how quickly can we maximize solar?

the importance of growth.

Matthew Yglesias, Roko, and Tomas Pueyo have made the case that humans are very far from running out of resources. Our limitation isn’t resources, but technology.

With desalination, Roko estimates that we could satisfy the thirst of 10 quadrillion people. There are 1 quintillion cubic meters of water on the planet earth (and theoretically more could be made by combining hydrogen together with oxygen).

Regarding showering, there are shower loop systems which can recycle and re-use water, purifying it from the drain back to the shower head. But, even assuming that each person uses 150 gallons of water a day (an hour-long shower per day), that would total 54,750 gallons per year, or 207 cubic meters. This would allow 4.8 quadrillion people to take hour-long showers every day.

The problem is not physical resources, but energy. Theoretically, if we could cover the sun with solar panels, this would provide 384 octillion watts of energy.

How quickly could we cover the sun in solar panels?

Currently, humanity as a whole uses 15 trillion watts per year for 8 billion people, which is 1,875 watts per person. By maintaining that ratio, we could have 205 septillion humans. If we wanted to allow each person to use 100 times as much energy as they currently do, that would still allow for 2 septillion humans.

However, the surface area of the sun is 6 trillion square kilometers. A square kilometer contains 1,000,000 square meters. Currently, solar panels cost over $10 per square meter, but assume this can be brought down to $1 per square meter.¹ This means that the cost would be $1 million per square kilometer, or $6 quintillion. Global GDP is $100 trillion dollars, which would mean the global economy would have to grow by 60,000x. If we assume that the global economy doubles every 25 years, then it would be possible to achieve this in approximately 397 years.

Concerning the physical material of these solar panels, assume that they can be as thin as 0.005 meters (half of a centimeter). Consider the panels as a bent plane, forming an orb entirely, surrounding the sun, forming a surface of 6 quintillion meters. The total volume of this ultra-thin orb would be 30 quadrillion cubic meters. The entire volume of the earth is 1.083 Quintillion cubic meters. This means that this ultra-thin orb would require 2.77% of the entire Earth to construct. Since the Earth’s crust is only 1% of the Earth’s entire mass, this would require strip mining the entire Earth’s surface, nearly three times over.

It is unlikely that these solar panels can be made out of common elements, but will probably require rare Earth minerals. Even for the most common element, Silicon, there are limitations. The Earth’s crust is 27.7% Silicon. Assuming that this ratio remains the same for the mantle and core, this would require that we mine 10x the Earth’s crust, or 10% of the Earth’s volume, in order to extract the necessary Silicon.

The Al Shaheen Oil Field has one of the deepest holes ever drilled. It drilled down 12,289 meters in 36 days, or about 341 meters per day. If we assume that the hole was 1 meters wide in diameter, then the surface area of the hole would be 0.7854 square meters. The total surface area of the Earth is 510.1 trillion square meters, which would require 649 trillion “Al Shaheen” drillings, 10 times over, to dig up 10% of the Earth’s volume. This represents a total of 6.49 quadrillion drillings, each taking 36 days. Even assuming that drills could be made that are faster, there would still be time needed to sort, extract, and refine the silicon.

Under 100,000 oil wells are drilled per year with a global GDP of $100 trillion. Assuming a global GDP of $6 quintillion in 2421, the proportionate number of oil wells drilled would be 6 billion per year. At that rate, it would take over a million years to extra all the necessary silicon. The reason that oil wells were used for this calculation rather than mining data is to represent the difficulty of digging super-deep mines miles underneath the Earth’s crust.

But it may be more realistic to just look at mining data.

Every cubic meter of silicon weighs about 2.33 metric tons. Currently, there are 9 million metric tons of silicon extracted per year, which is 3.86 million cubic meters of silicon. 30 quadrillion cubic meters of silicon is required.

Even assuming exponential economic growth (economy doubling every 25 years), silicon mining would only reach sufficient cumulative levels by 2712 to provide the needed 30 quadrillion cubic meters of needed silicon.

All of this assumes that the economy doubles every 25 years, which represents a growth rate of 2.773% per year. According to Tom Davidson at Open Philanthropy, this level of growth is historically unusual. Prior to 1750, economic growth was less than 1% per year, and prior to the 10th century, economic growth was typically less than 0.1% per year. With that level of growth, the doubling time changes from 25 years to 694 years.

The difference between pre-industrial economic growth and post-industrial economic growth is 18,518 years, regarding the time it would take to extract sufficient silicon to cover the sun in solar panels. And yet, CAGR > 1% is historically very rare. It may go as quickly as it came.

The maintenance of current levels of growth requires a complex interplay of stability and competition. Too much stability gives rise to gerontocracy, monopoly, and guild systems. But without any stability, economic growth would also be difficult to maintain.

The most important aspect of growth is global trade. This requires that both sea and air are guarded from piracy by an international police force. Currently, that force is America. The response to the Houthis and Somalis has been lackluster. Is America willing or able to maintain the global infrastructure of trade? If not, is there anyone who can take America’s place?

China’s Belt and Road initiative is a clear plan to conquer Europe, in the same way that America conquered Europe. But it leaves out America. The Chinese can, at best, split the world in two. American unipolarity has been very good for GDP growth. Motivating nationalistic, selfish, petty, egotistic, populist, and uneducated humans to support American unipolarity in a democratic system will not be easy. Chinese and Russian propaganda flows freely, and even America’s allies tactically push isolationism. This is an uphill battle.

Already what America has accomplished in the last three centuries has won it immortal glory. What comes next is only a question of will.

1. The panels orbiting the sun would have to be high quality to avoid degradation due to head and radiation damage, and they would also have to be connected with interstellar power lines to transport the energy to earth.