Renewable Roundup: How refrigeration figures in climate change action
Most of the attention on Global Warming quite rightly goes to renewable electricity and EVs. But we have to thank those who focus on the less glamorous parts of the problem. Refrigeration, including air conditioning, turns out to be another critical issue.
Fluorinated gases are not the only refrigerants available. Alternatives, such as ammonia or captured carbon dioxide, can replace these powerful greenhouse gases over time.
Pursuant to the Kigali accord signed in 2016, the replacement of HFC refrigerants with a mix of alternatives can result in a range of emissions reductions equivalent to 43.5-50.5 gigatons of carbon dioxide from 2020-2050. Although the exact mix of alternatives is not projected and so the cost of adoption is not yet modeled, current and emerging refrigerants and appliances (including ammonia, carbon dioxide, and propane) can replace between 67%-82% of HFC refrigerants by 2050.
Ammonia is usually manufactured by burning the carbon in methane, and combining the hydrogen with nitrogen from the air. Work is being done on other methods that would be carbon-neutral.
Chemists are tackling the refrigeration problem from many different angles.
Refrigerants are used as working fluid in commercial refrigeration systems, in household appliances such as air conditioners and refrigerators, in refrigerated containers used for carrying perishable goods, as air conditioning systems onboard cars, trains, aircrafts, and ships, and in industrial cooling systems, etc. There are various classes of refrigerants.
Chlorofluorocarbons (CFCs) are ozone depleting substances and have been phased out under the Montreal Protocol; Hydrochlorofluorocarbons (HCFCs) are also being phased out. HFCs, which do not deplete the ozone, emerged as an alternative to HCFCs and have grown to extensive use. All refrigerants have a high GWP [global warming potential], and their release into the environment contributes to global warming.
Considering the large impact which the release of refrigerants has on global warming, world leaders have agreed to phase out HFCs and replace them with natural refrigerants with much less warming potential under the Kigali Accord in October, 2016. Refrigerants are emitted into the environment during the production process, from refrigerant banks due to leakages, and during end-of-life disposal of the appliances.
Substantial emissions reductions could be achieved through the adoption of practices to (1) avoid leaks from refrigerants and (2) destroy refrigerants at end of life, both after the adoption of alternatives to HFC refrigerants. Over thirty years, an increase of over 79% percent of refrigerants that may be released can be contained, avoiding emissions equivalent to 57.8 gigatons of carbon dioxide. Although some revenue can be generated from resale of recovered refrigerant gases, the costs to establish and operate recovery, destruction, and leak avoidance outweigh the financial benefit—meaning that refrigerant management, as modeled, could incur a net cost of $629.4 billion by 2050.
Scientists estimate the Kigali accord will reduce global warming by nearly one degree Fahrenheit. Still, the bank of HFCs will grow substantially before all countries halt their use. Because 90 percent of refrigerant emissions happen at end of life, effective disposal of those currently in circulation is essential. After being carefully removed and stored, refrigerants can be purified for reuse or transformed into other chemicals that do not cause warming.
The kitchen refrigerator is an obvious contributor to global warming because it usually sucks in electricity that was made by burning fossil fuels. But it turns out that the refrigerator does harm to the environment before it is even plugged in because the insulating foam in its innards is made with a gas that is more than 1,000 times worse, molecule for molecule, than carbon dioxide.
Now manufacturers are working to replace the HFCs. One choice is a hydrocarbon molecule called cyclopentane, which has a global warming potential of 3 to 10. But the cyclopentane turns out to have another benefit; it makes a better insulator. The new foam is about 4 percent better, said Paul Surowiec, general manger for refrigeration at GE’s appliances and lighting division.
The company has converted its refrigerator factory in Decatur, Ala., for use of the new blowing agent. The effect will be to eliminate emissions that are equivalent to 400,000 metric tons of carbon dioxide a year, about the same global warming impact as 78,000 cars, the company said.
In February, GE announced a deal with a company called Appliance Recycling Centers of America that will collect old refrigerators from six states. GE will crush the styrofoam and capture the gas that was in the bubbles.
Cooling Your Home but Warming the Planet: How We Can Stop Air Conditioning from Worsening Climate Change
Today, approximately 20% of the total electricity used in buildings around the world goes towards air conditioners and electric fans. Energy use for space cooling has been on the rise for years. The International Energy Agency expects space cooling energy needs to triple by 2050.
Some of the warmest countries, especially those with burgeoning economies, are expected to become much heavier air conditioning users over the next few decades. Countries with high air conditioning use, like China and the Unites States, already have a huge footprint in space cooling energy use and HFC leakage. Head of the Climate and Clean Air Coalition Secretariat at the UN Environment office in Paris, Helena Molin Valdés, has reported that HFCs “the fastest-growing [source of greenhouse gas] emissions in every country on Earth.”
Heat pumps can use less electricity for heating than a resistance heater, and less for cooling than conventional air conditioning. Using less electricity saves carbon emissions where carbon is burned in power plants. They contain refrigerants of the same kinds as refrigerators and AC, but do not need as much for the same cooling effect.
(Crossposted with DailyKos.)