1 August 24, 2015

The role of hydrofluorocarbons (HFCs) for ozone and climate protection

Guus Velders

The Netherlands

(RIVM)

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HFCs offset climate benefits Montreal Protocol

Dual protection Montreal Protocol: to Ozone layer and Climate change– Already achieved climate benefits 5-6 times larger than Kyoto

Protocol targets for 2008-2012

Climate benefits can be offset by projected increases in HFCs– HFC emissions can reach 9-19% of CO2 emissions in 2050

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Range of different chemicals

CFCs: fully halogenated● CFCl3 (CFC-11), CF2Cl2 (CFC-12), etc.

Other ozone depleting chemicals:● CF3Br, CF2ClBr (Halons – bromine containing species)

● Methyl bromide/chloride, methyl chloroform, CCl4

Alternatives: HCFCs: partially halogenated● CHF2Cl (HCFC-22), CH3CFCl2, CH3CF2Cl

Alternatives: HFCs: no chlorine● CH2FCF3 (HFC-134a), CHF2CF3 (HFC-125), CH3CF3 (HFC-143a)

● New: CF3CF=CH2 (HFO-1234yf), CF3CH=CHF (HFO-1234ze)

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Range of different applications (1)

Refrigeration and air conditioning● Domestic, commercial and industrial:

– Originally: CFC-11, CFC-12– Now: HCFC-22, HFCs, NH3, CO2, hydrocarbons

● Mobile air conditioning– Initially: CFC-12– Now (since ~1995): HFC-134a (all cars)

Foam blowing: insulation, packaging● Originally: CFCs● Now: HFCs, hydrocarbons, others

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Range of different applications (2)

Solvent: Dry cleaning, electronics industry● Originally: CFCs, carbon tetrachloride (CCl4), methyl chloroform (CH3CCl3)

● Now: - mostly not-in-kind technologies, water, other chemicals- HFCs for some specialized uses

Aerosols: Metered dose inhalers, spray cans (deodorant, hair)● Originally: CFC-11● Now: hydrocarbons, not-in-kind, HFCs (limited uses)

Fire fighting agent in aircraft and high-tech facilities● Originally: halons and CCl4● Now: Inert gas (e.g. CO2), water, HFCs

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Ozone depletion through Cl and Br atoms

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Ozone depletion through Cl and Br atoms

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Montreal Protocol to protect ozone layer

● Montreal Protocol of 1987● Subsequent amendments

● Universal ratification

● EESC is a measure of Cl/Br available to destroy ozone

● Also important for ozone recovery● CO2, CH4 and N2O emissions

● Very short lived species● Rockets, aircraft● Volcanoes● Geoengeneering

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Montreal Protocol changed chemicals used

● Montreal Protocol on Ozone Depleting Substances● It caused a change in chemicals used for refrigeration, AC, foam

blowing, cleaning, fire extinguishing, etc.:

CFCs HCFCs + other techn. HFCs + other techn.

● Well known benefits for ozone layer

● CFCs, HCFCs, HFCs are all strong greenhouse gases● Global Warming Potentials (GWPs):

– CFCs: 4,700 – 11,000– HCFCs: 100 – 2,200– HFCs: 130 – 4,200– HFOs: <20

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Well known benefits Montreal Protocol

● Large decreases in CFC production (>98%) and emissions (60-90%)● Concentrations also decreasing

● Emerging evidence of start of ozone layer recovery● Full recovery before 2050, later in polar regions

WMO (2011)

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Metrics used here

● Impacts on climate expressed by– CO2-equivalent emissions = Emission x GWPs

– Radiative forcing of climate = Abundance x Radiative eff. (W/m2/ppb)

● Impacts on ozone layer expressed by– CFC-11-equivalent emissions = Emission x ODPs– Eq. Eff. Stratospheric Chlorine = Abundance x Frac. release + time delay

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Different metrics for ozone depleting chemicals

● Ozone layer:– ODP-weighed emissions– Equivalent Effective Stratospheric

Chlorine (EESC)

● Climate change:– GWP-weighed emissions– Radiative forcing

WMO (2011)

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Large climate benefits Montreal Protocol

World avoided by the Montreal Protocol

Reduction Montreal Protocol of ~11 GtCO2-eq/yr

5-6 times Kyoto target

(incl. offsets: HFCs, ozone depl.)

CO2 emissions

Velders et al., PNAS, 2007

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Radiative forcing leading to climate change

Reduction in radiative forcing of ~0.23 Wm-2 in 2010 about 13% of CO2 emissions of

human activities

• ~0.1 °C cooling from Montreal Protocol (Estrada et al.; Pretis and Allen, 2013)

Velders et al., PNAS (2007)

Forcing: delay of ~10 years cf CO2 emissions

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HCFC growth

● CFC phaseout globally in 2010 Accelerated increases in HCFCs

● Developing countries:– HCFC consumption increase: 20%/yr (up to

2007)– CFC+HCFC increase: 8%/yr

● Starting point new scenarios

● HFC-23 emissions not considered

Montzka et al., GRL (2009)

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HFC: Expected large growth

● HCFCs– Developed countries: controls since 1996– Developing countries: controls since 2013– Phaseout in 2030/2040

Much of application demand for refrigeration, AC, heating and thermal-insulating foam production to be met by HFCs– Current forcing small (<1% of total GHG forcing)– Current growth rates of HFCs: 10-15% per year

● Increases directly attributable to Montreal Protocol● Climate effect is a unintended negative side effect

Photo W.S. Velders

Montzka, NOAA/ESRL

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HFC scenarios

● New HFC scenarios developed– Unchecked emissions– Extrapolating developed country use patterns

● Based on– Increased HCFC consumption developing countries– Atmospheric observations of HCFCs and HFCs– Observed replacements patterns: HCFCs to HFCs– IPCC-SRES: growth rates GDP and population– Provisions Montreal Protocol– Increases in HFC-134a use in mobile AC– Saturation of HFC consumption

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Replacing HCFCs with HFCs

● Refrigeration, air conditioning, foam production● Replacement scheme developed countries:

– HCFC-22 35% R404A, 55% R410A, 10% NIK– HCFC-141b 50% HFC-245fa, 50% NIK– HCFC-142b 50% HFC-134a, 50% NIK– R404A, R410A: Blends of HFC-32, -125, -134a, -143a

● Applied to developing countries

● Mobile AC: HFC-134a● Inhaler: HFC-134a● Foam, aerosol: HFC-365mfc,

HFC-152a (minor use)

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HFCs offset climate benefits Montreal Protocol

• In 2010, CFCs could have reached 15–18 GtCO2-eq yr-1

(in absence of Montreal Protocol)

• In 2050, HFC emissions: 5.5–8.8 GtCO2-eq yr-1

= 9–19% of global CO2 emissions

● Larger in comparison with CO2 stabilization scenarios from IPCC/AR4

Velders et al., PNAS, 2009

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Offsets in terms of radiative forcing

● In 2010, reduction due to Montreal Protocol 0.23 W/m2 (incl. offsets)

● In 2050, forcing HFCs 0.25–0.40 W/m2

– Compared with CO2 (BAU) of 2.9–3.5 W/m2

– Equivalent to that from 6–13 years of CO2 emis.

●In 2050, HFC forcing ~ reduction from CO2 stabilization scenario

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Montreal Protocol and Kyoto Protocol

● Montreal Protocol:– Protection of ozone layer (UNEP treaty 1987)– Production and consumption– Gases: CFCs, halons, HCFCs, methyl bromide, etc.– Phase-out schedule (CFCs 2010, HCFCs 2030/2040)– Climate considerations taken into account– Very successful: Universal ratification

● Kyoto Protocol:– Protection of climate (UN treaty 1997)– Emissions– Basket of 6 gases: CO2, CH4, N2O, HFCs, PFCs, SF6

– ~5% reduction from 1990 by 2008-2012– Emissions reductions of “gases not covered by the Montreal Protocol”– Successful?

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What is happening in the political arena

● Amendments proposed to include HFCs in Montreal Protocol– Strong support

– Problem caused by Montreal Protocol– Instruments available– Climate considerations are in the text of the Montreal Protocol– Bali decleration by 100+ countries

– Strong opposition– HFCs to not destroy ozone– Already in Kyoto– Financial/legal concerns

● Sept. 2013: G20 supports initiatives to use expertise and institutions of Montreal Protocol to phase down HFCs

● Climate and Clean Air Coalition

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What is happening in industry (car makers)

● Since 1990s all mobile air-conditioners use HFC-134a (GWP 1370)

● In EU: mobile AC directive:– Refrigerant should have GWP <150– From 2011 for new type of vehicles (derogation

until 12/2012)– In 2013: German car maker still used HFC-134a

France blocked registration of new Mercedes

● Alternatives for HFC-134a:– HFC-1234yf (more or less drop in replacement)– CO2 promoted by German EPA (needs redesign of

engine)– HFC-152a (flammable)

Honeywell (2008)

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Wide range of HFC lifetimes and GWPs

● Fully saturated HFCs:– HFC-32, -125, -134a, -143a, -152a– Lifetimes: 1 to 50 yr– GWPs: 100 to 4000

● Unsaturated HFCs (HFOs):– HFC-1234yf, -1234ze– Lifetimes: days to weeks– GWPs: ~20 or less

● If current HFC mix (lifetime 15 yr) were replaced by HFCs with lifetimes less 1 month forcing in 2050 less than current HFC forcing

Velders et al., Science, 2012

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Changes in types of applications

● CFCs (1980s) used in very emissive applications● Spray cans, chemical cleaning● Release within a year

● HFCs used mostly in slow release applications● Refrigeration, AC: release from 1 – 10 yr● Foams: release > 10 yr

Velders et al., ACP, 2014

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Role of the banks increases

● Banks: HFCs present in equipment: refrigerators, AC, foams, etc.

● Bank about 7 times annual emission

● Phaseout in 2020 instead of 2050● Avoided emission: 91-146 GtCO2-eq

● Avoided bank: 39- 64 GtCO2-eq

Banks: climate change commitment

● Choices:● Bank collection, destruction: difficult/costly● Avoid the buildup of the bank: early phaseout

Velders et al., ACP, 2014

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Alternatives to ODSs and HFCs

● Replacing high-GWP HFCs with substances with low impact on climate:– Hydrocarbons, CO2, NH3, unsaturated HFCs

– Alternative technologies

● Reducing emissions:– Changing designs– Capture and destruction

● Low-climate impact alternatives already available commercially in several sectors:– Fiber insulation materials (e.g., mineral wool)– Dry powder asthma inhalers– Hydrocarbons, CO2, ammonia in refrigeration systems

– Unsaturated HFCs introduced for foams, aerosols and mobile AC

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Life cycle climate performance (LCCP)

● Important is the total effect on climate

● Direct climate forcings– GWP-weighted emissions, Radiative forcing

● Indirect climate forcings – Energy used or saved during the application lifespan– Energy used to during manufacturing

● Total effect on climate Life cycle climate performance

● Also important: costs, availability, flammability, toxicity, humidity, etc.

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Conclusions

● Dual protection Montreal Protocol: to Ozone layer and Climate change:

● Already achieved climate benefits 5-6 times larger than Kyoto Protocol targets for 2008-2012

● Climate benefits Montreal Protocol can be preserved by limiting HFC growth

● Challenge for policymakers: identify how this can be accomplished

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Work performed in close collaboration with: David Fahey (NOAA) John Daniel (NOAA) Steve Andersen (formerly at EPA) Mack McFarland (DuPont) Susan Solomon (MIT)

Thank you for your attention

References: - Velders et al., Proc. Natl. Acad. Sci., 104, 2007- Velders et al., Proc. Natl. Acad. Sci., 106, 2009- Velders et al., Science, 335, 922, 2012- Velders et al., ACP, 14, 2757, 2014- Velders et al., ACP, 14, 4563, 2014

HFC-134a and its main IR-frequency