Hasta la victoria siempre

Sunday, September 6, 2009

Este energia regenerabila o solutie?

Energia regenerabila se referă la forme de energie produse prin transferul energetic al energiei rezultate din procese naturale regenerabile. Astfel, energia luminii solare, a vânturilor, a apelor curgătoare, a proceselor biologice şi a căldurii geotermale pot fi captate de către oameni utilizând diferite procedee. Sursele de energie ne-reînnoibile includ energia nucleară precum şi energia generată prin arderea combustibililor fosili, aşa cum ar fi ţiţeiul, cărbunele şi gazele naturale. Aceste resurse sunt, în chip evident, limitate la existenţa zăcămintelor respective şi sunt considerate în general (a se vedea teoria academicianului român Ludovic Mrazec de formare anorganică a ţiţeiului şi a gazelor naturale) ne-regenerabile. Dintre sursele regenerabile de energie fac parte: energia eoliană; energia solară; energia apei; energia hidraulică; energia mareelor; energia geotermică etc.

Pentru unii, energia regenerabila poate fi o solutie de salvare de la o disparitie iminenta a stilului de viata consumerist. Se stie ca resursele planetei sunt insuficiente pentru a permite tuturor un stil de viata afluent, materialisto-consumerist. Totusi, oare progresele tehnologice, in speta utilizarea surselor de energie reinnoibile, nu pot reprezenta calea de iesire, astfel incat consumerismul sa poata continua fara insa a duce la accentuarea degradarii mediului inconjurator?

In articolul sau „Renewable Energy: No Solution for Consumer Society”, publicat in The International Journal of Inclusive Democracy, vol.3, no.1, (ianuarie 2007), Ted Trainer explica de ce raspunsul la intrebarea de mai sus este, cel mai probabil, negativ. Aceste surse de energie se dovedesc cu totul insuficiente, astfel incat evitarea unui dezastru planetar inseamna echivaleaza cu evitarea principalei sale cauze, consumerismul.

Sa urmarim, cu cateva exemple, stadiul in care s-a ajuns cu folosirea energiei regenerabile si ce sanse de viito are ea.

Energia eoliana:
„An examination of wind maps indicates that the annual quantity of wind energy that is available could well be considerably greater than demand, but the important question is what fraction of this can be harvested in view of the variability problem; that is, sometimes there is little or no wind. In the past it was usually assumed that for this reason wind might be able to contribute up to 25% of demand. However, the Germans with far more wind mills than any other country, and the Danish with the world’s highest ratio of wind output to electricity consumption, have run into problems “integrating” wind into the grid while wind is supplying only about 5% of demand.

A mill at a good site might run over time at 33% of its maximum or “peak” capacity, but this should not be taken as a performance likely from a whole wind system. Sharman reports that even in Denmark in 2003 the average output of the wind system was about 17% of its peak capacity and was down to around 5% for several months at a time. The E.On Netz report for Germany, the country with more wind mills than any other, also says that in 2003 system capacity was 16%, and around 5% for months. They stress that 2003 was a good wind year.”

Asadar, tari care au inregistrat progrese mondiale in utilizarea energiei date de vant, ca Germania si Danemarca, nu au reusit decat performante modeste.

Energia solara:
„After wind, Europe’s best option for renewable electricity will probably be solar thermal plants located in the Sahara region. These will impose significant transmission losses but their big advantage is their capacity to store energy as heat to generate and transmit electricity when it is needed. However, the magnitude of the potential is uncertain, and especially doubtful in winter. Solar thermal trough systems do not work very well in lower solar incidence. Even in the best locations output in winter is about 20% of summer output. The winter incidence of solar energy in the Sahara is not that impressive, perhaps 6 kWh/m/d towards Libya and Egypt and a long way south of the Mediterranean.
Solar thermal dishes perform better than troughs in winter, but they cost more and their big disadvantage is that because each tracks the sun it is difficult to take heat via flexible couplings to a central generator or store. They are being developed with Stirling engine generators at each focal point, meaning that heat energy can’t be stored to generate electricity when it is needed. Central receiver or tower systems can store, but like troughs they have reduced winter performance.
It is likely that solar thermal systems will be located only in the hottest regions, will have to supply major demand centres by long transmission lines, and will not be able to make a large contribution in winter.”

Evident, doar cateva regiuni de pe Glob sunt suficient de incalzite si expuse razelor solare incat sa se inregistreze un cumul semnificativ de energie, in cea mai mare parte, anotimpul rece scazand considerabil cantitatea de energie obtinuta astfel.

In concluzie, o economie mondiala bazata primordial pe energia eoliana sau solara intampina cel putin doua obstacole decisive:
„Renewables could provide a considerable fraction of electricity demand, probably in excess of 25% in some countries, but a) much of the generating capacity would have to be duplicated in the form of fossil or nuclear plant for use when there is little sun or wind, b) the amount of coal use still required would far exceed safe greenhouse gas emission limits.

There are weighty reasons why we are not likely to have a hydrogen economy. If you make hydrogen from electricity you lose 30% of the energy that was in the electricity. If you then compress, pump, store and re-use the hydrogen the losses at each of these steps will result in something like only 25% of the energy generated being available for use, e.g., to drive the wheels of a fuel-cell powered car.”

Dupa ce Trainer se refera si la alte surse de energie regenerabila, aungand la aceleasi rezultate ca mai sus, conclude:
„All of the above references have been to the difficulty or impossibility of meeting present energy demand from renewables. That is not the focal problem for the evaluation of the energy viability of consumer-capitalist society. The crucial question is can renewables meet the future demand for energy in a society that is fiercely and blindly committed to limitless increases in “living standards” and economic output. The absurdity of this commitment is easily shown.
If 9 billion people were to rise to the “living standards” we in rich countries will have in 2070 given 3% p.a. economic growth, then total world economic output would be 60 times as great as it is now!”

Pe scurt, o crestere de 60 de ori a activitatii economice mondiale echivaleaza cu un dezastru ecologic imposibil de reparat de folosirea energiilor alternative.
Singura solitie de evitare a catastrofei ramane abandonarea consumerismului de tip Occidental:

„Such multiples mean that the problems cannot be solved without enormous reductions in the volumes of industrial/commercial producing and consuming going on, perhaps to 10% of present levels. The numbers are so big that no plausible assumptions regarding technical advance, energy conservation, etc. could show that the problems can be solved without moving to a zero-growth economy on a fraction of present GDP.”

Mai exact,
„consumer-capitalist society is grossly unsustainable. It involves rates of resource use and environmental impact that are far beyond sustainable levels, and could never be extended to all the world’s people.
Consumer-capitalist society is also grossly unjust, imposing a global market system which delivers most of the world’s wealth to the corporations and consumers of the rich countries. A market economy inevitably gears the productive capacity of the Third World to the effective demand of the rich and cannot attend to the needs of people, society or future generations. Again it is obvious that Third World problems cannot be solved until the rich countries stop taking most of the world’s resource wealth; as Gandhi said long ago, “The rich must live more simply so that the poor may simply live.” That is not possible in a society committed to affluence and growth. Thus considerations of sustainability and of justice both lead to the conclusion that the problems cannot be solved without huge and radical systemic change.”

Capitalismul consumerist este un devorator de resurse naturale si un sistem profund nedrept si inegal. Iesirea din impasul ecologic nu poate fi continuarea pe panta progresului si dezvoltarii economice, adica acolo unde duce capitalismul, ci abandonarea economiei bazate de profit si o reducere a cresterii economice. Redistribuirea actualelor realizari economice, laolalta cu o reducere a activitatii economice in general, par solutii indicate.

„a good society cannot be an affluent society. (...) The only way out of this alarming and rapidly deteriorating situation is to move to some kind of Simpler Way. This must involve non-affluent (but quite sufficient) material living standards, mostly small, highly self-sufficient local economies. Economic systems under social control and not driven by market forces or the profit motive and highly cooperative and participatory systems. Obviously, such radical systemic changes could not be made without profound change in values and world view, away from some of the most fundamental elements in Western culture, especially to do with competitive, acquisitive individualism.”

Standarde materiale decente, economii locale, auto-suficiente, aflate sub control social, ce presupun un grad ridicat de participare democratica din partea comunitatilor, aceasta este schita pentru o posibila societate eliberata de valorile sinucigase ale consumerismului si singura care poate promite un viitor indelungat al umanitatii pe Terra. Daca un astfel de viitor ne dorim, e clar ca nu pe utilizarea consistenta a energiilor regenerabile trebuie sa ne bazam, in speranta desarta ca ne va salva de efectele dezastruoase spre care ne conduce capitalismul consumerist.
In urmatoarea postare, vom vedea mai in detaliu in ce consta solutia propusa de Trainer.

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