Increasing Density — Corn, Cities, Fuels and Circuits

Whether it’s the number of transistors on a microchip or the number of bushels of corn per acre, there is an undeniable trend toward increasing density. This creates efficiency and thus leads to an increase in productivity. In fact, one of the key components of successful technology is its ability to be miniaturized. The rate of change, governed by different parameters, is different for each industry, but the trend is clearly up and to the right everywhere you look.

Agriculture: Bushels of Corn per Acre (USDA)


Farming productivity has steadily increased. For example, from 1950 to 2000, the average yields of America’s three most important crops (corn, soybeans, and wheat) rose 3.5x, 1.7x, and 2.5x, respectively. (SMIL/USDA 2000) It was the continuous introduction of new technologies that enabled these gains, allowing us to meet the caloric needs of a rising population. The technology came first (before 1950, of course) in the form of draft animals and the use of manure for fertilization; then came synthetic fertilizer, pesticides, and combustion engines to drive harvesters and planters. From here, the transition to automated labor (think the Google car plus a combine) and more controlled environments like greenhouses and eventually vertical farms will inevitably lead to further gains.

Urbanization: From the Fields to the Cities (the Economist)


The number of Americans working on farms has steadily decreased, and by 2000, less than 5% of the US population were farmers. Gains in agricultural efficiency led to a mass migration of people from rural areas to cities, resulting in a large increase in the density of people per acre. This transition further led to gains in productivity as people lived closer, shared resources, and collaborated more. These advances in productivity mean that places like New York City can have the lowest energy emissions per capita. Cities are now cultural hotspots (see the rise of the Creative Class), not too different than biodiversity hotspots, and this urbanization will continue, mostly in Asia, as the rural become the urban around the world. Urbanization is in effect an increase in the density of people per unit of area, which leads to lower energy usage per capita and a host of other efficiencies.

Energy: US Major Fuel Transitions (EIA)


The US has undergone a number of energy transitions, from wood to coal to oil, throughout our history, and each of these was one of increasing density. Wood (16.2 MJ/kg) was replaced by coal (24 MJ/kg), a 1.5x increase in energy density. Coal was then replaced by oil, which was refined into gasoline (46 MJ/kg), leading to a 1.91x increase in density. Recently, methane (55.6 MJ/kg) or natural gas has passed coal. Methane is technically denser by mass than both coal and oil, but storing large amounts of gas in a confined space has its challenges (i.e., it requires extremely high pressures or cold temperatures).

Looking at trends this way can become a good filter. For example, ethanol at 25.65 MJ/liter compared to gasoline at 34.2 MJ/liter doesn’t look like such a great improvement. Hydrogen at 123 MJ/kg and uranium at 83,140,000 MJ/kg would be logical next steps, though. We are a long way from hydrogen-powered cars, and the development of nuclear power has been all but halted due to the recent accidents in Japan, however. Still, it’s interesting to note that each major transition over the last 200 years has been one to higher energy density.

Technology: Moore’s Law


Lastly, we come to the one everyone knows — Moore’s Law, which states that every two years, the number of transistors on an integrated circuit will double. This increase in density is what has given us the Internet, mobile phones, and even solar panels (as costs have dropped due to similar production techniques). What’s interesting about this trend is the magnitude of it — in the last 40 years, computers have become 500,000x more dense. There appears to be no end in sight as just when a physical limit appears to be reached, a new technology emerges again. Ultimately, we may find ourselves with quantum or DNA computers, both of which could lead to further increases in density.

Observations and Questions

1. Trends: What’s amazing to me looking at these charts is how smooth they are. Those lines represent the culmination of technology over decades, and yet they are clear, consistently escalating trends. These are trends that you can depend on, that are investible, and that you should be aware of. If you’re starting a business, you need to think about where you’re going to be when you go to market, not just today.

2. Transitions: There are times in each of these trends when there is a major technological shift or leap. And in fact, I think we’re in the midst of one right now with farming as we move towards more controlled indoor environments. These are step changes where there is opportunity and where wealth gets created, but investing alongside incremental changes is a tough business — the solar industry has seen one company after another go out of business as they pursue small incremental changes in panel efficiency.

3. Normal vs. Log: While the lines may look similar, the technology chart is logarithmic. Every unit is a 10x increase as opposed to a 1x increase for the corn chart. This is an enormous difference: in agriculture, a gain of 2-3x over 50 years is huge, yes, but in technology, the gain may be 500,000x over the same period. The physical world behaves differently — has different constraints — than the world of software.

4. Next: You would think there have to be limits to these trends, and we may in fact eventually witness some such barriers, but the trends in yield, the trends in urbanization, the transition to methane, and the trends in technology (chips, solar, sequencing) all seem intact for the foreseeable future. These are all good things — we’ll produce more food with fewer resources, we’ll live on less land, we’ll use more efficient fuels, and we’ll have even more powerful computers in our pockets.

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  1. […] with the example of the glassmakers moving to Murano, innovation seems to follow from increased density. This makes you appreciate city planning and zoning—otherwise seemingly simple zoning decisions […]

  2. […] ship. But there are long-term trends and transitions, and they typically are towards cheaper and denser fuels. The large-scale trends seemingly evident now are that solar and natural gas are on their way up, […]

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