Intro by yaoyufang


									  Dazzled by Diesel? The Impact on
Carbon Dioxide Emissions of the Shift
 to Diesels in Europe through 2009

                      Lee Schipper
Senior Research Engineer, Precourt Energy Efficiency Center,
                 Stanford University and
 Project Scientist, Global Metropolitan Studies, UC Berkeley
              Tel 202 262 7476; 510 642 6889

•Voluntary Agreement Between EU and Manufacturers 1998-
   •New car emissions to fall to 140 g/km by 2008
   •146.5 g/km achieved by 2009
   •Lack of achievement led to mandatory 120-130 g/km by 2012-2016.
•Many point to diesel as a way of saving fuel and emissions
   •Recent letter to EU
   •Prominent in advertising (“Blue Motion”, etc.)
   •Years of experience (Taxis in Europe)
•Measuring the Impact Difficult
   •Examine disaggregated diesel and car data (km/car, fuel/km)
   •New stock-wide on road usage, not just new sales and characteristics
   •Count energy and emissions, not just volume of fuel
• Examine New Vehicle Test Fuel Intensities year by year
   – EU data base (1995-2009) countries by fuel, sales, test emissions
   – New vehicle properties (mass, kW, cc of engine)
   – Supplemented by national data 1980-2000 for 8 countries
• Note On-Road Fuel Intensities (fuel or emissions/km)
   – Numbers of gasoline and diesel cars on road, km/car/year, fuel/km
   – Data from official/authoritative sources BE, ES, FR, DE, IT, NL, SE, UK
• Diesel and Gasoline Prices
          New Diesel Trends – EU Wide
• New Vehicle fuel economy/emissions
   – New diesels fell 16% from 1995 to 2009
   – New gasoline fell 17% from 1995 to 2009
   – The aggregate fell 18%
• New Vehicle Characteristics (through 2006, then turn-
   – New diesel car power up 48%, weight up 24%
   – New gasoline car power up 14%, weight up 15%
   – Aggregate power up 41%, weight up 26%
• Comparison with new Gasoline
   – Diesel share of new cars 46% in 1995, 55% in 2008, then 48% in
   – Diesel power and weight grew more than that of gasoline
   – Diesel emissions fell less than those of gasoline
       Results of Laspeyres Decomposition
• Overall Changes in Emissions
   – > 95% of change came from decline in both gasoline and diesel
   – < 5% came from shift from gasoline to diesel among new vehicles
   – Thus dieselization per se had little impact on emissions/km of new

• Other Sources of Changes in Emissions/km small
   – Trends observed in almost all EU Countries
   – Shift of the relative size of new car markets by country had little
   – Diesel emissions fell less than those of gasoline
      Results for Entire Fleet for the EU-8
          Represent Roughly 85% of cars in EU-15

• Overall Changes in Emissions Intensity
   – In new vehicles 18% from 1995 to 2008 (gas. 18%; diesel 15%)
   – In on-road fleet 9% drop in emissions/km (gas 9.4% diesel 6.7%)
• Diesel Vehicle Use: Surprise
   – In 1995, 20500 km/car, 172% of gasoline vehicle use
   – In 2008, 17300 km/car, 175% of gasoline vehicle use
   – Overall diesel/gasoline driving gap increased
• Huh? Is this a Rebound Effect? (Mostly NO)
   – Diesel vehicles on road newer, newer vehicles driven more
   – Diesels selected by long-distance drivers, company car
   – Per Capita car km in the EU8 up slightly but km/gdp down 12%
                        Main Findings
• Diesel is an efficient vehicle technology – that’s not the point
   – In matched pairs, diesels tend to save 25-30% of energy and 15% of
     emissions over gasoline
   – EU wide 2009 diesels saved zero energy. 5% of emissions compared
     to gasoline
   – Diesel advantage over gasoline has been shrinking
• Diesel was not deployed principally to save energy
   – Diesel cars with low cost fuel were first mileage extenders
   – New diesel cars invaded highest classes of cars – weight, power rose
   – New diesel cars attractive to those with company car benefits
• Careful Interpreting results:
   – People who bought diesels were different than others (selection effects,
     including long distance drivers)
   – Greater power and weight absorbed half of real efficiency gains
   – rebound effects (on driving) small – car use/capita flat over six years.
                 Policy Implications
• You Can’t Save Energy or Emissions from Cheap Fuel
   – Until recently driver to diesel was cheap fuel
   – In on-road fleet 9% drop in emissions/km (gas 9.4% diesel
   – Expectations about the impact of improved vehicle technology
     on fuel use and emissions must be tempered by considerations
     of rebound and selection effects, i.e., the differences in who
     drives one vehicle technology versus another.
• Technology vs People – The People Always Win
   – Diesel remains an efficient technology
   – People (manufacturers, buyers, drivers) used it differently
   – People like big cars, as long as they are cheap to own and use
• Implications for other Strategies
   – “Green car” strategies and subsidies not promising
   – Technology strategies must be backed by price signals

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