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Environmental aspects of energy –
introductory remarks
Filip Černoch
cernoch@mail.muni.cz
State of the global environment
• Five concerning trends:
• 1) Population growth
• 2) Economic development
• 3) Decline of life support ecosystems
• 4) Global atmospheric changes
• 5) Loss of biodiversity (variety and variability of life)
Source: Česká
televize
Population growth
Source: US Census
Bureau via Wiki
Population growth
• Driven by fecundity (reproductive rate) – how many
offspring individual may have in his lifetime.
• A population doesn´t grow to its full potential (indefinitelly).
• Limits of population growth – conditions for life and
reproduction.
• Food, temperature, space...
• Limiting factors – density (in)dependent - plateau
• Carrying capacity – number of inhabitants that ecosystem
can sustain with available sources.
Population growth
•Limits of growth supressed by „infinite“ amount of
energy from fossil fuels. – mechanisation of
agriculture + medical advances + savage systems +
living in formerly unhabitable places.
Demographic transition model
Source: W. Thompson
Development of the society – maximalisation
of energy flows
• „In every instance
considered, natural
selection will so operate as
to increase the total mass
of the organic system, to
increase the rate of
circulation of matter
through the system, and to
increase the total energy
flux through the system so
long as there is present and
unutilized residue of matter
and available energy (Alfred
Lotka, 1922).
The first energy era
• Human metabolism + fire.
• Muscles to secure food, shelter, aquiring material.
• Useful work of healthy adult – 50 – 90W.
• Energy returns in foraging – barely positive to as much as 40x .
• Densities less than 1 person/km2, agriculture societies 20-30
people/km2.
• First usage of draft animals to cultivate the fields.
• Sustainable (= able to be maintained at a certain level) economy =
damages were reparable.
• = If the ecosystem was harmed too much and stopped providing the
resources, people moved to another place.
The first energy transition
• Domestication of draft animals + fire to produce metals = increase of
energy usage.
• Animals – 200 – 500W.
• Fire to produce bricks and containers and to smelt metals.
• Charcoaling to convert wood to charcoal to iron (inefficient process).
• Nearly complete deforestation of some parts of Mediterranean
(Spain, Cyprus, Syria – iron) and the Near East (Iran, Afghanistan –
copper).
• considerable impact of people on the environment. Development is
prevented by the limits of the environment.
• Still no spare resources for education, science, tech development.
First prime movers
• Muscles replaced by waterwheels and windmills to grain milling, oil
pressing, wood sawing etc.
• Late 11th century England – more than 5600 water mills, 1/350 people.
• Higher performance of draft animals (better harnessing, shoeing etc.)
• Production of metals limited by the limits of environment:
• Early 18th century – typical English furnace produced app. 300 tons of
pig iron/year. 8kg of charcoal per 1kg of iron, 5kg of wood per 1kg of
charcoal = annual demand 12 000 tons of wood. All natural forests gone.
• 1 mill tons of iron requires ¼ of the British Isles under coppiced wood.
• = in 1200 London surrounding is deforested, by 1500 metal ores shipped
to Ireland, Scotland, Wales for smelting, then the the industry moves to
U.S.
Industrial age
• Substitution of animate energy by engines and energies of fossil fuels
(still in process – Africa)
• By 1900 several European countries energized by coal
• Previously the lack of energy prevents the population from (also
economic) expansion. No spare resources for education, science,
technological development. It was changed by the fossil fuels.
• Watt´s steam machines 20kW. Industrialization, transportation, rise
of well being. An inexpensive and reliable supply of heat and
electricity.
• But environmental consequences (serious changes of interactions in
the ecosystem)
• = fossil fuels provided a critical amount of energy for the humankind
to develop. They (for uncertain period of time) removes the limits of
(economic and population) expansion.
Latest energy transition
• Started by the first electricity plants in 1880s
• Electricifaciton and inovation
• An inexpensive and relable supply of electricity transformed every
aspect of everyday activities – light, time-saving gadgets, energizing
transport, boosting industrial production.
• By 1950 oil and gas approx. 35 % of the world´s primary energy
supply and by 2000 their combined share over 60 %. With coal fossil
fuels provides90 % of all commercial primary energy supply.
• = fossil fuels drive up farm productivity and hence reducing
(drasticaly) agricultural population by mechanizing industrial
production and letting the labor force move into the service sector.
• But their impact on the environment is tremendous.
Development in energy consumption
14
Development of energy consumption
= combination of the expansion of consumption of fossil fuels
+ population growth = pressure on the environment = impact
on humankind.
Ecological footprint
Source: EEA