Although these quotes were written early in the twentieth century, they provide a fairly good summary of where we are at the beginning of the twenty-first century. The technical issues related to operation of engine/fuel systems are different, the societal issues driving change are different, the sophistication of engine and fuel technology is much greater, but the search for better engine and fuel systems continues.
Today, Earth's population tops 6 billion people and more than 700 million cars and trucks are in use ( Figure 6.1). This means that only 12% of us are realizing the benefits provided by engine-powered vehicles. No other transportation technology gives us the freedom to go wherever we want, whenever we want, with whomever we choose, carrying whatever we need. This connectivity is what drives the nearly universal aspiration people have for “auto-mobility.”
To satisfy this demand in the future, we must realize sustainable auto-mobility. With the world's population predicted to reach 7 billion by 2015, the global car park will grow to nearly 850 million vehicles over the next 15 years if the ownership rate remains at 12%. While this represents significant growth in the demand for our products, as an industry we need to be thinking bigger than this. If the ownership rate increases just 3 points—to 15%—the car park in 2015 would exceed 1 billion vehicles.
We will not be able to take advantage of this market opportunity unless auto-mobility is truly sustainable. Energy forms that are renewable and vehicle technologies that have zero impact on the ambient environment will be required for society to continue to enjoy and expand the benefits of personal mobility.
One way to understand how the nature of supplied energy for both mobile and stationary sources might change during the next 100 years is to compare the primary energy forms used at both the beginning and the end of the twentieth century ( Figure 6.2). Although the changes might not appear substantial at first glance, the transition in energy forms has been significant. Why did the shift occur? It occurred because human needs for greater amounts of practical energy and reduced environmental impact demanded the shift and technological advances enabled the changes. As a result, society is better off due to the transition that took place.
Where are we headed in the next 100 years? My version of Figure 6.3 was published in 1996 in Daedalus, the journal of the American Academy of Arts and Sciences. A figure from the paper suggests that the calculated hydrogen-to-carbon (H/C) ratio of total energy consumed in the world is increasing at an exponential rate. Although this assumption can surely be debated, I believe the important point of this figure is the trend in the data, not the mathematical relationship used to fit the trend. General Motors believes this trend will continue well into this century, culminating at the point of its implied conclusion—a hydrogen economy. Extrapolating the data in this plot 100 years into the future takes “fortune-