Hydropower has always been touted as a clean source of generating electricity, despite of the facts that it displaces thousands of people from their natural abodes, destroys their lives and livelihoods and submerges huge amounts of lands and forests.
Now, a new study
claims that it is also accelerating global warming. Hydropower isn’t as clean as we thought as building huge reservoirs means generating more Green House gasses and creating a big probability of reservoir-induced seismicity.
They are sold as the means to produce ‘green energy’ as they do not burn fossil fuel unlike thermal power plants. But, here also truth is just reverse as they contribute global warming; basically in two ways: on the one hand, they submerge a large amount was forests and greenery and as forests arrest global warming by carbon fixation, they destroy trees and on the other hand, methane is produced in large amount by their reservoirs and methane is a more potent global warming gas than carbon dioxide. This is confirmed by a new study that concludes that reservoirs may produce 20 times more methane than normal during water ‘drawdown’.
The study is done by Washington State University
the has found that during times of drawdown — a period in which the water level behind a dam is rapidly lowered — temperate reservoirs can produce up 20 times more methane than normal.
Methane is a greenhouse gas 25 times more effective than CO2 at trapping heat in the atmosphere over 100-year period, and is a hundred times more potent over 20 years. It is produced naturally in reservoirs thanks to biological activity.
During drawdowns, though, when layers of decaying plants, among other things, are exposed, the amount of methane in the water column skyrockets. A doctoral student at Washington State University-Vancouver, measured dissolved gases in the water column of Lacamas Lake in Clark County and found methane emissions jumped 20-fold when the water level was drawn down. A fellow WSU-Vancouver student, Maria Glavin, sampled bubbles rising from the lake mud and measured a 36-fold increase in methane during a drawdown.”
Over the longer term, the research could help establish a tracking mechanism to inventory natural greenhouse gas emissions internationally in order to better understand the magnitude of the problem.
Hydropower produces 1.3% of Greenhouse gas emissions which is more than Canada’s net greenhouse gas production. Another study, which will be published next week in “Bioscience” – established that the reservoirs represent an important source of methane, which is a GHG which is 34 times more damaging that carbon dioxide, trapping 86 times more heat than CO2 over 20 years. The methane in reservoirs is produced by microbes living in the water consuming organic matter. It is important to be aware that hydropower-derived emissions are not yet considered in these inventories.
Little wonder, while the developed world is abandoning hydropower as many old dams in the US have simply been abandoned by their owners. According to the Michigan Department of Natural Resources (MDNR), several abandoned small dams have been washed out during storms in recent years. “These failures,” says the MDNR, “have caused extreme erosion, excessive sediment deposition and destruction of aquatic habitat accompanied by the loss of the fisheries.” Michigan taxpayers, through the MDNR, have had to pay for removing several “retired” hydroelectric projects, while their ex-owners have suffered no financial liabilities. The largest dam removal project in history is in the USA where the Elwha Ecosystem Restoration project on the Olympic Peninsula of Washington began in 2012. Similarly, in Australia, a huge dam built on Glory River, costing over 2 billion dollars is being decommissioned. So the developed world is dumping this anti-people and anti-environment technology to the developing world, as in India only, If all proposed and under construction dams in the Himalayas (including Jammu and Kashmir, Himachal, Uttarakhand, Sikkim, and the remaining North East are built, then Indian Himalayas would have: the Highest Dam Density in the World Dam density of the region would be: 0.3247/1000 km, nearly 62 times greater than current average global figures; the average of 1 dam for every 32 km of river channel would be 1.5 times higher than figures reported for U.S. rivers.