U.S. industry energy-saving potential, 2010–2050

Increased adoption of energy efficient technologies as well as cogeneration and waste heat recovery systems will reduce energy use by an additional 4.7 quadrillion BTUs from business-as-usual. These and other changes (energy changes due fuel switching or transformation in other sectors) can reduce projected primary energy use by 27% in 2050.

 

Energy flow through a typical internal combustion engine drivetrain

This chart shows why less than 0.5% of the energy in a typical modern auto’s fuel actually moves the driver, and only 5–6% moves the auto. An auto's weight is responsible for more than two-thirds of the energy needed to move it. All told, 86% of the fuel energy never reaches the wheels.

 

Vehicle retail price and curb weight, new U.S. car sales, model year 2010

Lightweight autos needn’t cost more. The MY 2010 U.S. new-car fleet shows little or no correlation between lighter weight and higher prices.

 

Sales-weighted curb mass and density of new autos sold in U.S., 1986–2009

Autos in the U.S. have increased in weight by 16% since 1986 to an average of 3,533 lb. in 2009. Cars have also gotten denser, rising 14%—from 28 to 32 lb per interior cubic foot. Yet since 1986, U.S. adults got only 8% heavier.

 

Tractive load formulas

Powertrain efficiency from tank to wheels can't exceed 1.0, and is around 0.17 in a typical modern car or 0.35 in a good "full hybrid," but the energy needed to move the car can be reduced severalfold by making it lighter and more slippery.

 

Horsepower to overcome aerodynamic drag

Each 10% decrease in an auto’s aerodynamic drag can raise its fuel economy by very roughly 3%.

 

Drag coefficient and retail price, new U.S. car sales model year 2010

As with lightweight autos, more aerodynamic autos needn’t cost more. A survey of currently available autos shows that lower drag vehicles, as a whole, cost no more than less aerodynamic ones.

 

2050 installed capacity by case

The required generating capacity and its breakdown are very different in each of Rocky Mountain Institute’s four scenarios for the future U.S. electricity system (detailed here).

 

Power to accelerate 0–60 mph in 9 seconds

Every 10% decrease in an auto’s weight can raise fuel economy by roughly 6%.

 

2050 generation by case

Each of Rocky Mountain Institute’s four scenarios for the future U.S. electricity system (detailed here) will have a very different electricity generation mix.

 

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