Are renewables necessarily sustainable?

Renewable energies are seen as THE solution to all of our climate change, peak oil… and probably also bad conscience issues! However one big solution usually is too simple to really solve any problem. So let’s step back for a minute and think again about renewables’ real potential.

Renewables are all hydraulic, wind, solar, biomass and geothermal energies. In fact, biomass is considered as renewable only as far as it is produced more than it is consumed. But what’s more important is to identify which energies are “clean”, sustainable.

Biomass for instance is often burnt and therefore produces CO2 which doesn’t solve any environmental issue (on the contrary, concerning climate change). Geothermal energy is based on the idea that earth and water aren’t at the same temperature on different depths and that you can extract the relative heat to produce energy. The problem is that this process simply leads to cool the earth or the water down, often destabilizing the local ecosystem. The energy source is renewable since it comes from both the core of Earth and the sun and it is to be counted in billions of years. However, the ecological impact is not neutral in the short run and immediate environment.

On the other hand, hydro, wind and solar power basically face the same issue, and although it is not that bad yet in terms of ecological impact, it can’t be neglected from a longer-term perspective.
The thing is that all three consist in capturing energy in the environment that is resulting in either movement, heat, or light. In the process, energy is taken away from its orginal destination, reducing waterflows and wind speeds or preventing the earth or plants to receive the heat or light they were used to.
Until now, as renewables are still at their start, it didn’t have any major ecological impact. But what when they will be massively used? Can’t we imagine meteorological changes in zones coming just “after” a wind farm? Or algae species dying near water turbines because they could feed only thanks to the current’s high speed? For solar energy the arbitration is more about sharing space. And to me, as we can have solar panels on the top of buildings we probably should spare the ground for farming and grazing.

All in all, to me, renewables are a powerful answer to too high greenhouse gas emissions. But we should beware of becoming extreme in taking that direction. A very important aspect of energy management and of the energy transition is to reduce our needs and avoiding energy leaks and losses. There is no simple solution and in the long-term, there is probably no sustainable way to avoid tackling another real problem: we are consuming more than what the Earth can produce whereas the law of conservation of mass says “Nothing is lost, nothing is created, everything is transformed.”.

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