Electricity Production from Renewables Energies

1.2. The issue of renewable energies

1.2.1. Observations

The growing interest in the development of renewable energies is caused by several elements: climate change, increasing energy demand, limits of fossil fuel reserves, low global efficiency of the energy system and energy dependence, especially in the case of Western countries [CHA 04].

Climate change

The growing “greenhouse effect” leads to the increase of the global temperature at the surface of the planet. And yet, because of human activities, the concentration of greenhouse gases has soared since the pre-industrial era (1750–1800). Carbon dioxide concentration (CO₂) (the main greenhouse gas) has increased by 30% since the pre-industrial era. The combined effects of all the greenhouse gases (CO₂, methane, ozone, etc.) nowadays amounts to a 50% CO₂ increase compared with this period.

Since 1860, the mean temperature at the surface of the Earth has risen by 0.6°C. Several prospective scenarios are predicting that by 2100, this temperature will increase further between 1.5 and 6°C, if energy systems and current consumption habits do not change. This significant increase would be accompanied by a sea level rise from 20 cm to 1 m. If the climate change seems non-reversible, this evolution can however be slowed down, by significantly reducing greenhouse gas emissions.

The natural CO₂ wells, such as land, trees and oceans, would only be able to absorb a little less than half of the CO₂ production resulting from human activities ...