Over at IEEE Spectrum, Vaclav Smil has an excellent piece demolishing the absurd idea that Moore’s Law is a good general guide for technological progress. I’m sure you’ve heard these ideas that there is a “Moore’s Law” for solar power.
Just recently, we were being told there is a Moore’s Law for fracking. Of course, there is nothing of the sort. But misguided techno-optimists continue to believe it is true, regardless of actual evidence.
As always, Smil provides numbers where others provide assertions
Corn, America’s leading crop, has seen its average yields rising by 2 percent a year since 1950. The efficiency with which steam turbogenerators convert thermal power to electricity generation rose annually by about 1.5 percent during the 20th century; if you instead compare the steam turbogenerators of 1900 with the combined-cycle power plants of 2000 (which mate gas turbines to steam boilers), that annual rate increases to 1.8 percent. Advances in lighting have been more impressive than in any other sector of electricity conversion, but between 1881 and 2014 light efficacy (lumens per watt) rose by just 2.6 percent a year, for indoor lights, and by 3.1 percent for outdoor lighting (topped by the best low-pressure sodium lamps).
The speed of intercontinental travel rose from about 35 kilometers per hour for large ocean liners in 1900 to 885 km/h for the Boeing 707 in 1958, an average rise of 5.6 percent a year. But that speed has remained essentially constant ever since—the Boeing 787 cruises just a few percent faster than the 707. Between 1973 and 2014, the fuel-conversion efficiency of new U.S. passenger cars (even after excluding monstrous SUVs and pickups) rose at an annual rate of just 2.5 percent, from 13.5 to 37 miles per gallon (that’s from 17.4 liters per 100 kilometers to 6.4 L/100 km). And finally, the energy cost of steel (coke, natural gas, electricity), our civilization’s most essential metal, was reduced from about 50 gigajoules to less than 20 per metric ton between 1950 and 2010—that is, an annual rate of about –1.7 percent.
Let’s compare Smil’s array of facts with the assertions from a recent book, The Infinite Resource by Ramez Naam:
The trend in increasing efficiency – of travel, of steel production, of food production, of carbon fiber manufacture, or of anything else – happens so slowly that at times we underestimate it. It’s an exponential process, not a linear one. The amount of carbon fiber you can buy for a dollar has increased at a rate of somewhere around 9% per year. Over a year or two we may not notice it. But in the long term, it works like compound interest. It’s an exponential process. The gains don’t add up year over year. They multiply. Over 40 years of 9% gain, we don’t end up able to buy 360% more carbon fiber per dollar. We end up able to buy 3000% more. Inventor and author Ray Kurzweil has argued that we humans have a tendency to look at exponential gains and over-estimate the short term impacts, while under-estimating the long term impacts. If you’d asked anyone in 1960 or 1970 to predict the food yields, carbon fiber prices, or energy efficiency of lighting in 2010, you’re likely to have gotten answers that tremendously under-estimated the amount of progress we’ve made.
All of the assertions made by Naam here are demonstrable false, as Smil’s numbers show. It’s incredibly easy to claim things are improving exponentially, but it is also incredibly easy to check whether they are improving exponentially. Why is this so difficult in practise?