FOLDER 1 Energy in a Nutshell

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Energy in a Nutshell

World energy flow is depicted on the diagram below and for many millennia there was a balance between incoming energy from the sun (rate of energy flow = 1.7 x 1017 Watts) and that leaving through either direct reflection or via infra red (IR) radiation from a "hot" earth. The diagram, in this simplified form, showed that humankind was in harmony with nature and that the small amount of energy used humans, for fires, windpower (perhaps) and the like, had a negligable effect on the energy balance.

Food for humans was provided from plants and animals and the sunlight gave warmth. The sun is, indeed, an enormous energy source as it heats the earth up to temperatures close to 20 oC so sustaining plant and animal life.

As time progressed the simple energy diagram has become more complex with two new sources of energy appearing :- fossil and nuclear fuels. Both these are finite resources and will eventually be depleted and renewable energy will then be the only option for the peoples of the world.

(Note - there are some very large numbers involved with global energy but we see how easily these are generated. The global population is approximately 7.5 billion. If each person had a "one-bar" electric fire ( 1kW ) switched on all the time then the total global use of electricity would be: 7.5 x 109 multiplied by 1 x 103 giving 7.5 x 1012 W ) 

Pre-industrial era. Any energy that humans used presented no problems as only the RENEWABLE ENERGY box (GREEN BOX) was included in the energy flow; plants for food, timber for burning or construction and animals for transportation or doing work or food products. It was a sustainable existence for mankind and nature.

Civilizations grew up under this regime - Egyptians, Chinese, Incas, Greeks, etc -with cultural and social developments occurring. Immense feats of construction were carried out - Pyramids, Wall of China, Machu Picchu, Parthanon - not to mention the construction of cities and towns with many magnificent state buildings, palaces, homes and places of worship throughout the world.

Wind and water power were harnessed as sources of energy and drying commodities in sunlight has been used from time immemorial.

Industrial era Nineteenth century life has led to the box FOSSIL FUEL being added to the diagram and over these recent years the increasing use of fossil fuels (coal, oil and gas) has changed the way the earth looses its heat. Since the gas carbon dioxide, CO2 a by-product of burning fuel, interacts with the IR emitted radiation the so-called greenhouse effect has arisen and the earth is getting hotter. If the ice caps melt at the North and South Poles then the Reflected Sunlight (6 x 1016Watts on the diagram) becomes less and hence this will further add to global warming leading to more ice cap melting - it is a process that feeds on itself and behaves like a chain reaction. Thus we see that in the last few decades the earth has been driven into severe imbalance.

The energy box NUCLEAR ENERGY has arisen since the late 1950's and, as yet, no one has developed a safe strategy of containing radioactive nuclear waste. There is no CO2 involved with nuclear power and therefore this form of energy looks to be a likely saviour for the environment. However, other threats such as radioactive material finding its way into the hands of terrorists could be equally damaging to the survival of the human race. Using Breeder Reactors will extend the supply of nuclear fuel as it provides a method of converting U238 to a fissile material but this technology is still in its infancy. ENERGY FROM FUSION will remain a scientific curiosity for a considerably long time so we cannot rely on fusion to satisfy our immediate needs.

Industrial and Information era One could hope that the information era would help to lower our energy needs. However, this can only give savings at a fairly modest level. Working from home, say, will cut traveling cost but the home may need heating for longer periods. With Smart metering one may achieve greater efficiency in energy use but, again, the savings will be modest.

On reading the above one can't help thinking that civilization had matured largely by 1900 without using fossil fuels at all and, our last 100 years or so, has added little to the stature of humankind. Oh yes, we have given way to pleasure seeking on a gigantic scale and communications (through either electronic means or via transportation) has made the world into a global village, more people are certainly living longer but are often confined to "homes" for the last decade of their lives. You must judge for yourselves whether humankind is ascending or descending.

To summarize, the long term future has to rely on RENEWABLE ENERGY as fossil and nuclear fuels are only finite resources and will eventually run out. The diagram shows that there is a rich diversity of renewable options ( green connecting lines ) - sunlight, water and wind, biomass and tidal and geothermal. It has to be acknowledged that these sources are not in a nice concentrated form that is the case for fossil or nuclear fuels but they are sustainable. As the past has shown, civilization was established with these energy sources.

One of the biggest worries is that the environment is presently being so badly damaged that the earth will not be capable of supporting plant, animal and human life as it did in those pre-twentieth century times.

Additional information

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Photovoltaic (PV) charging systems

PV interfacing to Proton Exchange Membrane (PEM) electrolysers for hydrogen gas production


Soil not oil Vandana Shiva, Zed Books 2008. The last paragraph of the book needs to be read-- "Climate chaos, brutal ecomonic inequality and social disintegration are jointly pushing human communities to the brink. We can either let the process of destruction, disintegration and extermination continue unchallenged or we can unleash our creative energies to make systematic change and reclaim our future as a species. We can either keep sleepwalking to extinction or wake up to the potential of our planet and ourselves". Now start at page 1 ( explains entropy (page 9 here) in meaningful terms)

Future Scenarios David Holmgren, Green Books, 2009. Four scenarios are offered for the future - Brown Tech., Green Tech., Earth Stewardship and Lifeboats. The graph on page 47 shows global energy consumption peaks at 12,000 million tonnes oil equivalent around the year 2015 ( in power units 2 x 1013 Watts ).

The Long Emergency James Howard Kunstler, Atlanta Books, 2006. The recurring theme of this book - fossil fuels are a unique endowment from Mother Earth for humankind - past, present and future. Our generation is set to consume all these riches in little over a century, i.e. a mere life-time. It is as if we are children saying "we have found the ball and no one else is going to play with it". Well, this book leaves us in no doubt that the emergency is real and just around the corner.

The Transition Handbook Rob Hopkins Green Books Ltd 2008 Most of us are in denial about global warming or fossil fuel depletion but not this book. It spells out clearly how a descent from high energy dependence can be tackled in a positive way with examples now in progress. The Transition Initiatives are based on four key assumption:

1. That life with dramatically lower energy consumption is inevitable and that it is better to plan for it than to be taken by surprise.

2. That the present structure of our society and our life-style lack resilience to weather this severe energy shock

3. That only by acting collectively and acting now will orderly change be made.

4. That we can build ways of living that are more enriching and more connected to the stewardship of our planet.

This must be the way forward.

Sustainable Energy - without the Hot Air David MacKay UIT 2009 - an extremely useful text as all the author's topics are backed up by rigorous calculations. (Will be referred to by capital letters "SE-HA" in later sections .) The complete text is freely available on-line. Sadly, David died in 2016 from cancer and his expertise is now lost for ever.

The Hot Topic: How to tackle Global warming and still keep the lights on by Gabrielle Walker and David King Bloomsbury 2008

Renewable Energy - power for a sustainable future Edited by Godfrey Boyle Oxford Press 2004

Global warming - Al Gore "An Inconvenient Truth (2006) Film and DVD

The Vanishing Face of Gaia - A Final warning - James Lovelock. This author, an eminent scientist, has been expressing his grave concerns about our treatment of planet earth ( Gaia in his words ) since the 1970's. Amongst his many writings he sees, in this book, a desolation of humanity to come unless an immediate lifestyle change is adopted.

Earth: The power of the planet - the TV series given by Dr Iain Stewart. The video clip about Explosive Permafrost shows that methane is trapped in permafrost in Alaska and Siberia but will be released if these parts of the world are warmed a few degrees. Again, this is a feedback effect, or some may call it a vicious circle, in that more methane release gives rise to more warming which results in yet more methane release.

Sunday Times magazine, November 2007 - 4 parts

Agreement at UN climate change talks, Valencia, Spain November 2007

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