Mankind’s Use of Energy


Defining ‘civilization’ is almost as difficult as defining energy. From a linguistic point of view, it is the act of taking a person out of the wild and civilizing them within a city. But this definition seems to miss hunter / gatherers and family farms. Yet collections of people with these lifestyles could well constitute a civilization. In the following sections we’ll provide some of our thoughts on civilization.

Let’s first take a look through history so as to understand civilization a bit better.


Humanity has had exponential growth in population, knowledge, achievements and hope over the last 40 000 years; pretty well since the end of the last major ice age. In that time, we have built the wonders of the modern and ancient world. All achievements needed energy. Any achievements set forth in plans for the future must also consider the energy expense. So, if we look at the past, we may get ideas for the future. The following table shows some of our progress to date.

Event Date Cost Manpower Effect
Egyptian Pyramids ~4000 BC[1]
Stonehenge ~2000 BCE
Assyrian invasion
of Egypt
671 BC Over-extended nation
Greek Acropolis 500 BC
Alexander the Great 400 BC Half a ton of silver talents a day for army pay Needed to continue conquering to pay for army
Roman Expansion 200 AD 1 legion = 1.5M denari per annum 30+ legions Over-extended nation.
Coinage debasement led to inflation,annual budgets, and income policy
Teotihuacan 200
Danegeld 800 40M silver coins Prevented invasion. Forged single national currency
Crusades 1180 150 000 silver marks ransom Funded by taxes on all moveable property and all income
Chinese Flotilla 1405 27 800 crew, 1180 ships Political stoppage caused China to receive European sailors rather than vice versa.
Spanish Armada 1580 4M ducats 130 ships South American plunder was squandered. English drew Genoan bills to reduce available loans
War of the Spanish Succession 1694 English invent ‘national debt’ and create Bank of England. Initiated perpetual loan at defined interest rate.
American Revolution 1776 General acceptance of paper money. Hyperinflation as no control of printing presses.
Napoleanic Wars 1815 £15M loaned by Britain to allies Commercial banks main source of funding. Britain’s national debt grew from £273 to 816M
U.S. Civil War 1860’s $5.2B Created state and income tax for federal revenue. Inflation reduced value of money by half.
Suez Canal 1869 $80M Facilitated economy
Fanco-Prussian War 1871 5B Franc indemnity Money raised through lending
Schloss Neuschwanstein/
1886 31.2M Marks Bankrupts nation
Canada’s cross country rail line 1886 $150M, 59% by taxpayers Joint private/public funding
Trans-Siberian line/ BAM 1905 and 1991 Trans-Siberian ? / BAM=$30B Rail lines connected country
World War I 1914 10’sM £ 1st billion £ loan
Panama Canal 1914 $400M Facilitated economy
Hoover Dam 1935 $165M 21 000 Fully paid by power production
World War II 1930’s-40’s $288B for US millions 3% loan rate set as maximum in GB.
US national debt grew from $40B to 260B at 2.5%
Manhattan Project 1945 $2.2B 130 000 staff Expand technology
Apollo moon landing 1960’s $9.3B 300 000 staff Expand technology
Channel Tunnel 1993 £9B Facilitate economy
Troll/Kollsnes 1996 35.5B NOK Resource acquisition
3 Gorges Dam 2003 $25B+ US Resource acquisition
International Space Station 2005+ $35-160B over 40 launches Expand technology
Jiaozhou Bridge 2011 $1.5 to 8.8B 10,000people, 450000tons steel, 2.3e6m3 concrete Reduce commute by 20 minutes
Fibre optic connection 2011 $300M save 3 milliseconds travel
Lunar Development soon $25B 100’s of thousands Facilitate economy, expand technology, acquire resources

Telling in the above is the increasing amount of energy and effort being recently allocated to recovering stores of energy. Gone are the simple days of energy stores, petroleum, bubbling up out of the ground. Now it is pried from more and more difficult and hazardous places, i.e. a lower EROEI. Eventually we will need more energy to obtain stores of energy than the amount of energy in the stores. At this moment, our supplies of energy stores will be effectively gone.

Note 1: Some people postulate that the pyramids were built by an agrarian community during the previous inter-glacial warm period about 40 000 years ago. If true, this is an example of a human civilization that rose to greatness and then completely vanished.

Humanity has had exponential growth in population, knowledge, achievements and hope over the last 40 000 years. We have built wonders of the modern and ancient world. All achievements needed energy. Any achievements set forth in plans for the future must also consider the energy expense. The following table shows some of our recent progress; let’s assume that cost and energy are directly related.

Event Date Cost Effect
Shanghai-Hangzhou 200km rail link 2010 $US4.35B Facilitate travel, showcase technology
Shanghai-Beijing 1318km rail link 2014 $US32.5B Facilitate travel, showcase technology
Macau gambling 2010 +$US13B Pleasure

If you have examples of large energy expenditure that you’d like us to share, please contact us.


Humanity needs energy to power themselves into the future. Energy fuels bodies and enables technology. Insufficient energy necessitates an inability to sustain people at the desired technological level. A sufficient energy supply means that the expected number of people will live a full life at a desired technological level. A reasonable strategy for civilization’s future is to ensure that there is always a greater supply of energy than the demand. Let’s see.

We can assess the future of humanity using just three parameters; energy availability, number of people and technological level. We know the number of people on Earth continues to increase. The level of technology and its associated energy consumption equally increase. The limits to energy supplies on the finite Earth mean limits to both technology and number of people. Choosing an energy expensive future whether from a large number of people or enhanced technology requires continual access to large energy resources. Decreasing the supply of energy without decreasing the number of people and/or their practicing level of technology will lead to unwelcome shortages. Our strategy needs to consider these.

Measuring a technological level is a challenge. People do live at different levels of technology. However, defining technological levels is more difficult than counting the number of people. Aside from fictitious examples set in civilization styled computer games, there aren’t any definitive levels. Further, there are various degrees of technology in use throughout the world. In large cities of the developed countries, people drive cars, communicate over cell phones and often have a computer or robot that aids them. In developing countries there are villages where people exist in a manner that is little changed from their predecessors of thousands of years ago. We will return to this later.

If we choose then we can define qualified levels of technology. Further, we can estimate the number of people who live at this level. Last, we can estimate the energy factor associated with the technological level. The result is an estimate of the current energy demands for the current civilization. From this, we have an estimate of the total energy demand for all the people and all their technology levels. And we can make plans for the future.

Let’s play contrarian for a moment. Assume infinite energy and a robust number of people. Here anything is possible. Happenstance can direct the choices as any wrong choices can simply be corrected. Thus we don’t need plans for the future as there are no negative consequences. Perhaps we’ve been operating under this concept recently?

Let’s play realist. The amount of energy is limited and can diminish to zero. In this extreme, plans are worthless as nothing is possible because no work or action is achievable. Could this become possible if we consume all the fossil fuels and we haven’t made plans for a future without them?

Let’s look at some strategies. We can decide on a plan that forsakes technology. We know that in the past there were millions of people who consumed no more energy than their biological needs. This was sustainable and perhaps we can return to this level if the associated supporting ecosystem can return to its previous level. Yet, this would obviate the technological and social progress of the previous tens to hundreds of thousands of years of advancement of our species. This is a possible strategy but gives little credit to our species.

Aficionados of science fiction stories know well of another future. This one is dedicated to technology. All life on Earth is bent to promote an increased human population which uses their numbers to advance technology. In this future, all competitors to the human species, all other energy-using non-beneficial living things, are exterminated. This future optimizes humanity’s energy availability but leads to a sterile planet with little room for errors in ecology. With little knowledge or experience in deciding on the efficacy of other species, this future is hazardous but quite possible for humankind. But there is no turning back from this strategy.

The optimum future, the optimum strategy probably accounts for the likely number of people, a declining supply of available energy, increased technology and a worsening of the ecosystem. A future without technology or a future with only technology leads to too great a risk of no future for humanity. A strategic plan must take into account the available supply of energy. And a sustainable strategy would include a robust ecosystem that we can draw upon. We just need the strategy and the confidence to embrace it.

Let’s now return to a few snapshots in history to review and see the impact of energy and technology.

Qadesh – 1300 BC

The mighty empires of the Pharoah’s and the Hittites came to blows about the year 1300 BC near the town of Qadesh in Syria. The town of Qadesh is about 600 km from the centre of power for each of these kingdoms. The typical army speed of the times was 25 kilometres per day. Therefor each army needed about 30 days to get to battle and 30 to return (i.e. a 60 day campaign).

Lengthy battles seldom occurred as most ended in 2 to 3 days. The logistics or provisioning could well be the reason.

In this late bronze age, battles were often fought after the harvest time of May. With the serfs being freed of chores, the leaders put them into the army and headed out to make war. Let’s check the energy cost.

Hittite energy costs. In their army, they had;

  • 3700 chariots each with 3 horses
  • 40 000 infantry

A man marching with full gear would need 3600 kCal a day. Similarly, a horse pulling a laden chariot needs about 25000 kCal of digestible energy a day. Given this and assuming that the number for the Hittite infantry includes their charioteers then their daily energy needs would be;

Men + horses = 40000×3600 + 3700x3x25000 = 4.2×1011Calories each day.
And for the campaign of 60 days, the total energy needs would be 2.5×1013Calories (about 1×1014 Joules).

Egyptian Energy Costs. The Egyptian logistic issues were similar to the Hittites. Each kingdom’s centre was about equal distance from the town of Qadesh hence each had to travel the same distance. Also each army likely traveled at the same pace so their traveling time would be the same. In the Egyptian army there were;

  • 4 corps of 5000 men each
  • Each corp included 4000 infantry and 500 chariots each with 2 charioteers running two horses.

Their total energy expenditure is thus;
Men + horses = (4000×4 + 500x2x4)x3600 + 500x2x4x25000 = 1.72×1011Calories.
And for the campaign of 60 days, the total energy needs would be 1.0×1013Calories (about 4×1013 Joules).

Campaign Energy Costs

The total energy cost would be about 3.5×1013 Calories (1.5×1014joules) though this assumes all the people and horses who went to battle also returned. This amount of energy is on the same scale as the amount of energy needed to launch the space shuttle into orbit.

This is a huge quantity of energy but only includes food. The energy needs to dress each person, build the chariots and manufacture all the spears, bows, arrows, and knives would increase this amount. This would need a full logistics analysis to arrive at an estimate.

Biological Energy Source

The biological energy source is the net primary production in the area. This must be a surplus from that needed to feed the farmers, administrators and other support elements for the army. Today’s wheat yields about 3.5×109 calorie per tonne. Ancient wheat, without the genetic refinement, likely was less than a tenth the source of energy, or 3.5×108 calories per tonne. Therefore, this campaign would need 10 000 tonnes of wheat (assuming all food came from wheat). The going rate was about a tonne per hectare so the campaign would need the excesses from 50 000 hectares (or 500 square kilometers, i.e. a tenth the area of present day Lebanon).

Isn’t it amazing how we’ve been applying energy from even such a long time ago!

Caesar and the Rhine, 56BC

For the full story or this model, see here.

Julius Caesar, man of his times, undertook and completed many wondrous accomplishments during his tenure in consul in Rome. In June 56 BC, he took his legions into Gaul to further subjugate the locals. But, his aggression resulted in the slaughter of hundreds of thousands of local. To maintain his image, in a show of political propaganda and military strength, he built a bridge to allow his army to cross the Rhine river and for the first time, extend Rome’s influence directly into the territory of the Germanic tribes.

Engineering a bridge has never been trivial and the Romans had little historical precedence to build upon. Nevertheless, they were master engineers and had the necessary material at hand. With his 40 000 men and the surrounding forest, Caesar created a solid platform for his force to safely cross the Rhine river and undertake a few weeks pillage.

Caesar recounts this amazing endeavour within his diaries. He graphically describes using huge stones to ram logs into the river bottom and then laying long timbers to establish a support and platform.

This undertaking utilized energy through a number of ways. The men had to be feed. The trees captured energy from the Sun and stored large quantities of energy in their wood. And the effort to chop, clean, move and install the wood added to the total.

Caesar had 40 000 men work for 10 days thus needing 1.3e13 Joules of biological energy.

Assume Caesar used fir trees. Multiplying the energy content of each with the likely number of trees results in an energy content of 8.8e13 Joules.

Felling and clearing the trees would use considerable effort but is difficult to measure. However, Caesar spoke of a stone pile-driver pushing the logs into the river bottom. Lifting and dropping the stone the likely number of times results in an energy expenditure of 2e7 Joules.

The rough energy total for building the bridge is over 1e14 Joules. This is greater than the energy needed to loft the space shuttle into orbit. It is approximately the same as the energy released by the atomic bomb dropped on Hiroshima.

Sadly, given that the bridge was for propaganda purposes rather than practical purposes, Caesar destroyed it on his return.

Rome,the city today

Our civilization grew by leaps and bounds once we started living in cities. These communities allowed individuals to specialize. Rather than a subsistence living, individuals could rely upon others for some of their various needs and they could use their time to focus upon a singular goal. For example, painters expanded from iconic images on cave walls to surrealistic images on canvas. Cities gave them the opportunity, our civilization has flourished by enabling people to specialize.

At first, cities relied upon adjacent lands with which to supply the needs of their populace. Neighbouring farms produced much more food than could be consumed by the farmer. They sold the excess at market. City residents bought the food with money that they earned through their specialized craft such as candle making. All benefited and new produce and capabilities made the populace ever more capable.

Today, in our global community, city residents can contemplate minutiae such as atomic physics while munching upon food grown thousands of kilometres away. This is the state of things as we now know it. However, what would happen if city residents couldn’t draw upon the produce of the globe and had to rely upon the immediate surroundings again? Let’s look.

Take Rome, a modern city in Italy. With some simple checking on the Internet, we can learn a lot. It has about 2.7 million residents and officially encompasses an area of 1285 square kilometres. The Internet can also give us an energy balance for this city with a little deductive reasoning. First, consider the local land cover types. These are available from the GlobCover project ( as determined by satellite data down to fidelity of 300metres. By plotting the data we can determine the land cover as shown in the following figure.

The red pixels indicate a non-vegetative land cover, a land type that does not capture energy from the Sun. These are effectively the city footprint. The other colours, yellow and green and such represent land with cover that contains vegetation that is capturing energy from the Sun. The extent of the figure is to match the official size of the city rather than to follow the city’s actual boundary.

The satellite shows us detail that wouldn’t be easy to see from the ground. For instance, 29% of the above region has insufficient vegetation to register with the satellite. That is, the human made structures are so dense that there is no evidence of vegetation.

The land cover tells us another story. From it, we can determine an energy balance for the city of Rome. The Italian nation has an annual energy consumption of 6.84e18 Joules per annum. Given this and the population of the city then the resulting energy draw down is 3e17Joules per annum. We can also determine the energy stored in the vegetation by using the land cover type and an estimate of the Joules per gram of vegetation. The result is 5e14Joules. That is, in one year, the city of Rome uses more than 600 times the amount of energy that’s immediately available within their city.

Let’s extend the above region to the point where the local availability of energy satisfies the annual need of the people of Rome. For this we have the push the limits out about 11 times as shown in the following figure.

The above clearly shows Rome in the centre of the Italian peninsula. It also shows the wide expanse of vegetation that would need to be consumed by the populace of Rome so as to satisfy their energy demands for one year. This doesn’t take into account the energy demands of all the other people and cities in the same region.

The purpose of this exercise is to demonstrate the energy availability if people were to satisfy their needs using immediate resources. While the possibility exists, assuming a lossless energy transfer, recall that so doing would only satisfy the energy needs for one year. Then after, no vegetation would exist for subsequent years. Thus, a strategy of returning to being a local agriculturalist is not viable.

stone city


Cities represent the hallmark of our civilization. They indicate our ability to nurture and grow specialists. A specialist, whether a doctor, lawyer, plumber or other, can focus upon their task without undue concern about gathering food or protecting their family. Effectively, in cities, they can allocate all their effort and energy in pursuing their speciality.

Keep in mind that the concept of a city was not pre-planned. Thus, they may not be the optimal accommodation for humans. Perhaps a future plan will have better.

The above section describing Rome set its energy consumption at 5e14 Joules. Where does this get used? While it would be difficult to follow the trail of all the energy usage, we could look at a city’s tax structure for an estimate. The following table is one example of a structure.

A High-Tech City of 1 Million
Allocation Percent
Education 18.66
Public Transportation 13.85
Security (police) 12.83
Social Services and health 11.25
Debt 9.51
Safety (fire and paramedics) 8.64
Administration, planning 7.46
Roads and Traffic 6.7
Parks, Recreation, Culture, Conservation 5.17
Garbage, Recycling 4.09
Library 1.85

The above doesn’t include the effort to provide a potable water supply. For this example, it’s a function of the amount used and it is about a 50% increase on the above.

It’s interesting to note that planning is not readily visible. On inspection, the planning and economic development portion amounts to 0.22%. While it’s great that some thought is put into planning for the future, we suspect that most planners only look at their immediate surroundings.

Technology Factor

We have already mentioned the challenge of allocating a level to technology. We maintain that this is challenging. However, we can estimate a technology factor.

The overall energy is then the number of unknowledgeable people multiplied by a person’s biological needs plus the number of knowledgeable people multiplied by the biological need and multiplied by a technology factor. The technology factor is the increase in energy needed to keep a person at their desired technological level. The following equation represents this relationship.

Total Energy = Number of unknowledgeable people * Personal dietary needs
Number of knowledgeable people * Personal dietary needs * (1 + technology factor)

The increase in energy usage as a function of technology is dependent upon the amount and type of technology. For example, consider all of Canadians as technology experts. This country’s population is about 32 million people. Assume an individual dietary need of 10 MJ/person/day. In the year 2003 Canadians consumed 11.5 x 1018 joules of energy (page 10 of report ). From this, we know the technology factor is 100. That is, Canadians use nearly 100 times the biological needs of energy to sustain themselves at their technology level. Let’s keep this in mind as we plan the future.


Technology can mean about anything. Using a stick to dig a furrow for growing plants is a form a (agricultural) technology. Digging material from the ground, purifying it then forming it into sheets allows for light weight flying vehicles with aeronautic technology.
While we’ve experimented with many technologies, not all have made the grade. For instance, supersonic air transit has fallen to the wayside. So has human space travel. We just don’t consider these technologies worthwhile.

We can get an idea of the technology in use by looking at energy usage as put into gross categories. The following three images show divisions for the world, Canada and the United States.

World Consumption

Canada’s Consumption


US Consumption

All images are from other researchers. Note that the image for world consumption does not indicate the loss due to energy conversion. The US Consumption image sets our energy loss to a value of 60%. That is, while we are consuming almost 500 exajoules, we only use about 40% or 200 exajoules. The remainder dissipates as waste heat. We need to keep this efficiency factor in mind when making plans.

The above images are current. They result from a free market mentality where the supply of energy has always been greater than the demand. But, consider when the energy demand exceeds the energy supply. Would supply management take over from the free market? Would we choose what to let go, which technologies to leave behind. Are particle accelerators more important than toasters? Are cars in third world countries more important than airplane travel. These questions need to be addressed even though they won’t appear upon any news line. Do you wonder if energy supply management is necessary for a sustainable future?


World War II introduced humanity to a broad range of good and evil. It cemented the world as a collective entity. It highlighted the role of humans as great effectors. Some saw this and understood its association to the availability and use of energy. One of these was Prof Leslie White. Prof White introduced quantitative metrics into the study of culture. His views on human survival vouchsafed;

  • Technology is an attempt to solve the problems of survival.
  • This attempt ultimately means capturing enough energy and diverting it for human needs.
  • Societies that capture more energy and use it more efficiently have an advantage over other societies.
  • Therefore, these different societies are more advanced in an evolutionary sense.

The third bullet above speaks directly to his expectation that a society’s culture followed a relationship of C = E T where;

  • C is culture
  • E is energy consumption
  • T is the efficiency of energy consumption

Interestingly Prof White assessed culture as a species wide characteristic.

Associating the success of a culture with its ability to consume energy may be accurate. Does it bode well for the future? As Kardashev noted, energy is the key to an expansive future. Can a culture adapt to less energy? Or we can keep finding new and better sources of harnessable energy. How do we bring this into a viable strategy for the future of our civilization?

Civilization’s Space Future

Our civilization’s future has many opportunities and constraints. Especially, while we remain fixed to Earth’s gravity well, we are limited to material that is available on Earth. Thus our future on this planet is constrained by the amount of available resources; in particular, energy. One can even scale a civilization by its energy availability as in the following table.

Civilization Types

Type 1

a civilization that harnesses all the energy on one planet

Type 2

a civilization that harnesses all the energy from one star

Type 3

a civilization that harnesses all the energy from one galaxy

Nikolai Kardashev

If our strategy includes extending our resource utilization to include beyond Earth then we may progress to a Type 2 civilization.

Take a look at our plan for this.

Or go to our page on Limits to learn of some of our challenges.



In the above we introduced many aspects about civilizations. We considered some from the past. And we postulated some on the future. We could leave it to luck and hope for the best future to whichever civilization exists. Can you think of a better way than hoping? Care to plan with us to ensure the best future possible? Contact us and let’s get a viable plan together.