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Evaluation of the possibilities of substituting potent greenhouse gases (HFCs, PFCs and SF6) 1 BackgroundConsumption In 1999, the industry in Denmark used approx. 980 tons of HFC substances, approx. 13 tons of SF6 and approx. 8 tons of PFC substances. The table below shows the consumption and environmental impacts hereof:
The figures are from the Danish Environmental Protection Agency's analysis of the ozone layer depleting substances and potent greenhouse gases in 1999 (the Danish Environmental Protection Agency 1991). Tomas Sander Poulsen, COWI, has prepared this report. 3% of CO2 emission If this entire amount of substance is emitted to the atmosphere, it will result in an increased emission of greenhouse gases corresponding to approx. 1.83 million tons, which corresponds to approx. 3% of the total Danish emission of CO2 (55.7 million tons in 1999). It should be emphasised that the figure represents the raw materials consumption and thus the potential emission of these substances. The real emission will depend on the extent of the collection and destruction of these substances. The consumption of HFC substances has been heavily increasing as these in some cases are used as substitution for CFC and HCFC substances. The consumption is however stagnant, and a small decrease has occurred in the consumption from 1998 to 1999. Seen from an environmental point of view, it is better to use HFC substances than CFC and HCFC substances as the impact on the ozone layer hereby is eliminated. CFC and HCFC substances are moreover very potent gases with significant GWP even though opinions differ about the exact contribution of the substances to the greenhouse effect. The substances contribute with two opposing effects: They are very potent greenhouse gases with GWP values of e.g. 4,000 (CFC-11), 8,500 (CFC-12) and 1,700 (HCFC-22). On the other hand, the substances contribute to depletion of stratospheric ozone, which is also a greenhouse gas. It should also be mentioned that the contribution to the greenhouse effect from different HFC substances covers GWP values ranging from 140 (HFC-152a) to 11,700 (HFC-23). Activities up till now Danish Environmental Protection Agency Through the Danish Environmental Protection Agency's programmes (i.a. the Cleaner Products Programme), a great deal of activities have been subsidised in order to develop products and production processes, which do not make use of HFC or other potent greenhouse gases. In co-operation with the industry, refrigerators and pre-insulated district heating pipes have i.a. been developed with hydrocarbons as blowing agent in the insulating foam as well as supermarket systems using natural refrigerants, use of water and inert gases in fire extinguishing equipment, etc. Natural refrigerants What is meant by natural refrigerants is use of naturally occurring substances, i.e. ammonia, hydrocarbons, CO2, water and air. Some of these refrigerants can be produced chemically, e.g. ammonia. The Danish Energy Agency The Danish Energy Agency also subsidises the development of new energy-efficient refrigeration systems using natural refrigerants. Development of refrigeration systems using water as refrigerant (the LEGO system) can be mentioned as well as development of commercial refrigerators (bottle coolers, ice cream freezers and commercial kitchen appliances) using hydrocarbons as refrigerant and ammonia refrigeration systems as demonstration project in a large city hotel. It should be mentioned that the total consumption of CFC substances was nearly 6,000 tons per year at the end of the 1980s. Most of the previous applications of CFC have thus been substituted by substances which are naturally occurring i.a. hydrocarbons in aerosol cans, hydrocarbons in insulating foam and in certain refrigeration systems, water for cleansing of electronic components, ammonia in certain refrigeration systems, etc.
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