The main types of renewable energies are reviewed in relation with currently available technologies, planet's emergencies and strategies towards sustainable development. The discussed issues are: the limited space for living, the biospheric degradation upon fossil fuels burning, the change of paradigm of human happiness from consumption to cultural development, a continuous improving of conversion of the low density and intermittent sun light on final energy on an industrial scale, the need to reintroduce the concepts of “enough” and “equity” while developing the know-how patrimony and good practices for the next generations.
TopWe Need A Change
Energy is the most important resource of mankind. Fossil fuels have offered astounding opportunities during the 20th century in the rich countries of the western world, but now the reserves of fossil fuels are progressively decreasing and their extensive use produces harmful effects such as pollution that threatens human health and greenhouse gases responsible for global warming.
Nevertheless, fossil fuels continue to be extensively used and the energy request is continuously increasing. Today the global energy consumption is equivalent to 18 trillion watts (18 TW) of power demand. Continuing along this trend, by 2050 with a population of over 9 billion, the overall consumption should exceed 40 TW (Smil, 2003). Such a trend, however, is unsustainable for mankind.
Excluding light coming from the Sun, Earth is a closed system (Figure 1).
Figure 1. View of the Earthrise seen from the moon evidencing that our planet is a close system
The second law of thermodynamics states that, in a closed system, there are limitations that cannot be overcome; apparently, several economists are not acquainted with this simple principle. We must never forget that human economy vitally depends on the planet’s natural capital (e.g. oxygen, water, biodiversity, etc). Fortunately, part of this capital is regenerated for free by the direct and indirect action of sunlight on the biosphere, but drawing on the natural capital beyond its regenerative capacity results in depletion of the capital stock. Humanity’s load corresponded to 70% of the capacity of the global biosphere in 1961, and grew to 100% in the 1980s and to 140% in 2005 (GFN).
This simply means that we are living above our possibilities. Furthermore, we make extensive use of resources that cannot be regenerated by the biosphere. This is not only the case of fossil fuels, which are irremediably consumed when used, but also that of metals (Bardi, 2014).
Clearly, Earth has a limited carrying capacity. It has been calculated that if all current world’s 7.3 billions of inhabitants were to live at USA ecological standards, we should look around for other three Earths to accommodate them (GFN).
On the contrary, there are countries, like Ethiopia, India, and Afghanistan, with ecological standards very low (15%, 13%, and 9% compared with USA) (GFN). These data show that there is a great disparity among Earth’s inhabitants and we are all aware that the stability of human society decreases with increasing disparities.
As passengers of Earth we are deeply interested in finding solutions to the energy crisis. As parents, we wish to leave our planet in a good shape for the benefit of future generations. As scientists, we do have the duty to contribute to the discussion on the impending energy crisis. As chemists, we can help improving energy technologies and, hopefully, finding scientific breakthroughs capable of solving the energy problem at its root. Finally, as citizens of the affluent part of the world, first class passengers of spaceship Earth, we should ask ourselves how we can really help passengers now traveling in much worse compartments of this spaceship. We know that our lifestyle, based on consumerism, may cause disparities. Disparity is, indeed, the most prominent characteristic among Earth’s inhabitants and, in the long run, the most dangerous problem. Finding a correct solution to the energy crisis could offer the opportunity to reduce disparity and create a more peaceful world.
TopEnergy And Quality Of Life
Energy is embodied in any type of goods and is needed to produce any kind of service. It is easy to understand that a hospital consumes a huge quantity of energy. Perhaps it is more difficult to reckon the colossal amount of energy embodied in and consumed by a stealth bomber. Modern agriculture, which provides any kind of food and delicacies to Western consumers, is one of the most energy intensive human activities. For example, the energy of 7 liters of oil is needed to produce 1 kg of beef, reaching the conclusion that modern industrial agriculture is, in fact, the use of land to turn oil into food.