Tuesday, May 28, 2013

Loss of tropical rainforests reduces hydro output

Brazil is one of the countries that heavily relies on hydropower. In fact, hydroelectric power plants satisfy around 90% of electricity demand in Brazil. Sadly, Brazil is also known for rapid deforestation of Amazon rainforest and the loss of tropical rainforests could soon result in decreased hydropower output in Brazil.

The most recent study by the researchers at the Proceedings of the National Academy of Sciences argues that extensive deforestation of tropical rainforests will leave less water in the rivers to generate hydropower.

To put things in more clearer perspective we first need to know that there is an increase in river flows when the trees along streams are removed. The water in the soil,  in this case not beeing taken up by the tree roots and sent into the atmosphere, moves directly into streams and rivers. Though this looks like the positive thing to increase output from hydro power plants we must also be aware that at the same time large areas of tropical forest actually create rain clouds as moisture from their leaves evaporates meaning that the elimination of swaths of these forests leads to decrease in rainfall. What this means is that once enough trees are cut, the indirect impact of lost rainfall outweighs the direct impact of removing trees leading to smaller hydropower output.

The loss of tropical rainforests is a major environmental issue. Tropical rainforests play vital role as carbon sinkers meaning that their ongoing loss accelerates worldwide climate change by removing a large carbon sink that absorbs carbon dioxide from the atmosphere.

The developers of new hydroelectric power projects should therefore focus more on this issue and make sure they do not cut too much trees because this will lead to reduced rainfall and this will reduce the stream flow.

Moisture from forests is what feeds rain clouds and the link between forest cover and hydro production should be high on the list for all new hydro developers, especially in this time when hydro seems to be getting plenty of focus in much of the world as a proven and reliable source of "clean electricity".