Three sources of energy that could get us there

Elon Musk is convinced that his company can make humanity an interplanetary civilization by reaching Mars. However, becoming such a civilization involves much more than just creating a habitat on the Red Planet. To thrive, humans would need energy security and this is something we have not yet fully mastered on Earth.

From the beginnings of using stone-based tools to artificial intelligence (AI), humanity has come a long way. This has been possible thanks to our ability to harness diverse energy sources, from firewood to fossil fuels, and more recently, turning a new leaf by harnessing the energy of wind, sunlight and other renewable energy sources.

But we haven’t yet figured out how to harness all the major energy sources we have. Only after this will we achieve Type I or planetary civilization status, a necessary stepping stone before becoming interplanetary.

What is a type 1 civilization?

A Type I civilization is the first of three types of civilizations that can potentially exist, according to Soviet astronomer Nikolai Kardashev. This classification into three types is based on the amount of energy a civilization has, which also reflects its technological progress.

Kardashev’s classification is based on the simple principle that the more technologically advanced a civilization is, the more energy it can harness, which in turn leads to more technological improvements.

This has also been evident in human history, where technological advancements have led to more ways to harness energy, which then led to further technological advancements. But Kardashev uses the scale to assess whether civilization is planetary, stellar, or spans a galaxy.

According to him, a Type I or planetary civilization is limited to a single planet but has reached the level where it can access all available energy. A Type II civilization can exploit all the available energy of its star and colonize several planets in the solar system.

Nearly a decade after Kardashev proposed this classification, American astronomer and planetary scientist Carl Sagan, in 1973, estimated that humanity was perhaps at 0.7 and closer to a Type I civilization on a scale of 0 to 1. Over the years, humans have tapped into various other energy sources. SO how far away are we to be a Type I civilization?

According to the Kardashev scale, a civilization would have to be able to harness 10^16 watts of energy to be classified as Type I. Our energy consumption, according to globally aggregated data, amounts to 18.8 terawatts or 1.8 x 10^13 watts. We are therefore still three orders of magnitude away from reaching the energy levels of a type 1 civilization.

The question arises, how to get there?

Energy sources we can harness

It is well known that our energy consumption comes mainly from fossil fuels. Coal, oil and natural gas combine to produce nearly 80% energy consumed. The remaining 20% ​​comes from a mix of nuclear and renewable energy sources, including biofuels.

However, given the impact of carbon emissions generated by using primarily non-renewable fuel sources, we need to harness more carbon-free or low-carbon alternatives. Even if we manage to design effective measures to combat carbon emissions, we are getting closer to exhausting these reserves.

Estimates suggest we only have about 47 years of oil left at current consumption levels. Global coal reserves stand at 1.1 trillion tonnes and could last just over 130 years, but natural gas reserves are also rapidly depleting and could be exhausted within the next 100 years.

At the turn of this century, the world could come to a screeching halt if alternative energy sources that meet our energy demands are not commercially available. With fossil fuel reserves completely depleted, humanity will only have renewable and natural energy resources to meet its energy needs.

Technological improvements in wind and solar energy must therefore be accelerated, not only to improve efficiency, but also to generate greater returns to meet growing demand. By the turn of the century, these sources are expected to completely take over from fossil fuels. In addition to already commercialized technologies, humanity would also need to exploit new natural energy resources.

Geothermal energy has grown in importance and is currently contributing to four gigawatts of energy consumption in the United States alone. With improved geothermal energy systems, researchers are looking to dig deeper, and even volcanoes and geysers are considered to generate a reliable source of energy. Estimates suggest that this technology could potentially generate around 2,000 GW of energy globally.

Wave energy is another potential source that remains untapped. Although the technology to do this is still in its infancy, the Intergovernmental Panel on Climate Change (IPCC) estimates that wave energy could produce more than 29,500 TWh energy per year.

Together, these two sources could generate 5,300 GW or 5.3 TW of energy, closing our current deficit to reach the Type I civilization classification. However, the looming deficit caused by the depletion of fossil fuels must be addressed. This is where nuclear fusion could help.

Nuclear fusion could prove essential

Human civilization discovered nuclear fission in 1938. Over the next 20 years, the technology was commercialized to enable the production of electricity through fission reactions. On the other hand, the technology surrounding nuclear fusions is more nascent, with the first net gain experiment having been carried out in December 2022. However, the progress has been significant enough to place us on the cusp of commercial production of energy.

Unlike fission, the fusion reaction does not produce radioactive waste in the long term, nor does it require the processing of heavy elements. Using deuterium and tritium, isotopes of the smaller element hydrogen, as reaction fuel, fusion allows us to extract large amounts of energy.

When comparing the mass of fuel, fusion produces four million times as much energy as fossil fuels. A 1,000 MW power plant would require 2.7 million tons of coal each year, but can only operate on 551 pounds (250 kg) of fuel using fusion technology.

Deuterium and tritium are needed in equal amounts but make up only a very small portion of the plasma used to drive fusion reactions. Deuterium exists in all types of water and can easily come from abundant seawater. Estimates suggest that each cubic meter of seawater contains 33 grams of deuterium.

Interestingly, tritium is produced during the fusion reaction itself, when neutrons react with lithium used in the wall of the fusion reactor. Since large reserves of lithium have already been discovered and this element can also be extracted from seawater, both fuel components of nuclear fusion are available in abundance.

More importantly, the reaction produces large amounts of energy without any carbon emissions and could also help solve the problems plaguing human civilization today. Once mastered, nuclear fusion can also help us accelerate our transition from a Type I to a Type II civilization. Startups are already working on using fusion technology for interplanetary travel.

Therefore, replicating the reaction that occurs in stars is not only a scientific quest but necessary.