With all the talk about reducing greenhouse gas emissions across the world, the conversation inevitably leads to what types of renewable sources of energy are the best and which ones can have the greatest impact in regards to producing electricity. While there is much excitement about wind and solar power, both depend on the wind and sun being around to power the turbines. Wind, as we all now is highly variable except for a few places on earth and is not always blowing with the same tenacity if it is blowing at all. While an excellent option, it is subject to the whims of the weather. The same holds true with the sun. There are very few places on earth, except the hottest deserts, where there is almost constant sun that can power turbines necessary to produce constant electricity to homes. If clouds move in, electricity output diminishes or cuts off all together. While hydropower is also subject to different variables, it has one important thing going for it, the capability of holding back water in its reservoir to maintain continuous electricity output. In recent years there has been a surge in the building of dams across the developing world as countries seek to sustain their growing economies. In 2008 and 2009, hydropower saw its largest output of electricity yet world wide. However, as I mentioned, there are new variables that need to be taken into account when looking at placement of new dams and their future efficacy.
The biggest hurdle these days in dealing with new dams is the effect that climate change (i.e. global warming) is having on rainfall. Many areas that would normally be ripe for placement of a dam now have to rethink efforts due to recent sever droughts that could leave reservoirs almost dry or without enough water to make the dam worthwhile. In China, at the Three Gorges Dam, there has been recent severe drought which has effected shipping lanes on the Yangtze and also the output of electricity from the dam. There has also been severe drought across southern and central America over the past decade which has negatively impacted the output of electricity from dams in those regions. Contrarily though, what is a negative for one region is usually a positive for another. In Norway, rainfall has generally increased over the past few years and is expected to do so thus increasing the potential output of electricity from dams in those regions. The effects of climate change need to be taken into account when designing new dams, especially smaller ones, to make sure that A) money isn't wasted and B) electricity is able to flow continuously from the dams being built.
There are other, and in my mind, bigger hurdles that need to be overcome with hydropower. These hurdles involve the displacement of individuals from the areas that will be flooded, the destruction of cultural sites and the environment in general, and the effect that the damming of a river will have on those living downstream from it. In China, while the Three Gorges Dam may indeed produce the most electricity from water of any dam (as it is the largest in the world), how does that compare to the millions of people the reservoir displaced and the cultural sites that are now buried under water? There were many small towns that were forced to relocate along the upper Yangtze river. These towns had existed for hundreds of years in peace and quiet, their buildings alone able to convey generations of family stories and now the residents of these towns have been forced to move uphill to cookie cutter apartment buildings built en masse with no character and no thought put into their design. The cultural sites along with the people displaced would be enough for me to have not built the dam. Seeing as how they are now dealing with drought that could directly impact the efficacy of the dam, it seems like it may not have worthwhile afterall. Currently in Chile, there are protests being staged over the possibility of damming of a few rivers flowing through a remote part of Patagonia. There needs to be much consideration placed into all the effects that a dam will have, both positive and negative, and all these effects should be taken into account before dam construction begins.
All in all, if hydropower is used responsibly and undertaken with great care, then it is a great asset in our arsenal of renewable energy sources. However, I must stress the word responsibly here. Often times, governments especially rush into projects without taking into account all the variables such as climate change, dam efficacy, and most importantly the impact on local people, cultures and the environment. If we do not take care of the people and environment in which we hope to build a dam, then what is the point? We should strive to maintain, as much as possible, the surrounding landscape and cultures in the area that a dam is being built in. Inevitably, an area will have to be flooded in order for a dam to function; you can't have hydropower without it. That being said, the best place for a dam to be most effective might be the worst in regards to local culture and environmental destruction. It is very hard to weigh all the alternatives, but if we do so with care, then I believe hydropower will have an even stronger resurgence than it already has. In addition to building new dams, we also need to look into retro-fitting and improving the functionality of dams already in existence so that we do not need to build new ones and we can gain even more power from them. New turbines and electrical equipment are much more effective now than they were when some of these older dams were built and simply by replacing the equipment we could increase the electrical output of them. We need to constantly explore the best and newest ways to incorporate renewable energy sources into our power grid so that we can eventually drastically reduce our greenhouse gas emissions. For now, lets try and use a little electricity in our homes and make sure we turn lights off when we leave a room.
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