Carbon Footprint of New Energy Vehicles

The carbon footprint calculation made by the Renewable Fuels and Sustainable Transportation Branch of the American Solar Energy Society after taking into account all the external factors of manufacturing and refueling shows that a small car can travel 30 miles on 1gal gasoline, and the tailpipe emits a carbon footprint of CO₂ 3.5t per year. This figure should also take into account the 4.5t 'upstream' external emissions carbon footprint of car production, for a total of 8t. In addition, solar- and wind-charged electric vehicles have also been calculated to be 60 to 3,000 times more efficient than biofuel engines. This will make zero-emission electric vehicles and plug-in hybrids more attractive.

For electric vehicles powered by batteries, the actual range of traditional lead-acid batteries is limited to 20~30mi, and modern lithium-ion batteries can increase the range to 40mi or even 200mi. For conventional hybrid vehicles, the battery is used for low power operation and the internal combustion engine power is used for acceleration. The IC motor stops when the car is parked, and drives when it is loaded. Heavy-duty hybrids have no efficiency advantage over conventional IC vehicles, and when driven over long distances, hybrids lose their efficiency advantages. A plug-in hybrid is a hybrid vehicle that uses a large battery stack that can be charged from the grid. In a typical situation, it can travel about 40mi on battery power alone. CNG vehicles are typically used in fleets, but the lightweight Honda Civic GX is also available in the utility market. In some major metropolitan areas, CNG fuel is supplied from filling stations, but the scope of supply is limited by the need for enhanced high-pressure fuel tankers. Its main advantage is low greenhouse gas emissions: about 0.53lb of CO₂ per mile. 16 states in the United States have CNG filling stations for private vehicles. According to local pricing, the fuel cost can be reduced by about $2/gal equivalent.

Turbocharged diesel internal combustion engines have more energy due to the use of diesel fuel, which contains more energy than gasoline. They can operate at maximum duty cycle conditions without modification for operation with any biodiesel blend. Fuels using oils with high biomass content, however, condense at low temperatures, and for this reason these engines are often powered by fossil diesel in winter and vegetable oil in summer.

1. The use of different fuels has different carbon footprints

The relevant data are as follows:

Gasoline burning in the carbon footprint of a piston engine produces about 19.561b CO₂/gal (2.34kg/L);

Diesel fuel carbon footprint produces approximately 22.38lb CO₂/gal (2.68kg/L);

Biofuel carbon footprint (vegetable oil and ethanol) yields about 3.31b CO₂/gal (0.39kg/L);

Burning coal with a carbon footprint in modern power plants produces about 1.371b CO₂/(kW•h) (0.62kg/(kW•h)).

2. Low carbon footprint of using biofuels (E85 or B100)

The carbon footprint of any electric vehicle powered by a non-carbon source (photovoltaic, wind, nuclear) is: 01b CO₂/mi.

3. Carbon emissions of any PHEV (eg Prius PHEV, Volt PHEV) driven in electric mode only

The carbon footprint of the Honda Insight car is 0.061b CO₂/mi;

Volkswagen TDI car has a carbon footprint of 0.071b CO₂/mi;

Toyota Prius, Honda Civic Hybrid or PHEV with a carbon footprint of 0.091b CO₂/mi in hybrid drive mode;

A typical old motorcycle or small car runs at 42mi/gal and has a carbon footprint of 0.091b CO₂/mi;

Mercedes Smart has a carbon footprint of 0.11b CO₂/mi;

Nissan Altima Hybrid/Toyota Camry Hybrid (drive train) has a carbon footprint of 0.121b CO₂/mi;

Various small cars (30mi/gal) have a carbon footprint of 0.131b CO₂/mi;

Honda Accord Hybrid has a carbon footprint of 0.151b CO₂/mi;

The carbon footprint of the Chevy Malibu RO powered/Saturn Aura Green Line car is 0.151b CO₂/mi;

The Lexus GS450h has a carbon footprint of 0.17lb CO₂/mi;

Ford Escape Hybrid/Toyota Highlander Hybrid SUVs have a carbon footprint of 0.171b CO₂/mi;

The Lexus LS600HL has a carbon footprint of 0.191b CO₂/mi.

4. Minimum carbon footprint for using fossil fuels (gasoline, diesel, natural gas or coal-fired electricity)

Honda Insight car with a minimum carbon footprint of 31b CO₂/mi;

Electric vehicles or PHEVs driven only in electric mode, with a minimum carbon footprint of 341b CO₂/mi; Toyota Prius, with a minimum carbon footprint of 431b CO₂/mi;

Honda Civic Hybrid or PHEV driven in hybrid mode with a minimum carbon footprint of 471b CO₂/mi;

A typical old motorcycle or small car (42mpg) with a minimum carbon footprint of 471b CO₂/mi;

Mercedes Smart cars with a minimum carbon footprint of 491b CO₂/mi;

Volkswagen TDI car (or similar) with a minimum carbon footprint of 51b CO₂/mi;

Honda Civic GX with a minimum carbon footprint of 531b CO₂/mi;

Nissan Altima/Toyota Camry hybrid with a minimum carbon footprint of 591b CO₂/mi;

The minimum carbon footprint of any small car (30mpg) is 651b CO₂/mi;

Chevy Malibu/Saturn Aura hybrid with a minimum carbon footprint of 721b CO₂/mi;

Honda Accord Hybrid with a minimum carbon footprint of 751b CO₂/mi;

Lexus GS450h with a minimum carbon footprint of 821b CO₂/mi;

Ford Escape/Toyota Highlander hybrid SUVs with a minimum carbon footprint of 851b CO₂/mi;

Lexis LS600HL with a minimum carbon footprint of 93Lb CO₂/mi.

Under the shadow of the global economic crisis, EU member states announced in early November 2008 to reset the 2015 vehicle CO₂ emission limits. The 27 member states have unanimously agreed to defer the CO₂ emissions target for new cars by three years to 2015. With the same environmental goals, the carbon footprint of new cars sold in the EU will be no greater than 130g CO₂/km. The Volkswagen Golf ranks among the most popular cars in Europe and currently emits between 119 and 174g CO₂/km, depending on engine type and size. For all cars, the carbon footprint now averages 158g CO₂/km. Limiting CO₂ emissions to 130g CO₂/km by 2015 is the goal of the entire European automotive industry. In Italy, Fiat is targeting 122g CO₂/km, while in France the Renault and Peugeot-Citroen will achieve 126g CO₂/km and 127g CO₂/km respectively. For Volkswagen, the limit will be 132g CO₂/km.

Read more: Configuration of Electric Vehicle Charging Stations