Computers vs. peak oil

Computers have become entwined in our daily lives.  Imagine, if you can, a day in which you didn't interact with a computer in some form or another.  Media, communication, personal finance, and commerce have become reliant on these technologies for success.  Will personal computers remain so readily available to everyone indefinitely?  It is easy to extrapolate form past experiences.  Computers have become steadily cheaper and more powerful for decades, but there is no real guarantee that this trend will continue.  This has also been confined mostly to Western Europe and the Anglophone nations, with computers remaining widely unavailable in developing nations.

Petroleum is very important in the manufacturing of electronics.  Over 40% of the chemicals used for creating semi-conducting devices rely on petroleum in some aspect of their manufacturing.  It is true that in most of these cases substitutes exist, but we don't rely heavily on these substitutes for a reason—either they are more expensive or cannot meet current demands.  Without cheap petroleum, manufacturing of semi-conductors will also rise in price, which will adversely effect the supply of these machines.

The energy requirements for producing electronics is enormous.  For example, one study found that manufacturing a laptop requires between 3000 and 4000 megajoules of energy—the equivalent of 24 and 32 gallons of gasoline, respectively.  Furthermore, these products often contain plastic components, in an effort to reduce costs.  Plastic can be replaced with metals, such as aluminium—many high-end models already use these materials.  But, this increases the price of products, as metals are harder to shape than plastics and are more expensive, in general.

Personal computers will remain available, even as petroleum supply dwindles; however, it is reasonable to expect that the price of these machines will likely increase.  Businesses will continue to rely on computing to run efficient operations, and the wealthy may have access to personal computers.  However, the poor may have to rely on publicly available machines—such as those at libraries.  This may have the effect of widening the gap between these groups of people, contributing to greater levels of wealth inequality.

Population of the United States

Calculating the change in a population is easy:$$\text{Population change} = \text{Births} - \text{Deaths} + \text{Immigration} - \text{Emigration}$$ Estimating the number of births and deaths—and the effects of migration—in any given year is difficult.  The number of births can be estimated from the total fertility rate (TFR)—the average number of children a woman will have during her life time.  The number of deaths can be inferred from a life-table, like those used by actuaries.  I've put these statistics together into a simple model for forecasting populations.  Today, we'll look at two hypothetical futures—two assumptions about the behavior of people in the 21st century.

The darker line assumes a constant fertility rate, equal to that of 2012.  The lighter line assumes a decreasing fertility rate.

In the 1960s the United States entered  a period of relatively low fertility.  The population hasn't decreased, because of immigration.  In the past few years, approximately one million people have come to this country each year—compared to about four million births per year.  In the graph above, the darker line shows the expected population if the fertility rate and immigration continue as they were in 2012.  In this case, we would expect the population to level off by mid-century around 350 million people.

The United States has also experienced declining fertility since the mid 2000s.  The lighter line assumes that fertility will continue to fall to 1.4 by the year 2025—this fertility rate would be similar to that of South Korea today.  If you were born in the 1990s, it is likely that none of your children will be born during the 2040s—the decade where the curves diverge.  The parents of these children already exist though—they are young children today.  After this point, the population would decline rapidly, as those born near the end of the 20th century begin to age and die.  We currently face an aging population, but the effects would be much more pronounced in this scenario.

Schedule

After some thinking—and observing my viewing statistics—I have decided to eliminate two posts per week: Monday and Friday.  Posts will also come earlier in the day.  My hope is that this will benefit the quality and variety of my writing and increase reader engagement.

Until tomorrow.

Endangered element: zinc

Sphalerite is the primary ore for zinc.

Why is zinc an important mineral?  By far the most common use of zinc is corrosion resistance, accounting for 80% of the metal's use in the United States.  Steel has two useful properties; it's strong and light-weight.  It also has the disadvantage of being susceptible to rusting.  Stainless steel doesn't rust, but is substantially weaker than other kinds of steel.  Any steel structure that will be exposed to the elements needs to be protected from corrosion.  The solution to this problem is to simply coat the surface of the metal in zinc, which forms a layer of zinc carbonate over time.  This application, however, doesn't threaten future supplies.

Increased demand for zinc will likely be driven by zinc-air cells, useful for creating electric cars.  In 2012, the United States used 26.7 quads—quadrillion BTUs—of energy for transportation, primarily supplied by petroleum.  Zinc-air cells carry about 1600 BTU per kilogram—c.f. 43,000 BTU per kilogram for gasoline.  To replace every conventional car on the road would require 17 billion tonnes of zinc-air cells.  I don't know how much zinc is used to make these batteries, but there are only 1.9 billion tonnes of identified zinc resources in the world.

Can everyone in the world have an electric car?  Probably not—but this answer is too dismissive.  Everyone may not need to own a car in the coming decades.  Greater availability to public transit and autonomous cars could substantially improve the efficiency of transportation.  However, the United States only has 4% of the world population.  Increased demand from the rest of the world—particularly developing nations—could offset any gains from improved efficiency.  The future population of the world is uncertain as well.  Some countries may experience growth in population; others may experience contraction in population.  No single technology will likely be able to replace petroleum burning cars.  Instead, societies will need to rely on a variety of solutions.

Hydrogen fuel cells

How much energy is needed to make each kilogram of gasoline?  This may sound like an unusual question, because we tend to think of gasoline as a source of energy.  When one kilogram of gasoline is burned it releases about 45 megajoules (MJ) of energy in the form of heat, that can then be converted into other forms of useful energy.  However, 9 MJ are needed to produce a kilogram of fuel.  Though this number is non-zero, the important point is that less energy goes into the fuel than is recovered from it.  This feature makes petroleum good as a fuel source, among other properties.

In a previous post, I wrote about the energy requirements of producing hydrogen.  Every kilogram of hydrogen contains roughly three times as much energy as a kilogram of petroleum—about 140 MJ.  Steam methane reformation requires 135 MJ per kilogram of hydrogen; this represents a net gain in energy, but a very small net gain.  Furthermore, it relies on the same non-renewable resources that it is meant to replace.  However, even if we rely on electrolysis to manufacture hydrogen, the fuel cells extract energy by performing the electrolysis reaction in the opposite direction.  That is to say, the energy recovered by fuel cells is the same as the energy used in manufacturing the fuel.  At best, this only allows electricity to be converted to a more portable form.

There are difficulties in making hydrogen portable, as well.  Because gasoline is relatively dense, it can carry a large amount of energy in a compact space.  Hydrogen pressurized to 5,000 psi, would occupy over eight times as much space as the equivalent amount of gasoline, at room temperature.  Instead, hydrogen is typically cooled to about −400 degrees Fahrenheit.  At this temperature, the same hydrogen would occupy a similar amount of space as gasoline, but this temperature would need to be maintained.  Gasoline can sit for years before being used, but hydrogen would likely need to be used shortly after it is brought to temperature.

Power of the brain

How much power does the human body use?  Evolution is less survival of the fittest, and more survival of the most efficient.  The calculation is simple.  A typical caloric intake is 2500 kilocalories—known simply as Calories, in the United States—per day.  This is the equivalent of 120 watts.  This is rather impressive.  You and I are kept alive with about as much power as in used by a standard incandescent light-bulb.  Furthermore, the brain only requires 20% of the body's energy usage, which comes—that is, 24 watts.

How does this compare to computers?  Personal computers use a modest 65 to 250 watts, but don't possess the ability to match the functions of the human mind.  Artificial intelligence is, for now, run on supercomputers.  For example, WATSON consumes 85 kilowatts—the equivalent of roughly 1,000 PCs.  Koomey's law is similar to Moore's law, but deals with the energy usage of computers.  It states that the number of calculations for every unit of energy doubles every one-and-a-half years.  A quick calculation shows that WATSON could match the human brain in energy usage by the 2030s.  These computers only mimic one aspect of human cognition, but how these technologies will be used remains uncertain—there are a number of possibilities I intend to explore more fully.

That being said, I'm confident that human minds are not at risk of obsolescence.  The human brain is incredibly efficient, and already possesses a powerful set of skills.  Furthermore, the problem solving capabilities of groups of people exceeds the sum of the parts.  What is not clear is the number of people who will be able to take part in these kinds of activities.

Endangered element: helium

In a previous post, I wrote about  the concept of endangered elements—elements whose supply may not be able to meet demand within the next hundred years.  If we expect certain technologies to improve and to reach ever more people, the scarcity of these elements could prove to be a major impediment.  It's important to understand how we currently obtain and apply these materials.  We'll begin with helium.

Most helium found on earth was produced through the nuclear decay of uranium—or other heavy elements—which then dissolved into natural gas and oil over millions of years.  This isn't good news; most fossil fuel resources aren't projected to outlast the century, but bad policy making could produce shortages much sooner.  Helium, despite being common in the cosmos, is rare on Earth, and in the atmosphere.  It's effectively a non-renewable resource, and will be difficult to obtain once our current supplies run dry.

Helium has the lowest boiling point of any material at only 7 Fahrenheit degrees above absolute zero, which allows other objects in contact with liquid helium to be maintained at this temperature.  The next lowest boiling point belongs to hydrogen—at 36 Fahrenheit degrees above absolute zero.  Unsurprisingly, 32% of helium is used for cryogenics, particularly for cooling the magnets used in MRI machines.  Unfortunately, this means that MRI may become less available as helium supplies dwindle.  This could have a large impact on the standard of care, unless a substitute for MRI can be found.  I suspect that this will be problematic for the widespread adoption of quantum computing technologies, as well.  Such technologies my be adopted on a small scale, by wealthy institutions and organizations, but may remain beyond the reach of most.