In-car air conditioning has grown much more quickly than expected, while revised estimates have led to a doubling of emissions from the magnesium industry and significant increases for refrigeration.
HFC emissions accounted for about 80% of the total and are predicted to fall steadily from 2005. PFC emissions are expected to level out at around 0.3mtCO2e, with a substantial contribution from aluminium production despite the hefty reduction achieved by the industry in the early 1990s.
Sulphur hexafluoride emissions peaked in 2000, but are expected to level off at around 1.2mtCO2e. A sectoral breakdown is not offered because of Nike's commercial sensitivity over its use of the gas in trainers (ENDS Report 342, p 34 ).
AEA also offers an estimate of emissions of nitrogen trifluoride. The gas has a global warming potential up to 13,100 greater than CO2 over 100 years, but is not at present covered by either the Kyoto Protocol or the UK's climate change programme.
Most NF3 emissions are believed to arise in the electronics sector. AEA puts emissions in 2000 at nearly 1.4mtCO2e, falling to 0.47mtCO2e in 2005 as a result of improved abatement. Thereafter - and in stark contrast to the other fluorinated gases - emissions are forecast to rise steeply to perhaps 1.9mtCO2e by 2025.
Ironically, the electronics sector is turning to NF3 for use in chamber cleaning to help meet its voluntary commitment to reduce PFC emissions - which appear to have a smaller overall warming impact (ENDS Report 294, pp 8-9 ). AEA quotes manufacturers' data which suggest that the sector will keep its PFC emissions down to roughly 0.1-0.2mtCO2e through an "ambitious" programme of abatement. The earlier March report had suggested a considerably higher figure.
The report notes that many sectors have already introduced measures to reduce emissions, including several voluntary agreements signed in the mid-1990s. Little information has been made available on their effectiveness - but the report suggests that further agreements, or strengthening of existing ones, are the most effective options for further reductions.
Several new voluntary agreements are under discussion. The first, involving mandatory registration of up to 100,000 refrigerant fluid handlers, is nearing completion and is expected to reduce HFC emissions from refrigeration by some 20% from 2010.
The second option being developed is an agreement on the use of HFCs in firefighting which could potentially reduce emissions by 44% by 2010. Discussions on an agreement to reduce the rapidly growing use of HFCs in foam blowing are at an earlier stage.
AEA says that cost-effective reductions, costing less than £100 per tonne of CO2e saved to 2015, could reduce emissions in 2010 by of about 0.53mtCO2e or 5%.
Installation of further incineration units to abate HFCs from halocarbon production offers the biggest potential saving of 0.88mtCO2e, and at a low cost. The report suggests that the involvement of the two main manufacturers, Ineos Fluor and Rhodia, in the UK emissions trading scheme is likely to bring forward investment in additional abatement (ENDS Report 338, pp 4-5 ) - although it could be argued that these improvements should be made mandatory under pollution control legislation.
The next most important source of cumulative emission reductions would be to replace HFCs in mobile air conditioning with CO2-based systems. However, AEA suggests that this may be a costly option.
Measures to reduce fluorinated gases from mobile air conditioning and other sources have also been proposed by the European Commission (ENDS Report 342, pp 58-59 ). It is as yet unclear what overlap these may have with the UK options set out in AEA's report.