unesco desire – net project sustainable development pietro la mendola...

UNESCO UNESCO Desire – Net projectDesire – Net project

SustainableSustainable DevelopmentDevelopment

Pietro La MendolaPietro La Mendola

[email protected]@casaccia.enea.it

UNESCOUNESCORome, 2007 5-19 FebruaryRome, 2007 5-19 February

• HOW DEVELOPMENT IS DEFINED AS “SUSTAINABLE”?

and

• WHAT IS THE ENERGY ROLE ?

HOW DEVELOPMENT IS DEFINED AS “SUSTAINABLE”?(IPCC)

SUSTAINABLE HUMAN ACTIVITIES

Some requirements of the so-called “sustainable” or “eco-efficient” activities are:

• Prevention of negative environmental behaviours;

• Reversibility of changes on the environment;

SUSTAINABLE HUMAN ACTIVITIES• The possibility of putting anew the materials

used in the technological processes in the environment at the end of the cycles;

• Multiple “cascade” use of materials and different forms of energy that deal with the process, with the aim of obtaining a decrease in the size of the transformations.

DOES ENERGY DISAPPEAR?

• Energy can not be created nor destroyed

• Words as “production” or “consumption” of

energy, often used by technicians, are not

correct and misleading.

ENERGY CAN BE TRANSFORMED

• We are able only to design, make or use tools which transform energy into a different form

• Words as “renewable”, “inexhaustible” or “clean” and so on, have been often used to describe new technologies regarding energy transformation

ENERGY AND NEW PROCESSES

• The progress of science promotes

processes which transform the energy in a

more efficient way

• Nonetheless, the total demand of energy

to be transformed is increasing, as well as

the number of potential users.

PROBLEMS OF “NON - SUSTAINABILITY”

• Exhaustion of materials because they are non renewable;

• Desertification of some large regions, and as a result, quickly alteration of local climate;

• Extinction of animal and vegetal species, or decrease of related population.

DEVELOPMENT AND VARIABILITY OF EARTH CLIMATE

• In the last decades, the attention has being focused on the effects that energy models, based on the uncontrolled abuse of burning, can cause to the evolution of distribution of climatic zones in our planet.

• The illusion about regularity and immutability of climate is due to the short life of human being in comparison with the age during which climatic phenomena usually evolve.

DEVELOPMENT AND VARIABILITY OF EARTH CLIMATE

• We are not surprised if we find out, in the same geographic area and in different beds, fossils of animals and plants which are typical of savannah and polar climate animals.

• Observations of solar activities have pointed out that sun energy on Earth is subject to relevant variations of intensity depending on explosive phenomena of enormous proportions.

Anthropogenic Climate Change (IPCC)

Socio-EconomicDevelopment

Paths

Climate Change

Impacts

EmissionsM

itig

atio

n

RISK OF INSTABILITY

• The main worry is from the risk of introducing, through human activities, a perturbation in well- balanced systems, but under conditions of “maximum”, compared to the sum of all forms of stored energy.

RISK OF INSTABILITY • According to the pessimistic hypothesis, these

perturbations could affect the earth energy systems, that we are not able to describe mathematically for all possible interactions, leading them to conditions of progressive instability.

RISK OF INSTABILITY

• This event could cause effects of divergent sizes, not proportional to the causes which have produced them, or even phenomena like “dominoes” acting in unforeseeable directions.

GLOBAL WARMING AND “GREENHOUSE” EFFECT

“Average temperature” would be a definable value if domain and moment were indicated calculating the mean. But temperature does not count the energy stored in the earth biosphere, for the following important elements:

GLOBAL WARMING AND “GREENHOUSE” EFFECT

• latent energy of fusion and vaporisation

• atmosphere pressure

• kinetic energy of air and sea waves

• wave and tide motion

• elevation

• saline unbalance

GREENHOUSES AND GREENHOUSE EFFECT

• Old and modern greenhouses working is based on solid panel able to transmit the radiant energy and to stop the transmission of the heath carried by the air convective motions.

• Nothing alike occurs in the earth’s atmosphere, where, except the mountains, there are no solid screens, and the motion of the mixture of gasses, solids and fluids constituting the air is unceasingly supplied through large amounts of energy.


• The considerable attenuation of thermal shocks caused by solar radiation, occurring in the surface of heavenly bodies without atmosphere, is due to a large number of mechanical, thermodynamic and thermo kinetic phenomena, among those the most important seem to be closely linked to water phase changes and to the stored energy as latent heat of vaporisation.


• In climatic environments where the relative humidity is very low, in fact, very high day-night temperature ranges occur making animal and vegetal life hard.

• The stabilising effect of atmospheric water is known even if it is not easy to calculate.

• In the vapour phase water is quite transparent through solar radiation in visible and thermal spectrum.

• In the solid microcrystalline phase reflects the most of thermal radiation.


• The daily transparency and night cloudiness enable the storage of solar energy in the atmosphere and the following energy conversions.

• CO2 of atmosphere can not work through the same physical schema because:

• It is a very heavy gas stagnating near the ground. • It has a very low solidification temperature being not

easy to reach, in the quota where it is. • It is in the atmosphere in little concentrations in

comparison with water


• CO2 is supposed acting through the selectivity of its range of emission - absorption that could let go higher frequency than solar radiation and terrestrial reflection, absorbing and turning the lowest frequency into thermal energy.

• We must say that carbon being on Hearth, through the

CO2 component of the atmosphere, takes part in a lot of processes, one correlated to another, and not all of them are well known.

INCREASING OF CO2

Growth rate of vegetation will be higher if CO2 atmosphere content increases

Each hectare of land changed to desert puts on the atmosphere thousands of tons of CO2

INCREASING OF CO2 • The metabolism of living organisms • The vegetal life cycle and creation - destruction of

humus• The animal life cycle; production and disappearance of

carbonates. For example coralline barriers.• The mineral cycle of equilibrium carbonates -

bicarbonates • The equilibrium of solubility of CO2 in terrestrial waters

depending on temperatures• All combustions of material of living source and

mineral reactions.

CO2, AND RADIOACTIVE C14

• Fossil combustions and mineral dissociations introduce into the atmosphere a kind of different CO2, which can be distinguished from the one coming from other cycles, thanks to the absence of the C14radioactive component because of decay.

• Measures, aiming at highlighting the contribution of human activities in the increasing CO2 in the atmosphere, did not result successful, probably for the quantitative ratio with other exchange processes.

Carbon sinks and the carbon cycle


• Terrestrial ecosystems play an important role in the global carbon cycle. Around one-third of global anthropogenic carbon emission in the past one hundred fifty years resulted from land-use change, namely forest clearing in the tropics and elsewhere.


• On an annual global basis, land-use change results in emissions of 1.6 + - 0.8 giga tonnes of carbon (GtC). This account for around 25 % of emissions from fuel combustion and cement production.


• These and other findings were assessed by the UNEP/World Meteorological Organisation (WMO) Intergovernmental Panel on Climate Change. Its Special Report, published in 2000, concluded that land-use change, and forestry can contribute to the reduction of greenhouse gas emissions by avoiding deforestation and increasing carbon uptake through afforestation, reforestation and improved management of forests, crops and grasslands.

THE PROBLEMS THAT FACES US ABOUT THE ENVIRONMENT AND THE ENERGY

• The strategy, or often the strategy absence, in the energy field, on which the economic politics of powerful states of XIX and XX centuries have been based, has been founded on the convictions that dominated the ancient world:

• limitless economic scenario • continuous and limitless discovery of new natural

resources • infinite ability of the environment to receive human

waste• ability to impose the price of raw materials

ENVIRONMENT FOUNDED PARTIES

• The economists and the scientists will have to begin to communicate correctly among them and will have to try to travel through new roads.

• The public opinion of all the nations, that have elective governments, currently have a greater sensibility to the environment than they had in past times and it can influence the choices of the governments

TO RESTORE THE NATURAL ATMOSPHERE. WHAT AGE?

• Many international movements of opinion ask the governments to adopt environment political measures, oriented to cancel the modifications produced by mankind.

• The result of these provisions would be the restoration of the previous environmental conditions.

TO RESTORE THE NATURAL ATMOSPHERE. WHAT AGE?

• What we consider natural environment, because it is previous to the current excessive use of energy conversions, it often was already deeply modified by human presence as well as through natural phenomena.

• A correct approach is trying to achieve goals for planned modifications of the territory. It is hoped for consequences of the modifications in the long term which are foreseen and that we are able to correct the errors.

ENERGY WITHOUT GAS EMISSIONS

• The prevailing definition of sustainability of the energy conversions is founded currently on the hypothesis of the modification of the distribution of climates in the Earth for effect of the excess of gaseous emissions in the atmosphere.


• In particular are seen in way negative the energetic processes in which fossil fuels are burnt: fossil coal, oil, methane. Since many scientists think that the nature is not able to recycle with biological processes in short time the excess of inorganic carbon emitted in form of CO2 by means of these combustions of uncontrollable diffusion


• The conversions that use the energies from solar, wind, hydraulic origin, and, with opportune limits, the combustions of short cycle organic material (biomasses) satisfy this requirement because they do not produce immediate and directed emissions of CO2 in the atmosphere or produce equivalent removal of it.

• The precaution principle demands careful analysis of the energetic cycle and of its impact on the environment.

ENERGY CONVERSION ONLY IF NECESSARY

• It is not possible converting energy without degrading a part of it into a so low temperature heat that it cannot be used anymore.

• On the other hand, the high enthalpy energy tends to be converted spontaneously and therefore every form of accumulation always is a danger.

• The greater is danger, the larger is the amount of accumulated energy and the higher is the enthalpy.


We can consider:• large hydroelectric river basins at a high altitude• large deposits of combustible materials • big tanks of high pressure compressed gasses • etc. • The most prudent behaviour about the energy

problems is to help the use of kind of energy fitting to the aims and to resort to the conversion when it is the only solution.


For example, the use of the energy as electricity is reasonable for:

• Motors

• Lighting system

• Communications

• Computer science


On the contrary, it is not justified resorting to a cycle including the conversion of high temperature heat in electricity, losing beyond 60%, in order to make a second conversion in a low temperature heat:

For example:

• electrical water heaters

• electrical stoves


A different budget can be made when the energy as electricity is reconverted in order to realize thermodynamic cycles allowing to use heat supplies already available by raising the temperature.

• For instance, the heat pump systems of heating.• Or electrical oven in comparison with those heated by

fuel without thermal recovery like the gas kitchen oven.

In cases as these, the conversion of the electricity in heat can be justified, since it takes part in a favourable total cycle.

CENTRALIZED OR DIFFUSE CONVERSION ?

• The heat conversion in electrical energy has had a greater expansion than it was technically justifiable.

• Power stations have been built more and more powerful in the same place, because of:

• better efficiency for the scale factor• difficulty to find new locations being favourable for the

construction, especially for nuclear power stations• lower expenses for the staff devoted to managementOn other hand, the constructions of single or few

number systems have become too much expensive.


• The hydroelectric plants, where energy conversion does not occur since the natural resource is already mechanical energy, are built in a position obliged by the hydro geologic situation.

• Often the big systems have deeply modified the territory. They force people to leave the flooded regions and they are not free from risks.

• The electric power coming from these plants in centralized way usually needs be distributed in far localities.


• The convenience criteria about the transformations of solar or wind energy are opposite.

• The solar radiation has a power density of equivalent magnitude as one demanded for final use and it is very discontinuous.

• The wind energy has a greater power density, but it is characterized by extreme irregularity.


• Any is the applied technology both these natural resources will become convenient if:

• The primary conversion occurs close to the place of the final use

• Accumulation of energy is obtained through small and distributed devices

• The final uses do not needs energy in continuous way• Integration with energy from other sources is

achievable.


The solar and wind low power systems and distributed in the territory also offer the advantage of being cheaper than those that are centralized, because they can be manufactured in series and in unified way.

Moreover, they can be installed and managed by staff with modest technical qualification.

In the current condition of technology, hardly it will become convenient converting the solar and wind energy in centralized way and distributing energies in the territory that are naturally already available in distributed way.

FROM SUN DRINKABLE WATER, CLIMATISATION

AND ONCE-THROUGH COOLING • Many applications of the solar energy do not

demand the conversion in mechanical energy otherwise realizing favourable and economic cycles.

• The solar energy has been for millennia used for the salt separation from the sea water through evaporation, because the valuable material was the salt and the technical knowledge allowed only this process.

FROM SUN DRINKABLE WATER, CLIMATISATION

AND ONCE-THROUGH COOLING

Nowadays, in many places the precious material is the freshwater and efficient processes can be developed in order to obtain it from the sea.

• through photovoltaic cells and osmotic membranes• through multiple stage evaporation process at low pressure

The freshwater or feebly salt water for agricultural and alimentary use can easily be accumulated and distributed.

It re-enters in the energetic resources of the type of entropy reduction.

FROM SUN CLIMATISATION

AND ONCE-THROUGH COOLING • Other human needs, which can be satisfied by the

solar energy in disseminated modality without the phase of the conversion in electricity, are related to the air conditioning.

• The necessity to heat or to cool air in the buildings, thermally insulated from the outside, in order to obtain comfortable conditions for people or in order to conserve fresh goods, can be satisfied resorting to plants that take advantage of the solar heat, or directly or through refrigeration cycles.

• Systems of this type need for the construction and the management staff with basic technical knowledge.

ATMOSPHERE MODIFICATIONS DUE TO TAKING ENERGY AWAY

• It is obligatory, even if we use the sources of energy defined renewable, operating with great precaution and respect for the nature.

• Taking hydraulic, solar and wind energy away can modify also deeply the atmosphere in which beings exist and they reproduce themselves.

HYDRAULIC ENERGY Beyond the accumulating hydroelectric systems,

which have been pointed out, all kinds of hydraulic systems steal energy from water course reducing the natural ability to modify, through the erosion and the carrying materials, the shape of the river bed and the depuration of the water with the turbulence and the oxygenation.

HYDRAULIC ENERGY The species living in the water course would be

established in modified environment regarding:

• oxygen presence

• temperature

• organic sediments and bacterial flora

• other species of the alimentary chain

• The equilibriums among species are often unstable and they can change strongly.

ENERGY FROM THE WIND

Equally it can happen when energy is captured excessively from the atmospheric currents at a low altitude.

The air kinetic energy participates in a great number of dynamic and thermodynamic phenomena.


Its decrease can cause remarkable changes regarding:

• Composition

• Organic and inorganic pollens and other carried materials

• Temperature pressure and humidity


Its decrease can cause remarkable changes regarding:

• Ability to dilution of injurious elements and transport at distance of nourishing substances

• Perhaps there is not any risk to change the climatology of the Earth, but locally the living rainfall and equilibriums among species can be modified, above all among bugs which are often in relation with the vegetation, and the alimentary chains are based on them.

SOLAR PANELS• The absorption and radiation factors of the land

surface can be modified through installation of large extensions of solar panels in order to obtain either low temperatures or high temperatures through concentration systems or direct conversion panels.

• These installations have effects on the atmosphere which are comparable to what it would happen destroying forests or asphalting great extensions of land.

• They change the thermal upward currents and all the local meteorology and the all living beings suffer the situation.

SAVING AND REASONABLE USE • The actions on the natural energetic system are

renewable and sustainable only if they are accurately planned and if the concentration limits are not exceeded, which are different for each type of territory.

• As consequence of the natural limits impending over every modality of taking energy away we can always rely on:

• saving of energy• reasonable use of the type of energy• temperature at final use as much as possible near to

the primary one of the used resource

SAVING AND REASONABLE USE • Saving and reasonable use are certainly the

most renewable and sustainable sources of energy we can imagine. These sources have to be integrated with all the judiciousness and the knowledge that is available as far as the watchful saving of the entropy and constant separation of all those materials reacting spontaneously or blending themselves or containing latent energy, that can still be useful if correctly managed.

SAVING AND REASONABLE USE • Do not mix sewer waters and waters containing

detergents • Recycle glasses, metals, cellulose, feeds etc • Recover the heat of lukewarm waters before releasing

in the atmosphere• Recover the heat discharged from the thermodynamic

cycles (co-generation)• Construct buildings with low energy loss • Power lines with low dispersion• Transports optimized for the impact on the

atmosphere and the conversion of energy

SAVING AND REASONABLE USE • The low temperature heat comes from thermodynamic cycles

and industrial waste, but also from lukewarm water from civil use, whose residual heat can be captured through opportune means.

• Other resources of heat at low temperature are of natural origin due to secondary volcanic activity.

• The recovery of the heat, destined in great part to the civil uses, demands the construction of complex and expensive thermal nets.

• The countries that have this kind of nets are typically those that have very cold climates and short time of investment recovery. With raise of the fuel price and the costs of the pollution the thermal nets will be able to be diffused also in different climatic areas.

THERMAL NETS AND GEOTERMIA, INVESTMENTS AND SAVINGS

• The thermal energy at temperature =< 100 °C has a relevant economic value and it can be recycled with great advantage for the safeguard of the environment because the following aspects are avoided:

• the alteration of the thermal condition of the atmosphere where the unusable heat is discharged

• the combustion of valuable materials and the emission of corresponding smoke

• the improper use of energy sources adapted to reach higher temperatures

ENERGY FROM THE SEA, PLANS OF

FLOODING OF THE LOW LEVEL AREAS

• Another source of not renewable energy, free from atmospheric emissions energy, that it is proposed but it must be estimated with great precaution, is the hydroelectric exploitation of the sea water through the flooding of areas that are under the sea level.

• Often in the past these areas were invaded from the sea from which they were separated by the movements of earth.


FLOODING OF THE LOW LEVEL AREAS Their flooding, beyond the exploitation of the

water energy in the filling phase, can carry some mitigations of the climate and the possibility of sustainable activities, such as:

• fish breeding • drinkable water from the sea • fishing • inland navigation


FLOODING OF THE LOW LEVEL AREAS

For the immense extension of these areas, these plans must be examined with precaution, because the alteration of the environment connected to them can large and hardly expectable.

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