Can civilization rebuild without fossil fuels? Read more
Author:Lewis Dartnell
Imagine that the world as we know it ends tomorrow. A world-wide catastrophe occurs: a pandemic, an asteroid impact, or nuclear annihilation. Most people die, civilization collapses, and the survivors of the post-apocalyptic era
They found themselves in a post-catastrophe world: cities were deserted, people robbed each other, and the law of the jungle became the new law of survival.
Even if it sounds bad, this is not the end of humanity. We will always come back. Just like countless times in history, peace and order will be reestablished sooner or later, and stable communities will gradually take shape and painfully start from scratch.
Rebuilding the technological foundation. But here is a question: How far can such a society go? In a post-apocalyptic society, is there any chance to rebuild a technological civilization?
To be more specific, today we have consumed most of the easily mined oil, and a considerable part of the superficial and easily mined coal reserves. Fossil energy is not only the core of the organization of modern industrial society, but also the birth process of industrialization itself.
A key role in the process. And this is a unique role - even if we can not rely on fossil energy to some extent today (which we cannot), can we regain today's technological level without fossil energy at all?
But there's another problem.
Therefore, on a planet that does not rely on fossil energy reserves to rebuild civilization, is it possible to achieve a new industrial revolution? In other words, what would happen if the people on earth never had oil and coal energy? Our civilization, will
Will it not inevitably stagnate in the pre-industrial era before the 18th century?
It's easy to underestimate today's world's dependence on fossil energy. When we think of fossil energy, our most intuitive uses are fuel-driven vehicles and thermal power generation provided by coal and natural gas. But we also rely on a wide range of industries.
Raw materials. In most cases, extremely high temperatures are required to convert raw materials into usable products, such as manufacturing glass and metal products, cement, fertilizers, etc. In most cases, the heat energy required for these manufacturing processes comes from fossil fuels: petroleum, coal
, natural gas and oil.
The problem doesn't stop there. From pesticides to plastics, a large number of the chemical products that the modern world needs to function are organic matter derived from crude oil. As the world's crude oil reserves further dwindle, there is arguably no more wasteful application of these limited resources than
Burn it. For these precious organic compounds, people have to be very careful to preserve the remaining limited resources.
But the topic of this article is not what we should do now - probably everyone knows that people must transition to a low-carbon economy no matter what. What I want to answer is a (hopefully) more theoretical question: a
Does the rise of technologically advanced civilization necessarily rely on easily accessible ancient energy? Is it possible to establish an industrial civilization without fossil energy? The answer is: maybe - but it is extremely difficult.
Sun and wind: How far can sustainable energy take us?
The first is a natural thought. Many alternative energy technologies are already very developed. For example, more and more roofs are equipped with solar panels for home or commercial use. A tempting idea is whether Civilization 2.0 can
How about picking up the legacy of our predecessors directly from the rubble and using renewable energy as the starting point for industrialization?
Well, it is possible in a very limited sense. If you were a survivor in a post-apocalyptic world, you could indeed collect enough solar panels to live on for a while and maintain an electrified lifestyle. Photovoltaic cells have no moving parts and need
They require little maintenance and are resistant to harsh environments. But they also wear out over time: moisture eats away at their exterior, and sunlight itself reduces the purity of the silicon layer, and the power it provides declines by about 1% per year over several generations.
In the future, all solar panels passed down will wear out and become unusable. What should we do then?
Making new solar panels from scratch is extremely difficult. Solar panels require extremely pure, thin silicon wafers. Although the raw material is just common sand, complex and sophisticated technology is required to process and refine the silicon. This technical capability
That's pretty much what we need to make modern semiconductor electronic components. It has taken a long time to develop this technology, and probably just as long to recover it. So a society in the early stages of industrialization may not have the ability to produce photovoltaics.
Solar energy.
However, starting with electricity is probably the right approach - most of today's renewable energy technologies produce electricity. In the course of our own history, the core phenomenon of electricity was discovered in the first half of the nineteenth century, much later than
The early development of steam machinery. At that time, heavy industry already relied on mechanical devices based on internal combustion. Since then, electric energy has mainly played an auxiliary role in the process of organizing our economic structure. But can this order be changed? Can the process of industrialization
Requires thermal machinery to appear first?
On the face of it, it is not absolutely impossible that a progressive society would be able to build electric generators, connect them to simple windmills and waterwheels, and later develop wind turbines and hydroelectric dams. In a
In a world without fossil energy, we can imagine an electric civilization that largely bypasses the history of the development of the internal combustion engine. Its transportation infrastructure relies on electric trains and trams to support long-distance transportation and urban transportation. The reason why it is said that "
"To a large extent," it's because we can't completely bypass it.
Although electric motors may be able to replace coal-fired steam engines for mechanical applications, as we have seen, our society still relies on heat energy to drive many essential chemical reactions and physical transformations. How can an industrialized society produce products without coal?
What about key building materials like steel, bricks, stucco, cement and glass?
You can certainly use electricity to produce heat. We already use electric furnaces and electric kilns, and modern electric arc furnaces are already used to produce cast iron and recycle steel. The question is not whether electricity can be converted into heat, but that meaningful industrialization
Production requires the support of a huge amount of energy. If we only use renewable energy generation as a source of heat energy, such as wind power and hydropower, it will be quite stretched.
Another possible idea is to directly use solar energy to produce high temperatures. Rather than relying on photovoltaic panels, solar thermal farms can use huge mirrors to concentrate the sun's rays on a small point. The heat energy concentrated in this way can be used to drive
A specific chemical or industrial process, or the production of steam to drive a generator. But even so, this system is still difficult to generate (for example) the high temperatures required inside a blast furnace for melting iron. It is also obvious that the energy efficiency of solar thermal concentration is still
Depends heavily on local climate.
Unfortunately, if we want to generate the "white heat" needed for modern industry, we really don't have many good options other than burning things.
But that doesn't mean we have to burn fossil energy.
The power of burning: Can we return to the age of wood?
Let's take a quick look back at the "prehistory" of modern industry. Long before coal, charcoal was widely used to melt metals. It was actually more advantageous in many ways: it burned hotter than coal and had fewer impurities.
Much more. In fact, impurities in coal were one of the main factors that slowed down the progress of the Industrial Revolution - impurities released during the combustion process would contaminate the heated product. During the melting process, sulfur impurities would seep into the molten iron,
This makes the finished product brittle and brittle, causing safety issues during use. People spent a long time solving the problem of how to apply coal in industrial production, and during this historical period, charcoal performed quite perfectly.
But then, we no longer use charcoal. Looking back, that's a shame. As long as charcoal comes from sustainable sources, it is inherently carbon neutral because it does not emit new carbon into the atmosphere - although this
For early industrial civilization, it was not something worth worrying about.
But the charcoal-based industry has not all died out. In fact, it has survived and is experiencing a renaissance in Brazil. Due to its rich iron ore reserves and scarce coal mines, Brazil is the world's largest charcoal producer and also the world's largest charcoal producer.
The ninth largest steel producer, this is not a small workshop-style industrial production, so the Brazilian case provides an inspiring example for our thought experiment.
The trees used to make charcoal in Brazil are mainly fast-growing eucalyptus, which are specially bred for this purpose. The traditional method of making charcoal is to pile the chopped and naturally dried wood into a dome-shaped pile, and let the wood smolder while
Cover with turf or soil to isolate air flow. Brazilian companies have greatly expanded the scale of this traditional skill so that it can be used for industrial production. The air-dried wood blocks are stacked in low cylindrical masonry kilns in long rows.
They are arranged in rows to facilitate sequential loading and unloading. The largest production point can accommodate hundreds of such kilns. After the wood is placed, the entrance and exit are sealed and ignited from above.
The charcoal production technology actually involves retaining just enough air required for the reaction inside the kiln. It needs to have enough combustion heat to generate enough heat to drive away moisture and volatile substances and pyrolyze the wood, but the heat cannot be high.
to burning the wood directly into a pile of ash. The kiln manager needs to monitor the combustion status at all times, carefully monitor the smoke emitted from the kiln mouth, and open or seal the vents with clay at any time to regulate the entire process.
Haste makes waste, and this low-temperature charcoaling method of strictly controlled smoldering takes about a week. Similar methods based on this have been used for thousands of years, but the uses of the fuel produced in this way are very modern. Charcoal made in Brazil is
Trucked out of the forest and transported to blast furnaces, the ore is smelted into pig iron, the basic raw material for modern mass production of steel. These "Made in Brazil" products are exported around the world, where they are processed into cars, sinks, bathtubs and
Kitchen supplies.
About two-thirds of the charcoal produced in Brazil comes from sustainable cultivation systems, so the modern use of charcoal has the reputation of "green steel". Unfortunately, the remaining one-third comes from unsustainable logging of native forests. Although
In this way, the Brazilian case does provide an example: besides fossil energy, what other ways can we supply the raw materials needed for modern civilization.
In addition, wood gasification may also be a related option. The use of wood to provide heat energy is as old as human history, and burning wood alone uses only one-third of its energy; the other energy is burned as gas and steam
It is released in the process and disperses in the wind. Under the right conditions, even smoke is flammable. We don't want to waste it.
Promoting the pyrolysis of wood and collecting the gases produced is better than simply burning it. If you light a match, you can observe this basic principle: the bright flame does not appear directly on the wood: it dances on the match stem.
Above, there is a clear gap between the two. The flame is actually supported by the heat provided by the pyrolyzed wood, and the gas only burns when combined with oxygen in the air. Look at a match up close.
So fun.
To release these gases under controlled conditions, we roast the wood in an airtight container. The oxygen is tightly controlled so that the wood doesn't catch fire directly. It undergoes a complex chemical molecular breakdown process called pyrolysis, and then
The high-temperature carbonized charcoal at the bottom of the container reacts with the decomposed products to produce flammable gases such as carbon monoxide and hydrogen.
The "producer gas" synthesized in this way is a versatile fuel: it can be stored or transported through pipelines, used in street lights or heating systems, and can also be used in complex machinery such as internal combustion engines. During World War II, during the gasoline shortage, millions of people around the world
More than one wood gas vehicle ensured the operation of civilian transportation. In Denmark during the occupation, more than 95% of agricultural machinery, trucks and fishing boats were powered by wood gas. About three kilograms of wood (depending on its dryness and density)
The energy contained is about the same as a liter of gasoline, and the energy consumption unit of a gas-powered car is miles per kilogram of wood rather than miles per gallon. Wartime gas-powered cars can travel about 1.5 miles per kilogram of wood, and today's designs
Further improvements were made on this basis.
But in fact, "wood gas" has a lot of potential besides driving cars. In fact, it is suitable for any of the aforementioned manufacturing processes that require heat energy, such as powering kilns that make lime cement bricks. Wood gas generator sets can easily power agriculture and industry.
Equipment and various pumps provide electricity. Sweden and Denmark are world leaders in the sustainable use of forest and agricultural waste in this area. They use this energy to run steam turbines in power stations. Once the steam is in the "heat and power combined
After the CHP is utilized, it is transported to nearby towns and factories for heat supply, enabling this CHP power plant to achieve 90% energy efficiency. This kind of plant demonstrates the excellence of an industry that is completely no longer dependent on fossil energy.
prospect.
But how much wood do we have available?
So is this a solution? Can we rebuild a new society based on wood energy and renewable energy supply? Maybe, if the population is quite small. But there is a problem. What are these alternatives?
The premise is that the survivors have the ability to build efficient steam turbines, combined heat and power plants, and internal combustion engines. Of course we know how to make these things, but if civilization has been destroyed, who knows if the knowledge of these processes will disappear with it? If even the knowledge
If they disappear, how likely is it that future generations will be able to rebuild them?
In our own history, the first successful application of steam engines was for pumping water from coal mines. This was a fuel-abundant environment, so it didn't matter that the original design was extremely inefficient. The growing coal production was first used to melt iron raw materials
, and then shaped the iron into shape. The iron parts were used to create more steam engines, eventually used to mine mineral deposits or drive blast furnaces in iron foundries.
Moreover, it is obvious that machine shops also used steam engines to make more steam engines. Only after the steam engine was built and put into use, subsequent engineers could start to improve its efficiency and energy saving. People later developed methods to reduce the volume and weight and use it for transportation
Or the various methods of factory production. In other words, there was a positive feedback loop at the heart of the Industrial Revolution: the production of coal, iron, and steam engines all supported each other.
In a world without existing coal mines, people might not have had the opportunity to test the extravagant steam engine prototypes that would become more sophisticated and efficient over time. Without the use of simpler steam engines,
Combustion engine - a steam engine with independent boiler and cylinder piston. How much hope does a society have to fully understand thermodynamics, metallurgical technology and mechanical mechanics to create more complex, precise and effective internal combustion engine components?
In order to reach the height of contemporary technology, we have consumed a lot of energy, and it would probably take a lot of energy to do it all over again. Without fossil energy, it means that our future world will require a terrifying amount of wood.
In a temperate climate like the UK, an acre of broadleaf trees can produce four to five tonnes of biofuel per year. If fast-growing varieties are cultivated, such as willow or miscanthus, the yield can be four times that. The trick to maximizing wood production, is to use "
Coppice method: Cultivate tree species that grow from their own piles, such as ash or willow, which can be cut down again in 5-15 years. This ensures a continuous supply of wood without worrying about surrounding areas.
The cutting down of trees has caused an energy crisis.
But here’s the rub: Coppice technology was already well developed in pre-industrial England. It couldn’t keep up with the rapid pace of society. The core problem is that even if trees are managed well, they still need to be integrated with other land uses.
Conflict occurs - mainly over agricultural land. The twin dilemma of development is that as the population grows, people need more farms to provide food and more wood to provide energy, and these two needs compete for the same land.
In our own history, here's how it went: Starting in the mid-16th century, Britain responded to this dilemma by mining massive coal mines—essentially tapping the energy of ancient forests beneath the ground without reducing agricultural output. An acre
The energy produced by a small forest in a year is equivalent to 5-10 tons of coal, but the latter can be dug directly from the ground much faster than waiting for the forest to grow back.
It is this thermal energy supply limitation that will become the biggest problem for societies without fossil energy to try to industrialize. This is true in our post-apocalyptic world, or in any hypothetical world that fails to utilize fossil energy. A society without these conditions
To achieve industrialization, efforts would have to be focused on specific, highly advantageous natural environments—not islands riddled with coal mines, like England in the 18th century, but fast-flowing rivers, like Scandinavia or Canada.
It provides hydropower energy and sustainable thermal energy provided by vast vegetation.
Still, an industrial revolution without coal reserves would be, to say the least, very difficult. Today our use of fossil fuels is actually growing, and many of the reasons for concern are too familiar to need repeating here. Towards Low Carbon
The economy is imperative. But at the same time, we should also know how these accumulated thermal energy reserves have supported us step by step today. If they had never been there, people might have taken a difficult path and used renewable energy and sustainable
Using biofuels to slowly advance mechanization may eventually succeed—but it may not. We had better hope that the future of our own civilization is optimistic, because we may have exhausted the energy needed for any successor society to follow in our footsteps.