When I was a kid, I loved the taste of soft drinks. I didn't have a strong preference for Coca-Cola versus Dr. Pepper versus Pepsi. As long as it was cold, sweet and syrupy I would drink it. The first time someone gave me a diet soda I thought I was going to throw up. I could not understand why anyone would drink the stuff.
Nonetheless, I eventually converted to diet soda under the mistaken belief that forgoing the empty calories of regular soda would keep me trim and healthy. I was wrong. I weigh more than I did when I switched to diet soda. I am also not alone. Studies have shown that drinking diet soda does not promote weight loss. Most people compensate, or over compensate, for the calories they save by eating more. Some research actually shows that people who switch from regular soft drinks to diet soft drinks gain weight.
Interestingly, the same type of thing happens with energy saving technology. You might assume that if you could design an automobile engine that was twice as efficient you could cut gasoline consumption by half. The experience of the past several decades shows this is not the case.
Over the past 30 years, the efficiency of automobile engines has increased greatly, but average mileage rates have increased only slightly. The National Bureau of Economic Research has concluded that, "If weight, horsepower, and torque were held at their 1980 levels, fuel economy for both passenger cars and light trucks could have increased by nearly 50 percent from 1980 to 2006. Instead, fuel economy actually increased by only 15 percent."
The idea that technological innovations lead to increased, rather than decreased, fuel consumption was first explored by the 19th century economist William Stanley Jevons. Examining the use of coal in Britain, Jevons found that the increase in the efficiency of engines, especially the invention of the steam engine, had resulted in an increase in Britain's consumption of coal. Jevons concluded: "It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth."
Jumping from the 19th century to the 20th century, we see clear examples of the effect Jevons described. New fluorescent and LED bulbs used for household lighting are far more efficient than incandescent bulbs. Yet, because the new bulbs are highly efficient many people are far less diligent about turning them off.
Researchers at Sandi National Laboratories have been looking at the history of household lighting over the past 300 years. Despite innovations that have moved from candles to kerosene lamps to gas lights to incandescent bulbs to fluorescent and LED bulbs, there has been almost no change in the fraction of household income spent on lighting. Lighting has gotten far cheaper, but people have not spent less. They have simply used much more lighting.
The history of technological innovation suggests that it is unlikely technology will produce massive reductions in energy consumption. In fact, the opposite may occur. E. F. Schumacher observed that, "Any intelligent fool can make things bigger, [and] more complex ... It takes a touch of genius -- and a lot of courage - to move in the opposite direction." For Schumacher, the opposite direction was not more technology. It was smaller and simpler. That thinking may provide a better answer to energy conversation than technological innovation.