TITLE:
A Review of Greenhouse Gas Emissions by Hydropower Reservoirs
AUTHORS:
Marco Aurélio Dos Santos
KEYWORDS:
Hydropower Reservoirs, Carbon Emission, Methane, Carbon Dioxide
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.9,
September
22,
2023
ABSTRACT: Hydroelectric reservoirs have environmental impacts as many other sources of energy. Regarding hydropower, these
effects include flooding cultivated and forest areas, changes in water
quality, negative impacts on water biodiversity, conflict with indigenous
people and fish migration. In the nineties, researchers put in evidence of another important impact of dam construction: the greenhouse gases generated by
flooding organic matter by reservoir flooding. Scientists argue that
like natural human water bodies, the
hydropower reservoirs emit biogenic gases into the
atmosphere. The diffusive gas flux is associated
with the difference between gas partial pressure of each
chemical substance considering the aquatic system and the
atmosphere. Ebullition is a process where
some chemical substances are not soluble in water and bubbles are formed
in the sediment at the bottom of the reservoir.
Ebullition is often the dominant pathway of CH4 that is released from aquatic ecosystems. The phenomenon is episodic and irregular and depends mainly on hydrostatic pressure and
other physical influences, such as currents, temperature gradients and the bathymetry of the water
body. At hydropower reservoirs, other pathways
for gas emanation to the atmosphere are the degassing by water passing
through turbines of the powerhouse and the gas diffusion across the river downstream dam. This paper gives a review of the state-of-the-art and advances in the research of greenhouse gas emissions
and removals from hydropower reservoirs.