The sustainable energy is the energy capable of meeting the needs of the present moment without compromising the ability of future generations to meet their own needs. In energy sources sustainable, it usually ranks all sources of renewable energy, such as hydro, the solar energy, the wind, the wave energy (more exactly, the swell), the ‘ geothermal energy, energy from the biomass or the tidal energy. In addition,
Some people include some non-renewable sources, such as nuclear or coal with geological storage of CO 2, if certain conditions are respected (in particular, consumption sufficiently reduced for it to last for a long time); However, others strongly dispute the classification of such sources from sustainable energy sources.
Many definitions have been given to the notion of sustainable energy, including:
- “In concrete terms, the share of energy capable of meeting the needs of the present moment without compromising the ability of future generations to meet their own needs. […] Sustainable energy has two key components: renewable energy and energy efficiency. – Renewable Energy and Energy Efficiency Partnership .
- “A dynamic harmony between the equitable availability of energy-intensive goods and services on the one hand and the preservation of the Earth for future generations on the other. “The solution will lie in the ability to find sustainable sources of energy and more efficient ways to convert and use energy. – Sustainable energy by JW Tester et al. , Published by MIT Press.
- “Any source of generation and conservation of energy for which resources are available on a scale large enough to extract a significant part of the energy consumed over the long term, preferably a hundred years. “- Invest, a nonprofit organization that promotes green technologies.
- “The amount of energy that can be naturally regenerated for a human lifetime and whose extraction does not cause any long-term environmental hazard. – Jamaica Sustainable Development Network .
These definitions show that the concept of sustainable energy differs significantly from other notions of renewable energies such as alternative energies or green energies: the sustainability of an energy source depends on its ability to provide energy, Energy for a long time. Sustainable energy can generate a certain level of pollution in the environment, provided that it is low enough not to obstruct the massive use of the energy source for an indefinite period of time. The concept of sustainable energy is also different from that of a “low carbon economy”
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As we saw in the introduction, it is not easy to classify a given energy in sustainable energies or not. It is necessary to adopt the most comprehensive vision possible, taking into account the whole cycle of production and consumption of energy. It is not enough to consider only primary energy. It is necessary to consider all the materials used for the production of the production units (in particular of electricity, etc.) and for their operation, with respect to the lifetime of the latter.
For example, renewable energies (solar, wind …) require large quantities of metals. Moreover, the intermittent nature of the production of solar or wind electricity requires the development of techniques for storing electricity. But currently, the most efficient storage techniques are based on the use of lithium, whose reserves are limited.
Proponents of nuclear energy point out that virtually zero emissions of greenhouse gasses are in its favor. However, resources uranium for nuclear fuel for pressurized water reactors, and zirconium , for the manufacturing of sheaths that surround the fuel for these reactors are limited. Not to mention the ecological footprint of the construction of nuclear power plants and the treatment of waste, nor talk about the risks of nuclear accidents or nuclear proliferation.
Moving towards energy sustainability imposes changes not only in how energy is extracted and obtained but also in how it is consumed. To do this, reducing the amount of energy needed to produce goods and services is essential. The reduction opportunities are just as rich and varied side energy demand as the side of the energy supply, and reductions in energy demand are often accompanied by significant financial savings.
Energy efficiency and renewable energy are often seen as the “two pillars” of a sustainable energy policy . Both must be developed concomitantly to stabilize and then reduce carbon dioxide emissions. Better energy efficiency slows down the growth of energy demand so that the supply of renewable energy can gradually replace fossil fuels. If the energy consumption grows too fast, then the development of renewable energies will only run after a hare that advances faster than it. Similarly, unless the renewable energy supply is rapidly created, A slowdown in demand growth will only begin to reduce cumulative emissions; Reducing the carbon content of energy sources is also a necessity .
On the economic front, the renewable energy and energy efficiency sectors no longer appear to be niche markets, which only environmentalists supported by a few isolated governments would promote. According to a trend analysis of the United Nations Environment Program, climate change concerns , high oil prices and increased support from many governments explain the high rates of investment seen in recent years in Industries in the sustainable energy sector. According to NEP , global investment in this sector peaked in 2007 with 148 billion US dollars, An increase of 60% over the previous year. Total financial transactions in the sustainable energy sector, including procurement transactions, were $ 204 billion.
A network of solar mirrors is an example of a green energy source.
The green energy is the energy that can be extracted, processed and/or consumed without significant negative impact on the environment. The terrestrial biosphere has a natural ability to regenerate, meaning that pollution that does not exceed this natural regeneration capacity can always be considered “green”.
Green energy is only a part of renewable energy: it only includes renewable energy resources and energy extraction technologies that offer the greatest environmental benefit. For example, the US Environmental Protection Agency defines green energy as electricity generated from sun, wind, geothermal, biogas, biomass, and small hydroelectric sources environmental impact. Consumers buying green power usually do to avoid negative environmental consequences of energy production and promote a reduction in emissions of greenhouse gas.
However, green energy sources are not limited to electricity generation: some of them allow for the direct production of heat, chemical energy (eg in the form of hydrocarbons) Mechanical energy, etc. The common thread among all these sources is that they incorporate natural energy processes that can be exploited in the manner of crops and with a limited level of pollution. The anaerobic digestion, the geothermal energy, the wind energy, small hydro, the solar energy, energy from the biomass, Tidal energy or wave energy (more precisely wave energy ) fall into this category. Some definitions may also include derivatives of waste incineration.
Some people, for example, George Monbiot and James Lovelock have explicitly classified nuclear energy as a green energy. Others, including Greenpeace, refuse to do so, arguing that nuclear waste management and the risk of a nuclear accident (such as the Chernobyl disaster ) create an unacceptable risk to both the environment and the environment. ‘humanity.
There is no energy source that has absolutely no impact on the environment. All the technologies for obtaining energy themselves require energy and generate a certain level of pollution, at least during their construction and often during their operation.