With the invention of the first practical steam engines at the turn of the seventeenth century, and mechanical energy’s increasing utility to replace the physical labour of humans and animals, human civilisation took a new turn.
Now when a contemporary human catches public transport to work; drives the car to socialise with friends or family; washes and dries their clothes or the dishes; cooks their food; mows their lawn; uses a power tool; phones a friend or associate; or makes almost anything; they use power once provided by slaves, servants or animals.
We still often measure physical work in terms of horsepower per hour. A horsepower (hp) is aproximately equivalent to the energy available from a draft horse on a sustainable basis during a four hour shift. This was defined during the Industrial Revolution as being equal to 33,000 ft-lb/sec = 775.7 Watts. A healthy human can produce about 1.2 hp briefly and sustain about 0.1 hp indefinitely; trained athletes can manage up to about 2.5 hp briefly and 0.3 hp for a period of several hours. Some horses can deliver up to 14.9 hp for brief periods* and can pull with the strength of 50 'circus' men.
On balance, a good 'rule of thumb' is that on a sustained basis, one horsepower is equivalent to the physical work of around ten people.
The average hand held hair dryer consumes about two horsepower (1500 Watts) ; equivalent to the work of around 20 servants pedalling away to drive a generator for the time it takes to dry a woman's hair.
To deliver clean water to our homes and to dispose of our sewage consumes the energy equivalent of thousands more horsepower each year; and to provide us with food and housing; thousands more again. If we use air conditioning at home; in the workplace; on public transport; or in the private car; many more horsepower hours are consumed. If our recreations involve travel: by ship; air; train; or bus; or motors of any kind, for example in the snow fields; the list extends.
Many other things we do today would be impossible in a slave economy. There would be no television or radio; no mobile phones; and no computer networks or World Wide Web; as all of these rely on a modern electricity generation and distribution networks. When our electricity fails as it did for me in New York in the 70's we suddenly get a taste of what it was once like without: light; heating; cooling; lifts; trains; traffic lights; water; sewerage; communications; or entertainment. Could we go back to the start of the 20th century?
A Good Life
As travel and museum visits quickly teach us, most of these things are extraordinarily recent; and, when they existed at all, were the province of the hyper-wealthy.
Most of this energy we use so liberally is still fire based. From the internal combustion engines to electricity generation stations the majority of energy used in the world today still requires that something is burnt. Before the systematic use of agriculture, humans were hunter gatherers. We shared, with various other members of the genus homo, sufficient intelligence to master the primitive use of fire. In the case of homo sapiens sapiens, early humans, fire was used to extend our range into cold climates; to keep in other animals at bay; in hunting; to extend the range of edible foods; and to improve tool making.
As agricultural technology developed, fire was used more extensively. Now kilns were added to fire pottery used for food storage; cooking, processing and presentation; in addition to the manufacture of oil lamps; ornaments and jewellery. Civilisation had begun.
As metals smelting was discovered fire became even more important to civilisation. But any mechanical effort such as grinding, lifting or transporting still needed to be provided by humans and/or domesticated animals. Until quite recently civilisation depended on human slavery, either formal, as slaves or prisoners, or economic; for example through serfdom or indentured service. In the Bible, for example, slaves and servants are treated as a fact of life. The ability of one group to live well depended on the slavery, or equivalent impoverishment, of a vastly larger group, often simply to provide their physical labour.
Water wheels began to complement muscle power from perhaps the third century BCE and commercial wind powered machinery dates from perhaps the 11th century CE but it was not until the invention of a practical steam engine that animal sweat and brawn began to be replaced in a significant way.
Many have asserted that it is not how much wealth one has, but how one lives one’s life that's important. While this is no doubt true, it is difficult to live a ‘good life’ as a slave in real or economic chains; deprived of education; without a career choice; or denied the benefits of travel and other wider experiences.
Of course a slave may still be happy or have moments of enjoyment; they may not even have to work very hard; but can such a life be described as good? For a more in depth discussion about the difference between a ‘happy life’ and a ‘good life’ read my essay to my children: The Meaning of Life on this website.
That a ‘good life’ is now accessible to ordinary people is therefore entirely due to the harnessing of energy. But on a more sombre side, energy has also made the availability, production and delivery of food relatively less costly and this has fuelled an enormous human population explosion.
The net effect for humanity, considered as a single organism, has not been much improvement in achieving a universal 'good life'. One of the most profound outcomes of the increasing availability of new sinew-less energy to the the global human organism has been a ten fold increase in its size since the invention of the steam engine.
While it is true that tens of millions now live in comparative comfort, enjoying the benefits that cheap energy and related technology has brought, thousands of millions more have been born into abject poverty, disease and a short and ignorant life.
In my lifetime the number of poor and ignorant in India alone, has risen by close to a thousand million people. Most of central and Northern Africa is in an even worse state and this is echoed in various parts of South and Central America. Because of runaway population growth almost all of the benefits of the improving quality of life in the developed world have been offset by a massive increase in the abject poor of the third world. For every one of these poor that survives several have died. Thus during my lifetime several thousand million undernourished babies, impoverished children and diseased young adults have already died; prematurely in ignorance and poverty. The 'good life' was far from their reach.
This is a holocaust on a scale unprecedented in human history. But now this out of control growth in the global human organism threatens to destroy the habitability of the very planet.
The lesson from those parts of the world where population is not growing is that improved living and educational standards for all, but particularly for women, are urgently required. Girls need to be released from cultural servitude and the dominance of men and to be empowered to take control of their own reproduction. The outmoded cultural values and wrong beliefs** that are counter to these imperatives are at the root cause of the present holocaust.
To initiate this progress, and as progress is itself made, very much higher levels of personal energy use in the third world will necessarily follow. Thus, in energy terms, the present impact of growing population on the planet will be exacerbated by the increase in personal energy use required to achieve the necessary improvement in individual living standards necessary to curtail fertility. Multiplying these two factors yields projections of a large and exponential growth in demand for energy by the global human organism.
This behemoth, the global human organism, is chewing into the fossil and other resources of the planet evermore voraciously; so that fossil deposits that were laid down over hundreds of millions of years are being consumed in a few tens of years and in a very real way the behemoth now depends on and survives through its consumption of these energy resources.
Any constraint placed on these resources, without alternative sources of energy becoming available, is likely to result in severe damage to global humanity, in the form of social disruption and many premature deaths. An alternative source of energy is desperately required.
How long can this continue?
In my view the two central issues facing us are:
- Constraining the growth of the global human organism, so that it puts energy to good use, improving the lives of its participants, rather than simply growing larger and even more voracious.
- Progressively replacing fire-based energy technology with more advanced and/or alternative energy sources.
In particular we need to mobilise the mass-energy equivalence identified by Albert Einstein in 1905 in his famous equation stating that energy equals the square of the speed of light times the mass of matter converted: E = MC2. Thus a few kilograms of matter can provide more energy than we can possibly consume. This conversion is where the sun's energy comes from and is the original source of the energy embodied all the fuels we burn today.
In addition to sunlight an important reason that the Earth remains habitable is that its outer core, below a viscus mantle and the relatively very thin crust, remains molten. We are warmed from below as well as above. The heat lost to the surface is continuously topped-up by internal nuclear fission, predominantly due to the ongoing decay of Thorium-232, Uranium-235, and Uranium-238, but there are many more natural radioactive isotopes that also contribute. There is considerable, apparently deliberate, misinformation on this subject. For a reliable scientific analysis follow this link. Today's fission reactors consume the isotopes of heavy elements, usually uranium, that have been ejected from the Earth's natural internal fission reactor.
We are beginning on a very small scale, around 500 operating power stations and a similar number of ships, to exploit Einstein's mass energy equivalence in conventional nuclear fission reactors. Some 44 countries already have or are planning to build such power stations but this number is still insignificant in comparison to worldwide coal, gas and petroleum fired electric power generation and internal combustion engines. These presently supply about 6% of civilisation's annual energy consumption.
To reduce our dependence on fire based energy we need to increase our use of indirect nuclear energy as well. Solar, wind and hydro power exploit the Sun's fusion heat and geothermal power exploits the Earth's internal nuclear reactor. But each of these is constrained by similar commercial viability issues to those that have limited the growth of conventional nuclear power; and each has additional special geographical constraints and technical shortcomings. Hydro-power, is by far the most important of these 'renewables' and contributes about half as much energy worldwide as conventional nuclear energy. But the remaining 'alternatives' contribution to global energy production is a presently a fraction of this. Wind and solar are by far the most important of these remaining 'alternatives'. Together wind and solar provide around one hundredth of the energy consumed annually worldwide. All other 'alternatives' collectively, including wave, tidal and geothermal, contribute less than half of that.
The projected contribution and practicality of the available alternatives is analysed in more detail in the article 'Renewable Electricity'. These practical constraints are unlikely to be overcome to the extent necessary for these ' renewables' and 'alternatives' to significantly replace fossil fuels, before serious damage is done to the planet and/or to the viability of the present human population.
At the moment the only hope lies in conventional nuclear fission. But with a bit more technical effort and commitment we should be able to tame then make commercial the power of the fusion reaction to exploit the oxide of deuterium, heavy hydrogen, widely found in our oceans. This is the reaction that already powers modern nuclear (hydrogen) weapons; and provides the energy of the sun. It leaves no decay products (nuclear waste) to dispose of and the resource is, to all intents and purposes, inexhaustible.
We need progress on these things; our future life depends on them.
* But at full power a human has more endurance than a horse. A marathon held in Llanwrtyd Wells in Wales every June between horses and humans demonstrates that an exceptional athlete can sometimes run-down a fast horse over 22 miles; it takes about two hours. Native hunters still run-down game in this way.
** These values and beliefs need to be broken down and corrected. All beliefs that cannot be tested are intrinsically subjective and personal. In a pluralistic society religious beliefs can have no universal validity or scope. Private religious beliefs should not be allowed to determine public policy; nor should they be allowed to confer a right to direct or otherwise interfere in the lives of others.